True Learn Salient Points Flashcards

Question

How much will Succinylcholine increase your serum Potassium levels in healthy kidney functioning patients? How much in ESRD?

Answer 1

0.5 mEq/L and normalizes in 10-15 minutes in normal patients Same as chronic renal failure patients

Answer 2

Intraop IV mannitol prior to vessel clamp release has been shown to decrease post-transplant kidney injury (No effect on graft rejection)

Answer 3

Radicular pain - Edema/Inflammation around the nerve root - Ex: herniated disc or spondylosis (degenerative changes of bone spurs or osteoarthritis)

Answer 4

Chronic hypothyroid patient who undergoes physiologic stressor - Treat with Levothyroxine

Answer 5

Dialysis the day before surgery - If done same day, risk of hypotension - if dialysis not done, watch out for volume overload, uremia, hyperkalemia and acidosis

Answer 6

Increased PTH Increased Calcium Decreased Phosphate Non-gap metabolic acidosis Normal to high 24 hour urinary calcium

Answer 7

Treatment: Hydration Oxygen Descend Altitude Acetazolamide - Treats the respiratory alkalosis Dexamethasone Non-benzodiazepine sleep aids

Answer 8

2 hours = Clear Liquids (Water, pulp free juice, black coffee, carbonated beverages) 4 hours = Breast milk 6 hours = Infant Formula, Non-human milk, Light meal (Juice with pulp) 8 hours = Fatty or full meal

Answer 9

Uremia interferes with platelet QUALITATIVE FUNCTIONING problems 1. Platelet activation and aggregation (primarily via effects on vWF and GPIIb-IIIa) 2. Leads to increased production of platelet inhibitors (e.g. prostacyclin and nitric oxide).

Answer 10

1. QTc prolongation (20%, very rarely clinically significant) 2. Headache (11%) 3. Transient AST/ALT increases (5%) 4. Constipation (4%) 5. Rash (1%) 6. Flushing/warmth (\< 1%) 7. Dizziness (\< 1%).

Answer 11

MELD 1. Dialysis \>1 times per week 2.Creatinine \>4 3. Bilirubin 4. INR 5. Sodium **MELD: "I Crush Beer Daily" - INR, Creatinine, Bilirubin, Dialysis** Childs Pugh Score 1. Bilirubin 2. Albumin 3. INR 4. Ascites 5. Encephalopathy \*\*NOTE: Bilirubin and INR are in both\*\* **Child-Pugh: "I pour Another Beer At Eleven" -**

Answer 12

**1. FiO2 1.0** **2. Notify surgeons to flood the field** **3. Left Lateral Decubitus Position if possible**

Answer 13

Think SLUDGE! 1. Salivation / Lacrimation 2. Urination (incontinence) 3. Defacation (Hypermobility) 4. GI Upset (Diarrhea and increased gastric secretion) 5. Emesis Also, Bradycardia (from ACh on heart) Bronchoconstriction (ACh on bronchial smooth muscle) Miosis (On pupils)

Answer 14

Inhibition of DNA synthesis with chronic exposure (Recreational N2O abuse causing megaloblastic anemia)

Answer 15

1. Median Nerve Damage 2. Distal Ischemia due to lack of collateral circulation 3. CRBSIs (Catheter related Blood Stream infections) for 1:1000 catheter days

Answer 16

Primary excretion = **Hepatobiliary excretion** (Prolonged paralysis in cirrhosis and liver failure) 25-30% **Renally excreted** Normal T 1/2 = **1.2 - 1.6 hours** ESRD T 1/2 = **1.6 - 1.7 hours**

Answer 17

**Derm**: Flushing **Cardiac**: Tachycardia, Arrythmia, and Carcinoid Heart Disease (Right Heart) **Pulmonary**: Bronchospasm **GI**: Diarrhea, Malnutrition

Answer 18

Spinothalamic Tract 1. Skin --\> Dorsal Horn of the Spinal Cord 2. Dorsal Horn to contralateral spinothalamic tract to the thalamus

Answer 19

Higher risk of jaundice after multiple PRBC transfusions Gilbert's syndrome is due to a mutation in the UGT1A1 gene which results in decreased activity of the **bilirubin uridine diphosphate glucuronosyltransferase enzyme.** Hepatocyte uptake of UNCONJUGATED bilirubin Blood transfusions increase serum bilirubin levels approximately 250 mg per unit transfused

Answer 20

1. Lingual Nerve 2. Recurrent Laryngeal Nerve 3. Hypoglossal Nerve

Answer 21

**Glycine and Cytal (Mannitol and Sorbitol) now used** - Decreased incidenence of HYPONATREMIA which was causing cerebral edema and hemolysis Still can develop hyponatremia

Answer 22

**Normeperidine** --\> Seizures - Increased HR because meperidine resembles atropine **1. Morphine-6-glucuronide** --\> 100 fold greater potency --\> Respiratory Depression **2. Morphine-3-glucuronide** - Myoclonus - Allodynia (hypersensitive to pain)

Answer 23

Opioid Analgesic for neuropathic pain (Chronic) **Mechanism**: NMDA and Serotonin Reuptake Antogonist

Answer 24

Peribulbar **Pros** **1.** Decreased risk of retrobulbar hemorrhage 2. Decreased optic nerve injury (less central spread) **Cons** **1.** Longer Onset Time (9-12 minutes) 2. Lower incidence of complete akinesia

Answer 25

1. Maintain temperature 2. Maintain fluid homeostasis 3. Maintain hemodynamics Autonomic instability with hypotension

Answer 26

**Charcot–Marie–Tooth disease (CMT) i**s one of the hereditary motor and sensory neuropathies of the peripheral nervous system characterized by progressive loss of muscle tissue and touch sensation across various parts of the body. Hereditary - Mutations in Myelin and Axonal Genes **Motor & Sensory Neuropathy** **Caution** with **paralytics** and **regional anesthesia**

Answer 27

Ceiling effect - Beyond certain dose, unlikely to gain effect

Answer 28

Reduce fasciculations Has no effect on post-operative myalgia

Answer 29

Teeth - Long incisors - Overbite - Less 3 cm intercisor distance - Poor prognathic ability Neck - Thick - Short - Decreased neck extension Interior structures - Uvula not visible when tongue protruded - Highly arched or very narrow palate - Stiff mandibular space, indurated or occupied by mass TM \< 3cm **Poor HOMBR 46 / 30 TTT Neck** Age \>46 Limited TM distance \<6 to 6.5 cm Sternomental distance \<12.5 to 135 cm Teeth Presence Thick / Stiff Neck Neck movement less than 90 degrees \> 43 cm Interincisor Distance \<4-4.5 cm

Answer 30

Desflurane - 0.42 Nitrous Oxide - 0.46 Sevoflurane - 0.69 Isoflurane - 1.46 Halothane - 2.54

Answer 31

Blood supply altered --\> inadequate oxygenation and nutrients to the liver Reperfusion occurs --\> disruption of sodium potassium pumps secondary to decreased ATP and glycogen

Answer 32

**1. Pain on injection** **2. PONV increased risk** **3. Superficial Thrombophlebitis** **4. Adrenal Insufficiency (Even after one dose)**

Answer 33

1. NSAIDs 2. Elastic Stockings 3. Superficial Thrombectomy

Answer 34

1. Increased chest wall stiffness 2. Loss of muscle mass 3. Flattened diaphragm 4. Increased compliance of lung parenchyma 5. Closing Capacity \> FRC and will eventually surpass TV

Answer 35

Increases in: **FRC CC RV** Decreases in: **Inspiratory Capacity (IC) TLC**

Answer 36

GH = Anabolic Hormone - IGF-1 mediated 1. Hyperglycemia 2. Insulin Resistance 3. Lipolysis (Growth) (Also seen in Acromegaly)

Answer 37

Hyperventilation leads to Decreased CBF *_1 mmHg of decrease PaCO2_* correlates to **CBF drop of 1-2 mL/100g/min**

Answer 38

Continue CPB for 20-30 minutes after reaching goal temperature to ensure adequate cerebral cooling prior to stopping circulation

Answer 39

1. Protein metabolism altered (loss causes dramatic body composition changes) 2. Fat deposits in their face (moon facies), shoulders, neck (buffalo hump) 3. Truncal obesity 4. Muscle wasting in upper and lower extremities 3. Elevated BGL 4. Hirsutism 5. Mood changes

Answer 40

**Urine Studies (Urine sodium concentrated)** 1. Urine Osmolality \> 100 mOsm (Often \>200-300) 2. FENa \>1% 3. Urine Na \> 20 mEq/L **BMP Studies** 1. Low serum uric acid BUN 2. Dilutional, euvolemic hyponatremia (Na below 135)

Answer 41

1. *_Vasospasm between days 3 and 15_* 2. **Rebleeding** occurs within the **first 48 hours after SAH**

Answer 42

**CaO2 = 1.39 x SaO2 x Hgb + (0.003 x PaO2)** Dissolved oxygen component = 0.003 x PaO2 *_Hyperbaric oxygen therapy will increase PaO2 as high as 2000 mmHg (3 atm of pressure) when the SaO2 and Hgb are optimized._*

Answer 43

**Plateau waves = Lundberg's A wave** Steep increase in ICP Rise in ICP may last for 20 minutes and is typically represented by: 1. High PaCO2 2. Stimulation (inadequate anesthesia)

Answer 44

**Etiology** Iatrogenic (Supplemental Magnesium i.e. Pre-eclampsia treatment) **S/S:** Reduced Deep Tendon Reflexes, Cardiac depression, ECG changes, muscle weakness, hypotension, bradycardia

Answer 45

Treatment: **1. Atropine** **2. Pralidoxime Chloride (2-PAM)** More definitive = Antidote by removing organophosphate compound from organophosphate-inactivates acetylcholinesterase 3. Decontamination 4. Supportive Therapy 5. **Prophylaxis - Pyridostigmine** - Prevents organophosphate induced irreversible acetylcholinesterase inhibition in the periphery (if given 30 minutes prior to exposure)

Answer 46

1. Male 2. American Medical Grads 3. Low ITE test scores

Answer 47

Parathyroid hormone increases serum calcium by: ## Footnote **1. Stimulating osteoclastic bone resorption** **2. Distal tubule calcium reabsorption** **3. Conversion of vitamin D to calcitriol.**

Answer 48

Status Post MI per American College of Cardiology / American Heart Association 2014 **14 days** after balloon angioplasty **30 days** after Bare Metal Stent **60 days** if no coronary intervention **180 days** after Drug Eluting Stent (DES) for elective non-cardiac surgery

Answer 49

Bottom Line: Infective endocarditis prophylaxis is recommended for *_cardiac conditions_* listed below **High risk cardiac conditions:** *_1) Prosthetic cardiac valve or prosthetic material used in valve repair_* *_2) Previous endocarditis_* *_3) CHD only in the following categories:_* - Unrepaired cyanotic congenital heart disease - Completely repaired congenital heart disease with prosthetic material or device within six months - Repaired congenital heart disease with residual defects *_4) Cardiac transplantation recipients with cardiac valvular disease_* **PLUS:** 1) Dental (mucosal, gingival) procedures 2) Respiratory tract (tonsillectomy, adenoidectomy, bronchoscopy with incision/biopsy) procedures or 3) Infected skin/musculoskeletal tissue procedures **Infective endocarditis prophylaxis is NOT recommended for:** 1) Routine/simple dental procedures without infected tissue 2) Gastrointestinal/Genitourinary procedures 3) Bronchoscopy without mucosal incision 4) Mitral valve prolapse, HOCM, bicuspid aortic valve

Answer 50

Monitoring prothrombin time (PT) Gives the clinician a better understanding of acute hepatic protein synthesis capabilities.

Answer 51

CI = Decreased CVP = Increased SVR = Increased

Answer 52

**CVP**: 2-6 mmHg **PCWP**: 6-12 mmHg **CI**: 2.5 - 4 L/min/m2 **SVR**: 800-1200 dynes\*sec/cm5

Answer 53

Preservation of Total Hepatic Blood Flow amongst volatile anesthetics at 1 MAC, from greatest to least, is sevoflurane \> isoflurane \> halothane.

Answer 54

1. Blunting of hypoxic pulmonary vasoconstriction 2. Microatelectasis

Answer 55

**Shunt**: V/Q = Zero - Not ventilated but perfused **Dead Space**: V/Q = Infinity - Ventilated but not perfused

Answer 56

Midazolam: 1.7 - 2.6 hours (102 minutes - 156 minutes) Flumazenil: 0.7 - 1.3 hours (42 min - 78 minutes)

Answer 57

**Cricothyroid muscle** = **External branch of superior laryngeal nerve** ## Footnote *_All other muscles = Recurrent laryngeal nerve_*

Answer 58

Studies have shown that patients who report penicillin allergy and who: 1. Do not have a history of severe reactions IgE mediated responses 2. non-IgE-mediated can safely receive cephalosporin antibiotics.

Answer 59

Buffering of excess hydrogen ions High amounts of excess hydrogen ion in the serum results in lower free bicarbonate ion levels due to bicarbonate’s buffering effect. This physiology produces a high anion gap because of the loss of free bicarbonate ion.

Answer 60

**MOA:** 1. Central = Dopamine antagonist 2. Peripheral = Cholinergic agonist **Class** = Promotility and weak anti-emetic *_Dose needs to be 25-50 mg IV_* to be effective, albeit higher risk of extrapyramidal side effects.

Answer 61

**1. Unstable coronary syndromes** **2. Decompensated heart failure** **3. Significant arrhythmia** **4. Severe valvular disease** **5. Recent or acute myocardial infarction**

Answer 62

1. Hypercarbia (ETCO2 \>40) 2. Acidosis 3. Hypercarbia (Hypoventilation) 4. High 2, 3 BPG

Answer 63

The cardiovascular effects of milrinone can be summarized as: *_increased_* inotropy *_increased_* lusitropy *_increased_* ejection fraction *_increased_* stroke volume *_increased_* cardiac output **decreased** afterload **decreased** preload pulmonary **vasodilation** systemic **vasodilation**.

Answer 64

A *_dopamine D1 receptor agonist*_ that is used as an _*antihypertensive agent_*. ## Footnote **It lowers blood pressure through arteriolar vasodilation.**

Answer 65

Ketamine is associated with a high incidence of psychomimetic reactions early in the recovery period. - Hallucinations - Nightmares - Altered Cognition - Altered Short Term Memory The incidence of these reactions can be decreased by co-administration of benzodiazepines, propofol, or barbiturates. Give the Midazolam prior to induction with Ketamine.

Answer 66

Tetanus acts by preventing neurotransmitter release (glycine and GABA) from inhibitory neurons in the spinal cord. The lack of inhibition causes increased muscle contractions to the point of tetanus. Botulism toxin has a similar mechanism of preventing neurotransmitter release (acetylcholine), but botulism affects the alpha motor neuron causing flaccid paralysis

Answer 67

**Myasthenia Gravis** *_Mechanism_*: Antibody mediated destruction of the Postsynaptic ACh receptors at NMJ *_S/S_*: 1.Extraocular, Bulbar and Facial Muscle Weakness 2.Fatigue with Exercise 3.Myalgia uncommon 4.Normal Reflexes *_Female \> Male_* *_Co-existing disease_* = Thymoma **Anesthetic Implications**: 1. Resistant to Succinylcholine 2. Sensitive to Non-Depolarizing Neuromuscular Blockers 3. Anti-cholinesterase responsive **Myasthenic Syndrome (Lambert-Eaton Syndrome)** *_Mechanism_*: Presynaptic decreased in released from nerve terminals •Destruction of presynaptic voltage gated calcium channels in the NMJ *_S/S_*: 1. Proximal Limb Weakness 2. Exercise Improves strength 3. Myalgia Common 4. Decreased Reflexes **Male \> Female** *_Co-existing disease_*: Small Cell Lung Cancer **Anesthetic Implications**: 1. Sensitive to Succinylcholine 2. Sensitive to Non-Depolarizing Neuromuscular Blockers 3. Poor response to anti-cholinesterase's

Answer 68

1, 2 = Telencephalon 3, 4 = Midbrain 5-7 = Pons 8-12 = Medulla Cranial nerves **III, VII, IX, and X** have **parasympathetic** components that lie in the brainstem. The component for cranial nerve III lies in the midbrain, while the components for the others lie in the medulla oblongata.

Answer 69

The post-partum period is associated with an increase in MS symptoms and often exacerbations. **Post-partum exacerbations** occur in **20-40% of patients with MS.**

Answer 70

Sitting craniotomies can have several complications due to positioning including: 1. **Venous air embolism** (which occurs in 25-45% of sitting cranial surgeries) - It occurs because non-collapsible venous channels such as venous sinuses can be violated during surgery and air is entrapped in them due to the negative pressure gradient between the surgical site and the heart. 2. **Hypotension** 3. **Midcervical quadriplegia** 4. **Pneumocephalus** 5. **Peripheral nerve injury** 6. **Facial swelling**

Answer 71

Volatile anesthetics decrease CMRO2 therefore decrease CBF (albeit minimal effect) via flow-metabolism coupling, even at low concentrations (MAC 0.5 - 1) At high concentrations (1.5-2 MAC) they can increase CBF due to cerebral vasodilation.

Answer 72

Carotid Endarterectomy (CEA) Detect: 1. Blood flow velocities 2. Detect embolization to the brain 3. Identify shunt function or malfunction 4. Detect asymptomatic carotid artery occlusion 5. Hyperperfusion syndrome. The technique involves assessment of the middle cerebral artery.

Answer 73

Difficult Airways Orthopnea Obstructive Sleep Apnea Severe Anxiety Claustrophobia Young Age Psychiatric Disorders

Answer 74

\*\*Quadriplegia = Above T1 (In between C1-C8)\*\* Above C4 = Require ventilatory support C6 - C7 = May require secondary support as could have loss of chest wall innervation and inability to clear secretions \*\*Paraplegia = Below T1 (In between T1 - L5)\*\*

Answer 75

Eye-opening: - Spontaneous: 4 - To sound: 3 - To pain: 2 - Nil: 1 Verbal Response: - Oriented: 5 - Confused: 4 - Inappropriate words: 3 - Incomprehensible sounds: 2 - Nil: 1 Motor Commands: - Obeys commands: 6 - Localizes to pain: 5 - Withdraws to pain: 4 - Flexion: 3 - Extension: 2 - Nil: 1

Answer 76

Cord Perfusion: 75% - From One Anterior Spinal Artery (Motor tracts) - From anterior radicular arteries in the thoracic segment of the spinal cord Largest radicular artery = Artery of Adamkiewicz 25% - From Two Posterior Spinal Artery (Sensory Tracts) From vertebral artery in cervical segment

Answer 77

1. Free Water Replacement 2. DDAVP (Desmopressin aka exogenous vasopressin)

Answer 78

Preoperative criteria predictive of postoperative mechanical ventilation in a patient with MG include: 1. Duration of disease \> 6 years 2. Pulmonary disease(s) unrelated to MG 3. Vital capacity of \< 2.9 L \*\*MOST PREDICTIVE\*\* 4. Daily pyridostigmine dose \> 750 mg 5. NIF \< 20 cm H2O. (Negative Inspiratory Force) The leading predictor for postoperative respiratory failure is the inability to clear secretions and produce a strong cough.

Answer 79

During an AH episode, the intense sympathetic response below the level of SCI can cause acute hypertension (≥ 20-40 mm Hg above baseline), reflex bradycardia, cardiac arrhythmias, and myocardial infarction. The hypertension can further lead to headaches, blurred vision, retinal or intracranial hemorrhage, stroke, seizure, and/or cerebral edema. Below SCI: Intense vasoconstriction leads to cool, dry, pale skin of the lower extremities. T Above SCI: The reflex cutaneous vasodilation above the level of the SCI leads to nasal congestion; diaphoresis; and warm, flushed skin on the upper extremities, shoulders, neck, and face.

Answer 80

Pathophysiology: Following neurologic injury to the brain due to: 1. Massive sympathetic discharge 2. Intracranial hypertension Picture: Rapid onset Severe Pulmonary Vascular Congestion Intra-alveolar hemorrhage Protein-rich Edematous Fluid Treatment: Relieve the ICP - (Treatment for cardiogenic pulmonary edema doesn’t work here)

Answer 81

Hyperkalemic periodic paralysis is caused by a sodium channel defect Precipitated by hypothermia, hypoglycemia, metabolic acidosis, rest after exercise, or potassium infusions. Treatment includes restriction of potassium and thiazide diuretics.

Answer 82

35 - 36 degrees BGL 140 - 180 mg/dL

Answer 83

Nitrous oxide causes: 1. Increase in cerebral metabolic rate, which increases cerebral blood flow. 2. Increase in cerebral blood flow and cerebral metabolic rate causes ICP to be increased with the use of nitrous oxide.

Answer 84

Descending Neuromotor Pathway - Monitor anterior spinal cord Lower Limb Cortex Internal Capsule Brainstem Corticospinal Tract Peripheral Nerve

Answer 85

Acquired: 1. Healthcare workers Inherent: 1. Children with Spina Bifida (repeated exposure to latex) 2. Urogenital Syndromes 3. Allergies to - Banana, Avocado, Kiwi, Pineapple, Mango and Tropical Fruits

Answer 86

Aminosteroid NMBDs (Pancuronium, Pipercurium, Vecuronium and Rocuronium) Cosmetics share similar quaternaries ion that are in these NMBDs (Found in toothpastes, detergents, shampoos)

Answer 87

2014 ACC/AHA Guidelines for Preoperative Cardiovascular Evaluation for Non-cardiac Surgery endorsed by ASA Class I: Benefits \>\>\> Risk No Class I recommendations for Preoperative 12 lead ECG Class IIa: Benefits reasonable \>\> Risk For elevated risk surgery its reasonable to perform: CAD, Arrhythmia, PAD, CVA, Structural Heart Disease

Answer 88

Both phase 1 and phase 2 blockades of succinylcholine administration display decreased contraction with single twitch stimulus. Phase 1 blockade is associated with fasciculations, minimal fade to TOF (TOF ratio \>70%), and enhancement of neuromuscular blockade (NMB) by anticholinesterases. Phase 2 blockade is associated with repeated doses or an infusion of succinylcholine, resembles NDNMB, and can be partially reversed with anticholinesterases.

Answer 89

Elevated T3 Elevated T4 free Elevated T4 Total Elevated Thyroid Hormone Binding Ratio Low / Normal TSH

Answer 90

MAP \> 60 mmHg UOP \> 1 mL/kg/hour LVEF \> 45%

Answer 91

Hypocalcemia occurs in approximately 20% of patients undergoing total thyroidectomy and develops 24-96 hours after surgery. Stridor can be a sign of hypocalcemia, and should be treated with IV calcium.

Answer 92

1. Forced Elbow Extension after NMBD 2. Iatrogenic Trauma from IV in the AC area

Answer 93

Immersion ESWL (Extracorporeal shock wave lithotripsy) is performed by passing external shocks through the patient to break up renal calculi. - Mechanical shock waves passed through water and the wave encounters different densities (Until it hits the calculus) The best way to prevent dysrhythmias is by synchronization of the shock to the R wave on the ECG. (Shocks are timed to the R wave of the ECG).

Answer 94

Halothane-caffeine contracture test - Highest sensitivity and is considered the current gold standard for diagnosis of malignant hyperthermia. - Genetic testing for mutations of the ryanodine receptor has become increasingly common, not all genetic defects representing malignant hyperthermia have been identified.

Answer 95

Increased systemic vasopressin levels are primarily responsible for increased SVR during pneumoperitoneum for laparoscopic surgery.

Answer 96

Hydroxyethyl starches are synthetic colloids useful for volume resuscitation due to prolonged intravascular half-lives. Hetastarches are traditionally associated with a higher risk of coagulopathies (platelet adhesion interference, reduced factor VIII:C and vWF levels, and PTT prolongation) than the newer, lower molecular weight tetrastarches.

Answer 97

Ulnar Nerve Injury Male, Thin/Obese patients EMG testing

Answer 98

Type of Surgery

Answer 99

Failure of ADH to secrete UOP: High (Polyuria) High Plasma Osmolality (Dehydrated) Low Urine Osmolality Hypernatremia

Answer 100

250 Category 1 CME credits are required every MOCA cycle.

Answer 101

Large negative pressure developed by inspiration against occluded airway Increased Preload & Afterload → increases pulmonary venous blood volume & pressure Increased hydrostatic pressure and formation of pulmonary edema Hypoxia and Hyperadrenergic responses → Translocation of blood from systemic to pulmonary circulation increases pulmonary pressures

Answer 102

Causative Agent: Varicella Zoster Virus lies in dorsal root ganglia after infection (chickenpox) Immunity declines and then VZV becomes active (shingles) \>80 years old = 5-10: 1,000 Most common: Thoracic Nerve Roots Dermatomes V1 - Ophthalmic Division of Trigeminal Nerve V2 - Maxillary Division of the Trigeminal Nerve Cervical Spinal Roots Sacral Spinal Roots

Answer 103

24 hour urinary 5-HIAA (Metabolite of serotonin) of \> 30 mg (Normal 5-HIAA is 3-15 mg)

Answer 104

24 hours urinary Vanillylmandelic acid (VMA)

Answer 105

2 hours Clear fluids (e.g. water, juice without pulp, carbonated beverages, unsweetened tea, black coffee) 4 hours Breast milk 6 hours Infant formula and non-human milk (Cow, Goat, Soy), & light meals (e.g. toast and clear liquids) 8 hours Full meal (e.g. steak and potatoes)

Answer 106

1. Initial treatment for hypermagnesemia in the face of hemodynamic compromise or extreme muscle weakness is calcium chloride or gluconate. (Magnesium is an L-Type Calcium Antagonist so you can give Calcium to reverse this effect) 2. Dialysis is the definitive treatment but may take a long time to institute.

Answer 107

Methylene Blue = 65% Methemoglobinemia = 85% Carboxyhemoglobin = 100%

Answer 108

The symptoms of discogenic back pain are variable but are typically: 1. Exacerbated by sitting (increased pain with bending/sitting) 2. Relieved with upright postures (standing)

Answer 109

Cardiac - Widening of the QRS - Prolongation of QT interval - Ventricular Arrhythmias - Tachycardia - Hypotension Neurological - Altered Mental Status - Reduction in seizure threshold (Paradoxical) - Delirium Anticholinergic symptoms (Opposite of sludge) - Hyperthermia (Atropine fever) - Flushing - Dry Mouth - Mydriasis - Constipation - Urinary Retention

Answer 110

Differences: 1. Larger Relative Tongue 2. Greater Collapsibility Tend to obstruct more 3. More Cephalad position of the larynx Infant C3-C4 (Adult is C4-C5) 4. Omega-Shaped Epiglottis - Difficult to pick it up Infant = Stubby (Adult = Flat) 5. Slanted Vocal Cords Difficult in passing the tube 6. Functionally Narrow Subglottic Region Narrowest at the cricoid ring (Subglottic)

Answer 111

Factor 7 - Shortest Half Life of Vitamin K dependent factors

Answer 112

Buprenorphine is a partial mu agonist Its maximum opioid effects are less than those of full agonists Thus, higher doses of drug can be given with fewer adverse effects (such as respiratory depression) whereas higher doses of full agonists result in both more analgesic effects but more adverse effects as well.

Answer 113

1. Nephrolithiasis 2. Abdominal Pain 3. Osteopenia 4. Bone Pain 5. Psychological Depression

Answer 114

It can cause respiratory symptoms by preventing the release of acetylcholine containing vesicles from the axon terminal into the synaptic cleft (Cleaves SNARE proteins and thus cannot release ACh vescicles) TrueLearn Insight : Botulinum toxin acts inside the axon terminal at the neuromuscular junction.

Answer 115

Treatment usually includes: 1. Anticholinergic medications - Help restore balance to the dopaminergic and cholinergic balance - Diphenhydramine (Both anticholinergic and antihistamine) - Benztropine 2. Benzodiazepines

Answer 116

Aldosterone and cortisol promote renal potassium secretion leading to losses through the urine. Insulin and thyroid hormones enhance cellular potassium uptake (Lowers serum levels)

Answer 117

Serum Na - Low Serum Osm - Low Urine Na - High Urine Osm - High Volume Status - Euvolemic

Answer 118

Serum Na - High Serum Osm - High Urine Na - Low Urine Osm - Low Volume Status - Euvolemic

Answer 119

Serum Na - Low Serum Osm - Low Urine Na - High Urine Osm - High Volume Status - Hypovolemic (Same as SIADH but you are hypovolemic)

Answer 120

Serum Na - Low Serum Osm - Low Urine Na - Low Urine Osm - Low Volume Status - Euvolemic

Answer 121

1. Phenoxybenzamine - Long acting non-selective alpha blocker 2. Doxazosin, Terazosin, Prazosin - Selective Alpha 1 blockers also used

Answer 122

After an intubating dose of succinylcholine in an otherwise healthy patient, potassium can be expected to rise 0.5 mEq/L.

Answer 123

Wound Problems: - Immunosuppression - Increased infections - Delayed Wound Healing - Reduces Skin Graft Success Others: Osmotic Diuresis Delayed Gastric Emptying Sympatho-adrenergic stimulation Increased Mortality Exacerbates ischemia to brain, cord, renal Worsens TBI Post Op cognitive dysfunction in CABG However, most providers will aim for a goal of below 180-200 mg/dL for all surgeries (NICE-SUGAR trial and others), noting that cardiac surgical patients and neurocritical care patients may be at higher risk for complications from hyperglycemia.

Answer 124

The 4Ts include: 1) Thrombocytopenia 2) Timing of the reduced platelet count 3) Presence of thrombosis 4) The exclusion of other causes for thrombocytopenia A score of 0-3 suggests a low probability whereas a score of 6-8 indicates high probability for clinically-relevant HIT.

Answer 125

Positive pressure ventilation exerts deleterious effects on renal function via alterations in hemodynamics, neurohormonal secretion, and biochemical mediator release. (Try to minimize TV to ~6 mL/kg) "Renal Protective ventilation"

Answer 126

Ang II - Increased Inotropy, Chronotropy, Catecholamine release/sensitivity - Increased levels of Aldosterone, Vasopressin - Increased Cardiac Remodeling through AT1 receptors

Answer 127

The PT is the best test to measure synthetic function of the liver. The PT is often elevated 1.5 times normal when severe liver disease is present. The PT measures the clotting time of the extrinsic pathway involving factor VII, which has the shortest half-life of the clotting factors.

Answer 128

P50 = ~27 mmHg Corresponds to PO2 at 50% Hgb saturated

Answer 129

1. Methimazole 2. Propranolol

Answer 130

Factors that affect flow across constant tubular cross section 1. Laminar 2. Non-turbulent Q = Change in Pressure (n \* radius^4) / (8 x viscosity x length) N = Mathematical constant

Answer 131

Subendocardial Ischemia More common than transmural ischemia Subendocardial ischemia is more commonly seen than transmural injury because the small capillaries and arterioles at the subendocardial level are subject to occlusive high intraventricular pressure Transmural Ischemia The epicardial coronary arteries in comparison are distant from the high intraventricular pressures and thus generally unaffected unless acute occlusion from a thrombus, spasm, or embolism occurs.

Answer 132

ST Elevation New ST elevation at the J point in two contiguous leads with the cut-points: ≥ 0.1 mV in all leads other than leads V2–V3 where the following cut-points apply: ≥ 0.2 mV in men \> 40 years ≥0.25 mV in men \< 40 years ≥ 0.15 mV in women ST depression and T wave changes New horizontal or down-sloping ST depression ≥ 0.05 mV in two contiguous leads and/or T inversion ≥ 0.1 mV in two contiguous leads with prominent R wave or R/S ratio \> 1

Answer 133

The stellate ganglion is the fusion of the inferior cervical and first thoracic sympathetic ganglia and first thoracic ganglia. preganglionic sympathetic fibers from T1-T6. Why block? CRPS in upper extremity The major landmark for performing a stellate ganglion block is Chassaignac tubercle, which is the transverse process of C6. Anatomy - The location of the stellate ganglion is in the neck generally anterior to the C7 vertebral body Directly superior to the ganglion is the transverse process of C6, which is referred to as the Chassaignac tubercle (or carotid tubercle). Because of its prominence and proximity to the stellate ganglion, the Chassaignac tubercle is often used as the landmark to perform the block.

Answer 134

The anterior approach to the stellate ganglion block is performed in the supine position. Palpates the Chassaignac tubercle, generally at the level of the cricoid just lateral to the trachea. The needle is then placed there and advanced until it hits the tubercle. You then direct medially and inferiorly and withdraw 1-2 mm and inject (after negative aspiration for blood). This procedure may also be performed with fluoroscopic guidance, which would require recognition of the C6 transverse process by radiograph. Success 1. Ipsilateral temperature changes is the most reliable for block success. 2. Development of Horner syndrome in the patient generally designates a successful block, but is not the most useful sign as cephalad spread of the local anesthetic can cause this syndrome. Other potential side effects associated with this block include pneumothorax, phrenic nerve paralysis, accidental vertebral artery injection leading to seizures, brachial plexus injury, and intrathecal injection. The patient should therefore be closely monitored during and immediately after performing the block.

Answer 135

When a patient is administered 75% nitrous oxide the gas will rapidly diffuse from the blood and into air-filled cavities. A pneumothorax will double in size by 10 minutes and triple by 30 minutes.

Answer 136

FENa: [(PCr x UNa ) / (PNa x UCr)] x 100. PCr = plasma creatinine, UNa = urine sodium, PNa = plasma sodium, UCr = urine creatinine PreRENAL FENa (%) \<1 Intrinsic and Postrenal FENa (%) \>2

Answer 137

Patient selection for dialysis depends on chronicity of the disease, patient symptoms, and degree of metabolic derangements. Reasons for emergent dialysis include AEIOU: Acidosis Electrolytes Ingestions (toxins) Overload Uremia

Answer 138

RF for Emergence Delirium in Pediatrics \<5 years old ENT / Optho surgery Use of Volatile Anesthetics Rapid Emergence Intraop Opiate use Anxious Parents Poor Socialization Treatment: Be sure to treat pain, nausea, and hypoxia 1. Clonidine - 2 mcg/kg IV - 4 mg/kg PO 2. Dexmedetomidine - 15 mcg/kg IV Fentanyl - 2.5 mcg/kg IV - 1 mcg/kg IN Ketamine - 0.25 mg/kg IV Nalbuphine - 0.1 mg/kg IV

Answer 139

A metabolic acidosis Normal PaO2 Falsely elevated calculated SaO2 Falsely elevated SpO2.

Answer 140

1. Check 12 Lead ECG - Prolonged QTc The methadone derivative levacetylmethadol is also effective in the treatment of opioid dependency but has been linked with QT prolongation and torsade de pointes. Studies suggest that the methadone-induced prolonged QT may be due to the drug’s effect on cardiac repolarization. 2. Check for P450 altering meds - Concomitant P450 (especially CYP3A4) inhibition can lead to QT prolongation with smaller methadone doses due to higher plasma concentrations of the drug.

Answer 141

S. pneumoniae is the most common pathogen in adults GBS the most common in pediatric cases

Answer 142

Depletion of oxygen tank Oxygen Regulators: 1st Stage Regulator - Prefers to use pipeline (larger in-house oxygen supply) - Closes off the lower pressure tank - Lower Pressure 50 - 55 psig If faulty → Depletion of backup tank Lowest Pressure 40 - 45 psig

Answer 143

1. Large negative pressure (-50 to -100 cm H2O) developed by inspiration against occluded airway 2. Increased Preload & Afterload → increases pulmonary venous blood volume & pressure → Decreases cardiac output 3. Increased hydrostatic pressure and formation of pulmonary edema 4. Increased afterload → Decreased cardiac output Increase in pulmonary blood volumes with decreased CO → increase pulmonary transudative pressures → PVR increases causing shift in IV septum → Left Ventricular Diastolic dysfunction → Further increases in pulmonary hydrostatic pressures 5. Hypoxia and Hyperadrenergic responses → Translocation of blood from systemic to pulmonary circulation increases pulmonary pressures OSA patients → Impeded pulmonary lymphatic drainage increases tendency to form pulmonary extravascular fluid

Answer 144

Intolerant of hemodynamic changes 1. Unstable Angina 2. Severe Aortic Stenosis 3. HFrEF

Answer 145

1. Platelet Count (Ensure no HIT) 2. See when last Heparin Dose was - Wait 4-6 hours before epidural placement - Peak effect of Heparin 1-5 hours after SQ injection

Answer 146

Indications: Distorted Anatomy Difficult Visualization from fluids/trauma Failed Attempts with DL/Video Emergent airway need where vocals not visualized (blood/secretions/distorted anatomy) Unstable cervical spine Method: IV Needle - Access trachea percutaneously Cricothyroid membrane ~ C6 level under constant aspiration with fluid syringe Aim cephalad and introduce the guidewire retrograde or plastic catheter Use a Jaw thrust at this point Once at nose/mouth advance tube Slide Tube over wire Confirm with Fiberoptic Scope Contraindications: Thyroid Goiters Coagulopathy Landmarks not identifiable - Obesity, Goiter, Distorted Anatomy Laryngeal Disease - Laryngeal stenosis, Retrograde intubation, Local infection

Answer 147

Treatment: 1. Alpha Blockers Phenoxybenzamine (Preoperative) Phentolamine Doxazosin 2, Beta Blockers Labetalol can cause persistent hypotension and bradycardia after the tumor is removed Labetalol has Alpha:Beta receptor antagonist ratio of 1:7 (Potential for worsening the hypertension) Esmolol - Ultra short acting 3. Direct Vasodilators Nicardipine Nitroprusside Nitroglycerin 4. AMPT or Metyrosine Alpha-Methyl-Para-Tyrosine - Inhibits tyrosine hydroxylase (RL enzyme in catecholamine synthesis) 5. Avoid Histamine Releasing Drugs

Answer 148

CaO2 (Arterial Oxygen Content) = (SaO2 \* Hgb \* 1.34) + (PaO2 \* 0.003) SaO2 = Arterial Oxygen Saturation PaO2 = Arterial Partial Pressure of Oxygen

Answer 149

Acute normovolemic hemodilution causes: 1. decreased blood viscosity (Try to get Hgb 7-8) to balance viscocity 2. Decreased peripheral vascular resistance 3. increased cardiac output 4. increased regional blood flow. You give fluids and intentionally dilute patient's blood prior to significant blood loss \*Theory is that you have a lower [Hgb} concentration and there will be autologous blood available for transfusion.

Answer 150

Paradoxical muscular weakness is also possible with neostigmine, but appears independent of anticholinergic use. Clinical evidence confirms that vagal effects are mostly counteracted by the concurrent administration of anticholinergic medications, whereas the paradoxical worsening of neuromuscular weakness is not. It is more likely if neostigmine is administered following the complete recovery of neuromuscular function, or a second dose is administered in patients with a small degree of residual blockade.

Answer 151

Most vasodilating agents will also cause cerebral vasodilation. This may result in flushing and a headache.

Answer 152

The P50 is the oxygen tension at which hemoglobin becomes 50% saturated with oxygen. Under normal circumstances, a PaO2 of 27 mmHg yields a saturation of 50%

Answer 153

Administer 25 mL/kg of intravenous fluids (up to 50 mL/kg) Administer epinephrine: - 1 mcg/kg - max dose is code dose of 0.01 mg /kg - Adult dose is typically 50-100 mcg IV

Answer 154

Draw Mast Cell Tryptase Level after suspected anaphylaxis episode 1. Elevated = Anaphylaxis - Peak between 15-60 minutes in Grade I and II - Peak between 30 - 120 minutes in Grade III/IV reactions 2. Non-elevated = Histamine-Releasing medication - Does not preclude anaphylaxis - Draw 24 hours after insult to determine baselines

Answer 155

Multiple Surgeries Healthcare workers Atopic Histories Tropic Fruits - Avocado, Kiwi, Banana, Chestnuts, Stone Fruits

Answer 156

Mechanism: - Dopamine-1 agonist = Increases renal blood flow despite decreased systemic arterial blood pressure - No Dopamine-2 Receptor activity - Natriuretic - Sodium excretion - Diuretic - Free water excretion - Direct renal vasodilator and can produce hypotension - No Alpha 1 - Some Alpha 2 - No Beta Indications: - A dopamine D1 receptor agonist that is used as an antihypertensive agent (HTN crisis) - It lowers blood pressure through arteriolar vasodilation. - Hypertensive Crisis in those with decreased renal function

Answer 157

Risk Factors: Hypovolemia (Any volume variation) Hypervolemia Treatment: 1. Rate control - Beta Blockade - Metoprolol, Esmolol - CCB - Diltiazem 2. Amiodarone - Inhibits multiple ion channels 3. 25-80% will spontaneously convert in 24 hours 5. Rhythm control if Hemodynamically unstable with Cardioversion Narrow irregular: 120-200 J biphasic or 200 J monophasic; i.e., atrial fibrillation

Answer 158

Glucagon: 1. Decrease hepatic artery resistance 2. Increases hepatic artery blood flow

Answer 159

The CAM-ICU is listed below: 1. Is there an acute change in mental status or fluctuating course – yes/no 2. Is the patient inattentive or easily distracted – yes/no If the answer to both 1 & 2 are yes continue to 3 and 4. If either 1 or 2 has an answer of no than the patient does not have delirium per CAM-ICU screen. 3. Is there an altered level of consciousness or RASS other than 0 – yes/no 4. Does the patient experience disorganized thinking – yes /no

Answer 160

Agitation and Sedation Scoring System Positive - Agitated +4: combative, violent +3: aggressive, pulling on lines +2: agitated +1: restless, anxious, apprehensive RASS 0 (Zero) is defined as calm, alert, and appropriate Negative - Sedated -1: not fully alert, will awaken to voice -2: lightly sedated, brief awakening \<10 sec -3: moderate sedation, movement to voice -4: unconscious, deep sedation

Answer 161

1. Increased arterial puncture (vein overlies artery) - more than 30 degree rotation 2. Tortuous course (Malposition can occur) - 3% with RIJV, 19% with LIJV 3. Left IJV is ½ size of Right IJV

Answer 162

Ease of placement for a pulmonary artery catheter from easiest to most difficult is: 1. right internal jugular 2. left subclavian 3. left internal jugular 4. right subclavian.

Answer 163

Although uncommon, carotid artery cannulation can lead to embolization. Carotid embolization on the left poses a greater risk as the left cerebral hemisphere is dominant in the majority of the population. This is also one of the reasons why right-sided carotid massage is preferred over left-sided massage. Another reason is that some investigations have found a greater cardioinhibitory effect on the right side.

Answer 164

Patient Related Factors 1. Increased Age increase spread of local anesthetics (Anatomical changes with age) Compliance of space decreased (Expand less when LA injected thus spread cranially and caudally more) Less Fat in epidural space therefore more spread Dura mater is more permeable in the elderly due to the increased number of arachnoid villi. This allows local anesthetic to more easily reach the spinal nerve roots. Accordingly, epidural dosing should be reduced in the elderly. Procedure-related factors. 1. Volume of injection has the most significant impact\*\*\* 2. [Local Anesthetic] [Increasing] increases block height and affects block density/intensity 3. Positive airway pressure Intubated or CPAP (Increased intrathoracic pressure) Increases the spread (Compression of epidural space) Epidural space compression OR Decreased epidural space compliance 4. Lateral/Trendelenburg position Lateral → Greater blockade level Trendelenburg → Greater spread

Answer 165

Site of Injection High Thoracic → Spread caudally (low) Low Thoracic → Spread cephalad (high) Mid Thoracic → Spread both cephalad and caudad

Answer 166

Leukoreduction is the process of depleting donor blood products of leukocytes in an effort to reduce immunosuppression associated with blood product transfusion. Confirmed benefits of leukoreduction include: 1. Decreased transmission of CMV 2. Decreased inflammatory response 3. Decreased febrile reactions to packed red blood cell (PRBC) transfusions 4. Reduced inflammatory mediator accumulation during storage. 5. Decreased alloimmunization incidence 6. Reduced Hospital Length of stay 7. Decreased postoperative mortality and infections 8. Reduced transfusion-related tumor recurrence 9. Reduced Acute Lung Injuries

Answer 167

TPN is most associated with: 1. Hypercapnia 2. Hyperglycemia 3. Hypophosphatemia Additionally TPN can cause thrombophlebitis, hepatic steatosis, hypokalemia, hypomagnesemia, and hyperinsulinemia.

Answer 168

Cerebrovascular imaging should be obtained prior to a RARP in patients with an increased risk for intracranial aneurysm. The required steep Trendelenburg positioning significantly increases the risk of cerebral aneurysm rupture.

Answer 169

1. ADPKD 2. Marfans 3. Ehlers Danlos Cerebrovascular imaging should be obtained prior to a RARP in patients with an increased risk for intracranial aneurysm. The required steep Trendelenburg positioning significantly increases the risk of cerebral aneurysm rupture.

Answer 170

IgA Deficiency - Anaphylactic reactions to blood transfusions are likely due to IgA-containing blood being transfused to a deficient recipient. Treatment: - The transfusion should be discontinued - Future red blood cells should be washed to remove all traces of IgA from the blood. - IV Fluids - Epinephrine - Steroids - Anti-histamines

Answer 171

Class: NK1 antagonist Metabolism: Hepatic Half Life: 10 hours Side Effects: Malaise, Nausea, Rash

Answer 172

Class: Anti-dopaminergic Side Effects: 1. Dystonic Reactions 2. Extrapyramidal Symptoms 3. QT Prolongation (Dose dependent)

Answer 173

Side Effects (Opposite of SLUDGE) Delayed arousal in the elderly - THEREFORE AVOID IN OLD PEOPLE Dry Mouth Blurred Vision Delirium Urinary Retention Constipation Tachycardia

Answer 174

Bladder Perforation → Abdominal Pain (If done under spinal) 1. Extraperitoneal = Periumbilical, inguinal or suprapubic pain 2. Intraperitoneal = Diffuse, upper abdominal pain referred to chest and shoulders 3. Surgeon purview = the scope of the influence or concerns of something (irregular fluid not returning)

Answer 175

TURP Syndrome → CNS symptoms Hypo-osmolality Hyponatremia

Answer 176

Thus, to calculate the volume of nitrous oxide in an E-cylinder based on weight, the following formula may be used: Volume remaining (L) = (cylinder weight (g) – 5900 g) x 0.55 L/g Once the pressure gauge shows a value below 745 psig, the volume of nitrous oxide remaining at 20 °C can be calculated without weighing the cylinder using the following formula: Volume remaining (L) = (gauge pressure (psig) / 745 psig) x 253 L

Answer 177

FENa \<1% Urine Osmolality \>800 mOsm/kg (normal 300-900)

Answer 178

1. Plasma Protein Buffers (Hgb) and others (Immediate) 2. Renal compensation (Retention of Bicarbonate is compensatory response) - Hours to days to develop

Answer 179

Esters = Para-aminobenzoic acid (PABA) Amides = Methylparaben (Structurally similar to PABA)

Answer 180

Physical Dependence - Hypertension and Tachycardia (Withdrawal symptoms) after cessation Tolerance - Gradual requirements of higher doses to achieve the same effects Addiction - Continued use of opiates despite adverse consequences, craving, loss of control, compulsive use

Answer 181

Pathology: Portal Hypertension and resultant decreased renal perfusion Type I Fast onset Precipitating cause (SBP, sepsis, surgery) Responds to medical therapy and stabilizes after medical therapy is discontinued Type II Insidious onset Loss of intravascular volume from splanchnic dilation and ascites formation is compensated for with increased renal vasoconstriction and activation of the sympathetic, renin-angiotensin, and vasopressin systems Survival = 6 months Treatment: 1. Vasoconstrictors Midodrine, Octreotide, Norepinephrine, Vasopressin or Terlipressin 2. Volume Expanders - Albumin 3. RRT until they can get a transplant 4. Liver Transplant for Type I and Type II

Answer 182

(Greatest sensitivity) TEE Precordial Doppler Pulmonary Artery Catheter Transcranial Doppler End Tidal Nitrogen Monitoring End Tidal CO2 monitoring SpO2 Direct Visualization Esophageal stethoscope ECG (Least sensitivity)

Answer 183

SID = [Strong cations] - [Strong anions] - Cations = Sodium, Potassium, Calcium, Magnesium - Anions = Chloride, Lactate, Bicarbonate, Phosphate, Albumin, Unmeasured Anions SID + strong cations + strong anions = 0 SID Normal = 40 mEq/Liter Decreased SID = Decreased pH Hyperchloremia (From Large chloride infusions) results in SID due to decrease in Bicarbonate (in order to maintain net neutrality Decreased SID is from the decrease in HCO3 Hyperchloremic non anion gap metabolic acidosis Can also happen from low Cl (0.45% or mannitol) which will cause “dilutional acidosis) → Due to large infusions having SID of zero Increased SID = Increased pH Increased with large volume of fluid that has a SID of zero (Normal Saline)

Answer 184

1. Normal Saline - Dilutional effect - Rehydration prevents sodium and calcium reabsorption from thick ascending limb of the loop of Henle 2. Loop Diuretics - Promote renal calcium losses as temporizing measure - DO NOT give Thiazides (Would worsen the problem) Chronic Therapies: - Calcitonin 24-48 hours to work, 25% dont respond - Bisphosphonates

Answer 185

Effects seen: 1. Decrease in Temperature (Think about cold legs, no more than 1 degree) 2. Transient Metabolic Acidosis 3. Rise in ETCO2 4. SBP drop - Due to vasoactive mediators and venous pooling distal to the tourniquet 5. HR increase (10-15%) 6. Potassium increases (5-10%)

Answer 186

1 - A normal healthy patient. 2 - A patient with mild systemic disease. 3 - A patient with severe systemic disease 4 - A patient with severe systemic disease that is a constant threat to life. 5 - A moribund patient who is not expected to survive without the operation. 6 - A declared brain-dead patient whose organs are being removed for donor purposes

Answer 187

World Pain Ladder 1. Acetaminophen, 2. NSAID (Ibuprofen and Ketorolac), Aspirin, COX-2 inhibits (Rofecoxib, Celecoxib, Valdecoxib) 3. Mild Opiates - Codeine - Tramadol 4. Stronger Opiates - Morphine - Standard opiate for cancer pain - First line treatment and standard of care with moderate to severe cancer pain - 70-90% of cancer patients = Safe and effective Hydromorphone

Answer 188

Afferent Branch - Internal Branch of superior laryngeal nerve - Trachea and above cords Efferent Branch - Recurrent Laryngeal nerve - Intrinsic muscles of the larynx, with the exception of the cricothyroid muscle Muscles (Major adductors of the vocal cords responsible for laryngospasm) 1. Lateral cricoarytenoid muscles 2. Transverse arytenoid muscles

Answer 189

Clark Electrodes - Measures oxygen Galvanic Electrodes- Measures oxygen Paramagnetic Electrodes- Measures oxygen Severinghaus Electrode - Measures CO2 Sanz Electrodes - Measures pH

Answer 190

The maximum recommended dose of lidocaine for tumescent liposuction is: 35-55 mg/kg 0.055 mg/kg for epinephrine

Answer 191

1. vasovagal reactions 2. intravascular or spinal injection 3. Horner syndrome (miosis, ptosis, anhidrosis, enophthalmos, and hyperemia). 4. Phrenic nerve paralysis 5. Accidental vertebral artery injection leading to seizures 6. Brachial plexus injury

Answer 192

Complications from celiac plexus blockade include (but are not limited to): 1. Orthostatic hypotension 2. Diarrhea (para \> sympathetic) \*Top complications\* 3. retroperitoneal hemorrhage 4. hematuria 5. venous and arterial injection 6. aortic dissection 7. dysesthesia 8. Interscapular back pain and backache 9. reactive pleurisy 10. hiccups 11. loss of bladder function 12. transient motor paralysis 13. paraplegia

Answer 193

Treatment: 1. Hemodialysis 2. Folinic Acid 3. Slow metabolism in Liver and remove toxic metabolites - Ethanol - Competitive inhibitor of alcohol dehydrogenase - Fomepizole - Direct alcohol dehydrogenase inhibitor 4. Correct metabolic acidosis (AG) with bicarb and hyperventilation

Answer 194

Spironolactone Triamterene Amiloride

Answer 195

90% = Ischemic optic neuropathy, which to date is still considered an idiopathic process. Two Types 1. Anterior - More common in cardiac surgery 2. Posterior - More common in spine surgery Arteritic - Non-Arteritic - More common

Answer 196

1. Psychosomatic - Emotional, mental or behavioral factors 2. Nociceptive - Pain from actual/threatened damage to non-neural tissue and due to activation of nociceptors Types - Mechanical - Thermal - Chemical 3. Neuropathic - Lesion/Disease of the somatosensory system - Peripheral (Diabetic neuropathy) - Central (Phantom Pain)

Answer 197

Treatment: 1. Physical Therapy (cornerstone) 2. TCA 3. Gabapentin 4. Sympathetic Blocks (Stellate Ganglion) 5. Somatic Blocks 6. Spinal Cord Stimulators 7. Intrathecal Medications

Answer 198

The carotid body chemoreceptors are located at the bifurcation of the common carotid arteries bilaterally. The chemoreceptors are stimulated to increase minute ventilation in response to decreases in PaO2 (Partial pressure of oxygen) below 60-65 mm Hg.

Answer 199

Acute Worsening Factors: 1. Hypercapnia 2. Hypoxia 3. Acidosis Treatment: 1. Inhaled Nitric Oxide 2. Hypocapnia (PaCO2 of 25-30 mmHg) 3. High FiO2 to prevent hypoxic pulmonary vasoconstriction 4. Keep SVR \>\>\>\> PVR

Answer 200

Infra-Gluteal Sciatic Nerve Block Indications: 1. Posterior aspect of the thigh 2. Lower extremity structures at or below the knee Landmarks: 1. Greater Trochanter of the femur 2. Ischial Tuberosity 3. Sciatic Groove

Answer 201

Post CPB AKI RF: 1. Elevated Preoperative Creatinine (\>1.2) 2. Complex Cardiac Surgery (Combined valve procedures) 3. Emergency Surgery 4. Pre-operative intra-aortic balloon pump 5. Females

Answer 202

1. Liver Disease 2. Renal Disease 3. MAOI taking patients (Can lead to serotonin syndrome)

Answer 203

Contents: 1. All clotting factors 2. Plasma Proteins Indications: 1. Factor Deficiencies 2. Coagulopathy related to hepatic insufficiency 3. TTP 4. Dilutional coagulopathy following massive transfusion 5. Antithrombin III deficiency 6. Reversal of Warfarin Least Stable Factors Factor 5 and 8 (Ocho cinco is unstable NFL player) - Degrades above 4 degrees C HENCE, WHY WE FREEZE IT FOR STORAGE!!! Transfuse up to 5 days after thawing

Answer 204

Nitrous oxide administration should be avoided for: 1. 5 days after intraocular air injection 2. 10 days after sulfur hexafluoride injection 3. 30-90 days or longer after other perfluoropropane injection. This is because of blood:gas partition coefficient differences, which allows for nitrous oxide to readily diffuse into and expand the intraocular gas bubble.

Answer 205

Defined: Definition: Herpes zoster pain that persists beyond vesicular rash healing and can last 4 weeks to 6 months. Pathophysiology: The causative agent, varicella-zoster virus (VZV) Typically lays dormant in the dorsal root ganglia after initial infection (usually presenting as chickenpox in children). Immunity declines as a person ages or becomes immunocompromised, and the latent VZV can become active, resulting in herpes zoster (“shingles”). Treatment: 1. Anticonvulsants - Amitriptyline, Nortriptyline 2. TCA - Gabapentin, Pregabalin 3. Lidocaine Patch 4. Topical Capsaicin 5. Opiates 6. Tramadol - Mu receptor opioid, NMDA antagonist, Norepi reuptake inhibitor, SSRI 7. Spinal Cord Stimulator Gate Control Theory of Pain Large nerve fibers within the substantia gelatinosa may increase inhibitor GABA, and decrease excitatory glutamate and aspartate.

Answer 206

Activate the larger Aα and Aβ fibers to a greater degree than the smaller nociceptive Aδ and C fibers. This closes the “gate” in and impedes conduction of pain sensation past the substantia gelatinosa of the dorsal horn of the spinal cord

Answer 207

1. (Methicillin-sensitive Staphylococcus aureus (MSSA) 2. H. influenzae 3. S. pneumoniae 4. Proteus 5. Klebsiella 6. Enterobacter species

Answer 208

For each day after interruption of any agent, approximately 10% to 14% of normal platelet function is restored Thus it can take 7 to 10 days for an entire platelet pool to be replenished which irreversibly inhibits platelet function.

Answer 209

Static measurements (CVP, wedge pressure) are not reliable indicators of volume status. Dynamic measurements such as arterial pressure variation, which includes SVV (Stroke Volume Variation) and PPV (Pulse Pressure Variation), are more reliable indicators. The typical SVV cutoff used is 13%.

Answer 210

Primary Hyperaldosteronism: Produced in zona glomerulosa Physiology: Distal renal tubules absorb Sodium ions in exchange for urinary loss of Potassium and Hydrogen Ions Symptoms: Hypertension (Volume expansion as water follows sodium), Fatigue Labs: Elevated Serum Sodium Reduced Serum Potassium (\>30 mEq per day) Reduced Renin Activity (Negative feedback of aldosterone on RAA system) Metabolic Acidosis (Chronic H+ loss) Management: Spironolactone (K sparing diuretic but takes several weeks to take effect) Potassium (Only if \<3 due to arrythmogenicity) & Volume Repletion Avoid Hyperventilation (Will drive potassium lower) Cortisol

Answer 211

Metabolism Greatest to Least: 1. Sevoflurane (5-8%) 2. Isoflurane (0.2%) 3. Desflurane (\<0.2%) Why important? Fluoride concentrations increased and has minimal renal defluorination compared to previously used enflurane Sevoflurane undergoes the most extensive metabolism of the inhaled anesthetics used in clinical practice today. Despite demonstrated elevations in serum fluoride concentrations in long cases, it has not been shown to cause fluoride-induced nephrotoxicity.

Answer 212

In patients awaiting organ donation, many of the homeostatic mechanisms fail. Diabetes insipidus is common (\>65%) due to a lack of ADH production. THE TREATMENT 1. Free Water (1-3 mmol/hour or 12mEq/day) either PO or IV (Want to prevent brain shrinkage) Hypotonic therapy is preferred 2. Avoid Na of \> 155 mmol/Liter 3. MAPs \>60 mmHg but limit vasopressors 4. Avoid Hyperglycemia (Worsen diuresis) 5. Desmopressin (DDAVP) - IV or IN (higher duration of action) 6. Vasopressin (If fluids don't maintain electrolyte balance and UOP is excessive) 7. Furosemide - If hypervolemic and hypernatremic 8. Clofibrate (Chronic DI) 9. Chlorpropamide PO hypoglycemic agent that stimulates ADH release and sensitizes renal tubules

Answer 213

1. Using TPN with a lower glucose-to-lipid ratio 2. Stopping concomitant insulin infusions 3. Starting intravenous glucose with frequent blood glucose monitoring.

Answer 214

CBF = Coronary Perfusion Pressure / Coronary Vascular Resistance CBF = (Aortic Diastolic Pressure – LV End Diastolic Pressure) / Coronary Vascular Resistance

Answer 215

Myocardial Oxygen Demand 1. Oxygen Content 2. Coronary Blood Flow - Heart Rate - Coronary Perfusion Pressure - Coronary Vascular Resistance (See physiology for more details) \* NOTE, this is separate from myocardial oxygen demand which is affected by LVSP (Wall tension)

Answer 216

Aging effects on Cardiovascular Dynamics Not altered Resting left ventricular systolic function (ejection fraction and/or stroke volume) Decreased Diastolic Function Exercised induced CO, SV, HR Elevated - Plasma Catecholamines (Beta receptors are desensitized) \*Cardiac Output more reliant on atriac kick due to reduction and delay in LV relaxation and passive filling is reduced with age\* If they develop atrial fibrillation they are more affected by it

Answer 217

Methylprednisolone

Answer 218

1. Methadone Partial Opioid receptor agonist Re-uptake of NE inhibitor Re-uptake of 5HT inhibitor Can modulate neuropathic pain 2. Tramadol 3. Anti-epileptics - Antidepressants (TCA, especially and SNRI) 4. Tramadol (Non-opioid mechanisms)

Answer 219

Volatile anesthetics potentiate neuromuscular blockade (Potentiation = Enhancing the effect of something) 1. Decrease post-junctional skeletal muscle membrane sensitivity to depolarization 2. Increasing Skeletal Muscle Blood Flow Long case = More volatile is taken up by muscle (vasodilation) 3. Depression of Upper Motor Neurons by VA

Answer 220

Vomiting = Metabolic alkalosis (Loss of HCl) Diarrhea = Hyperchloremic, hypokalemic non-anion gap metabolic acidosis (Loss of Bicarbonate)

Answer 221

The AFFERENT nerve impulses of carotid sinus baroreceptors are transmitted by the Hering’s nerves to the glossopharyngeal nerve (CN IX) (see image below). Arterial wall stretch at the carotid sinus, within the internal carotid artery, activates the afferent impulse. This activation leads to stimulation of the nucleus tractus solitarius (NTS) in the caudal medulla. The NTS sends excitatory signals to other regions of the medulla which in turn inhibit stimulation of the preganglionic intermediolateral nucleus of the spinal cord which mediates the body’s sympathetic innervation. The NTS may also stimulate vagal nuclei to activate the parasympathetic nervous system via the vagus nerve. These two effects then lead to bradycardia and hypotension.

Answer 222

1. Equine (Horses) serum in patients older than one year old 2. Human-derived immune globulin for infants less than one year of age.

Answer 223

90% found in FFP and Platelets (Not Whole Blood) Rates: Hypocalcemia occurs at 6 Units / Hour (35 mL/min) is when Calcium levels drop Hyperkalemia occurs at 120 mL/min or more

Answer 224

- Intravascular volume should be restored with fluid administration Cardiac - Tachycardia may be managed with esmolol and/or propranolol - Digoxin or beta blockers can treat arrhythmias Steroidal - Hydrocortisone or dexamethasone can decrease hormone release - Antipyretics (e.g. acetaminophen) Thyrostatic - Propylthiouracil (PTU) and methimazole (MTZ) are both medications that can be used to inhibit the production of thyroid hormone (T4). In addition, propylthiouracil blocks the peripheral conversion of T4 to T3 - this makes PTU favorable over MTZ. These anti-thyroid drugs can be used as either definitive therapy or as a bridge to treatment with surgery or radioactive iodine. Thyroid Hormone Release Inhibition Potassium iodide can be given orally in high concentrations to inhibit the release of hormone from a high functioning gland. The effects are short-lived, however. Radioactive iodine (iodine-131) can be given orally to either severely restrict or completely destroy the thyroid gland. Because iodine is picked up almost exclusively by the thyroid gland, and even more so by overactive thyroid cells, the effect of treatment is completely localized to the thyroid gland.

Answer 225

Neostigmine - Use Glycopyrolate Edrophonium - Use Atropine Pyrirdostgmine - Use Glycopyrolate

Answer 226

Drug Onset Duration Neostigmine 7 - 11 minutes 4 - 6 hours Glycopyrrolate 2 - 3 minutes 2 - 4 hours Scopolamine 30 - 60 minutes Edrophonium 1 - 2 minutes 1 - 2 hours Atropine 1 minute 15 - 30 min Pyridostigmine 15 - 20 minutes 4 hours

Answer 227

Coronary Artery Disease Open Globe ICP from tumor/hemorrhage Cerebral aneurysms

Answer 228

One operator maintains the head and neck in a neutral position While another operator stabilizes the shoulders against the OR table, bed, or stretcher. This allows the laryngoscopist to intubate while focusing on minimal manipulation of the mid-cervical spine.

Answer 229

Decreased = Lidocaine, Midazolam, Propofol Increased = Etomidate No change = Methohexital, Ketamine, Succinylcholine

Answer 230

Ejaculatory failure in males

Answer 231

Phase 0: Calcium in Phase 3: Potassium Out Phase 4: Sodium in and Calcium in (sharper upslope here would mean that you have a faster HR)

Answer 232

Microlaryngeal Tracheal Tubes (ENT cases) Smaller internal diameter but length and cuff size appropriate for adults

Answer 233

Induces CYP enzymes Stopped 5 days prior to surgery

Answer 234

First line therapy = Hydroxocobalamin (B12) Hydroxocobalamin converts cyanide to the much less toxic cyanocobalamin. Cyanocobalamin is renally cleared. The use of hydroxocobalamin became first line due to its low adverse risk profile, rapid onset of action, and ease of use in the prehospital setting

Answer 235

Advantages of pH-stat management include: 1. increased speed of homogenous cerebral cooling through cerebral vasodilatation 2. Reduced CMRO 3. Increased CBF 4. Improved oxygen delivery to tissue. Disadvantages include: 1. Increased delivery of embolic load to the brain 2. loss of cerebral autoregulation

Answer 236

External Laryngeal nerve AKA External Branch of Superior Laryngeal Nerve This muscle is the only laryngeal muscle innervated by the superior laryngeal branch of the vagus nerve known as the external branch of the superior laryngeal nerve

Answer 237

Daily 60 minute weaning trials on Pressure Support Pass = Patients who are able to breathe spontaneously with minimal or no ventilator support for at least 30 minutes are usually considered candidates for extubation, presuming there are no other contra-indications to extubation.

Answer 238

SIADH Volume Status - Normovolemic or Hypovolemic [Sodium] Serum - Low (\<135) [Sodium] Urine - High (\>20 mmol) UOP - Normal Mechanism of Action - Increased ADH causing water restriction

Answer 239

Cerebral Salt Wasting Volume Status - Hypovolemic [Sodium] Serum - Hyponatremia [Sodium] Urine - High \>20 mmol UOP - High UOP Mechanism of Action - Excess secretion of Na and Water

Answer 240

Diabetes Insipidus Volume Status - Hypovolemic [Sodium] Serum - Hypernatremic [Sodium] Urine - Low (\< 5 mmOL) UOP - High Mechanism of Action - Decreased ADH causing free water loss

Answer 241

Doesn't change

Answer 242

Microcirculation undergoes reversible changes in the face of cardiogenic shock. These changes may be mapped through the manipulation of the Starling equation for Net fluid movement between the capillary bed and organ interstitium.

Answer 243

PVR = 80\*(PAP – PCWP)/CO normal 100-200 dyn-s/cm5. SVR = 80\*(MAP – CVP)/CO normal 900-1200 dyn-s/cm5.

Answer 244

[(2 x diastolic)+systolic] / 3 Think of this as the heart spends 67% of time in diastole

Answer 245

The ARDS Network demonstrated a 22% reduction in mortality when patients with ARDS were mechanically ventilated at tidal volumes using 6 mL/kg of PBW and plateau pressures ≤ 30 cm H2O. The appropriate tidal volume is derived from the predicted body weight (PBW), which can be approximated by the following: Males: 50 + 2.3 \* (height in inches - 60) Females: 45.5 + 2.3 \* (height in inches - 60)

Answer 246

Propofol LBW (Induction) TBW (Maintenance) Lean Body Weight (Opiates) Male LBM = 1.1(weight)−128(weight/height)2 Female LBM = 1.07(weight)−148(weight/height)2

Answer 247

Lean Body Weight (Opiates) Male LBM = 1.1(weight)−128(weight/height)2 Female LBM = 1.07(weight)−148(weight/height)2 Fentanyl LBW Remifentanil LBW

Answer 248

Ideal Body Weight Ideal body weight (kg) = height (cm) - 100 Paralytics - (IBW underestimates the dose) Vecuronium IBW Rocuronium IBW Cisatracurium IBW

Answer 249

Induction preference is Ketamine (1-1.5 mg/kg) or Etomidate (0.3 mg/kg) Goals for induction Fast HR Full heart (maximize preload) Forward (Avoid cardiac depressants) IVF resuscitation Avoid Positive Pressure (Decreased preload with PPV)

Answer 250

In a healthy lung with normal ventilation-perfusion matching, normal CO2 diffusing capacity, and a normal capillary-alveolar membrane, the arterial CO2 should equal the alveolar CO2 which should be 2 -9 mm Hg higher than the end tidal CO2 (due to physiologic dead space).

Answer 251

Ketamine is unique when compared to many other intravenous anesthetics: ## Footnote **Airway reflexes and respiratory drive are relatively preserved**

Answer 252

FENa = Excreted Na/Filtered Na x 100\ **(UNa x PCr)/(UCr x PNa x 100)** UNa – urine sodium PNa – plasma sodium UCr – urine creatinine PCr – plasma creatinine

Answer 253

**PAO2 = [(Patm – PH2O) \* FiO2] – (PACO2 / R)** Patm = 760 mmHg PH20 = 47 mmHg PaCO2 from ABG R = 0.8 **PAO2 = 713 \* FiO2 - (PACO2 \* (5/4))**

Answer 254

PAO2 = 713 \* FiO2 - (PACO2 \* (5/4)) PA02 at Fi02 1.0 = 663 mmHg PA02 at Fi02 0.8 = 520 mmHg PA02 at Fi02 0.6 = 377 mmHg PA02 at Fi02 0.4 = 235 mmHg PA02 at Fi02 0.21 = 100 mmHg

Answer 255

Under hypothermic conditions, water vapor pressure decreases allowing more parts per breath to consist of oxygen, which will **increase the PAO2.** PAO2 = [(Patm – **PH2O**) \* FiO2] – (PACO2 / R) **PH20 would be affected**

Answer 256

***_Relative Contraindications:_*** Implantable Cardioverter-Defibrillator Morbid Obesity Untreated UTI Large aortic/renal aneurysms Ureteral obstruction distal to the calculus ***_Absolute Contraindications:_*** Pregnancy Bleeding Disorders Anticoagulation therapy

Answer 257

Hydromorphone is primarily metabolized to **hydromorphone-3-glucuronide** which provides no analgesic effects. Buildup of renally-excreted hydromorphone-3-glucuronide can lead to neuroexcitatory effects including agitation, restlessness, and myoclonus.

Answer 258

Codeine is an opiate prodrug whose effects are primarily dependent on metabolism to morphine, which requires the **cytochrome P450 enzyme CYP2D6.**

Answer 259

*_Adults_* - Neuromuscular Blocking Agents **Children** - Latex

Answer 260

Simple febrile reactions to blood product administration are usually due to **antibodies that the host has formed against HLAs present on donor leukocytes**. The febrile period is usually mild, short-lived, and can be treated with acetaminophen.

Answer 261

1. **Hypoventilation** 2. **Ventilation / Perfusion Mismatch** 3. **Right to Left Shunt** (Intra vs. Extrapulmonary, hepatopulmonarry, or physiologic) 4. **Diffusion Impairment** 5. **Low PO₂**

Answer 262

For respiratory acidosis, the pH will decrease by ***_0.05_*** for every acute 10 mmHg increase in PaCO2. Bicarbonate will increase ***_1.0 mEq/L_*** per 10 mmHg acute increase in PaCO2. Bicarbonate will increase ***_4-5 mEq/L_*** per chronic 10 mmHg increase in PaCO2, and pH will return toward normal if hypercarbia persists long enough (i.e. 1-2 days).

Answer 263

1) Extremes of age (patients \< 1 year or \>70 years) 2) Use of (deliberate) total body hypothermia 3) Use of controlled hypotension 4) Anesthesia complicated by emergency conditions

Answer 264

1. **Decreased proteins** (Albumin and Alpha 1 - Acid Glycoprotein) - Increrase free fraction of opioids 2. **Paralytics** *_- Succinycholine exagerrated response_* *_- Non-depolarizing NMD build resistance_* - Burn patients also have *_increased protein binding_*, meaning less free drug is available to bind ACh receptors, further increasing dose requirements. - produced by competitively inhibiting ACh receptors, _the presence of more receptors (Upregulation of receptorsr)_ means a higher dose of free drug is required to produce neuromuscular blockade manifesting as twitch depression - Exception is Mivacurium (due to its degradation by pseudocholinesterase (levels of which are decreased in burn patients), requires the smallest increase in dosage for burn patients)

Answer 265

When the burned area exceeds 10% of the total body surface area (TBSA), succinylcholine administration between ***_24 hours and 1 year_*** after the injury becomes contraindicated due to exaggerated hyperkalemia.

Answer 266

When the burned area exceeds 30% TBSA, resistance to nondepolarizing neuromuscular blockers develops **starting 1 week following the burn and peaking approximately 5-6 weeks** following the injury.

Answer 267

Lorazepam premedication **can prolong extubation times** and does **not improve patient satisfaction scores.** Lorazepam has a more favorable pharmacokinetic profile (**10-20 hour elimination half time** versus 20-40 hours for diazepam), no active metabolites, and does not cause phlebitis or burning during injection. In doses of **25-50 mcg/kg (max dose of 4 mg)** significant amnesia may remain up to 4-6 hours after a dose without excessive sedation, but above 4 mg there is no added benefit and it will prolong sedation.

Answer 268

Treatment: **Lumbar Puncture with Opening Pressure** 1. 25% RF for Back Pain 2. 22% Headache 3. Paraparesis / Paresthesia 1.5% **Carbonic Anhydrase Inhibitors** **Corticosteroids** **Weight Loss** **Lumboperitoneal Shunting (Surgical intervention)**

Answer 269

**12-24 hours**: Smoking cessation shifts the P50 of hemoglobin to the right improving oxygen delivery to the tissues **48-72 hours**: increased secretions and a more reactive airway **2-4 weeks**: decreased secretions and less reactive airway **4-6 weeks**: immune system and metabolism normalize **8-12 weeks**: improved mucociliary transport and small airway function

Answer 270

**Reduced FRC** can result in lung volumes below that of closing capacity during normal tidal volume ventilation. **Expiratory reserve volume (ERV) is considered the MOST sensitive** indicator of obesity’s effects on pulmonary function. It is appreciably reduced with obesity. **ERV is the (Residual Volume - FRC)** Residual volume, closing capacity, FEV1 (forced expiratory volume in 1 second), and forced vital capacity typically remain unchanged.

Answer 271

Desflurane primarily **decreases arterial pressure by decreasing afterload**. - Desflurane increases heart rate and decreases both mean arterial pressure and systemic vascular resistance while maintaining cardiac output. Desflurane **increases heart rate**, particularly when the concentration is quickly increased, and also causes dose-dependent depression of myocardial function. **Cardiac output is maintained** and there is no significant effect on left ventricular diastolic function.

Answer 272

**20-40%** have autonomic neuropathy **5%** are symptomatic at baseline Diabetic autonomic neuropathy include **loss of heart rate variability, resting tachycardia, dysrhythmias, impaired ventilatory responses, gastroparesis with increased risk of aspiration on induction, and unawareness of hypoglycemia.**

Answer 273

Differential blockade with local anesthetics results in: 1. sympathetic blockade first (No myelin, small diameter) 2. pain/sensory blockade 3. Motor blockade last (Myelin, thick diameter) This is (at least in part) explained by differential susceptibility of nerve fibers to local anesthetics being **A-delta, A-gamma \> lA-alpha, A-beta \> C.** **-** unmyelinated C fibers are the most resistant to local anesthetic action. - myelinated A fibers are most sensitive and that amongst the myelinated A-fibers the smaller ones such as A-delta and A-gamma are more sensitive than the large ones such as A-alpha and A-beta

Answer 274

**1. Cardiac - Get Echo/ECG** **Pulmonary - Weak diaphragm & Airway responses** **GI Delayed Gastric Empyting** 2. Anesthesia - TIVA with Propofol & Non-depolarizing blockers - Avoid gas and succinylchole

Answer 275

Cardiotoxic effects occur specifically by TCAs due to their ability to **inhibit the fast sodium channels** in the His-Purkinje system and myocardium. This leads to decreased conduction velocity and increased repolarization duration. This disruption of the normal cardiac conduction system can manifest on the ECG as T wave changes, prolonged QRS complex, bundle branch blocks, PVCs, and even lethal arrhythmias such as ventricular fibrillation. **Sodium bicarbonate leads to an increase in pH of the serum which favors the non-ionized form of the drug**, *_making it less available to bind to the fast sodium channels._*

Answer 276

**1. Upregulation of ACh receptors** **2. Increrased Plasma Protein Binding** Mivacurium (Pseudocholinestase metabolism) which is decreased in burn patients, requires less drug

Answer 277

Correction to Colder = PaO2 drops and pH increases Correction to Warmer = PaO2 increaes and pH drops

Answer 278

Local anesthetic toxicity during tumescence liposuction occurs with much higher doses **(55 mg/kg) of lidocaine** There is no absolute number for maximum lidocaine used in tumescent anesthesia, however; most tests and experts recommend 55 mg/kg maximum. Some experts recommend that 35 mg/kg be the maximum dose if sedation is being used as it might cloud the patient's ability to sense the signs from toxicity. Others recommend the maximum dose of 55 mg/kg despite sedation being used.

Answer 279

The Valsalva maneuver causes *increased intrathoracic pressure by forced expiration against a closed glottis*. The increased intrathoracic pressure will force blood out of the heart, up the superior vena cava, and to the internal jugular vein (IJ). This leads to IJ distention with an increase in cross-sectional diameter. In a **mechanically ventilated patient, PEEP can be increased to achieve a similar result.**

Answer 280

Large quantities of blood products containing sodium citrate can lead to *_metabolic alkalosis_* as it can be metabolized into sodium bicarbonate. Typically, this is seen with large volume transfusions such as **more than 8 units.**

Answer 281

1. **Loss of gastric fluid** ("Remember up from stomach makes pH go up" 2. **Urinary losses** (diuretic use, hyperaldosteronism, and rare congenital syndromes such as Bartter or Gitelman syndrome.) 3. **Cellular shifts (**Severe hypokalemia**)** 4. **Exogenous administration of Bicabonate or Blood Products (Citrate --\> Bicarb)** Gastric losses are typically due to vomiting or significant gastric suctioning

Answer 282

SA node 60% RCA and 40% LCA (Not dependent on dominance)

Answer 283

**Right Dominant** In 85% of patients, the posterior descending artery (PDA) branches off the RCA and supplies the posterior 1/3 of the interventricular septum and the posteromedial papillary muscle. RCA gives rise to AV nodal artery which supplies AV node **Left Dominant** In about 15% of patients, the left circumflex gives rise to the PDA and these are known as left-dominant patients. **Co-Dominant** small portion of patients get dual blood supply to the PDA

Answer 284

**LAD** Anterior wall of the heart Interventricular septum Bundle branches Purkinje system **LCX** posterior and lateral walls of the left ventricle. **RCA** Inferior wall of LV Lateral and Posterior Walls of RV

Answer 285

PT (Half life of Factor 7 is 4 hours) \> Albumin (Half life is 3 weeks) in terms of function test

Answer 286

Goal = **32 to 36 Celcius for 12-24 hours** Meds = **Meperidine** - Meperidine blunts the shivering response to hypothermia which reduces total body oxygen demand. blunt the shivering response to hypothermia and prevent the associated significant increase in oxygen demand. Shivering in response to hypothermia can increase tissue oxygen demands by as much as 400-500%. It also increases oxygen consumption. Rewarm slowly - **Most codes happen on re-warming** **Endovascular cooling at 4 degrees Celcius per hour**

Answer 287

**Drug Onset of action (hours)** Cimetidine 1-1.5 Ranitidine 1 Famotidine 1 **Duration of action (hours)** Cimetidine 3-4 Ranitidine 9-10 Famotidine 10-12 **Dose of each** Cimetidine 150 - 300 mg PO or IV Ranitidine 50 - 200 mg PO Famotidine 40 mg PO

Answer 288

Greatest to Least: 1. Desflurane (60% increase) 2. Isoflurane and Sevoflurane (40%) 3. Nitrous Oxide (20%) **Aminosteroid** \> Benzylisoquinoline *_Length not extended_* but **intensity increased**

Answer 289

Sodium bicarbonate (mEq) = **0.2** \* **patient weight (kg)** \* **base deficit**

Answer 290

It does NOT consider determination of “who” caused an event to be a fundamental endpoint.

Answer 291

Scopalamine 5 mcg/kg (0.2 - 0.4 mg IV)

Answer 292

Obtuse Marginal = LCX **D**iagonal = LA**D** Septal = RCA and LAD

Answer 293

The axillary sheath contains the median, ulnar, and radial nerves. The musculocutaneous nerve is located outside of the axillary sheath.

Answer 294

Potential complications include **thrombosis** **infection** **median nerve injury**.

Answer 295

``` Middle = PDA Great = LAD ``` Anterior = RCA

Answer 296

While 85% of coronary blood flow to the left ventricle empties into the coronary sinus, 15% will eventually drain via **Thebesian veins into the atrial and ventricular cavities.**

Answer 297

Parathyroid hormone has been shown to be an important inhibitor of renal bicarbonate reabsorption. Increased renal bicarbonate loss leads to a **non-anion gap metabolic acidosis.** 7.3 / 38 / 20 / 12

Answer 298

Platelet dysfunction causing a **reduction in availability of glycoprotein 2b-3a on platelets** Thus, because of the decreased availability of the glycoprotein IIb-IIIa complex, platelets are *_not able to achieve the appropriate conformation to bind fibrinogen_*, which **negatively affects platelet aggregation.**

Answer 299

**Conduction dysfunction** **Cardiomyopathy** **Mitral Valve Prolapse**

Answer 300

Cortex Ischemia Sensory cortex supplied by MCA therefore SSEP (unlike EEG) can detect subcortical sensory MCA ischemia, which is especially important in carotid artery clamping **Decrease in amplitude (SSEP)** **Increase in latency (SSEP)**

Answer 301

**Pralidoxime** = Irreversible acetylcholinesterase inhibitor used to treat organophosphate poisoning (Along with Atropine) **Pralidoxime** works by binding to the organophosphate molecules and reactivating acetylcholinesterase. By reactivating acetylcholinesterase, it is effective in treating both muscarinic and nicotinic symptoms. It generally only works if given within the first 48 hours of exposure. **Atropine** is a cholinergic antagonist at the muscarinic receptors, therefore preventing cholinergic parasympathetic activity. It is therefore most usephysoful for drying pulmonary secretions and treating bradycardia. *_**Physostigmine** = Anticholinergic (Antimuscarinic) toxicity used to treat atropine overdose_*

Answer 302

Locus Coereleus - **Norepinephrine** Dorsal Raphe - **Serotonin**

Answer 303

Decrease tone

Answer 304

Increase (Unlike Non-depolarizers)

Answer 305

1 hour = Antibiotics 3 hours = 30cc/kg bolus

Answer 306

The proliferation of extrajunctional acetylcholine receptors in muscles in paralyzed limbs can lead to an increased response (T4:T1) to peripheral nerve stimulation following non depolarizing neuromuscular blockade compared to a normal non paralyzed limb in the same patient. ## Footnote **Compared to the “normal” ulnar nerve response, the response to stimulation of a nerve in a paralyzed extremity is exaggerated**

Answer 307

The occurrence of succinylcholine-induced fasciculations and *_increases in ICP*_ and _*intragastric pressure_* may be decreased by NDNB pretreatment. **Increases in IOP will occur despite** pretreatment and current recommendations are to avoid succinylcholine in open-eye injuries.

Answer 308

The ***_renal medulla_*** extracts oxygen at a ratio of ~80% making it exquisitely sensitive to small changes in renal blood flow. The mechanisms of many perioperative renal insults are based on the **disruption of adequate blood flow** (and therefore oxygen delivery) to the renal medulla.

Answer 309

Potassium Iodide

Answer 310

**60 weeks** Apnea of Pre-maturity can be seen following surgery can have apnea and bradycardia

Answer 311

ASIS (Anterior Superior Iliac Spine)

Answer 312

**Bradycardia (High doses)** **Hypotension (Rapid administration)** **Prolonged QT syndrome** **Endocrine** Hypothyroidism / Hyperthyroid storm **Pulmonary Toxicity (Fibrosis)** (Antibody mediated destruction of parenchyma or cytotoxic process) **Elevated LFT’s** **Dermatological** Blue Gray appearance

Answer 313

Mannitol - Vasodilatory effect causing engorgement of the brain & increased ICP Give over 10 minutes Dose: IV: 0.25 to 1 g/kg/dose; may repeat every 6 to 8 hours as needed (BTF [Carney 2016]; Grape 2012). Some suggest maintaining serum osmolality \<320 mOsm/kg (Rabinstein 2006).

Answer 314

Chronic use of dantrolene is associated with ***_hepatotoxicity_*** and, in severe cases, may lead to liver failure and death if unrecognized. Patients on chronic dantrolene therapy should routinely have ***_LFTs monitored_***

Answer 315

Chronic use of dantrolene is associated with ***_hepatotoxicity_*** and, in severe cases, may lead to *_liver failure and death_* if unrecognized. Patients on chronic dantrolene therapy should routinely have LFTs monitored

Answer 316

Excessive dosing of AChE inhibitors can cause weakness by motor axon sodium channel inactivation and presynaptic nicotinic receptor desensitization. Postsynaptic sodium channel inactivation and acetylcholine receptor desensitization also occur. Combined, these can lead to **significant muscle weakness.**

Answer 317

* *Fisher Grades:** 1: no blood detected 2: diffuse thin layer of subarachnoid blood (**\< 1 mm thick**) 3: localized clot or thick layer of subarachnoid blood (**\> 1 mm thick**) 4: intracerebral or intraventricular blood with diffuse or no subarachnoid blood

Answer 318

Individual lung volumes are noted in blue and lung capacities (the sum of 2 or more individual lung volumes) are noted in red. Expiratory reserve volume\* (ERV\*) indicates the volume that is forcefully exhaled from the lungs when pulmonary conditions promote early airway closure and atelectasis. (Volumes: RV = residual volume, ERV = expiratory reserve volume, TV = tidal volume, IRV = inspiratory reserve volume, ERV\* = expiratory reserve volume with atelectasis, CV = closing volume; Capacities: VC = vital capacity, IC = inspiratory capacity, TLC = total lung capacity, FRC = functional residual capacity, CC = closing capacity).

Answer 319

Closing capacity is the **volume at which the airways begin to close.** Closing capacity increases with age and typically exceeds FRC in the mid 60’s. Closing capacity will eventually exceed tidal volume in elderly patients. This is functionally similar to the lung mechanics of neonates and infants.

Answer 320

Midodrine is a ***_α1 receptor agonist_*** Ascites, refractory (off-label use): Oral: 5 to 7.5 mg 3 times daily Hepatorenal syndrome (off-label use): Oral: Initial: 5 to 10 mg 3 times daily; may increase to maximum dose of 12.5 mg or 15 mg 3 times daily (with a goal to increase mean arterial pressure [MAP] by at least 15 mm Hg from baseline) Hypotension in the ICU, vasopressor sparing (off-label use): Oral: Initial: 5 to 20 mg 3 times daily; increase dose incrementally until IV vasopressors are discontinued Hypotension, prevention of hemodialysis-induced (off-label use): Oral: 2.5 to 10 mg given 15 to 30 minutes prior to dialysis session Hypotension, symptomatic orthostatic: Oral: 2.5 to 10 mg 3 times daily during daytime hours (every 3 to 4 hours) when patient is upright; maximum dose: 40 mg/day (ESC [Brignole 2018]; Kaufmann 2019). Note: Avoid administering \<4 hours before bedtime to prevent supine hypertension; discontinue therapy if supine blood pressure increases excessively Vasovagal syncope (off-label use): Oral: Initial: 2.5 to 10 mg 3 times daily during daytime hours (every 6 hours) increased up to 15 mg per dose if necessary

Answer 321

**Transition from Phase I to Phase II Block** (Post-Junctional Membrane has become repolarized and sensitive to Acetylcholine) This may allow an acetylcholinesterase inhibitor (Neostigmine) to raise the [Acetylcholine]. **Dose is 0.03 mg/kg (30 mcg/kg)**

Answer 322

**Will not accept:** Allogeneic blood transfusions Autologous blood transfusions Whole blood Blood-containing fractionates such as platelets. **May accept:** Albumin Erythropoietin Immunoglobulins Factor concentrates should be discussed with the patient preoperatively.

Answer 323

Cause hypopnea (excessively shallow breathing or an abnormally low respiratory rate), hypotension (abnormally low blood pressure) and bradycardia (abnormally low resting heart rate) in response to noxious stimuli detected in the cardiac ventricles

Answer 324

Side effects from excessive cholinergic activity can be remembered with the mnemonic **SLUDGE Mi** ("SLUDGE ME"): Salivation, Lacrimation, Urination, Diaphoresis, GI upset, Emesis, Miosis

Answer 325

**1 - Beta** Beta = Type II Error The power determines the chance of correctly rejecting the null hypothesis (Ho) when the alternative hypothesis (Ha) is actually true.

Answer 326

**Airway Exchange** 1. Jet Ventilation 2. ETCO2 capabilities

Answer 327

1. Decrased airway radius 2. Turbulent Gas Flow (subglottic stenosis) Helium is useful with **increased airway resistance** and **turbulent flow**, as is seen with decreasing airway radius, because helium has a low gas density. The low gas density decreases resistance with turbulent flow and increases the chance for development of laminar flow.

Answer 328

CO = **VO2** / *_(CaO2 - CvO2)_*

Answer 329

Patients with heart failure with preserved ejection fraction (HFpEF) have EF greater 50% with a **normal left ventricular end-diastolic volume** and an **elevated left ventricular end-diastolic pressure**. Concentric remodeling and **left ventricular hypertrophy** from long-standing hypertension contribute to abnormalities in diastolic function such as a delayed and slowed relaxation, decreased recoil, slow and incomplete early filling, increased filling during atrial contraction, and decreased distensibility.

Answer 330

Right homonymous hemianopsia = Left PCA occlusion Left homonymous hemianopsia = Right PCA occlusion

Answer 331

**Broca/Wernicke = Left MCA** **Hemispatial Neglect = Right MCA**

Answer 332

**1 SD = 34.1% (68%)** **1 SD = 13.6% (95%)** **2 SD = 2.1% (99%)**

Answer 333

Sevoflurane

Answer 334

**Desflurane**

Answer 335

**Soda Lime** = Highest (Reduced incidence of Compound A and Fire Production) **Calcium Hydroxide** = Lowest reactivity

Answer 336

**Ethyl violet** is the pH indicator used in CO2 absorbents (typically colorless when fresh), which becomes **purple when the pH falls below 10.3**, indicating absorbent exhaustion.

Answer 337

**Mild** = Non-opiates (NSAIDs and Acetaminophen) **Mild - Moderate** = Mild Opaites (Codein) **Moderate - Severe** = Strong Opiates (Oxycodone) **Adjuvants** **Neuropathic pain** Antidepressants (eg TCAs), anticonvulsants, local anesthetics **Neural compression by mass** Corticosteroids **Bone pain** Bisphosphonates, calcitonin **Visceral pain** Anticholinergics **Limited Sedation** Caffeine

Answer 338

**Acid/Base** = Acidosis & Rhabdomyolysis **Drugs**: Beta Blockers NSAIDs Spironolactone ACE Inhibitors Heparin **Symptoms** Weakness, Palpitations, Bradycardia, N/V and Paralysis

Answer 339

**Calcium chloride and calcium gluconate** Stabilize cardiac myocyte membranes Onset is *_immediate_* No effect on serum potassium levels **Albuterol** Onset of action of *_10-30 minutes_* Standard inhaled dosing may lower serum potassium by *_1-1.5 mEq/L._* **Regular insulin** Onset of action is *_15-20 minutes_* and peak effect may occur after an hour. A dose of 10 units lowers serum potassium by approximately *_1 mEq/L._* **Sodium bicarbonate** Useful in the setting of metabolic acidosis. Its onset, when given intravenously, is 15 minutes *_Infusion of 2-4 mEq/min*_ lowers serum potassium by _*0.5-0.75 mEq/L._* **Sodium polystyrene (Kayexalate)** can be given orally or rectally Onset of action of 1-2 hours A dose of 25-50 mg lowers serum potassium by 0.5-1 mEq/L.

Answer 340

**Nerve injuries such as:** 1. *_Stroke / Spinal Corrd Injuries_* 2. *_Burns_* (24 hours until 1-2 years after) 3. *_Prolonged immobility (\>6.5 after 16 days in the ICU is greatest risk)_* 4. *_Myopathies (Duchenne and Beckers Muscular Dystrophy)_* **Denervation disorders** 5. *_Multiple sclerosis_* 6. *_Guillain-Barré_* * 7. _ALS (Amyotrophic Lateral Scloerosis)_* **Succinylcholine should be avoided in these patients due to exaggerated increase in potassium after giving succinylcholine**

Answer 341

**Treatment**: 1. **Larson Maneuver** - Medial and cephalad pressure at laryngospasm notch Located behind the earlobe, bordered by the base of the skull superiorly Matold Process Posteriorly Ramus of the mandible anteriorly 2. **PPV** 3. **Propofol Small Doses** - Increasing dose of anesthesia 4. **Succinylcholine** (0.1 - 0.5 mg/kg)

Answer 342

**Percentage of oxygen bound to hemoglobin in the blood returning to the right side of the heart** Measuring/Drawn from Pulmonary Artery catheter (venous blood from SVC, IVC & Coronary Sinus ***_Normal = 65 - 75%_*** (Oxygen “left over” after the body has extracted what it needs) Which denotes tissue oxygen extraction to be 25-35%. Normal PvO2 is 35-45mmHg. Measurement of global oxygen delivery

Answer 343

The Fick equation reveals: SvO2 = SaO2 – [VO2 ÷ (CO x Hgb x 1.36)] ``` SvO2 = mixed venous oxygen saturation SaO2 = arterial oxygen saturation VO2 = total body oxygen consumption (hyperthermia/hypothermia, shivering, pain, cyanide, sepsis, CO poisoning, Methemoglobinemia) CO = cardiac output (HR & SV & volume dependence) Hgb = hemoglobin concentration ```

Answer 344

**5-7 days** 1. Bowel Obstruction 2. Short Bowel Syndrome 3. Active GI Bleeding **Central Access** Infection and Thrombophlebitis are important to avoid with central access PIV - Cannot tolerated \> 750 mOsm/Liter (12.5% dextrose)

Answer 345

Hetastarch is a colloid that, when administered in large doses, is associated with coagulopathy. Hetastarch **reduces factor 8 levels, which prolongs PTT.**

Answer 346

*_Onset_*: **1. pKa** - Low pKa = High unionized fraction = Fast onset (able to cross quick) - High pKa = Low unionized fraction - Slower onset **2. Lipid Solubility** Duration related to Lipid Solubility - High solubility = Shorter Duration - Lower solubility = Longer Duration of Action - Low Solubility = Longer Duration

Answer 347

Remembering "4" will get you in the appropriate range for differences between alfentanil and fentanyl. Alfentanil has about 4 times faster onset. Alfentanil lasts about 1/4 the duration. Alfentanil is about 1/4 the potency (4x the dose of fentanyl).

Answer 348

Different: 1. **MH** - Euthyroid, *_Hyperkalemia_*, Myoglobinemia, Myoglobinuria, Lactic Acidosis, Elevated CK 2. **TS** - Hyperthyroid (Elevated T4 and Low TSH) *_Hypokalemia_*,

Answer 349

This effect is transient and hemodynamics usually **return to baseline within 10-30 minutes**. The increase in venous return causes an increase in **mean arterial pressure, pulmonary artery pressure, and left-ventricular end-diastolic pressure.** In patients with normal systolic function, the increase in venous return will lead to an increase in stroke volume, and hence an increase in cardiac index/output.

Answer 350

**A = Complete.** Complete cord injury with complete motor and sensory deficits in S4 and S5 nerve roots **B = Sensory Incomplete.** Incomplete cord injury with sensation preserved below the level of injury; intact S4 and S5 nerve roots (Motor) **C = Motor Incomplete.** Incomplete cord injury with motor function preserved below the level of injury; *_\< 3 out of 5_* motor strength in half of the major muscle groups **D = Motor Incomplete.** Incomplete cord injury with motor function preserved below the level of injury; *_≥3 out of 5_* motor strength in half of the major muscle groups **E = Normal.**

Answer 351

Physiology: Decreased temperature therefore PaCO2 decreases (Partial pressure ~ Temperature) CO2 tension 40 mmHg and a pH of 7.4 at 37 degrees (Normal values) CO2 tension 23 mmHg and a pH of 7.6 at 25 degrees Because partial pressure is proportional to temperature, blood cooled to room temperature will have a **lower PaO2, lower PaCO2, and higher pH compared to body temperature.**

Answer 352

***_Tetanus_*** Inhibit Inhibitory Neurons Retrograde Neuronal Transport of Toxin ***_Botulism_*** Prevent Vesicular Release of Acetylcholine

Answer 353

Hepatitis B (e antigen positive) seroconversion ~ 37-62%, significantly more than others Hepatitis B (e antigen negative) seroconversion is estimated at 23-37%. Hepatitis C seroconversion is estimated at 0.3-0.74%. HIV seroconversion is estimated at 0.3% HIV mucosal membrane is estimated at 0.09%

Answer 354

When **demyelination** occurs muscle fibers *_receive less neural input_* and therefore **muscle begins to synthesize immature acetylcholine receptors (AChR) as a compensatory mechanism.** Immature AChR have an *_epsilon subunit_* as opposed to a gamma subunit (See Photo) These receptors remain open longer and allow a larger efflux of potassium from the muscle cells. This increases serum potassium to a greater degree than normal AChRs.

Answer 355

- **Anemia** (No EPO) - **Hypocalcemia** * -Kidney cannot reabsorb calcium due to this not working25-Hydroxycholecalciferol to 1,25)* - Hyperkalemia - Hypermagnesemia - Hyperphosphatemia - Secondary hyperparathyroidism - **Hyperlipidemia - Hypertension** - Uremic bleeding diathesis

Answer 356

**Hypotension (intentionally)** Reduce shear forces on stent graft SBP goal of 70-80 mmHg **Transient Asystole** Adenosine (10 second half life due to vascular endothelial cells inactivating it) **Rapid Ventricular Pacing (Transvenous wiring)** \>180 bpm = Cease ventricular function After heart opened, returns to its regular baseline rhythm

Answer 357

**Renal Allograft Survival Rate** **Definition of TRIM**: Homologous (allogeneic) blood transfusion exerts a nonspecific immune effect on the recipient, termed transfusion-related immunomodulation (TRIM). When we transfuse a patient, causes *_proinflammatory*_ and _*immunosuppressive_* effects

Answer 358

**20 minutes**

Answer 359

Angiotensin-II-mediated vasoconstriction is produced within 20 minutes after the onset of acute hypotension or hypovolemia. The release of A2 is modulated by the RAAS. **Blockade of the RAAS by ACEIs and ARBs may cause profound and refractory perioperative hypotension**, particularly after induction of general anesthesia.

Answer 360

Classic post-synaptic muscle-type nicotinic acetylcholine receptor (nAChR) present in the neuromuscular junction is composed of **five subunits, two α1, one β1, one δ, and one ε (mature type).** On the other hand, the **neuronal-type pre-junctional nAchR is composed solely of α- and β-subunits.**

Answer 361

***_Train-of-four fade and tetanic fade are due to blockade of α3β2 prejunctional receptors._*** The specific nAChR involved in this **positive feedback is the α3β2-subtype, which is blocked by usual doses of non-depolarizing neuromuscular blockers** but not by succinylcholine (unless very high concentrations of succinylcholine are used). When these receptors are blocked, the positive feedback is lost and repetitive or continuous stimulation causes a progressive decline in acetylcholine release and muscle response. This is clinically seen as fade with tetanic and *_train-of-four stimuli, which is typical of non-depolarizing drugs but only seen after very high doses of succinylcholine._*

Answer 362

Upper Extremity: **Radial** \> Ulnar/Median *_(More susceptible than lower extremity)_* Lower Extremity: **Sciatic** \> Other lower extremity nerves

Answer 363

**Non-respiratory events.** The top three factors leading to death and permanent brain damage are: 1) ***_Cardiovascular events_*** (pulmonary embolism, stroke, myocardial infarction, arrhythmia, undiagnosed conditions) 2) Respiratory events (inadequate ventilation, esophageal intubation, difficult airway) 3) Equipment issues (failure or misuse)

Answer 364

***_MAC_* and Blood:Gas Partition Coefficient** **Isofluane**: ***_1.2_*** and 1.5 **Sevoflurane**: ***_1.8_*** and 0.65 **Desflurane**: ***_6.6_*** and 0.42

Answer 365

**Blood solubilities** = **Blood:gas partition coefficient** **Partition coefficient** describes how the anesthetic is split between the two phases (blood and gas). - **Lowest** = Des; Highest = Iso **FA** (alveolar concentration of an anesthetic) divided by the **FI** (inspired concentration) yields a value that can be used to assess the relationship of delivered anesthetic by ventilation and the degree of anesthetic uptake/removal. - **Lower Blood:Gas Partition Coefficient = Lower solubility** = **HIgh Fa/Fi = Faster uptake** And Vice Versa

Answer 366

**Cut dose to 3 mg recommended**

Answer 367

For regular narrow complex tachycardia, a starting dose of **50-100 J is appropriate.** For irregular narrow complex tachycardia, **120-200 J of biphasic or 200 J of monophasic is used.** **Unsynchronized cardioversion** is the best treatment for irregular wide complex tachycardia (like ventricular fibrillation).

Answer 368

The **carotid sinus** is a pressure regulating system. In high-pressure settings, the afferent impulse is transmitted by the **glossopharyngeal nerve** to the **nucleus tractus solitarius**, which results in: 1. inhibition of the sympathetic system 2. Activation of the parasympathetic systems to *_- Reduce blood pressure_* *_- Decrease heart rate_*

Answer 369

**Chloroprocaine**: 30-60 minutes Chloroprocaine (plain only): 12 mg/kg **Lidocaine**: 60-90 minutes Lidocaine without Epi - 5 mg/kg Lidocaine with Epi - 7 mg/kg **Ropivacaine**: 90-120 minutes Ropivacaine (plain only): 3 mg/kg **Bupivacaine**: \>120 minutes Bupivacaine without epinephrine - 2.5 mg/kg Bupivacaine with epinephrine - 3.0 mg/kg

Answer 370

***_Poor Ventilation = Poor Hombre 55/30_*** Poor OMBRE - 55 / 30 Protrusion of Mandible "hOMBRE" = Male OSA Mallamapti III or IV Beard Radiation Edentulousness **Difficult laryngoscopy** Poor HOMBR 46 / 30 **TTT** Neck Age \>46 *_Limited **T**M distance_* *_**T**eeth Presence_* *_**T**hick / Stiff Neck_*

Answer 371

**Chloroprocaine**: 30-60 minutes (Window of max dose) **Chloroprocaine** (plain only): 12 mg/kg *_Onset_*: **6 - 12 minutes** *_Duration_*: **45-60 minutes** (may be shorter when high volumes are used) **60-90 minutes** when mixed with epinephrine (1:200,000 used) **Elimination**: Plasma esterases (Half life of 21 seconds) Will be decreased in pseudocholinesterase deficiency

Answer 372

**Endocarditis Guidelines** **Antibiotic prophylaxis for dental procedures** 1. Prosthetic Cardiac Valve or Prosthetic material 2 .Previous Infective Endocarditis 3. Congenital Heart Disease Unrepaired cyanotic congenital heart disease (shunts/conduits) Completely repaired congenital heart disease with prosthetic material or device during 1st 6 months after the procedure Repaired congenital heart disease with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device (which inhibit endothelialization) 4. Cardiac Transplant with cardiac valvular disease **Antibiotic for dental procedures:** 1. Manipulation of gingival tissue or the periapical region of teeth, or perforation of oral mucosa 2. Tonsillectomy 3. Adenoidectomy

Answer 373

**Mechanism:** ***1. Promoting reabsorption of water in the kidney tubules through increasing the cell membrane permeability.*** Several target sites, many of which act by constricting vascular smooth muscle. This is most prominent in splanchnic, renal, and coronary vascular beds. Arginine vasopressin affects both V1 and V2 receptors. V1 receptor activation increases systemic vascular resistance without affecting pulmonary vascular resistance. (Great for pulmonary hypertension patients) V2 receptor activation increases blood volume. Vasodilation can be seen in pulmonary and cerebral vascular beds. Several target sites, many of which act by constricting vascular smooth muscle. This is most prominent in splanchnic, renal, and coronary vascular beds. ***2. Vasopressin increases circulating von Willebrand factor and factor VIII thus is a treatment for some types of von Willebrand disease.*** ***3. Vasopressin can also be used in the management of esophageal varices due to its vasoconstricting properties.*** **Side Effects:** Administration of vasopressin can cause myocardial ischemia due to vasoconstriction of stenotic areas

Answer 374

**Avoid DEHYRATION!!** ## Footnote Maintain Cerebral Perfusion Minimize ICP **Minimize Dehydration - So, we keep them Euvolemic or Hypervolemic** No colloids in Subarachnoid Hemorrhage No hetastarch (cerebral release of thromboplastin increases the risk of severe coagulopathies, making it a poor choice in this population)

Answer 375

Typical IV Bolus Dose - **150 - 300 mcg** Onset - **Rapid (most of all opiates)** Peak Effect - **1-2 minutes** Duration Effect - **\<10 minutes**

Answer 376

Typical IV Bolus Dose - **5 - 15 mcg** Onset **Immediate** Peak Effect **5 - 10 minutes** Duration Effect **\<30 minutes**

Answer 377

Typical IV Bolus Dose **1-5mg** Onset **15 minutes** Peak Effect **90 minutes** Duration Effect **240 minutes**

Answer 378

Typical IV Bolus Dose **0.2-0.4 mg** Onset **5-10 minutes** Peak Effect **15 minutes** Duration Effect **120 minutes**

Answer 379

Although the plasma half-life of morphine is ***_2 hours_***, its analgesic action may be about ***_4-5 hours_*** because of morphine's pharmacokinetic properties. Because morphine is less lipophilic than other opioids, morphine penetrates slower and achieves lower concentrations in the CNS, and is cleared from the CNS less rapidly.

Answer 380

CVP: 2-6 mmHg PCWP: 6-12 mmHg CI: 2.5-4 L/min/m2 SVR: 800-1200 dynes\*sec/cm5

Answer 381

It is recommended that great caution be used when injecting additional local anesthetics within **12 to 18 hours** of a tumescent anesthesia. **Plasma concentrations may peak more than 8 to 12 hours after infusion** of tumescent anesthesia.

Answer 382

The K+ **STA**ys with **Spironolactone, Triamterene, Amiloride**.

Answer 383

Both **Hypokalemia** Loop diuretics are associated with *_hypokalemia_* and are used in the treatment of hyperkalemia. Thiazide diuretics are associated with *_hypokalemia_*, hyponatremia, **hypercalcemia, hyperuricemia, hyperglycemia, and hyperlipidemia (GLUC)**

Answer 384

**Muscle weakness** - shoulders, hips and thighs Labs - **CK normal** Biopsy - **Atrophy without inflammation**

Answer 385

KDIGO1 guidelines define AKI as: **1. An increase in serum creatinine by 0.3 mg/dL over 48 hours** **2. An increase in serum creatinine to ≥1.5x baseline within 7 day** AND/OR **3. urine volume of \< 0.5 ml/kg/hr for ≥6 hours.**

Answer 386

The **musculocutaneous nerve** runs in the body of the coracobrachialis muscle and provides sensation to the lateral forearm as well as motor to the flexor muscles of the elbow (biceps brachii, brachialis, and coracobrachialis). The **ulnar nerve** runs in the ulnar groove and provides sensation to the 5th finger and motor to the intrinsic muscles of the hand. **The radial nerve** runs lateral to the biceps tendon in the antecubital fossa and provides sensation to the dorsum of the forearm and hand as well as motor function to the muscles of the dorsal forearm. **The median nerve** supplies sensation to the lateral palm of the hand and motor to the wrist flexor muscles. It can be located and blocked in the antecubital fossa medial to the brachial artery.

Answer 387

Subnormal production of corticosteroids in the absences of structural defects in the hypothalamic-pituitary-adrenal axis is termed *_functional adrenal insufficiency_* and it is the **most common cause found in patients with critical illness in the intensive care unit.**

Answer 388

**Primary adrenal insufficiency** occurs when the *_adrenal gland stops producing enough hormones to maintain appropriate bodily functions_*. The most commonly seen cause of primary adrenal insufficiency is autoimmune destruction of the gland, although it can also occur secondary to cancer or infection. This is not the most common cause of insufficiency in critically ill patients. **Secondary adrenal insufficiency** occurs when the p*_ituitary does not secrete enough adrenocorticotropic hormone or the hypothalamus does not secrete corticotropin-releasing hormone_*. This can occur secondary to many conditions. Examples of pituitary disease include tumors, cysts, infarction, and infiltrative lesions secondary to pituitary radiation or surgery. Examples of hypothalamic disease include mass lesions, radiation, trauma, infections, and infiltrative lesions. Secondary adrenal insufficiency is not the most common cause in critically ill patients. **Tertiary adrenal insufficiency** occurs *_following abrupt cessation of high-dose glucocorticoid therapy._* This is not the most common cause in critically ill patients.

Answer 389

**Bupivacaine** cardiac toxicity is due to bupivacaine’s stronger affinity for both resting and inactivated sodium channels within the myocardium compared with other local anesthetics *_All local anesthetics slow cardiac conduction to some degree._* *_They may produce both direct and indirect cardiotoxicity through blockage of the INTRACELLULAR portion of cardiac SODIUM ion channels._* *_This results in impairment of cardiac automaticity and conductance of cardiac action potentials._* Bupivacaine has been shown to dissociate from sodium channels during diastole at a rate much slower than lidocaine. `This slower dissociation impairs complete recovery of sodium channels following hyperpolarization.

Answer 390

**Increase Fresh Gas Flow Rate**

Answer 391

**Treatment of hypermagnesemia includes** 1) *_stopping_* the source of magnesium 2) antagonizing the effects of magnesium *_with calcium,_* and if moderate or severe 3) *_increasing elimination_* of magnesium with **loop diuretics** or possibly **hemodialysis (**A**E**IOU**)** **-** Loop diuretics coupled with D5W or 0.45% saline infusions greatly enhance renal magnesium excretion.

Answer 392

**Normal** serum magnesium concentration is 1.5-2.5 mg/dL **Hypermagnesemia** is \> 2.5 mg/dL **Therapeutic range** for preeclampsia treatment is 5-9 mg/dL. **Decrased cardiac output, prolongs the PR interval, and widens the QRS complex.** These effects can be seen with magnesium levels \> 5-10 mg/dL. Hypermagnesemia can cause **bradycardia** and **hypotension** at serum levels \> 7 mg/dL. **Deep tendon reflexes** are reduced at magnesium levels \> 5 mg/dL and are lost at \> 12 mg/dL. **Skeletal muscle weakness** begins to occur at magnesium levels \> 7-10 mg/dL. **Respiratory arrest** (due to peripheral and central effects) with serum magnesium levels \> 15-20 mg/dL. **Arrhythmias** occur at higher magnesium levels and asystole can occur at \> 25 mg/dL.

Answer 393

***_Autosomal Dominant with Variable Penetrance_*** **Point Mutations:** **1. RYR1 gene** coding for the ryanodine receptor Ryanodine receptor (RYR1) Ryanodine mutations have been found in 50% to 80% of patients and relatives who have positive contracture tests. **2. CACNA1A** gene mutation coding for the voltage-gated calcium channel. Voltage-gated calcium channel (CACNL1A3). **Diagnosis Testing** **Halothane-Caffeine Contracture Test - Gold Standard and highly sensitive (97%)** The fresh muscle is exposed to halothane and caffeine and the extent of the contraction is then measured. This is a reliable test and is the **“gold standard”** for diagnosis. The problem is that very few centers around the world actually perform this test, it is invasive Sensitivity and **specificity** are 97% and **78% thus some false-positive results may occur (20% False-Positive Rate)** Genetic Testing of Ryanodine receptor gene mutations - Less sensitive

Answer 394

Most experts agree that a HbA1c as **close to normal (6% to 8%)** is recommended before elective surgery can proceed. **Normal** levels are between **4% and 6%.** A HbA1c of: - *_6%*_ correlates with an average blood glucose of _*125 mg/dL_* - *_8%*_ correlates with _*180 mg/dL_*

Answer 395

**Inhalation inductions are slowed during L\>R and R\>L shunts** A right to left shunt slows the induction of anesthesia because the shunted blood containing no anesthetic mixes with the blood coming from the alveoli containing anesthetic Induction by an agent with a low blood gas partition coefficient (Des/Sevo) is slowed more by a right to left shunt as compared to the effect on induction by a volatile anesthetic with a higher coefficient (Iso) **IV inductions are accelerated by Left to Right Shunts only**

Answer 396

Norepinephrine is **more selective for β1 receptors than β2** and accordingly, does not cause significant bronchial smooth muscle relaxation.

Answer 397

**Child-Pugh** Bilirubin (Total), Albumin, INR, Ascites, Encephalopathy Child-Pugh: "Pour Another Beer At Eleven" - PT, Ascites, Bilirubin, Albumin, Encephalopathy **MELD Score** Dialysis at least twice in the past week, Creatinine, Bilirubin, INR, Sodium MELD: "I Crush Beer Daily" - INR, Creatinine, Bilirubin, Dialysis

Answer 398

High cardiac output will cause a small, narrow peak Low cardiac output will cause a tall, wide peak.

Answer 399

**20-30%** (Improve myocardial oxygen supply/demand ratio) **Mechanics**: balloon inflates during diastole, it increases **coronary perfusion pressure (increases supply)** and because it deflates suddenly right at the time the ventricle is about to eject blood, it **decreases afterload** *_(decreased wall tension -\> decreased oxygen demand)._*

Answer 400

1) The maximum diastolic pressure (and the diastolic area under the pressure-time curve) becomes greatly augmented due to the inflation of the balloon 2) Because of abrupt balloon deflation, the minimum diastolic pressure falls to lower levels that it would have on a non-assisted beat, this end-diastolic aortic pressure is the impedance the ventricle must overcome to eject blood (i.e. afterload). 3) Consequently, the ventricle can eject all of the stroke volume without developing high pressures, resulting in a lower systolic pressure in the beat following the IABP-assisted beat.

Answer 401

Calcium channel blockers inhibit the transmembrane influx of calcium into cardiac and vascular smooth muscle cells. **This results in:** 1. Decreased heart rate 2. Decreased cardiac contractility 3. Decreased conduction velocity 4. Dilation of coronary, cerebral and systemic arterioles

Answer 402

While labetalol is classified as a beta blocker, its receptor interactions are somewhat nuanced. It acts as a **β1 antagonist**, **partial β2 agonist**, and an **α1-receptor antagonist**. Ultimately, this results in a reduction in blood pressure without reflex tachycardia. Thus, labetalol is used to *_manage hypertension*_ and _*hypertensive emergencies_* **It does not affect uterine blood flow**, making it an excellent choice for the management of hypertension in parturients.

Answer 403

**Clopidogrel - 7 days** **Aspirin/Dipyridamole - 7 days** **Prasugrel - 7 Days** **Ticagrelor - 7 days** _Abciximab - 48 hours_ * Eptifibatide - 8 hours* * Tirofiban - 8 hours*

Answer 404

**1. Preoperative anemia** **2. Cardiac disease** **3. Recent cerebral vascular accident** **4. Clinically significant renal or liver disease** **5. Active infection**

Answer 405

**1. Increase fresh gas flow** **2. Decreasing Barometric Pressure** *Output Forrmula* _(carrier gas flow \* saturated vapor pressure)_ (barometric pressure - saturated vapor pressure) Of note, the partial pressure will remain the same according to the Dalton Law.

Answer 406

Concept: Different volatile anesthetics have different vapor pressures and therefore have different splitting ratios for gas flow. **If you replace a VA with one that has higher VP, then you would get higher output** EX: Sevoflurane Vaporizer (160mmHg) If you put Isoflurane (240 mmHg) in here, you would get higher output **If you replace a VA with one that has lower VP, then you get lower output** Example: Isoflurane (240) Vaporizer Filled with Sevo (160)→ Decrease vaporizer output When a vaporizer calibrated for a higher vapor pressure is filled with a volatile agent of a lower vapor pressure less output or a lower concentration is delivered.

Answer 407

**Obstructive Lung Disease** The flow-volume loop in a patient with chronic obstructive pulmonary disease (COPD) is characterized by: **1. An expiratory phase with a quick peak followed by a much lower than normal plateau phase.** This is representative of the dynamic, intrapulmonary airway obstruction that occurs with COPD during exhalation. *_The inspiratory phase is usually normal._*

Answer 408

**Unilateral Bronchial Mainstem Obstruction**

Answer 409

**Fixed Upper Airway Obstruction** A fixed upper airway obstruction or fixed large airway obstruction **e.g., foreign body, tracheal stenosis, large airway tumor** impairs BOTH inspiration and expiration leading to a flow-volume loop with plateaued and decreased inspiratory and expiratory flows.

Answer 410

**Variable extrathoracic Fixed Airway Obstruction** A variable EXTRAthoracic airway obstruction (e.g., vocal cord paralysis or dysfunction, proximal tracheal tumor, glottic strictures) produces a flow-volume loop with: **1. plateaued INSPIRATORY curve** **2. The flow rate is usually decreased.** During inspiration, the negative inspiratory pressure causes the obstruction to increase. The expiratory curve is usually normal since the positive airway pressure generated during expiration helps keep the airway open.

Answer 411

**Variable Intrathoracic Upper Airway Obstruction** A variable INTRAthoracic airway obstruction *(e.g., distal tracheal tumor or mediastinal mass)* produces a flow-volume loop with a: 1. Plateaued EXPIRATORY curve and the flow rate is usually decreased 2. During expiration, intrathoracic pressure becomes positive which further decreases the airway diameter, enhances the degree of obstruction, and impairs airflow. The inspiratory curve is usually normal since the negative intrathoracic pressure generated during inspiration helps keep the airway open.

Answer 412

Restrictive Lung Disease

Answer 413

**Residual Muscle Weakness (Neuromuscular Blockade)**

Answer 414

The onset of effect of a local anesthetic is affected by its: **Concentration (higher is faster)** greater the concentration, the faster the speed of onset since there is a steeper concentration gradient to drive local anesthetics intracellularly. **Lipid solubility (higher is faster)** - The more lipid soluble = Faster it can cross membrane **pKa (lower is faster)** - Lower pKA = More unionized so it can cross membrane faster (faster onset) **Bolded = Affect onset the most** **Environment pH (higher is faster)** Local infection = Acidic environment theefore drives LA to ionized form therefore decrease the onset **Epinephrine** - Local vasoconstriction which prolongs the effect of local anesthetic **Addition of Bicarbonate** - The addition of bicarbonate to a local anesthetic mixture **speeds the onset** of action by raising the pH of the anesthetic solution so that more of the unionized fraction is available. **Anything that increases the concentration or proportion of local anesthetic in its unionized form will speed the onset of analgesia.**

Answer 415

Pregnancy Morbid obesity Diabetes (chronic) **Hiatal hernia (symptomatic)** **Gastroesophageal reflux disease (symptomatic)** Ileus or other bowel obstruction Emergency care including trauma patients Enteral tube feeding (intubated)

Answer 416

LMWH for prophylaxis be administered **at least 12 hours** or more preoperatively, or **12 hours or more postoperatively**

Answer 417

**25-30 seconds**

Answer 418

**Clopidogrel** - 5-7days **Ticlopidine** - 10 days **Fondaparinux** - No recommendations **Warfarin** - 5 days and a normal INR

Answer 419

**Enhance the affinity of GABA binding to GABA_A receptors** Protein Binding **(75%)** Metabolism: **Liver ester hydrolysis to inactive metabolites** Excretion: **Excreted by the kidneys**

Answer 420

**Increased Preload** Sodium bicarbonate is hypertonic (~1,800 mOsm/L). In addition to the volume of solution itself, the osmotic effect rapidly expands intravascular volume, leading to increased preload

Answer 421

**Decreased LV Contractility** Serum ionized calcium concentration is transiently decreased by sodium bicarbonate administration. Left ventricular contractility is subsequently depressed since it varies directly with serum ionized calcium concentration.

Answer 422

Acute correction of an acidotic pH is associated with an increased hemoglobin affinity for oxygen, an effect that can last up to 8 hours. **This is primarily attributed to the Bohr effect (increased H+ or CO2 concentration reduces the oxygen affinity of hemoglobin)**, or rather, the inverse of it. In patients with already compromised circulation or oxygen delivery, this further impairment in oxygen delivery *_can worsen cellular hypoxia, leading to increased lactate production._*

Answer 423

**2nd generation PDE III inhibitor (Acts on cAMP specifically)** 1. Positive Inotropic agent 2. Arterial Dilator - Leads to RV afterload reduction - Leads to LV afterload reduction - Venodilator - Decreases preload

Answer 424

Plasma and red blood cell **esterases** = _clevidipine, esmolol, remifentanil_ **Pseudocholinesterase** = _succinylcholine, mivacurium, ester local anesthetics_

Answer 425

1. LMWH is ***_more selective for factor Xa_*** inhibition than UFH, with less effect on thrombin inhibition (Thrombin has other roles like immune/inflammatory other than coagulation system) * 2. LMWH less associated with HIT* Similarities: LMWH, such as enoxaparin and dalteparin, work similarly to UFH by binding the serine protease inhibitor ATIII. Binding of ATIII by UFH or LMWH induces a conformational change that increases ATIII’s activity by 1000-fold to inhibit activated factor X and thrombin. Inhibition of thrombin requires simultaneous binding of heparin to both ATIII and thrombin, but inhibition of factor Xa only requires heparin binding to ATIII. A longer polysaccharide chain (higher molecular weight) is required for the increased binding sites leading to thrombin inhibition. The shorter polysaccharide chains (lower molecular weight) of LMWH is more restricted in binding solely to ATIII, **therefore more selectively inhibits Xa.**

Answer 426

Isoflurane **high blood:gas solubility (KB:G)**, such as isoflurane and halothane, are most affected by minute ventilation. he FA/FI rises more rapidly if minute ventilation is increased. This effect is more pronounced in the agents with high solubility including halothane and isoflurane. The rate of inhaled anesthetic induction (FA/FI) is increased with increased minute ventilation. This effect is greatest with the agents with high solubility, including halothane and isoflurane.

Answer 427

Femoral nerve courses **beneath** the inguinal ligament where it **sits atop the iliopsoas muscle**. The femoral nerve lies just **lateral to the femoral artery (NAVEL)** The nerve travels beneath the **fascia lata and the fascia iliaca**. The femoral nerve supplies sensory innervation to the anterior portion of the thigh, and then branches into the saphenous nerve.

Answer 428

Sartorius contraction → Advance needle **deep and lateral** When the sartorius muscle twitches during a femoral nerve block, it is a result of **anterior nerve fibers supplying the sartorius muscle being stimulated.** The needle should be advanced and directed laterally in order to perform a successful block. A successful block occurs when the quadriceps is activated by the femoral nerve, because the needle and femoral nerve will be in the same tissue plane. **With sartorius twitch it is not known if the needle is in the same plane as the femoral nerve.**

Answer 429

Reduced cardiac output promotes a faster rate of inhalation induction. This phenomenon is especially true with **volatile agents readily soluble in blood (Isoflurane)**

Answer 430

A right-to-left intracardiac shunt ***_slows_*** the rate of **inhalational induction** of anesthesia since the shunted blood is not involved in gas exchange within the alveoli. A right-to-left shunt ***_speeds_*** the rate of **intravenous induction** because a portion of the drug bypasses the lungs, directly enters the left side of the heart and is quickly delivered to brain tissue.

Answer 431

The diagnosis of FES using the Gurd criteria requires at least: 1. **One major criterion** *_Respiratory insufficiency and/or Hypoxemia_* *_Petechial rash_* *_CNS involvement_* **2. At least four minor criteria** *_tachycardia_* *_fever_* *_unexplained drop in hematocrit or platelets_* *_elevated erythrocyte sedimentation rate_* *_retinal fat emboli_* *_fat in urine_* *_fat in sputum_* *_\presence of fat macroglobulinemia_*

Answer 432

Transverse process: nose Pedicle: eye Pars interarticularis: neck Superior articular facet: ear Inferior articular facet: front leg

Answer 433

The **vertebral arteries** most commonly originate from the subclavian arteries and are divided into four segments depending on their anatomic location. They traverse the neck anterior to the scalene muscle and enter the vertebral foramina of the sixth cervical vertebra. It can be a site for **inadvertent arterial injection** when performing an interscalene nerve block.

Answer 434

**Most common ocular complications following nonocular surgery is corneal abrasion.** Etiology *_1. Iatrogenic (e.g. direct injury by anesthetic mask, dangling name badge, etc.)_* *_2. Patient rubbing his/her eyes postoperatively while emerging from anesthesia_* S/S: Painful foreign body sensation, tearing, photophobia, and/or blurred vision **Prognosis: Most self-resolve within 24 hours.**

Answer 435

**Causes of Nicotinic AChR Upregulation: (avoid succinylcholine)** - Nerve Injuries o Stroke o Spinal cord injury o Intracranial lesions leading to upper motor neuron injury - Burns (24 hours up to 1-2 years after burn injury) - Prolonged immobility (greater than 24 hours) - Prolonged exposure to neuromuscular blockers - Myopathies o Duchenne muscular dystrophy - Denervating Disorders o Multiple sclerosis o Guillain-Barré syndrome o Amyotrophic lateral sclerosis

Answer 436

Synthesized from the **Weibel-Palade bodies** (*_storage granules of endothelial cells, the cells that form the inner lining of the blood vessels and heart_*) and **subendothelium**

Answer 437

Cryoprecipitate Contains **factor 8** and **fibrinogen**

Answer 438

**Both platelet number and function as well as fibrin cross-linking.**

Answer 439

The **critical temperature of nitrous oxide is 36.4 °C and that of carbon dioxide is 31.1 °C** *_both of which are higher than room temperature_* (generally 20-23 °C) the gas can potentially exist in both gaseous and liquid forms at room temperature when compressed in a medical gas cylinder. If the critical temperature of a gas is below room temperature (e.g. oxygen: -118 °C), the gas will never liquify at room temperature.

Answer 440

**Nicardipine**

Answer 441

Propofol causes a dose-dependent *_decrease in amplitude of SSEP_*s. Propofol *_increases SSEP latency._* *_Affects SSEP greatly_*

Answer 442

**clonus** **hyperreflexia** **tachycardia** **hyperpyrexia** **diaphoresis** **ataxia** **confusion** *_Hunter Toxicity Criteria Decision Rules._* - Spontaneous clonus - Inducible clonus plus agitation or diaphoresis - Ocular clonus plus agitation or diaphoresis - Tremor plus hyperreflexia - Hypertonia plus temperature \> 38 °C plus ocular clonus or inducible clonus

Answer 443

Note that **diaphoresis is more common with serotonin syndrome**. In contrast, xeroderma (dry skin) is more common with central anticholinergic syndrome (CAS).

Answer 444

**Muscle Rigidity** **Altered Mental Status**

Answer 445

Febrile reactions after transfusions are caused by **pyrogenic cytokines and intracellular contents released by donor leukocytes.**

Answer 446

Hemolytic transfusion reactions occur when *_recipient antibodies and complement system attack the transfused donor cells and cause intravascular hemolysis._* A direct antiglobulin test (DAT), also known as a direct Coombs test, can differentiate a hemolytic from a febrile reaction.

Answer 447

Transfusion-related acute lung injury (TRALI) is an **immune-mediated reaction that involves antibodies directed toward human leukocyte antigens (HLA)**, with the release of cytokines and vasoactive mediators that cause non-cardiac pulmonary edema.

Answer 448

**Polyvinyl Chlorride (PVC)**

Answer 449

**External intercostal muscles** aid in quiet and forced **inhalation.** **Internal intercostal muscles** aid in forced **expiration** (quiet expiration is a passive.

Answer 450

***_Andexanet alfa_*** is a recombinant derivative of factor Xa, and acts as a "decoy receptor", effectively binding factor Xa inhibitors (such as rivaroxaban, apixaban, and edoxaban) with higher affinity than factor Xa itself.

Answer 451

***_Idarucizumab_*** is a monoclonal antibody fragment that binds to the active site of dabigatran, a direct thrombin inhibitor with oral bioavailability. It is used for the management of serious bleeding caused by dabigatran but does not appear to be effective against bleeding caused by other direct thrombin inhibitors (such as bivalirudin or argatroban).

Answer 452

Clonidine is an alpha-2 agonist but is **less selective (1:200)** than *_dexmedetomidine (1:1600)._*

Answer 453

CO2 freely diffuses across the blood-brain barrier (BBB) while H+ is excluded. Thus, changes in arterial CO2 concentration are directly reflected in CSF CO2 concentration, which results in rapid changes in CBF. **Within normal ranges of PaCO2, CBF will increase 1 to 2 mL/100 g/min for each 1 mmHg increase in PaCO2 (***_Avoid hypercarbia to avoid increases in CBF_***)** Therefore, hyperventilation is only potentially useful as an acute therapy for elevated ICP.

Answer 454

**Cross sectional orifice area**

Answer 455

**Brainstem auditory evoked potentials** are the most resistant neuromonitoring modality to the effects of volatile anesthetics. Hearing sounds, such as talking, music, or conversations, is one of the most commonly reported experiences for patients with intraoperative awareness.

Answer 456

**Visual Evoked Potentials**

Answer 457

T3 = **Most potent** on account of its higher free serum concentration whereas T4 is more protein-bound. T4 = **More abundant** T3 made by by partial deiodination of T4 (peripheral conversion of T4)

Answer 458

The process of peripheral T4-to-T3 conversion is targeted in treating hyperthyroidism with the **drug propylthiouracil (PTU)**. In addition to central thyroid inhibition by inhibiting thyroperoxidase, PTU decreases peripheral conversion by inhibiting 5'-deiodinase.

Answer 459

**Hydrocortisone** is the *_agent used most frequently because it has equal glucocorticoid and mineralocorticoid activity._* (Hydrocortisone is the agent of choice for treating adrenal suppression during stressful surgeries because it has a 1:1 glucocorticoid: mineralocorticoid effect. ) The **total daily stress dose of 200 mg is given divided into three or four doses.** **100 mg given every 12 hours is the most common dosing regimen.** With that being said, a 200 mg total dose reduces side effects compared to a 300 mg daily dose. Additional mineralocorticoid administration is not needed with hydrocortisone.

Answer 460

**8 mg of dexamethasone** is equivalent to **200 mg of hydrocortisone** and will suffice to prevent adrenal insufficiency with most commonly performed surgeries; it may cover some major surgeries also.

Answer 461

Mineralocorticoid prophylaxis is most appropriate for patients with **primary adrenal insufficiency (unrelated to chronic steroid use)** ## Footnote **- Ex: Addison's Disease**

Answer 462

***_Pressures between 15 - 35 psi_*** should be used, and adequate time should be allowed for passive expiration to reduce the risk of pneumothorax. Contraindications to transtracheal jet ventilation include: **trauma and distorted airway anatomy** while *_relative contraindications include COPD and coagulopathy_*

Answer 463

**1. MAP** is the cuff pressure at which the **amplitude or magnitude of the oscillations is the greatest.** *_2. Pulse pressure increases_ as the cuff is moved more _distally._* - Hence, the SBP increases and DBP decreases more distally. **3. The order of accuracy for the automated method is MAP \> SBP \> DBP.**

Answer 464

~ **107 seconds**

Answer 465

**As a rule, 1 mg of protamine inhibits 1 mg of heparin (about 100 units).** Ex: 25,000 Units of heparin should have 250 mg Protamine?

Answer 466

Static electricity is a potential ignition source that can be significantly mitigated in the modern operating room in part by maintaining an ideal relative humidity of 50-55%. This is because static buildup on the body is less likely in these conditions than at a lower relative humidity.

Answer 467

**Rigid laryngoscopy/bronchoscopy** is useful in cases of mechanical obstruction such as foreign body aspiration and airway tumors.

Answer 468

1. P1V1 = P2V2 **Boyle's Law** 2. V1/T1 = V2/T2 **Charles Law** 3. P1/T1 = P2/T2 **Gay-Lussac Law**

Answer 469

Invasive blood pressure monitoring with an arterial catheter employs a **electromechanical pressure transducer** which senses mechanical energy and converts it into electrical energy. **Summation of multiple sine waves via Fourier Analysis** Summation of several pressure waves results in the arterial waveform.

Answer 470

The corneal reflex involves the: 1. Ophthalmic branch of the trigeminal nerve **(afferent limb)** 2. The temporal and zygomatic branches of the facial nerve **(efferent limb)**

Answer 471

Sternomental Distance of **\<12.5 cm** Thyromental Distance **\<6.5 cm** Intercisor Distance **\<3 cm**

Answer 472

Spinal anesthesia in infants has many differences compared to adults, including: **Increased** speed of onset **Decreased** duration of action **Lack** of hemodynamic collapse **Increased** block spread owing to anatomic differences in the spinal cord.

Answer 473

PGE1 is a direct-acting **vasodilator** via prostanoid receptors on the vascular smooth muscle of the ductus arteriosus. A neonate presenting with cyanosis and clinical suspicion of congenital heart disease within the first two weeks of life is likely to have a “ductal dependent lesion”. In this scenario, an empiric PGE1 infusion is often started as it is assumed progressive closure of the ductus arteriosus in the first few weeks of life is the inciting factor. ***_Side Effect = Apnea_*** **Hypotension** is a side effect, especially in the setting of hypovolemia. **Fever, flushing, bradycardia, gastric outlet obstruction, and CNS irritability** are additional side effects.

Answer 474

PGE1 can **open** the ductus arteriosus. **Indomethacin** can **close** the ductus arteriosus (Indo = "Ends all")

Answer 475

One of the major pharmacologic effects of uremia is **decreased protein-binding of drugs**. Because it is the free-fraction of a medication that exerts its physiologic effect, decreased protein binding of midazolam would cause an exaggerated effect and the dosage should, therefore, be decreased. *_**Desmopressin** can improve perioperative platelet dysfunction in uremic patients._*

Answer 476

Overall: **Binding of Alpha 2-Gamma subunit binding (Calcium channels) decreases the amount of Glutamate release (excitatory)** 1. Decreased glutamate release **decreases** the production of the pain mediator **substance P** 2. Thereby **decreasing** neuronal transmission of **pain signals.** 3. **Decreased** activation of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (**AMPA**) receptors on noradrenergic synapses, which attenuates the sympathetic response to pain.

Answer 477

NMDA antagonism **reduces the release of glutamate.** **Magnesium** is another NMDA antagonist.

Answer 478

*_Medulla - Dorsal_* *_Medulla - Ventral_* cerebral medulla, including both **dorsal (inspiration)** and **ventral (expiration)** respiratory groups. TrueLearn Insight : Mnemonic: "DIVE" for **dorsal = inspiration, ventral = expiration.** *_Pons - Upper Pontine -_* pneumotaxic center, **decreases respiration through its effect on the dorsal medullary group.** *_Pons - Lower Pontine_* apneustic center, **increases respiration through its effect on the dorsal medullary group.**

Answer 479

**"Gentle ventilation" with permissive hypercapnia (PaCO2 of \<65 mmHg)** using a low tidal volume strategy **PIP \< 25 cm H20** FiO2 + PEEP adjustment to maintain **preductal SpO2 of 90-95%**

Answer 480

A delay will result in **decreased PaO2, pH, and base excess values** and an **increase in PaCO2** ## Footnote *_(A more hypoxic and acidotic picture)_*

Answer 481

Entrainment of room air will tend to cause the **PaO2 value of the sample to approach the PO2 of room air (159 mmHg at sea level)** and result in a *_decreased measured PaCO2._*

Answer 482

Both describe hemoglobin's ***_AFFINITY_*** but to different tings **Bohr - Describes Hgb affinity for *_Oxygen_* in presence of CO2 and Protons** B * *O**xygen * *H**ydrogen **R**elease at tissue **HalDane** - [Oxygen concentrations] determine Hgb affinity for CO2 **H**emoglobins **A**ffinity l**D**ane - Carbon **D**ioxide

Answer 483

Double Bohr effect describes a condition in the placenta where the maternal Bohr effect and the fetal Bohr effect occur in opposite binding conditions. From the *_maternal side_* the hemoglobin is in an **acidic** environment, which **promotes oxygen offloading.** The fetal hemoglobin on the *_placental side_* is in an **alkalotic** state, which **promotes oxygen uptake or binding**. The double Bohr effect accounts for somewhere between 2-8% of oxygen transfer across the placenta.

Answer 484

Premature infant 90-105 mL/kg Full-term newborn 80-90 mL/kg Infant 3-12 months 70-80 mL/kg Child 1-12 years 70-75 mL/kg Adult male 65-70 mL/kg Adult female 60-65 mL/kg

Answer 485

Pyloric stenosis commonly presents as a **hypochloremic, hypokalemic, metabolic alkalosis with compensatory respiratory acidosis.** Hypovolemia secondary to vomiting and decreased oral intake **(Contraction Alkalosis)** **Bicarbonate** produced in the pancreas is exchanged in the stomach by Cl-. **Chloride-rich gastric fluids (HCl)** are lost in pyloric stenosis, and serum bicarbonate levels are elevated due to increased gastrointestinal absorption. **Hypokalemia** occurs through gastric losses, secretion of aldosterone, and H+/K+ exchange within the kidneys. **Increased urine specific gravity** and decreased urine chloride.

Answer 486

**High Pressure** The high-pressure section includes auxiliary E cylinders, which are drawn from when there is pipeline failure. **Intermediate Pressure** Intermediate-pressure includes the hospital pipeline supply and portions of the anesthesia machine with pressures reduced by secondary pressure regulators in the 15-30 psig range. Pipeline - The pipeline pressure for oxygen, nitrous oxide, and air ranges between *_50-55 psig._* **Low Pressure** Flow control valves & includes the flowmeters, vaporizers, & fresh gas supply line.

Answer 487

Bethanechol, carbachol, and pilocarpine are examples of **direct muscarinic acetylcholine agonists**. These drugs are resistant to breakdown by acetylcholinesterase. *_Clinical applications include postoperative urinary retention and increasing peristalsis in the gut._*

Answer 488

**Beginning in the 20th to 24th weeks of gestation,** the gravid uterus will start to exert a mass effect on the aorta and inferior vena cava which is known as aortocaval compression.

Answer 489

A maximum inspiratory pressure of **\> -20 cmH2O (i.e. -20 to 0 cmH2O) is a fairly sensitive predictor of wean failure**, but a value of \< -20 cmH2O is not necessarily predictive of a successful wean.

Answer 490

**MIP Values of \> -20 cmH2O (-20 to 0)** is correlated with a failure to wean from ventilatory support due to respiratory muscle weakness.

Answer 491

**P/F (PaO2 to FiO2)** ratio of \> 200 generally represents adequate oxygen transfer and may lend support for a prediction of a successful ventilatory wean *_Normal = \>400_* *_\<200_* indicative of a diminished capacity for oxygen diffusion and may be predictive of a failure to wean.

Answer 492

The **rapid shallow breathing index (RSBI)** is another bedside measurement that may have both negative and positive predictive value in predicting failure or success at weaning. *_RSBI of \< 105_* is thought to represent appropriately slow and deep tidal volume breathing which is potentially indicative of a successful wean. **On No pressure support or PEEP** **RR (Unsupported) / TV (Liters)** \< 105 breaths/min/Liters = reassuring *_~80 is about a cutoff_*

Answer 493

This value is typically between **3 to 4 mL/kg/min in an adult** Can be as high as *_8-10 mL/kg/min in a premature infant or neonate._*

Answer 494

Fluid Requirements = TBSA burned(%) x Wt (kg) x 4mL Give 1/2 of total requirements in 1st 8 hours, then give 2nd half over next 16 hours ## Footnote **Surface Area see photo**

Answer 495

Nitrous oxide should be avoided in patients with MTHFR deficiency. Nitrous oxide directly inhibits methionine synthase. The MTHFR gene encodes a protein used in the folate pathway and synthesis of purines for DNA. When this pathway is inhibited homocysteine levels rise. Use of nitrous oxide further increases the homocysteine level because of impaired mechanisms of metabolism. **Elevated homocysteine increases incidence of thrombosis and adverse coronary events.**

Answer 496

Propofol infusion syndrome is associated with **rhabdomyolysis**, **lactic acidosis**, **renal failure**, and **cardiac failure**. **Pancreatitis** secondary to hypertriglyceridemia **Bradycardia**

Answer 497

**Etiology**: Vascular rings are due to the failure of embryonic structures to regress. **Symptoms**: Wheezing, dysphagia, cyanosis, apnea, aspiration, and stridor. If rings are complete rings that encircle the trachea or esophagus, or they may be incomplete but cause significant compression.

Answer 498

**Consists of a right-sided aortic arch that gives rise to a left brachiocephalic artery, which then gives rise to a left subclavian artery and left carotid artery.** *_Diagnosis: MRI or CT_* * *ABCDE**: * *A**rch Location **B**ranching of Aorta **C**ompression of airway **D**iverticulum of Kommerell d***_E_***scending Aorta

Answer 499

**Muscle paralysis can further worsen airway weakness and compression, which leads to obstruction.** It is important to provide positive pressure during ventilation. **Otolaryngology teams may be needed for assistance with establishing the airway if invasive access is needed.** Once intubated, the surgical approach will depend on the presence of any intracardiac lesions that need simultaneous repair, which would dictate a sternotomy. **In the absence of these defects, left posterolateral thoracotomies are common.** The need for one-lung ventilation should be discussed with the surgeon. **After surgical repair, residual anatomic and dynamic compression of the airway may still be present so caution should be used when extubating these patients.** Vocal cord paralysis is common after this repair due to the proximity of the recurrent laryngeal nerve which is related to the aortic arch and may be abnormal in its location due to the divisions of the aortic arch in vascular rings.

Answer 500

**Hemodilution** can result in a decreased blood viscosity. This decreased viscosity can improve the flow characteristics of blood through the systemic circulation, **resulting in a decreased systemic vascular resistance and possibly hypotension if this normovolemic hemodilution occurs too rapidly.** Caution should be taken to ensure adequate oxygen delivery is maintained as while hemodilution improves the flow characteristics of blood, it also decreases its oxygen carrying capacity.

Answer 501

The Poiseuille Law relates the flow rate (Q) of a fluid with a given: **viscosity (μ)** travelling through a tube with **given diameter (D)** and **length (L)** under a given **driving pressure (Δp)** in the following relationship: **Q = (π \* Δp \* D4) / (128 \* L \* μ)**

Answer 502

Unlike most anesthetics which directly depress the RAS, **ketamine exerts its effects on the thalamus**, *_causing dissociation of the reticular activating system (RAS)_* from the cerebral and limbic cortices.

Answer 503

**CPAP (Continuous Positive Airway Pressure)** administers a continuous positive airway pressure throughout both inspiration and expiration and is analogous to positive end-expiratory pressure (PEEP) in most clinical scenarios. *_- Only improves Oxygenation throgugh optimization of V/Q Mismatch_* **BPAP (Biphasic Positive Airway Pressure)** adds pressure support ventilation (PSV) to CPAP. With each spontaneous ventilation, the patient is delivered a standard pressure-supported breath. In BPAP, the patient is able to control both their own inspiratory and expiratory times, as well as their respiratory rate, and is a ventilatory mode with high patient-ventilator synchrony and patient comfort. - The *_PSV support of BPAP in addition to CPAP helps to ensure alveolar ventilation*_ where CPAP alone does not. BPAP results in i_*mproved minute ventilation_* and dyspnea relief when compared to CPAP alone.

Answer 504

**Most Sensitive** Visual Motor Sensory Auditory **Lease Sensitive (Most resistance)** Visual evoked potentials are the most sensitive to the effects of volatile anesthetics. Brainstem auditory evoked potentials are the most resistant. TrueLearn Insight : Brainstem potentials are Barely affected, Sensory potentials are Somewhat affected, Motor potentials are Mostly affected, and Visual potentials are Very affected.

Answer 505

**1. Binding and inactivating the increased concentration of activated plasmin** that occurs following exogenous tPA dosing. ## Footnote **2. Direct Inhibition of Plasminogen to Plasmin**

Answer 506

This state is evidenced by the vastly increased LY30 value of 65% on preoperative TEG, where a *_typical normal LY30 value would be 6%_*. This coagulopathy has been shown to be reversible with antifibrinolytics such as **tranexamic acid (TXA) or aminocaproic acid**, both of which work by binding plasminogen and plasmin, effectively preventing further breakdown of fibrin.

Answer 507

1. **Direct Binding of Large Negatively charged molecules in serum** Protamine is a large, positively charged molecule that is given as an antidote to heparin. It chelates the large, negatively charged heparin molecule and prevents its binding with antithrombin 3 and its subsequent anticoagulant effect.

Answer 508

**1. Induction of the synthesis of VWF by endothelial cells** - Synthesis and release of von Willebrand factor from vascular endothelium which plays a critical role in platelet adhesion to wound sites.

Answer 509

**Increase in Factors 1972 (10, 9, 7, 2)** This clotting cofactor is essential in the conversion of clotting factors II, VII, IX, and X into their active forms. This is typically utilized in the setting of vitamin K antagonist overdose (Warfarin)

Answer 510

**Tympanic Membrane = Most sensitive** *_These 4 are true_* 1. Pulmonary Artery 2. Distal Aspect of Esophagus 3. Tympanic Membrane 4. Nasopharynx Not reliable = bladder, rectum

Answer 511

The nicotinic acetylcholine receptor is in a class of receptors known as ligand-gated ion channels. Other receptors in this class include serotonin-type-3 (5-HT3), glycine, GABAA, NMDA, AMPA, and kainate receptors. The **NMDA** receptor is a combined **voltage-gated and ligand-gated ion channel**

Answer 512

Acetylcholine = Ester with Quaternary Amide Sux = 2 ACh together with Chloride Ions

Answer 513

**Cryotherapy treats acute post-operative pain by:** 1. Decreasing the spread of inflammatory factors 2. Slowing nociceptive nerve conduction

Answer 514

Temperature sensation travels faster through the human body compared to pain. **Warm thermoreceptors** are thought to be part of **C fibers.** Meanwhile, *_thermoreceptors*_ that sense _*cold*_ are made up of both _*unmyelinated, slow-conduction C*_ nerve fibers as well as thin, _*myelinated A-delta nerves._* Therefore, the more sensitive an organism is to cold, the more sensitive they are to pain.

Answer 515

Mnemonic devices for muscarinic effects: **SLUDGE-Mi**"Sludge Me": Salivation, Lacrimation, Urination, Defecation, GI upset, Emesis, Miosis **DUMBELS**: Defecation/**Diaphoresis**, Urination, Miosis, Bradycardia/Bronchospasm, Emesis, Lacrimation, Salivation **Diaphoresis = Counterintuitive** **(Muscarinic receptors are also found at the sympathetic postganglionic junction innervating sweat glands)**

Answer 516

The **CYP 2D6** enzyme pathway is responsible for the metabolism of codeine to morphine, its active metabolite. Individuals with poor activity of this enzyme pathway are likely to experience treatment failure with codeine therapy. TrueLearn Insight : Mnemonic for **2D6** and codeine: co**D**eine has 2 letters, followed by a "**D**", then **4 more letters (2 + 4 = 6).**

Answer 517

**Epileptiform activity on the EEG/or grand mal seizure can be induced** Etomidate is therefore *_avoided in patients with a history of seizures_* (Use used to treat status epilepticus however on induction doses which is not intuitive)

Answer 518

**Diffusion hypoxia ("Fink effect")** observed following the cessation of an inhaled anesthetic involving the use of high concentrations of nitrous oxide. The relatively *_higher concentrations of nitrous oxide*_ (up to 70%) required to maintain general anesthesia compared to other more potent inhaled anesthetics, and its _*low blood solubility_* result in the rapid alveolar elimination of large amounts of nitrous oxide following cessation of the anesthetic. This **flooding of nitrous oxide results in the displacement of oxygen and carbon dioxide in the alveoli, leading to a temporary hypoxia.** This diffusion hypoxia typically lasts for 5-10 minutes immediately after emergence, and can be prevented by the use of supplemental oxygen while the nitrous oxide is being eliminated.

True Learn Salient Points Flashcards

(549 cards)