True Learn Salient Points Flashcards
Which TEE view shows the anterior and inferior walls of the LV (perfused by the LAD and RCA, respectively)?
The mid-esophageal two-chamber view shows the anterior and inferior walls of the LV (perfused by the LAD and RCA, respectively).
Pre-operative Anemia is a risk factor what what 4 post operative complications?
Preoperative anemia is an independent risk factor for morbidity and mortality after cardiac and non-cardiac procedures. It is associated with increased risk of: 1. Postoperative renal dysfunction 2. Adverse cardiac events 3. Stroke 4. Increased hospital stay
Why is a Biphasic Defibrillator better than a monophasic defibrillator?
Uses less energy and is equally effective or more effective than a monophasic defibrillator.
Why is Dobutamine used for cardiogenic shock?
Dobutamine is the preferred initial vasoactive agent in cardiogenic shock as it:
1. Improves cardiac output
2. Reduces afterload
3. Minimal increase in myocardial oxygen demand.
SVT patient with WPW can be safely managed with what drug?
What dose?
What is the max dose?
When do you stop the medication?
Procainamide Drug of Choice for stable wide complex tachycardia (Class IIa recommendation)
17 mg/kg at a rate of 20 - 50 mg/min; intravenously over 25 - 30 minutes
Give until: Arrhythmia is suppressed Patient develops hypotension QRS segment prolongs by >50% of baseline
Total of 17 mg/kg is given;
max 1 gram If effective,
start continuous infusion at 1-4 mg/min Continuous infusion has fewer adverse effects than bolus
Which is more common, heart tumors that are primary or secondary in origin?
Where are myxoma more likely to be found?
The most common primary tumor of the heart is a cardiac myxoma, which is typically located in the left atrium.
However, metastatic disease to the heart is not uncommon from adjacent lung or renal cancer and are more common than primary myxoma (Found in LA more than RA)
What is a mechanism that the heart does in order to protect itself from decreased perfusion?
Ischemic preconditioning is a defense mechanism of the heart that builds up a tolerance to ischemic events to further limit myocardial stunning and damage in the future. Ischemic Preconditioning = Natural defense mechanism that permits the heart to better tolerate cardiopulmonary bypass
What are the 4 most common indications for pacemakers (Per true learn - there could be others)?
Pacemaker placement is indicated for: 1. Second-degree (type II) AV block (Now at the bundle of His and definitely below the AV node) 2. Third-degree AV block 3. Any symptomatic bradyarrhythmia 4. Refractory supraventricular tachyarrhythmias
What are the three main determinants of myocardial oxygen demand?
- Wall tension 2. Heart rate 3. Contractility
What is the ACT testing on a basic level? When are ACT levels used? What is the average values? What are the typical valves before going on bypass> What can prolong ACT levels? (4 factors)
ACT is a functional assessment of the intrinsic and common final pathway of coagulation. It is used in cardiac and vascular surgery when high doses of heparin are given. The normal range for ACT is 70-120 seconds (Average 107 seconds)
A value between 400-480 seconds is typically used as a mark of adequate anticoagulation prior to going on bypass.
ACT is an imperfect lab test to evaluate the anticoagulant effect of heparin and can be prolonged by
- Thrombocytopenia
- Platelet inhibitors
- Hypothermia
- Hemodilution
What are the contraindications to spinal cord stimulation?
- Untreated Psychological disease 2. Substance Abuse 3. Lack of Social Support
Giving platelets carries what immunological concern?
Rh sensitization and you may have to give Rh Immunoglobulin (RhoGAM) to women of child bearing age or younger.
What is typically considered to be the most common blood product associated with TRALI?
Plasma but could also be PLATELETS Why? –> depending on the area (Male only plasma centers such as american red cross)
What is the innervation of sweat glands in terms of autonomic nervous system? Pre or post ganglionic fibers? What is the mechanism behind this?
Postganglionic sympathetic fibers Eccrine = Most of sweating Pregang (Ach) on nicotinic Receptors Postgang (Ach release)* onto muscarinic receptors) **ALL OTHER MUSCARINIC RECEPTORS ARE APART OF THE PARASYMPATHETIC SYSTEM**
Diagnostic Tests for: 1. Carcinoid Syndrome 2. Pheochromocytoma 3. Gastrin levels
- Carcinoid Syndrome - 5-HIAA (Hydroxyindoleacetic acid) 2. Pheochromocytoma - Urine metanephrines 3. Gastrin levels Gastrin tumors (Zollinger-Ellison syndrome)
What are the indictions for celiac plexus blocks? What are the adverse effects?
- Chronic, intractable abdominal pain coming from VISCERA (Lots of possibilities here)
Adverse SE
- Hypotension (Splanchnic dilation)
- Diarrhea
- Hiccups
- Pleurisy
- Retroperitoneal bleeding
- Abdominal Aortic Dissection
- Transient Motor Paralysis
- Paraplegia
What are the indications for TENS devices?
Symptomatic relief of: 1. Chronic intractable pain 2. Acute Post Surgical Pain 3. Post Traumatic Pain 4. Arthritis
The majority of patient’s with myelomeningocele have what other manifestation to keep in mind?
Chiari II Malformation (As opposed to the less pronounced tonsillar herniation seen with Chiari I, there is a larger cerebellar vermian displacement) Herniate through the brainstem through foramen magnum and then get non-communicating AKA obstructive HYDROCEPHALUS by blocking the 4th ventricle)
What are the 5 aspects of anesthetic management of cerebral aneurysm clippings?
- Avoidance of changes in MAP / ICP during induction and surgical stimulation 2. Large Bore IV Access 3. Adequate brain relaxation (brief hyperventilation ETCO2 30-35 and some mannitol) 4. Maintenance of Cerebral Perfusion Pressure 5. Rapid Wake up
What is the equation for cerebral perfusion pressure? What are the values for each on average?
CPP = MAP - ICP CPP > 70 mmHg MAP ~ 80 mmHg ICP < 10 mmHg Cerebral perfusion pressure is defined as the difference between intra-arterial pressure minus the central venous pressure or intracranial pressure (whichever is higher).
What type of solution if used during a Transurethral resection of the Prostate can lead to neurological complications?
Glycine containing irrigation solution during TURP Glycine –> Ammonia
- Hyper ammonia with encephalopathy and coma
- Visual changes (Glycine looks similar to aminobutyric acid which is inhibitory)
What is the most common laboratory finding of patient’s with DIC? What are the two forms of DIC? Levels of: 1. Fibrin Degradation Products? 2. PT levels? 3. PTT levels? 4. Fibrinogen levels? 5. Platelets? 6. Blood smear?
Thrombocytopenia (93%) of cases. Forms: 1. Hyperfibrinolytic - Rapid burst of fibrin (Trauma and OB) 2. Procoagulant - Sepsis Fibrin Degradation Products increased PT and PTT prolonged Fibrinogen decreased Platelets decreased Blood smear = Schistocytes and Helmet cells
A patient with Acute Intermittent Porphyria can be prophylactic treated with what methods?
- Decrease stress (hard to do for surgery) 2. Limit fasting times (stay in ASA guidelines though) - Give IV Glucose 3. Avoid these medications - Barbiturates - Sulfonamides - Ethyl Alcohol - Ergotamine 4. Hydration
Regarding neuro monitoring, what are affected by volatile anesthetics? What is the neuro monitoring that is least affected?
SSEP, MEP, EEG and Visual Evoked Potential (VEP) are all affected by dose dependent manner by volatile anesthetics Auditory Evoked Potentials are minimally affected
How much will Succinylcholine increase your serum Potassium levels in healthy kidney functioning patients? How much in ESRD?
0.5 mEq/L and normalizes in 10-15 minutes in normal patients Same as chronic renal failure patients
Why is Mannitol used in renal transplants?
Intraop IV mannitol prior to vessel clamp release has been shown to decrease post-transplant kidney injury (No effect on graft rejection)
When is an epidural steroid injection indicated?
Radicular pain - Edema/Inflammation around the nerve root - Ex: herniated disc or spondylosis (degenerative changes of bone spurs or osteoarthritis)
When is Myxedema Coma most often seen by Anesthesiologists?
Chronic hypothyroid patient who undergoes physiologic stressor - Treat with Levothyroxine
What timing is ideal for ESRD patient’s with dialysis for elective surgeries?
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
What are the lab findings for primary hyperparathyroidism?
Increased PTH Increased Calcium Decreased Phosphate Non-gap metabolic acidosis Normal to high 24 hour urinary calcium
What is the treatment for Acute Mountain Sickness?
Treatment: Hydration Oxygen Descend Altitude Acetazolamide - Treats the respiratory alkalosis Dexamethasone Non-benzodiazepine sleep aids
What are the NPO Guidelines for waiting for: 2 hours? 4 hours? 6 hours? 8 hours?
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
What is an important correlation between ESRD patients and platelet function?
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).
Ondansetron Side Effects in most common order?
- QTc prolongation (20%, very rarely clinically significant)
- Headache (11%)
- Transient AST/ALT increases (5%)
- Constipation (4%)
- Rash (1%)
- Flushing/warmth (< 1%)
- Dizziness (< 1%).
What are the criteria for the MELD Score?
What are the criteria for the Childs Pugh Score?
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” -
What are the immediate life saving interventions in management of a venous air embolism?
1. FiO2 1.0
2. Notify surgeons to flood the field
3. Left Lateral Decubitus Position if possible
What are the end organ effects of muscarinic Stimulation?
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)
What detrimental effect does chronic Nitrous Oxide have?
Inhibition of DNA synthesis with chronic exposure (Recreational N2O abuse causing megaloblastic anemia)
What are 3 of the potential complications of brachial artery cannulation of an arterial line?
- Median Nerve Damage
- Distal Ischemia due to lack of collateral circulation
- CRBSIs (Catheter related Blood Stream infections) for 1:1000 catheter days
What is the Metabolism of Rocuronium? What is the half life adjustments for ESRD?
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
What are the symptoms of Carcinoid Syndrome? (Break down by organ system)
Derm: Flushing
Cardiac: Tachycardia, Arrythmia, and Carcinoid Heart Disease (Right Heart)
Pulmonary: Bronchospasm
GI: Diarrhea, Malnutrition
Describe the pathway of the Pain and Temperature Sensation. Which tract is this?
Spinothalamic Tract 1. Skin –> Dorsal Horn of the Spinal Cord 2. Dorsal Horn to contralateral spinothalamic tract to the thalamus
What do patient’s with Gilbert Syndrome have risks of?
What enzyme do they have decreased activity in?
What is the consequence of this?
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
What nerve palsies are common with LMA?
- Lingual Nerve
- Recurrent Laryngeal Nerve
- Hypoglossal Nerve
For TURP procedures, what solutions are now used? What was formerly used? What clinical sequelae developed from these?
Glycine and Cytal (Mannitol and Sorbitol) now used -
Decreased incidenence of HYPONATREMIA which was causing cerebral edema and hemolysis Still can develop hyponatremia
What is the active metabolite of meperidine and what can it cause?
What is the active metabolite of morphine and what can it cause?
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)
When is Methadone indicated? What is it’s mechanism of action?
Opioid Analgesic for neuropathic pain (Chronic)
Mechanism: NMDA and Serotonin Reuptake Antogonist
What are the pros and cons of peribulbar blocks vs. retrobulbar blocks?
Peribulbar
Pros
1. Decreased risk of retrobulbar hemorrhage
- Decreased optic nerve injury (less central spread)
Cons
1. Longer Onset Time (9-12 minutes)
- Lower incidence of complete akinesia
What are the goals of multiple sclerosis patients in the perioperative period?
- Maintain temperature 2. Maintain fluid homeostasis 3. Maintain hemodynamics Autonomic instability with hypotension
What is Charcot-Marie-Tooth disease?
What are the manifestations of this disease?
How should you approach managing these patients?
Charcot–Marie–Tooth disease (CMT) is 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
What analgesic effect of NSAIDs and COX inhibitors have?
Ceiling effect - Beyond certain dose, unlikely to gain effect
If you pre-treat Succinylcholine with smaller dose before full dose (Self Taming Dose), what effect does this have on myalgia & fasciculations?
Reduce fasciculations Has no effect on post-operative myalgia
What are the 11 non-assuring findings of difficult intubation?
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
What are the blood: gas partition coefficients of important inhalation anesthetic agents?
Desflurane - 0.42 Nitrous Oxide - 0.46 Sevoflurane - 0.69 Isoflurane - 1.46 Halothane - 2.54
What is thought to be the mechanism of ischemia re-perfusion during liver transplant?
Blood supply altered –> inadequate oxygenation and nutrients to the liver Reperfusion occurs –> disruption of sodium potassium pumps secondary to decreased ATP and glycogen
Etomidate has what detrimental side effects?
1. Pain on injection
2. PONV increased risk
3. Superficial Thrombophlebitis
4. Adrenal Insufficiency (Even after one dose)
How do you treat superficial thrombophlebitis?
- NSAIDs
- Elastic Stockings
- Superficial Thrombectomy
What are the normal changes that occur in the pulmonary system in aging?
- 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
What are the changes in elderly in: IC FRC CC TLC RV
Increases in: FRC CC RV
Decreases in: Inspiratory Capacity (IC) TLC
What are the effects of Elevated (Increased) levels of Growth Hormone?
GH = Anabolic Hormone - IGF-1 mediated 1. Hyperglycemia 2. Insulin Resistance 3. Lipolysis (Growth) (Also seen in Acromegaly)
Why do you want to hyperventilate someone with a cerebral hemorrhage? (Use objective measures with numbers associated).
Hyperventilation leads to Decreased CBF
1 mmHg of decrease PaCO2 correlates to CBF drop of 1-2 mL/100g/min
Which of the following is important to ensure adequate cooling of brain parenchyma during deep hypothermia circulatory arrest?
Continue CPB for 20-30 minutes after reaching goal temperature to ensure adequate cerebral cooling prior to stopping circulation
What is the physiology of Cushing Syndrome and what effects do we see in the body?
- 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
What labs are seen in SIADH patient’s in both urine studies including Urine Osm, FENa, and Urine Sodium* and *BMP including BUN and Na level?
Urine Studies (Urine sodium concentrated)
- Urine Osmolality > 100 mOsm (Often >200-300)
- FENa >1%
- Urine Na > 20 mEq/L
BMP Studies
- Low serum uric acid BUN
- Dilutional, euvolemic hyponatremia (Na below 135)
For clinically significant vasospasm and re-bleeding, what is the timeframe respectively for when patient’s suffering from subarachnoid hemorrhage present?
- Vasospasm between days 3 and 15
- Rebleeding occurs within the first 48 hours after SAH
What is the Equation for Arterial Content of Blood? How does this relate to hyperbaric oxygen therapy?
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.
What type of waves are seen on ICP waveforms with increased intracranial pressure?
Plateau waves = Lundberg’s A wave
Steep increase in ICP Rise in ICP may last for 20 minutes and is typically represented by:
- High PaCO2
- Stimulation (inadequate anesthesia)
Hypermagnesemia? 1. Etiology? 2. S/S?
Etiology
Iatrogenic (Supplemental Magnesium i.e. Pre-eclampsia treatment)
S/S:
Reduced Deep Tendon Reflexes, Cardiac depression, ECG changes, muscle weakness, hypotension, bradycardia
What are the treatments for organophosphate poisoning? Include immediate treatment and also prophylaxis.
Treatment:
1. Atropine
2. Pralidoxime Chloride (2-PAM)
More definitive = Antidote by removing organophosphate compound from organophosphate-inactivates acetylcholinesterase
- Decontamination
- Supportive Therapy
- Prophylaxis - Pyridostigmine - Prevents organophosphate induced irreversible acetylcholinesterase inhibition in the periphery (if given 30 minutes prior to exposure)
What are the risk factors for those who develop substance abuse disorders in residency?
- Male
- American Medical Grads
- Low ITE test scores
How does PTH raise calcium?
Parathyroid hormone increases serum calcium by:
1. Stimulating osteoclastic bone resorption
2. Distal tubule calcium reabsorption
3. Conversion of vitamin D to calcitriol.
How long should a patient wait to have non-cardiac surgery after MI? List minimum waiting times for stents (both types), angioplasty, and no interventions, respectively.
For balloon angioplasty?
For Bare Metal Stent?
If no coronary intervention?
After Drug Eluting Stent (DES) for elective non-cardiac surgery?
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
When is Infective endocarditis prophylaxis is recommended for cardiac conditions?
Other surgeries?
What are considered high risk cardiac conditions?
Antibiotic prophylaxis not recommended for?
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
Which of the following tests is most useful to diagnose acute abnormalities in hepatic synthesis?
Monitoring prothrombin time (PT) Gives the clinician a better understanding of acute hepatic protein synthesis capabilities.
What neck circumference predicts difficult mask ventilation?
>60 cm
What are the hemodynamic variables of Obstructive Shock? Cardiac Index CVP SVR
CI = Decreased CVP = Increased SVR = Increased
What are the normal values of: CVP PCWP CI SVR
CVP: 2-6 mmHg
PCWP: 6-12 mmHg
CI: 2.5 - 4 L/min/m2
SVR: 800-1200 dynes*sec/cm5
Preservation of Total Hepatic Blood Flow amongst volatile anesthetics at 1 MAC, from greatest to least, is in what order?
Preservation of Total Hepatic Blood Flow amongst volatile anesthetics at 1 MAC, from greatest to least, is sevoflurane > isoflurane > halothane.
Increased oxygen concentrations leads to what phenomenon in the lungs?
- Blunting of hypoxic pulmonary vasoconstriction
- Microatelectasis
Using V/Q ratios, what is a shunt? What is dead space?
Shunt: V/Q = Zero - Not ventilated but perfused
Dead Space: V/Q = Infinity - Ventilated but not perfused
What is the half life of Midazolam? What is the half life of Flumazenil?
Midazolam: 1.7 - 2.6 hours (102 minutes - 156 minutes) Flumazenil: 0.7 - 1.3 hours (42 min - 78 minutes)
What is the innervation of the cricothyroid muscle? What is the innervation of the laryngeal muscles?
Cricothyroid muscle = External branch of superior laryngeal nerve
All other muscles = Recurrent laryngeal nerve
Penicillin allergies: Can they receive cephalosporin antibiotics?
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.
Which of the following is the primary cause of low serum bicarbonate in a patient with a high anion gap metabolic acidosis?
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.
What is the mechanism of action of Metoclopramide? What is the class of Metoclopramide? What is the dose to prevent PONV?
MOA:
- Central = Dopamine antagonist
- 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.
What are the active cardiac conditions (5) that require cancelling the case before elective surgery?
1. Unstable coronary syndromes
2. Decompensated heart failure
3. Significant arrhythmia
4. Severe valvular disease
5. Recent or acute myocardial infarction
What are the 4 major components that shift the oxygen dissociation curve to the right?
- Hypercarbia (ETCO2 >40) 2. Acidosis 3. Hypercarbia (Hypoventilation) 4. High 2, 3 BPG
List the effects of Milrinone with regard to: Inotropy Lusitropy EF SV CO Afterload Preload Pulmonary Vascular Effects Systemic Vascular Effects
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.
What is Fenoldopam?
A dopamine D1 receptor agonist* that is used as an *antihypertensive agent.
It lowers blood pressure through arteriolar vasodilation.
What drug(s) should you administer with Ketamine to reduce emergence delirium?
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.
How does Tetanus act? What are the effects of tetanus? What is the difference between tetanus and botulism?
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
What are the key differences between Myasthetic Syndrome vs. Myasthenia Gravis in terms of:
Association?
Symptoms?
NMB differences?
Anticholinesterases?
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:
- Resistant to Succinylcholine
- Sensitive to Non-Depolarizing Neuromuscular Blockers
- 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:
- Proximal Limb Weakness
- Exercise Improves strength
- Myalgia Common
- Decreased Reflexes
Male > Female
Co-existing disease: Small Cell Lung Cancer
Anesthetic Implications:
- Sensitive to Succinylcholine
- Sensitive to Non-Depolarizing Neuromuscular Blockers
- Poor response to anti-cholinesterase’s
Which CN are in each aspect of the brain? 1-12 Which CN are Parasympathetic?
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.
What population is especially susceptible to Multiple Sclerosis attacks?
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.
Sitting craniotomies can have several complications due to positioning including what (name 6)?
Sitting craniotomies can have several complications due to positioning including:
- 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.
- Hypotension
- Midcervical quadriplegia
- Pneumocephalus
- Peripheral nerve injury
- Facial swelling
How do volatile anesthetics affect CMRO2 and CBF at both low and high rate?
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.
What is Transcranial Doppler used for? What can it detect? (5) What artery is involved?
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.
What are the relative contraindications for awake craniotomy?
Difficult Airways Orthopnea Obstructive Sleep Apnea Severe Anxiety Claustrophobia Young Age Psychiatric Disorders
Spinal Cord Injury location for: Quadriplegia? Paraplegia?
**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)**
List the entire criteria of the Glascow-Coma Scale?
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
What is the distribution of spinal cord perfusion? (Which arteries) Which provides perfusion to motor nerves? Sensory nerves? What are the arteries involved? (Include Origins)
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
What is the treatment for Central Diabetes Insipidus?
- Free Water Replacement 2. DDAVP (Desmopressin aka exogenous vasopressin)
What is the leading predictor of Post operative Mechanical Ventilation Requirement for Myasthenia Gravis patients? What are the Preop Criteria (Risk Factors)?
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.
What is seen above SCI in Autonomic Dysreflexia? What is seen below SCI in AD?
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.
What is the pathophysiology behind neurogenic pulmonary edema? What is the clinical picture? What is the treatment?
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)
Hyperkalemic periodic paralysis Cause? Precipitating Factors? Treatment?
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.
What temperature should you keep patients undergoing neurological procedures? BGL range?
35 - 36 degrees BGL 140 - 180 mg/dL
Why is nitrous oxide not indicated for neurological surgery?
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.
What is the pathway of the Motor Evoked Potentials? What does it measure? What is the anatomy of structures?
Descending Neuromotor Pathway - Monitor anterior spinal cord Lower Limb Cortex Internal Capsule Brainstem Corticospinal Tract Peripheral Nerve
What are some of the risk factors for latex allergies? Acquired? Inherent?
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
Frequent Cosmetic Use is associated with what anesthetic drug allergy?
Aminosteroid NMBDs (Pancuronium, Pipercurium, Vecuronium and Rocuronium) Cosmetics share similar quaternaries ion that are in these NMBDs (Found in toothpastes, detergents, shampoos)
When should you get a 12 lead ECG on a patient undergoing non-cardiac surgery?
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
What does a Phase I block include? (TOF? What symptom seen right after? How do anticholinesterases effect?) When is a Phase II Block seen? What does it resemble during monitoring? How How do anticholinesterases effect?
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.
Primary Hyperthyroidism is characterized by what lab values? T3 T4 free T4 Total Thyroid Hormone Binding Ratio TSH
Elevated T3 Elevated T4 free Elevated T4 Total Elevated Thyroid Hormone Binding Ratio Low / Normal TSH
What are hemodynamic goals for brain-dead donors? MAP, UOP, LVEF?
MAP > 60 mmHg UOP > 1 mL/kg/hour LVEF > 45%
What are some important aspects of post-operative management of a patient with Total Thyroidectomy?
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.
What are two common mechanism for median nerve injury post op?
- Forced Elbow Extension after NMBD 2. Iatrogenic Trauma from IV in the AC area
What is a detrimental side effect of ESWL immersion therapy?
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).
How do you test for Malignant Hyperthermia?
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.
What is the primary mechanism responsible for increased SVR during pneumoperitoneum during laparoscopy?
Increased systemic vasopressin levels are primarily responsible for increased SVR during pneumoperitoneum for laparoscopic surgery.
What are Hetastarches? Hetastarches compared to tetrastarches have what side effects?
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.
What is the most common perioperative peripheral neuropathy? What are the Risk Factors? How do you test for this?
Ulnar Nerve Injury Male, Thin/Obese patients EMG testing
What is the biggest RF in determining postoperative hepatic dysfunction?
Type of Surgery
Diabetes Insipidus Presents with: Low, Normal or High Urine Output? Low, Normal or High Plasma Osmolality? Low, Normal, or High Urine Osmolality? Low, Normal or High Serum Sodium levels?
Failure of ADH to secrete UOP: High (Polyuria) High Plasma Osmolality (Dehydrated) Low Urine Osmolality Hypernatremia
How many CME credits are required every MOCA cycle?
250 Category 1 CME credits are required every MOCA cycle.
What is the mechanism behind negative pressure pulmonary edema?
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
What is the pathophysiology of Active Herpes Zoster? What are the most common distributions of nerves?
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
How do you diagnose carcinoid Syndrome?
24 hour urinary 5-HIAA (Metabolite of serotonin) of > 30 mg (Normal 5-HIAA is 3-15 mg)
How do you diagnose Pheochromocytoma?
24 hours urinary Vanillylmandelic acid (VMA)
List the 2-4-6-8 rule for NPO Fasting Guidelines?
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)
Hypermagnesemia treatment? (Acute vs. Definitive)
- 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.
SPO2 READINGS IN: High Methylene Blue levels? High Methemoglobin levels? High carboxyhemoglobin levels?
Methylene Blue = 65% Methemoglobinemia = 85% Carboxyhemoglobin = 100%
What are the symptoms of discogenic back pain?
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)
What are some of the overdose effects of Carbamazepine?
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
For the pediatric airway what are the differences? Comment on the: 1. Tongue 2. Larynx anatomy 3. Epiglottis 4. Laryngeal inlet 5. Narrowest point of airway
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)
What is the most reliable test for Severe Liver Dysfunction? (Include why)
Factor 7 - Shortest Half Life of Vitamin K dependent factors
What is the mechanism of action of Buprenorphine? Why would we consider using this medication?
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.
What is the constellation of hypercalcemia symptoms?
- Nephrolithiasis 2. Abdominal Pain 3. Osteopenia 4. Bone Pain 5. Psychological Depression
How does Botulism Toxin work?
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.
What is the treatment for Acute Dystonic Reactions?
Treatment usually includes: 1. Anticholinergic medications - Help restore balance to the dopaminergic and cholinergic balance - Diphenhydramine (Both anticholinergic and antihistamine) - Benztropine 2. Benzodiazepines
How do each of these affect [Potassium]? Aldosterone Cortisol Insulin Thyroid Hormone
Aldosterone and cortisol promote renal potassium secretion leading to losses through the urine. Insulin and thyroid hormones enhance cellular potassium uptake (Lowers serum levels)
What is the Serum Na, Serum Osm, Urine Na, Urine Osm and Volume Status for: SIADH?
Serum Na - Low Serum Osm - Low Urine Na - High Urine Osm - High Volume Status - Euvolemic
What is the Serum Na, Serum Osm, Urine Na, Urine Osm and Volume Status for: Diabetes Insipidus
Serum Na - High Serum Osm - High Urine Na - Low Urine Osm - Low Volume Status - Euvolemic
What is the Serum Na, Serum Osm, Urine Na, Urine Osm and Volume Status for: Cerebral Salt Wasting
Serum Na - Low Serum Osm - Low Urine Na - High Urine Osm - High Volume Status - Hypovolemic (Same as SIADH but you are hypovolemic)
What is the Serum Na, Serum Osm, Urine Na, Urine Osm and Volume Status for: Primary Polydipsia
Serum Na - Low Serum Osm - Low Urine Na - Low Urine Osm - Low Volume Status - Euvolemic
What medication is used for pheochromocytomas preoperatively?
- Phenoxybenzamine - Long acting non-selective alpha blocker 2. Doxazosin, Terazosin, Prazosin - Selective Alpha 1 blockers also used
How does potassium change (Qualitatively and Quantitatively) after Succinylcholine administration?
After an intubating dose of succinylcholine in an otherwise healthy patient, potassium can be expected to rise 0.5 mEq/L.
What are some of the consequences of perioperative hyperglycemia? What is goal for BGL levels?
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.
What are the 4 T’s of classifying HIT? What score is low probability? What score is high probability?
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.
What is the relationship between PPV and renal function?
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”
What are all the deleterious effects of Angiotensin II and Why are ACE-Inhibitors / ARBs effective systemically?
Ang II - Increased Inotropy, Chronotropy, Catecholamine release/sensitivity - Increased levels of Aldosterone, Vasopressin - Increased Cardiac Remodeling through AT1 receptors
What is the best test to assess for synthetic liver function?
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.
What is the normal P50 value? What does this correspond to?
P50 = ~27 mmHg Corresponds to PO2 at 50% Hgb saturated
What are some important Long term treatments of Graves disease?
- Methimazole 2. Propranolol
What is Poiseuille Law? What are the two factors and necessary conditions of that law?
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
Which is more common: Subendocardial vs. Transmural ischemia? Why?
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.
What are the criteria for true ST elevation & depression on ECG in the operating room?
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
For Stellate ganglion Blocks: Indications for using this? Anatomy landmark?
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.
Stellate Ganglion Blocks Approach? Success signs? Side effects?
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.
What is the relationships between of Nitrous Oxide and Pneumothorax?
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.
How do you calculate FENa? What is FENa ranges for pre-renal, intrinsic and post-renal etiologies?
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
What are the 5 indications for emergent dialysis?
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
What are the risk factors for emergence delirium? What are the treatment options for it?
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
What will an ABG show in CO poisoning (Moderate to Severe)?
A metabolic acidosis Normal PaO2 Falsely elevated calculated SaO2 Falsely elevated SpO2.
What two things should you check before administering methadone in the OR?
- 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.
What is the most common organism for meningitis: For Adults? For Kids?
S. pneumoniae is the most common pathogen in adults GBS the most common in pediatric cases
If the first-stage oxygen regulator is faulty, which of the following could occur?
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
What is the Pathophysiology of negative pressure pulmonary edema?
- 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
What are some of the indications of peritoneal dialysis?
Intolerant of hemodynamic changes 1. Unstable Angina 2. Severe Aortic Stenosis 3. HFrEF
Before placing an epidural to a patient on the floor, what two things should you check?
- 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
What are the: Indications Methods Contraindications For Retrograde Intubation>
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
What drugs should be use correctly and cautiously in Pheochromocytoma and why?
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
What is the equation for CaO2 (Arterial Oxygen Content)?
CaO2 (Arterial Oxygen Content) = (SaO2 * Hgb * 1.34) + (PaO2 * 0.003) SaO2 = Arterial Oxygen Saturation PaO2 = Arterial Partial Pressure of Oxygen
What is the principle behind acute normovolemic hemodilution?
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.
What is the potential problem with using Neostigmine if there is full neuromuscular blockade recovery?
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.
How vasodilators have what effect on cerebral vasodilation? What side effects can you see from this?
Most vasodilating agents will also cause cerebral vasodilation. This may result in flushing and a headache.
What is the P50? What PaO2 yields this?
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%
What is the dose of epi in anaphylaxis? What is the dose of fluids in anaphylaxis? What are the Grades of Anaphylaxis?
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
What are the tryptase level timelines in anaphylaxis?
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
What are the risk factors for having latex allergies?
Multiple Surgeries Healthcare workers Atopic Histories Tropic Fruits - Avocado, Kiwi, Banana, Chestnuts, Stone Fruits
What is the Mechanism of Action of Fenoldapam? When would you consider using this medication?
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
Peri-operative Atrial Fibrillation - What are major risk factors? What do we use to treat?
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
How does glucagon affect Hepatic Artery resistance and Blood Flow?
Glucagon: 1. Decrease hepatic artery resistance 2. Increases hepatic artery blood flow
What is a screening tool for delirium in the ICU? What is the flowchart needed?
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
What is the RASS Scoring used for? What are the values?
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
Why is a left sided central line more problematic?
- 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
For central lines, what is the least to easiest to most difficult for central lines by type and laterality?
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.
Which is a worse artery to inadvertently cannulate; Right carotid or left carotid? If you were to do a carotid massage, which artery would you preferentially want to perform this on?
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.
What factors affect LA spread in an epidural?
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
For Thoracic Epidurals, how does the location of your epidural in the Thoracic spine dictate spread?
Site of Injection High Thoracic → Spread caudally (low) Low Thoracic → Spread cephalad (high) Mid Thoracic → Spread both cephalad and caudad
What is leukoreduction and why is it performed?
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
How does TPN affect Labs? CO2? BGL? Electrolytes? Insulin?
TPN is most associated with:
- Hypercapnia
- Hyperglycemia
- Hypophosphatemia
Additionally TPN can cause thrombophlebitis, hepatic steatosis, hypokalemia, hypomagnesemia, and hyperinsulinemia.
ADPKD patients should obtain what test before elective surgery?
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.
What three pathologies is steep reverse trendelenburg contraindicated without a workup?
- 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.
Anaphylaxis during blood transfusion most likely caused from what? Treatment?
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
Aprepitant: Class? Metabolism? Half Life? Side Effects?
Class: NK1 antagonist Metabolism: Hepatic Half Life: 10 hours Side Effects: Malaise, Nausea, Rash
Droperidol: Class and Side Effects (3)?
Class: Anti-dopaminergic Side Effects: 1. Dystonic Reactions 2. Extrapyramidal Symptoms 3. QT Prolongation (Dose dependent)
What side effects should you warn your patient’s about when administering Scopalamine? Who should not receive this medication?
Side Effects (Opposite of SLUDGE) Delayed arousal in the elderly - THEREFORE AVOID IN OLD PEOPLE Dry Mouth Blurred Vision Delirium Urinary Retention Constipation Tachycardia
What are three signs/indicators of bladder perforation during a TURP?
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)
Transurethral resection of the prostate Syndrome? What lab? What symptoms?
TURP Syndrome → CNS symptoms Hypo-osmolality Hyponatremia
How would you calculate the volume of nitrous oxide in an E-cylinder based on weight? How would you calculate the volume of nitrous oxide without weighing the cylinder using the following formula?
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
Pre-renal AKI What are values of: 1. FENa? 2. Urine Osmolality
FENa <1% Urine Osmolality >800 mOsm/kg (normal 300-900)
What is the compensation for respiratory acidosis? Immediate and Delayed?
- Plasma Protein Buffers (Hgb) and others (Immediate) 2. Renal compensation (Retention of Bicarbonate is compensatory response) - Hours to days to develop
Allergic reaction to Local Anesthetics: What is the culprit for esters? What is the culprit for amides?
Esters = Para-aminobenzoic acid (PABA) Amides = Methylparaben (Structurally similar to PABA)
In terms of opiates: What is the difference in physical dependence vs. tolerance vs. addiction?
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
Hepatorenal Syndrome What is the underlying pathophysiology? Types? Onset of each? Survival? Treatment? (4)
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
What are the diagnostic modalities for Venous Air Embolism? List them in order of greatest to least sensitivity?
(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)
Strong Ion Difference: What is the concept? What is the normal value? How does increasing or decreasing the SID affect pH?
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)
What are the acute treatments (2) for hypercalcemia?
- 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
For Tourniquet Removal, what are the effects that are seen for: Temperature? pH? ETCO2? SBP? HR? Potassium?
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%)
What are the ASA classifications? 1-6
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
What is the world pain ladder in terms of treatment?
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
What is the pathophysiologhy of a laryngospasm? Include nerves and muscles responsible
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
What does each of these electrodes measure: Clark Galvanic Paramagnetic Severinghaus Sanz
Clark Electrodes - Measures oxygen Galvanic Electrodes- Measures oxygen Paramagnetic Electrodes- Measures oxygen Severinghaus Electrode - Measures CO2 Sanz Electrodes - Measures pH
What is the maximum recommended dose of lidocaine and epinephrine, respectively for tumescent liposuction?
The maximum recommended dose of lidocaine for tumescent liposuction is: 35-55 mg/kg 0.055 mg/kg for epinephrine
What are some complications of stellate ganglion blocks?
- 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
What are some complications of celiac plexus blocks?
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
What is the treatment for Methanol overdose?
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
What are the three most common Potassium sparing diuretics?
Spironolactone Triamterene Amiloride
What are the lung volumes of morbidly obese? (FRC, RV, CC, FEV1, FVC)
Which of these is the MOST sensitive indicatorr of obesity pulmonary function?
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.
What type of nerves are most sensitive to local anesthetics, and why?
Differential blockade with local anesthetics results in:
- sympathetic blockade first (No myelin, small diameter)
- pain/sensory blockade
- 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
What branches do Obtuse Marginal branches come off of?
What branches do diagnonal branches come off of?
What branches do septal branches come off of?
Obtuse Marginal = LCX
Diagonal = LAD
Septal = RCA and LAD
What is the assiociation between:
Middle Cardiac Vein?
Anterior Cardiac Vein?
Great Cardiac Vein?
Middle = PDA Great = LAD
Anterior = RCA
What amplitude and latency changes arre indicated in cortex iscemia of SSEP?
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)
How do you determine Fisher Grades for Subarachnoid Bleeds?
- *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
Draw the lung volumes
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).
What is closing capacity?
What is the clinical relevance of closing capacity?
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.
What is the formula for Power?
What does Power mean in a statistical sense?
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.
What is Poiseuille’s Law?
What are the types of blindness that can happen with PCA infarcts?
Right homonymous hemianopsia = Left PCA occlusion
Left homonymous hemianopsia = Right PCA occlusion
What is the graph for a normally distrubted percentage of data based on standard deviations?
1 SD = 34.1% (68%)
1 SD = 13.6% (95%)
2 SD = 2.1% (99%)
What is the treatment for Laryngospasm?
Treatment:
- 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
- PPV
- Propofol Small Doses - Increasing dose of anesthesia
- Succinylcholine (0.1 - 0.5 mg/kg)
What is MVO2 dependent upon?
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
For IV Opiates:
What factors affect onset time?
What factors affect duration?
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
How are ABG affected when cooled in terms of PO2, PaCO2 and pH?
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.
What is the different mechanisms of Clotridium Botulinum vs. Tetanus?
Tetanus
Inhibit Inhibitory Neurons
Retrograde Neuronal Transport of Toxin
Botulism
Prevent Vesicular Release of Acetylcholine
What is the mechanism behind why Guillain Barre Patients cannot receive Succinylcholine?
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.
What is the classic post-synaptic muscle-type nicotinic acetylcholine receptor composed of?
What is the neuronal type pre-junctional nAchR composed of?
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.
Why do you see fade with Non-Depolarizing Paralytics (Roc)?
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.
How does a vagal manuever terminate a tachyarrythmia?
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:
- inhibition of the sympathetic system
- Activation of the parasympathetic systems to
- Reduce blood pressure
- Decrease heart rate
What are the criteria required for antibiotic prophylaxis for infective endocarditis?
Endocarditis Guidelines
Antibiotic prophylaxis for dental procedures
- Prosthetic Cardiac Valve or Prosthetic material
2 .Previous Infective Endocarditis
- 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)
- Cardiac Transplant with cardiac valvular disease
Antibiotic for dental procedures:
- Manipulation of gingival tissue or the periapical region of teeth, or perforation of oral mucosa
- Tonsillectomy
- Adenoidectomy
What are the 3 potassium sparing diuretics?
The K+ STAys with Spironolactone, Triamterene, Amiloride.
Label each image
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.
What is the difference in primary, secondary and tertiary adrenal insufficiency?
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 pituitary 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.
Normal Mag levels?
Therapeutic range of pre-eclampsia?
When are Deep tendon reflexes reduced? Lost?
When does skeletal muscle weakness occur?
When does respiratory arrest ocur?
When does the ecg changes occur?
When do arrythmias occur?
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.
How would thermodilution appear with a Low vs. High CO?
High cardiac output will cause a small, narrow peak
Low cardiac output will cause a tall, wide peak.
Red corresponds to IABP on
Blue is IABP off
Explain what is occuring at each arrow (Left to Right)
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.
What is the flow loop on the right showing?
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.
What is the flow loop showing?
Unilateral Bronchial Mainstem Obstruction
What is the flow loop showing?
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.
Normal Flow Loop vs. Abnormal, What is this showing?
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.
Normal Flow Loop vs. Abnormal, What is this showing?
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
- 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.
What is this flow loop showing?
Restrictive Lung Disease
What is this flow loop showing?
Residual Muscle Weakness (Neuromuscular Blockade)
What is the advantage of Enoxaparin vs. Heparin?
- 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.
Femoral Nerve:
What is superior, inferior, lateral to?
What is the sensory innervation?
What nerve does this branch into?
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.
Identify the part of the vertebrae
Label Left Top to Bottom (4)
Label Right Top to Bottom (2)
Transverse process: nose
Pedicle: eye
Pars interarticularis: neck
Superior articular facet: ear
Inferior articular facet: front leg
What is a potential complication of interscalene nerve blocks?
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.
What blood product would be most helpful in correcting abnormalities in K-time as well as alpha-angle which are measures of the speed and strength of clot formation?
Cryoprecipitate
Contains factor 8 and fibrinogen
Prolongation of the R time indicates need for what blood product?
FFP
Maximal amplitude is a characteristic of the maximal clot strength during the clotting cascade. This process is highly dependent on what two things?
Both platelet number and function as well as fibrin cross-linking.
How does propofol affect SSEP?
Propofol causes a dose-dependent decrease in amplitude of SSEPs.
Propofol increases SSEP latency.
Affects SSEP greatly
What is the amino acid synthesis sequence of catecholamines?
As gas flow through a bobbin rotameter increases, what will increase?
Cross sectional orifice area
How does the drug PTU (thyroid) work?
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.
Invasive BP monitoring employs what machine to read this?
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.
Blink Reflex:
Afferent?
Efferent?
The corneal reflex involves the:
- Ophthalmic branch of the trigeminal nerve (afferent limb)
- The temporal and zygomatic branches of the facial nerve (efferent limb)
What are the distances between each of these distances that would make intubation difficult, respectively?
Sternomental Distance
Thyromental Distance
Intercisor Distance
Sternomental Distance of <12.5 cm
Thyromental Distance <6.5 cm
Intercisor Distance <3 cm
What is the Bohr Effect?
What is the Haldane Effect?
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
Release at tissue
HalDane - [Oxygen concentrations] determine Hgb affinity for CO2
Hemoglobins
Affinity
lDane - Carbon Dioxide
What is the fluid requirements for burn patients?
How do you find out how to calculate burned surface area?
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
Surface Area see photo
What is the mechanism of action of tPA?
1. Binding and inactivating the increased concentration of activated plasmin that occurs following exogenous tPA dosing.
2. Direct Inhibition of Plasminogen to Plasmin
What is the mechanism of action of Protamine?
- 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.
What is the mechanism of action of DDVAP?
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.
What are the subunits of nicotinic acetylcholine receptor?
What type of channel is this?
What type of channel is NMDA channel?
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
Draw the acetylcholine molecule.
Draw the succinylcholine molecule
Acetylcholine = Ester with Quaternary Amide
Sux = 2 ACh together with Chloride Ions
