CA-2 ITE Flashcards
What are the symptoms of propofol infusion syndrome?
- Heart failure
- Bradycardia, hypotension
- Metabolic acidosis (lactic acidosis)
- Rhabdo
- Renal Failure
Max dose in peds of propofol (mg/kg/hr)
4 mg/kg/hr
What can dantrolene treat?
- MH
- Ecstasy overdose
- NMS
- Seritonin syndrome
- Muscle spasticity (CP)
What labs should you get for someone on chronic dantrolene?
LFTs; often elevated; can get hepatotoxicity
What does the SLN innervate?
- Branch of vagus
- Internal branch innervates sensation (lower pahrynx, inferior epiglotis, vallecula)
- External innervatses muscles of the criothyroid muscle (phonation and elongation)
Sensation of vocal cords and below
RLN (also branch of vagus)
- also innervates all intrinsic laryngeal muscles except cricothyroid
Gag reflex
Hypoglosal (IX)–afferent
Vagus (X)–efferent
Celiac plexus block side effects
Diarrhea and orthostatic hypotension (vasodilation of splanchnic vessels)
What effect does a labor epidural have on respiratory function?
Increase vital capacity (less splinting)
Caudal block dosing:
- Sacral____
- Low thoracic _____
- Mid thoracic ____
- Sacral dermatomes: 0.5 mL/kg
- Low thoracic dermatomes: 1 mL/kg
- Mid thoracic dermatomes: 1.25 mL/kg
Symptomatic wide complex (>0.09 s) tachycardia treatment
Cardioversion; if no cardiopulmonary compromise, then adenosine is OK
The _____ Effect is responsible for the change in the Oxygen-HGB dissociation curve with changing Co2 or pH
Bohr effect
The __ effect describes the ability of a HGB molecule to carry more CO2 at more deoxygenatied states
Haldene effect
When someone suffers an acute renal failure and they have cirrhosis, what is the most common cause?
Type 1 hepatorenal syndrome
- typically improves with treatment (unlike in type II)
Which three values are directly measured on an ABG?
- pH
- PaCO2
- PaO2
Which NDNMB has an active metabolite 80% as potent as the parent drug?
Where is this drug cleared?
Vecuronium (3-DAV)
- Renally cleared (thus can build up in pts with renal disease)
What is Eisnmenger syndrome, and why do anesthesiologists care?
Intial L-> R shunt; then Pul HTN develops, leading to a R-> L cyanotic shunt
- 30-50% M&M risk
- Goals: avoid drop in SVR and CO
Which two structures surround the illioinguinal blcock
Internal oblique and transversus abdominus
* TAPs block is the same plane
What three features do you see in a Pierre-Robin Patient which can be concerning for an airway?
- glossoptosis (downward displacement of the tongue)
- micrognathia
- airway obstruction
- maintain spontaneous breathing, avoid paralytics; consider videolaryngoscopy; have LMAs and ENT available
Why are pregnant ladies at higher risk of aspiration?
3-11x more difficult airway, makes aspiration higher chance
How long does an acceleration or a decelleration last to cause lasting changes in HR
> 10 minutes
What is the equation for myocardial oxygen consumption?
MVO2= CorBF * ([Arterial O2] - [Venous O2])
Normal fetal HR
110-160 BPM
Sinusoidal FHT
placental abruption–ominous
Early decells_______
Late decells_______
Varriable dcells_____
Early decells: fetal head compression
Late decells: uretoplacental insufficiency or myocardial hypoxia
Variable decells: umbilical cord compression
Emergent hyperthroid/thyroid storm treatment
Symptomatic control;
Consider beta blockers (both symptoms and reduce T4->T3), PTU, steroids
tHINGS that don’t cross the placenta
Heparin Insulin NDNMB Glycopyrolate Sux ...also phenylephrine
What are the contraindications to PCC? What factors foes PCC contain?
- DIC (further fuels the process)
- MI
- Agina
- PVD
- CVA/stroke
- Thromboembolic event
PCC contains factors II, IX, X
What are some of the uses of PCC (KCentra)?
- Tx of hemophelia
- Reversal of anti-coagulants (i.e. warfarin) (faster and more reliable than FFP and less infection risk)
- Surgical bleeding
What causes leftward shift on a CO2 ventialtory response curve?
Right?
Left: Arterial hypoxemia, acidosis, surgical stimulus, increased ICP
Right: Volatile anesthetics (no change in slope); opioids, sedative/hypnotics, barbituates
https://d1yboe6750e2cu.cloudfront.net/i/af40b03f296168c1a244ec689b8a5fdc8a7ce1f9
Following donor liver tranplant, INR peaks on which POD?
POD 1-3; be mindful with epidural placement and removal
Describe HPV. Does it affect smaller or larger segments more?
vasocontstriction of portions of the lungs that are exposed to hypoxia. Smaller areas vasoconstrict more–> shunt
What are some of the inhibitors of HPV?
Inhibitors: hypocarbia, vasodilators, infection, metabloic alcalemia, MAC >1
Others (indirectly): hypervolemia, vasoconstricting drugs, hypothemira, PE, large hypoxic lung segment
What are the three phases of coagulation?
- Primary hemostasis–PLTS form clot (measure plts, VWF, clotting time)
- Coagulation–Fibrin net/mesh (PT, INR, and specific factors)
- Fibrinolysis–clot broken down (fibrinogen levels–reduced in DIC)
How should coagulation be managed in liver disease?
Coagulation management in liver disease patients:
1) Maintain platelet count at 50-60; in high-risk surgery maintain >100
2) Keep fibrinogen >100
3) Transfuse to maintain Hgb > 7
4) Do not give FFP prophylactically or chase INR levels
- Increased INR in these patients does not necessarily reflect risk of bleeding
- If FFP is to be given, dose is 20-40 mL/kg
Which factors are reduced in liver failure?
Liver disease reduces factors II, VII, IX, X, as well as V, XI, and thrombin; Protein C is reduced, as well
Which factors are increased in liver disease?
Factor VIII and vWF are increased in patients with liver disease. These two coagulation factors are produced extra-hepatically.
Interstellate ganglion block target?
C6–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
- used for treatment of CRPS of the upper extremity
What are the anesthetic considerations for thalsemias?
Anesthetic considerations for these patients include:
Preoperative hemoglobin levels
Provision of leukocyte-reduced blood transfusions
Cardiac, endocrine, hepatic assessments
Bony deformities that may render the airway more difficult
Fragile demineralized extremities that may render positioning challenging
Post-splenectomy hypertension
Thromboembolism prophylaxis and treatment
What is the neural pathway for broncoconstriction?
Bronchoconstriction occurs mainly due to the parasympathetic nervous system via the vagus nerve.
The parasympathetic nervous system is the main pathway by which bronchoconstriction occurs in the pulmonary system. Receptors in the airways become stimulated and send a signal to the nucleus ambiguus in the brain stem. From here, the efferent signal is sent through the vagus nerve to the parasympathetic ganglia in the pulmonary system. This results in acetylcholine release and stimulation of the muscarinic receptors.
What effect does tolerance have on a dose response curve?
On a dose-response curve, drug tolerance causes a right shift of the curve, thereby increasing the median effective dose (ED50) and requiring greater dosages to achieve similar effects. LD50 (median lethal dose) does not necessarily increase with tolerance and may have serious implications.
What is TRALI and how is it treated?
Transfusion-related acute lung injury (TRALI) is treated with supportive management, and it includes intravenous fluid bolus for hypotension (C).
TRALI is described as an acute respiratory distress that occurs after transfusion and is commonly associated with plasma-containing blood products. It is most frequently seen with fresh frozen plasma and least frequently seen with packed red blood cells.
What are the symptoms of TRALI?
TRALI presents within 2-6 hours after transfusion. Patients have acute onset of dyspnea, tachypnea, and hypotension. Chest radiographs show bilateral pulmonary edema that is non-cardiogenic. Since the pulmonary edema is non-cardiogenic, pulmonary wedge pressure should be low or normal.
What are the 4 best IO sites?
the sternum, proximal tibia, distal tibia, and proximal humerus.
How do TENS units work?
Transcutaneous nerve stimulation (TENS) provides pain relief by stimulating A-beta mechanoreceptors (which inhibit A-delta and C pain fiber signaling), increasing levels of B-endorphins, and facilitating descending inhibitory pathways.
What three muscles make up the femoral triangle?
Femoral triangle is bordered by the inguinal ligament superiorly, the adductor longus muscle medially, and sartorius muscle laterally.
What are the L->R defect of the heart?
Left-to-right shunt defects include VSD (most common), ASD, ECD, and PDA.
What are the obstructive defects of the heart?
Obstructive defects include coarctation of the aorta, and stenosis of the atrial, mitral, or pulmonary valves.
What does methimezole do?
Methimazole is also used in the treatment of hyperthyroidism. It interferes with the synthesis of thyroid hormones.
What is the difference between Grave’s and Hashimoto’s?
Hashimoto thyroiditis is a form of inflammation resulting in decreased thyroid hormone production (hypothyroidism). It is caused by an autoimmune disorder in which the thyroid gland is attacked by a person’s immune system. The autoantibodies block TSH receptors in the thyroid, therefore destroying the receptors instead of stimulating them. In comparison, Graves disease is when the thyroid gland is hyperfunctioning with excessive secretion of active thyroid hormone (hyperthyroidism).
Who are the ideal patients for peritoneal dialysis (vs. hemodialysis)?
Peritoneal dialysis is the preferred dialysis modality for patients who are intolerant of the hemodynamic changes induced by hemodialysis. This may include patients with a history of unstable angina, severe aortic stenosis, or heart failure with severely reduced ejection fraction
Etomidate causes a _______________ in intracranial pressure, cerebral blood flow, and cerebral metabolic rate.
Etomidate causes a decrease in intracranial pressure, cerebral blood flow, and cerebral metabolic rate.
Etomidate inhibits the activity of ___________, an enzyme necessary for the synthesis of cortisol, aldosterone, 17-hydroxyprogesterone, and corticosterone. Even after a single induction dose of etomidate, adrenal suppression persists for 5 to 8 hours.
Etomidate inhibits the activity of 11-β-hydroxylase, an enzyme necessary for the synthesis of cortisol, aldosterone, 17-hydroxyprogesterone, and corticosterone. Even after a single induction dose of etomidate, adrenal suppression persists for 5 to 8 hours.
Infants have a CSF volume of ______, children have a CSF volume of ______, and adults have a CSF volume of _____ mL/kg
Infants have a CSF volume of 4 mL/kg, children have a CSF volume of 3 mL/kg, and adults have a CSF volume of 1.5-2 mL/kg
Compared to adults, Infants have a____ vagal tone and __________ sympathetic system.
Infants have a high vagal tone and immature sympathetic system.
What is the definition of severe AS?What are the S/Sx?
- Severe aortic stenosis is defined as a valve area less than 0.8 cm2 and a transvalvular pressure gradient higher than 50 mmHg.
- The “triad” of symptoms include: angina, syncope, and shortness of breath (dyspnea). The degree of symptoms does not correlate with the degree of stenosis.
What are the anesthetic goals for AS? HR\_\_\_ Contractility\_\_\_ Pre-load\_\_\_\_ Afterload\_\_\_\_\_
- HR: normal sinus rhythm should be maintained since loss of the left atrial contraction will result in a dramatic decrease in stroke volume and blood pressure. A normal to slower heart rate is beneficial to allow as much time for ventricular filling as possible. Furthermore, elevations in heart rate can lead to ischemia due to decreased diastolic time.
- Contractility: want to maintain, avoid depression of contractility which can lower stroke volume.
- Preload: want to have adequate volume.
- Afterload: must be maintained distal to the stenotic lesion to ensure coronary perfusion. A decrease in blood pressure can lead to myocardial ischemia which will further worsen contractility.
- Cardiac resuscitation is not typically effective in patients with AS; code situations must be avoided as it is generally not possible to created adequate stroke volume with chest compression in these patients.
What are the anesthetic goals for AI? HR\_\_\_ Contractility\_\_\_ Pre-load\_\_\_\_ Afterload\_\_\_\_\_
Aortic regurgitation:
- The magnitude of regurgitant volume depends on the diastolic time and the pressure gradient across the aortic valve (dependent on systemic vascular resistance).
- HR: must be kept above 80 bpm to prevent increases in the time for regurgitation. Decreased heart rates, which will increase diastolic time, will allow more regurgitation.
- Contractility: want to maintain.
- Preload: need adequate volume loading to ensure enough volume can move forward. Want to avoid overloading patient because this will increase regurgitant volume.
- Afterload: want to lower systemic vascular resistance which will attempt to prevent more regurgitation.
What is the concern with changing the glucose to lipid ratio in TPN?
Decreasing the glucose to lipid ratio of TPN results in less incidence of steatosis and of hypoglycemia after abrupt TPN discontinuation. While it is recommended that TPN be continued perioperatively, glucose levels should be monitored frequently and treated proactively whether TPN is held or continued.
What is responsible for post-stroke pain?
Post-stroke pain, paresthesias, and allodynia are likely a result of thalamic pain syndrome, which is a consequence of latent brain plasticity after a thalamic injury.
What are the indications for TPN? How soon can it be started?
Total parenteral nutrition (TPN) should not be started within the first 7 days of ICU admission. Absolute indications for parenteral therapy include: short gut syndrome, small bowel obstruction, active gastrointestinal bleeding, pseudo-obstruction with complete intolerance to food, and high output enterocutaneous fistulas (unless a feeding tube can be passed distal to the fistula).
What are the major opioid side effects?
Opioids can lead to a number of significant adverse effects:
- respiratory depression
- postoperative nausea and vomiting
- acute urinary retention
- skeletal muscle rigidity
- histamine release
- pupillary miosis
How do you help reduce nerve injury during a block?
Methods to help prevent peripheral nerve injury include injection pressure monitoring. The presence of a high opening injection pressure (> 20 PSI) is a sensitive sign of intrafascicular needle tip placement.
In renal failure, the following metabolites may cause neuroexcitatory (seizure, myoclonus) or neurodepressive (sedation, respiratory depression) effects:
- __________ (hydromorphone inactive metabolite)
- _________ (meperidine active metabolite)
- ___________ (morphine active metabolite)
In renal failure, the following metabolites may cause neuroexcitatory (seizure, myoclonus) or neurodepressive (sedation, respiratory depression) effects:
- H3G (hydromorphone inactive metabolite)
- Normeperidine (meperidine active metabolite)
- M6G (morphine active metabolite)
xWhat is the best way to prevent broncho-pulmonary dysplasia in newborns?
Nasal CPAP
Neonates have higher closing capacity and a lower functional reserve capacity compared to adults. This makes them especially prone to atelectasis. CPAP keeps the small airways open. This decreases atelectasis and maintains recruitment. Advantages of the nasal route are that neonates are obligate nose-breathers (until 5 months of age) and a full facemask may cause facial/nasal pressure necrosis. Also, there is some evidence that nasal CPAP is superior to intubation and mechanical ventilation in preventing broncho-pulmonary dysplasia.
Von Willebrand disease can be managed with ______ or ____________ or __________
Von Willebrand disease can be managed with DDAVP, VWF concentrates, and cryoprecipitate.
Cryoprecipitate contains ______________, ___________ , ________, and __________
Cryoprecipitate contains factor VIII, VWF, factor XIII, and fibrinogen.
What are the 3 types of VWD??
Type 1 VWD: partial decrease in VWF concentrations
Type 2 VWD: qualitative defect in VWF
Type 3 VWD: total depletion of VWF
When do you give recombinant factor VII?
Recombinant factor VII is rarely used in clinical practice given the advent of prothrombin concentrate complexes. Additionally, it is used most commonly for hemophilia patients. The use of recombinant factor VII is not supported by the evidence for most cases of major bleeding.
What is the most common manifestation of cyanide toxicity?
Metabolic acidosis (or base excess)Cyanide primarily causes toxicity by impairing cellular aerobic respiration. The cyanide ion (CN-) binds to the ferric ion (Fe3+) in mitochondrial cytochrome-c oxidase, inhibiting the final stage of the electron transport chain. Depletion of cellular ATP and the lactic acid produced by anaerobic metabolism can lead to profound acidosis.
Symptoms of cyanide toxicity include altered mental status, weakness, headaches, loss of consciousness, seizures, respiratory failure, and cardiac arrest. Blood cyanide levels will be elevated, although therapy should not be delayed for the laboratory result. The patients blood sample may appear “cherry red” due to normal circulating levels of oxygen with impaired utilization.
What are the modes on pacemakers?
What does placing a magnet over the PM do?
1: Pacing chambers
2: Sensing
3: Response to sensing
A magnet over a permanent pacemaker will induce a magnet mode of asynchronous pacing to avoid misreading electrocautery signals. In this particular case, a magnet will set this pacer in DOO at a preset rate.
What is the alveolar gas equation?
PAO2 = FiO2 * (Patm - PH2O) - PaCO2/RER
Patm=760; PH20=47; RER= 0.8
What respiratory changes are seen during pregnancy?
As the fetus and uterus grow, expansion of the uterus against the diaphragm leads to a decreased functional residual capacity (FRC). Yet a 20% increase in oxygen consumption and greater CO2 production lead to a higher minute ventilation mostly via increased tidal volume. In addition, progesterone centrally stimulates the respiratory center to further increase minute ventilation to 40-50% baseline and generate the physiological respiratory alkalosis of pregnancy. In this case, normal pH can vary from 7.40-7.47 and PaCO2 is closer to 30 rather than 35-40. Serum bicarbonate decreases to compensate. This combination of increased oxygen consumption and decreased FRC can lead to rapid desaturation after induction of general anesthesia.
What are pregnant ladies hypercoaguable?
Factor VIII, IX, X, and fibrinogen levels are increased while antithrombin and protein S levels decrease causing a hypercoagulable state.
What do you do to relieve aortocaval compression?
Left pelvic tilt–even during CPR
_________ are pregnancy category D and as their chronic use is associated with cleft lip, although some studies contest this. ________ is associated with growth retardation. __________may inhibit fetal skeletal formation and cause tooth enamel hypoplasia. ____________ during pregnancy are associated with fetolethality. _________ can cause mental retardation and skeletal malformation.
Benzodiazepines are pregnancy category D and as their chronic use is associated with cleft lip, although some studies contest this. Cocaine is associated with growth retardation. Tetracyclines may inhibit fetal skeletal formation and cause tooth enamel hypoplasia. ACE inhibitors during pregnancy are associated with fetolethality. Warfarin can cause mental retardation and skeletal malformation.
What are the effects of a VAE?
A venous air embolism causes circulatory compromise by impeding right ventricular filling and output. Initially, this can cause hypotension and decreased cardiac output. It can then progress to pulmonary edema, cor pulmonale, and potentially cardiovascular collapse and death. If sufficient air enters the pulmonary circulation, it can trigger bronchoconstriction (which may lead to shunting), respiratory distress, and can increase dead space ventilation. If air enters the left-sided systemic circulation, it can cause myocardial infarction, arrhythmias, and cerebrovascular compromise. Air can enter the left-sided systemic circulation via right-to-left intracardiac shunts (e.g., patent foramen ovale, which may be present in up to 25% of pediatric patients), though it is also possible for air to transit directly through the pulmonary circulation and into the left-sided systemic circulation in the setting of a large VAE.
What are the most sensitive ways to detect VAE?
In order from most to least sensitive, the following modalities can be used to detect a VAE during craniotomies: 1) TEE (adults) or precordial Doppler ultrasound (infants/children), 2) EtCO2/EtN2/PAP, 3) cardiac output/CVP, 4) SpO2/BP/ECG changes. Echocardiography and Doppler ultrasound are sensitive enough to potentially detect VAE even before physiologic changes can occur.
What are some of the most common causes of a sudden drop in ETCO2?
Acute processes causing impaired CO2 elimination and their associations:
- Cardiovascular collapse: significantly reduced cardiac index
- Massive venous air embolus (VAE): increased end tidal nitrogen
- Large pulmonary embolus (PE): ECG showing S1-Q3 pattern
- Dislodged or kinked endotracheal tube, esophageal intubation: low and rapidly falling SpO2
Processes that cause decreased production of CO2 include:
- Hypothermia
- Hypothyroidism
- Neuromuscular blockade
How do you treat autonomic hyperreflexia during pregnancy?
Neuraxial anesthesia
What is the MOA of heparin? LMWH?
Unfractionated heparin is an indirect inhibitor of thrombin and factor Xa while low molecular weight heparin is an indirect inhibitor of only factor Xa.
What is the MOA of fondaparinux?
Unfractionated heparin is an indirect inhibitor of thrombin and factor Xa while low molecular weight heparin is an indirect inhibitor of only factor Xa.
Which induction drug would you use fo cardiac tamponade?
Ketamine is the drug of choice for cardiac tamponade induction. Its maintenance of spontaneous ventilation and sympathomimetic effects without compromising hemodynamic goals make it the ideal agent for induction of general anesthesia for a patient in acute cardiac tamponade.
The flow of ________________ions across the membrane into the muscle cell and _______ ions out of the cell causes a local depolarization of the muscle cell referred to as an end plate potential. This is responsible for the generation of a muscle action potential
The flow of sodium (Na+) ions across the membrane into the muscle cell and potassium ions (K+) out of the cell causes a local depolarization of the muscle cell referred to as an end plate potential. This is responsible for the generation of a muscle action potential
Binding of acetylcholine to ACh receptors in the motor end plate causes ion channels to open and so allow the ____________ ions to flow across the membrane into the muscle cell. The opening of the ion channel does also allow other cations to pass across the membrane
Binding of acetylcholine to ACh receptors in the motor end plate causes ion channels to open and so allow the sodium (Na+) ions to flow across the membrane into the muscle cell. The opening of the ion channel does also allow other cations to pass across the membrane
If medical management of CRPS fails, what is the next step?
A diagnostic sympathetic block is the next step for failed medical management of complex regional pain syndrome.
Organophosphate toxicity and TX
Inhibit acytylcholinesterase–>increased ACH–>Increased muscarinic site activity
SLUDGE Mi (“Sludge Me”): Salivation, Lacrimation, Urination, Defecation, Gastrointestinal upset, Emesis, Miosis
treatment: Similar to managing the side effects of neostigmine, a cholinergic agent and competitive muscarinic blocker (e.g. atropine or glycopyrrolate) is administered to attenuate and block the muscarinic side effects of the agents.
What is the MOA of sux?
Succinylcholine works by binding to the post junctional neuromuscular receptors causing depolarization, which results in muscular fasciculations.
What do you do with maseter muscle rigidity?
Nasal intubation.
Masseter muscle rigidity (MMR) is a rare event. When it occurs, the clinician should be on the lookout for malignant hyperthermia (MH) as MMR has been linked to MH, although not all MMR will progress to MH. MMR can last a significant period of time and may not immediately resolve.
What is first order kinetics? How is it related to the proportion of the drug concentration?
With first-order elimination, the amount of drug eliminated is directly proportional to the serum drug concentration. All enzymes and clearance mechanisms are working at well below their maximum capacity, and the rate of drug elimination is directly proportional to drug concentration. Most drugs are eliminated in a first-order elimination process.
What are phase one reactions?
Phase 1 reactions include oxidation, reduction, and hydrolysis.
What are phase 2 reactions?
Phase 2 reactions, the resulting metabolites are conjugated with sulfate, glucuronide, or other groups
Drugs associated with 0-order kinetics?
PEA: phenytoin, ethanol, aspirin.
What are the components of the MELD?
The Childs-Pugh?
MELD: “I Crush Beer Daily” for INR, Creatinine, Bilirubin, Dialysis
Child-Pugh: “Pour Another Beer At Eleven” for PT, Ascites, Bilirubin, Albumin, Encephalopathy
When do you give epinephrine in non-shocakble rhythms vs. shockable?
AHA guidelines recommend epinephrine to be administered “as soon as feasible” for non-shockable cardiac arrest. The algorithm for shockable rhythms, on the other hand, calls for defibrillation then 2 min of CPR then defibrillation then epinephrine.
Will inhaled induction be faster in a pregnant lady or a non-pregnant lady?
Inhalational induction will be faster in a pregnant patient compared with a non-pregnant patient. The combination of increased minute ventilation, with a decreased FRC, and decreased MAC requirements causes a significantly faster inhalational induction.
The rate of inhalational induction is inversely related to __________
The rate of inhalational induction is inversely related to functional residual capacity (FRC). FRC is the volume of air in lungs at the end of passive exhalation. When describing an inhalational induction, FRC can be thought of as the lung volume diluting volatile anesthetics. A pregnant patient at term has a 20% reduction in FRC, thereby increasing the speed of an inhalational induction.
How does GBS affect lungs?
Guillain-Barré is an acute inflammatory polyneuropathy causing demyelination of peripheral nerves and restrictive lung disease. The patient loses the ability to inspire a deep breath as weakness worsens, and accessory muscles of respiration are affected. Restrictive type lung conditions demonstrate decreases in the FEV1 and FVC. However, the FEV1/FVC proportions remain normal.
What is the MOA of pregabalin?
Pregabalin is a GABAergic anticonvulsant and depressant of the central nervous system used commonly to treat neuropathic pain syndromes. Its mechanism of action is by binding to α2δ subunit-containing voltage-gated calcium channels and preventing the release of nociceptive neurotransmitters.
What is the difference between tetanus and botulinum?
Botulinum toxin acts inside the axon terminal at the neuromuscular junction. Tetanus toxin travels via retrograde axonal transport to the CNS where it acts.
What nutritional deficiency do you see with prolonged TPN use?
Hyperalimentation is commonly associated with hypophosphatemia, hypo or hyperglycemia, and acute liver injury. Patients on total parenteral nutrition (TPN) require vitamin K supplementation and often have an elevated prothrombin time.
How does acute vs chronic phenytoin use affect NMB?
Acute phenytoin administration potentiates the neuromuscular blockade of aminosteroid NDNBDs. Chronic phenytoin administration increases a patient’s resistance to the effects of NDNBDs and reduces their duration of action.
A continuous machine-like murmur heard best at the upper left sternal border may be identified on physical exam in a patient with a _______________.
Patent ductus arteriosus
Beta-blocker overdose
Beta-blocker overdose can cause atropine- and catecholamine-resistant bradycardia and hypotension. Interventions including pacing, dopamine, and glucagon will increase heart rate via nonadrenergic pathways and are recommended. Glucagon enhances atrioventricular conduction, heart rate, and myocardial contractility by increasing intracellular cAMP independent of adrenergic pathways.
Why is inhaled induction faster in kids?
Inhalational induction is faster with infants and children due to their increased minute ventilation-to-FRC ratio. Onset of hypoxia is quicker in infants primarily due to their increased oxygen consumption of 6 mL/kg/min versus 3 mL/kg/min in adults.
What is myotonic dystrophy?
Myotonic dystrophy is a group of hereditary (usually autosomal dominant) diseases resulting in persistent contracture of skeletal muscle (myotonia) following voluntary contraction or external stimulation. This occurs because, following release, calcium does not efficiently return to the sarcoplasmic reticulum and remains available for sustained muscle contraction.
What are triggers for myotonic dystrophy? and what about treatment?
Perioperative myotonia triggers include shivering from hypothermia, succinylcholine, neostigmine, and direct surgical stimulation of muscle. A myotonic episode can be treated with phenytoin, quinine, procainamide, direct infiltration of the affected muscle with local anesthetic, or a high concentration of volatile anesthetic. Paralytics are not effective for treating myotonia. Patients with myotonic dystrophy are sensitive to the CNS- and respiratory-depressant effects of anesthetic medications and may have exaggerated responses to neuromuscular blockers.
Highest seroconversion from needle stick?
Hep-B
Which molecular structures are affected by volatile anesthetics?
Volatile anesthetics are thought to manipulate background potassium channels, GABA receptors, and sodium channels
What drugs antagonize the NMDA receptor?
Ketamine, nitrous oxide, and xenon have sedative effects modulated by NMDA receptor antagonism.
Which NMBAs ore metabolized?
pancuronium, pipecuronium, vecuronium, atracurium, cisatracurium, and mivacurium are the only drugs that are metabolized or degraded
How is rocuronium eliminated?
Rocuronium itself actually undergoes no clinically significant metabolism. It is eliminated primarily by the liver, with a small fraction (≈10%) eliminated in the urine. It is taken up into the liver by a carrier-mediated active transport system where it is excreted into the bile.
How is atricurium eliminated? What are the two compounds it becomes?
Atracurium is metabolized through two pathways: Hofmann elimination and nonspecific ester hydrolysis. Hofmann elimination is a purely chemical process that results in loss of the positive charges by molecular fragmentation to laudanosine (a tertiary amine) and a monoquaternary acrylate, compounds that are thought to have no neuromuscular and little or no cardiovascular activity of clinical relevance. Of note, laudanosine has been shown to have central nervous system stimulating properties in animals, but in doses largely exceeding what would be obtained in a clinical situation. No deleterious effect of laudanosine has been demonstrated conclusively in humans.
When vecuronium is metabolized, what happens? In what kind of patients id the NMB prolonged?
The principal metabolite of vecuronium, 3-desacetylvecuronium, is a potent (≈80% of vecuronium) NMBD in its own right. The metabolite, however, has slower plasma clearance and longer duration of action than vecuronium. In patients with renal failure in the ICU, 3-desacetylvecuronium can accumulate and produce prolonged neuromuscular blockade.
Which two NMB are eliminated by Hoffman degradation?
Cisatracurium and atracurium are both metabolized via Hofmann elimination. An increase in body pH favors the elimination process where as a decrease in temperature slows down the process
What is the initial treatment for a pheo?
The most common alpha-adrenergic receptor antagonist used to treat pheochromocytoma is phenoxybenzamine
What dose rhabdo look like? What triggers it?
Rhabdomyolysis can be triggered by the use of succinylcholine in patients with a history of Becker (X-linked recessive) and Duchenne muscular dystrophy. Both of these conditions are associated with lack of the dystrophin protein complex leading to weakening of the myocyte cytoskeleton causing cellular lysis with contraction and consequent release of potassium, myoglobin, phosphate, and CPK. This sudden increase in potassium can lead to life threatening hyperkalemia which can appear on ECG initially as peaked T-waves and lead to a wide QRS complex rhythm, then degenerate into ventricular fibrillation.
How does MH present? Is there an association with MD?
Malignant hyperthermia would likely present with findings of hypertension, elevated temperature, and increased end tidal CO2. There is, however, no clear increased risk of malignant hyperthermia in patients with Duchenne or Becker Muscular Dystrophy.
What is the initial cause of heat loss?
The initial reduction in core temperature in patients under general anesthesia is the redistribution of heat from the core to the periphery.
What are the most common causes of metheglobinemia?
Important causes of methemoglobinemia include benzocaine, dapsone, and inhaled nitric oxide.
What is the oxygen carrying equation?
CaO2 = [(SaO2 * Hgb * O2 carrying capacity of Hgb) + (O2 solubility * PaO2)]
SaO2 is the fraction of Hgb that is saturated with oxygen, O2 carrying capacity of Hgb is 1.34 mL of oxygen per gram of Hgb, Hgb is grams of Hgb per 100 mL of blood, PaO2 is the oxygen tension, and the solubility of oxygen in plasma is 0.003 mL of oxygen per 100 mL plasma for each mmHg PaO2.
What do you see in CO toxicity?
CO binds with a high affinity to Hgb. (greater than 200-fold).
The CO-Hgb complex causes two main effects: less oxygen binding sites and reduction in oxygen release. As less oxygen is released, this effect consequently leads to a left shift in the oxygen-hemoglobin dissociation curve. Since the color of CO-Hgb appears similar to normal oxygenated Hgb, the blood may appear light red despite having low oxygen. In addition, the PaO2 will be normal as in methemoglobinemia but the measured oxygen content will be low and severe. Conventional pulse oximetry OVERESTIMATES true SpO2 since CO-Hgb competes with oxyhemoglobin in the absorption spectrum, thus the pulse oximetry may measure a normal saturation value. Lactic acidosis is present in severe cases and can lead to metabolic disturbances. Treatment focuses on administration of 100% oxygen, which functions to displace the CO from the hemoglobin and shortens the half-life of CO. Elimination of CO can be shortened from 4 hours to 40 minutes with the use of supplemental oxygen.
Radiation intensity (exposure) with respect to distance decreases according to the inverse square law: I ∝ 1 / r^2. Accordingly, doubling the distance from a radiation source decreases exposure by a factor of ________
Radiation intensity (exposure) with respect to distance decreases according to the inverse square law: I ∝ 1 / r^2. Accordingly, doubling the distance from a radiation source decreases exposure by a factor of 4.
How do opioids work?
Opioid agonists produce analgesia by binding to specific G protein-coupled receptors (GPCRs) that are located in brain and spinal cord regions involved in the transmission and modulation of pain. Some effects may be mediated by opioid receptors on peripheral sensory nerve endings.
What are the four receptors that opioids bind to? What is their effect?
Four major opioid receptor types have been identified: mu (μ, with subtypes μ1 and μ2), kappa (κ), delta (δ), and sigma (σ). All opioid receptors couple to G proteins; binding of an agonist to an opioid receptor causes membrane hyperpolarization. Opioid receptor activation inhibits the presynaptic release and postsynaptic response to excitatory neurotransmitters (acetylcholine, substance P) from nociceptive neurons.
What is Xenon’s affect on brain parameters?
Xenon produces reduction in CMRO2, but increases ICP and CBF through its action at the NMDA receptor. This is in contrast to nitrous oxide which produces elevations in all three parameters. In general, volatile agents produce increases in CBF and ICP with reduction in CMRO2 when given at > 1.0 MAC.
What is xenon?
Xenon is an inhaled anesthetic that works primarily via inhibition of NMDA receptors, much like nitrous oxide. However, in contrast to nitrous oxide xenon produces a decrease in CMRO2. Additionally, 1 MAC can be achieved at one atmosphere of ambient pressure with xenon but not nitrous oxide.
What qualifies as severe (stage C MR)?
To remember the severe MR criteria, think of 7-6-5-4:
•Vena contracta greater than 0.7 cm
•Regurgitant volume greater than 60 mL
•Regurgitant fraction greater than 50%
•Effective regurgitant orifice greater than 0.4 cm2
•Left ventricle dilation
tell me about fentanyl
Fentanyl is a potent synthetic opioid that interacts primarily with the mu-opioid receptor to give excellent analgesia (it is approximately 100 times more potent than morphine). It has a low molecular weight with high lipid solubility, making it suitable for delivery through a variety of mechanisms – oral, intravenous, intranasal, intramuscular, and transdermal. There have been numerous studies comparing transdermal fentanyl with oral sustained release morphine, especially in the chronic cancer pain population. In those patients, pain relief was as effective and preferred to the oral morphine formulations.
What are the 4 ways to isolate the lung?
- Double lumen endotracheal tube
- Single lumen endotracheal tube, cuffed or uncuffed, that is intentionally placed in the main bronchus of the non-operative lung
- Single lumen endotracheal tube with bronchial blocker that is extraluminal or intraluminal
- Univent endotracheal tube with a dedicated channel for the bronchial blocker
Garlic, ginger, ginkgo, ginseng, green tea, and saw palmetto are all thought to __________________.
Garlic, ginger, ginkgo, ginseng, green tea, and saw palmetto are all thought to increase perioperative bleeding.
Pericardial tamponade is seen with what changes on CVP?
Pericardial tamponade is associated with an exaggerated X-descent and attenuated Y-descent on the central venous pressure waveform.
What are the hemodynamic goals of cardiac tamponade?
Hemodynamic goals for cardiac tamponade are best described as keeping the patient fast (tachycardia), full (hypervolemia), and tight (increased SVR). Some sources describe the goals as “fast, full, and strong” where strong relates to contractility. Either way, cardiac output becomes mostly heart rate dependent so measures that reduce heart rate should be avoided.
Both hypothermia (especially < 27 degrees C) and hyperthermia (especially > 42 degrees C) may _________ the latency and ___________ the amplitude of evoked potentials.
Both hypothermia (especially < 27 degrees C) and hyperthermia (especially > 42 degrees C) may increase the latency and decrease the amplitude of evoked potentials.
What do you use to treat CRPS in lower limbs? What is a complication?
Bilateral lower extremity CRPS can be treated with serial bilateral lumbar plexus nerve blocks. In addition to intravascular, epidural, and intrathecal injection, bilateral lumbar plexus blocks can be complicated by ejaculatory failure in males.
Memantine is an_________________that may be used in the treatment of CRPS.
Memantine is an NMDA antagonist that may be used in the treatment of CRPS.
___________ is associated with a celiac plexus block (T5-12), which supplies innervation to all the intraabdominal organs, including most of the bowel.
Diarrhea is associated with a celiac plexus block (T5-12), which supplies innervation to all the intraabdominal organs, including most of the bowel.
what is esophageal Doppler? How deep should it go?
Esophageal Doppler monitoring is a non-invasive technique for continuous intraoperative cardiac output monitoring. Probes should be placed in the esophagus at a depth of approximately 35 cm with the goal of being seen at the T5-T6 vertebral interspace on chest radiograph.
Transtracheal injection of local anesthetic will block the _______________
Transtracheal injection of local anesthetic will block the recurrent laryngeal nerve.
What is abdominal compartment syndrome?
Intraabdominal hypertension is defined as IAP >12 mm Hg. In the setting of persistent or severe elevated IAP (especially if combined with decreased MAP), abdominal compartment syndrome can develop due to compromised organ perfusion. Clinical manifestations are seen earlier in patients with chronic renal insufficiency, cardiomyopathy, and pulmonary disease.
How does refeeding syndrome present?
Refeeding syndrome presents as hypokalemia, hypomagnesemia and hypophosphatemia
Name the block_______________: Located between C6-7. Can be blocked for pain (vascular, neuropathic, or visceral) that is related to the upper extremities and thorax. Complications include ___________________
Stellate ganglion: Located between C6-7. Can be blocked for pain (vascular, neuropathic, or visceral) that is related to the upper extremities and thorax. Complications include Horner syndrome, tracheal/esophageal injury, pneumothorax, and recurrent laryngeal nerve injury.
Name this block:_____________: Located beside the aorta and inferior vena cava at the level of L1. The block is frequently done with a posterior approach with the entry point just below the 12th rib. This block is done for pain relating to abdominal cancers. Complications include ______________________
Celiac plexus: Located beside the aorta and inferior vena cava at the level of L1. The block is frequently done with a posterior approach with the entry point just below the 12th rib. This block is done for pain relating to abdominal cancers. Complications include bleeding, diarrhea, retroperitoneal hematoma, chylothorax, perforation of nearby structures, and pneumothorax.
Name this block:______________________: Located anterior to L1-L5 and the block is done via a posterior approach. This block may benefit those with neuropathic pain in the lower limbs, phantom limb pain of the lower extremities, and visceral pain involving the intestinal/urinary system. Complications :______________
Lumbar sympathetic chain: Located anterior to L1-L5 and the block is done via a posterior approach. This block may benefit those with neuropathic pain in the lower limbs, phantom limb pain of the lower extremities, and visceral pain involving the intestinal/urinary system. Complications involve perforation of nearby structures, genitofemoral nerve injury, and bleeding.
As opposed to a standard interlaminar epidural injection, what is better treated by transforaminal epidural injection?
Transforaminal epidural injections are best suited for unilateral radiculopathies as compared to interlaminar epidural injections, which are better suited for bilateral neuraxial pain symptoms
What supplies the SA node?
The RCA (55%) and LCx (45%) are the main arteries involved in the blood supply to the SA node and occlusion of the vessel would lead to bradycardia, among other hemodynamic changes.
How do you treat extravisation of vasopressors?
Extravasation of vasopressors can be managed with limb elevation, warm compresses, irrigating with saline (Gault technique), injection of phentolamine, and/or a stellate ganglion block (for upper limbs).
WHere does most drug metabolism occur? What are PHase 1 and phase 2 reactions?
The liver is the principal site for drug metabolism. For many drugs, metabolism occurs in two phases.
Phase I involves modifying the drug through oxidation, reduction, or hydrolysis. These reactions typically inactivate the drug.
Phase II involves conjugation, where a molecule (glucuronic acid, sulfate) is added to the drug to make it more easily excreted from the kidneys and liver.
______________________is the most important enzyme system in phase I and catalyzes the oxidation of many drugs.
Cytochrome p450 is the most important enzyme system in phase I and catalyzes the oxidation of many drugs.
What is the most common arrhythmia in pregnancy? How is it treated?
Arrhythmias occur with increased frequency during pregnancy. The primary indication for adenosine is paroxysmal supraventricular tachycardia, the most common arrhythmia in pregnant women. Adenosine is the agent of choice for the acute management of tachyarrhythmias.
What is citrate toxicity?
Who is at most risk?
Citrate toxicity occurs when a patient receives any blood product that uses citrate as an anticoagulant. Citrate toxicity is highest during fresh frozen plasma administration, however, it can occur with any blood transfusion and is more common in the pediatric patient populations, those with significant liver disease, those undergoing liver transplantation, if the patient is hyperventilated, or if the patient is cooled.
What is FFP?
Fresh frozen plasma is prepared from whole blood collection or through apheresis. FFP is collected in citrate-containing anticoagulation solution. It is frozen within eight hours of collection and can be stored for up to one year at -30 degrees Celsius. FFP contains all clotting factors, fibrinogen, plasma proteins (particularly albumin), electrolytes, physiologic anticoagulants (protein C, protein S, antithrombin), and added anticoagulants (citrate).
What medications cause histamine release (2)
Histamine release associated with morphine and atracurium can potentially induce bronchospasm in patients with reactive airway disease. Succinylcholine is also associated with histamine release, but there is no evidence to suggest an increased incidence of bronchoconstriction with its use.
What are the initial treatments of asthma?
Initial treatment of asthma typically starts with a β2-agonist inhaler, such as albuterol MDI, which should be used for rescue therapy or for treatment prior to an asthma trigger, such as exercise. Along with albuterol, an inhaled corticosteroid such as fluticasone is typically initiated. In addition to these two drugs, cromolyn (a mast cell stabilizer) and/or a leukotriene receptor antagonist such as montelukast can be added for additional anti-inflammatory activity since leukotrienes promote inflammation, especially within the airway.
Patient is intubated and goes into bronchospasm. What is the best treatment?
Severe bronchospasm requires immediate action. Intravenous epinephrine and subcutaneous terbutaline both have very strong β2-agonist activity and will be helpful in this emergent acute setting. Intravenous epinephrine is also a mast cell stabilizer and works to reduce histamine release and inflammation within the bronchial tree.
Intravenous anesthetics, such as ketamine and propofol, can be used to rapidly deepen the level of anesthesia and alleviate bronchospasm.
What electrolyte disturbances are seen most often with MTP?
Massive transfusion has many complications including electrolyte imbalances such as hypocalcemia, hyperkalemia, hypernatremia.
What EKG changes are seen with hypocalcemia?
ECG changes in hypocalcemia include reduced P-R interval, prolonged Q-T interval, and T-wave flattening and inversion.
How frequently should antibiotics be redosed in surgery?
A: Intraoperative re-dosing is needed to ensure adequate serum and tissue concentrations of the antimicrobial if the duration of the procedure exceeds two half-lives of the drug or there is excessive blood loss during the procedure.
What is glycopyrolate?
Glycopyrrolate is an anticholinergic drug that works mainly at the muscarinic receptors. It is a competitive antagonist of acetylcholine at the acetylcholine receptors. Glycopyrrolate or atropine are used in conjunction with neostigmine to block the parasympathetic effects of the cholinergic surge cause by neostigmine
What are the effects of an antimuscarinic like gylco or atropine?
Cardiovascular: There are muscarinic receptors on the SA node of the heart. Blocking these receptors causes tachycardia.
Respiratory
- Muscarinic receptors in the airway mucosa and bronchi are responsible for salivation and respiratory secretions. Blocking these receptors therefore inhibits these secretions, which is beneficial when performing a fiberoptic intubation.
- Blocking muscarinic receptors in the bronchial smooth muscle leads to relaxation and decreased airway resistance.
Gastrointestinal
- Anticholinergic activity leads to decreased salivary gland secretions and gastric secretions. (xerostomia)
- Decreased gastric motility and peristalsis, which can lead to constipation.
Genitourinary
- Blocking muscarinic receptors in the smooth muscle of the bladder causes relaxation and decreased bladder and ureter tone. This can lead to urinary retention, particularly in males with an enlarged prostate.
Ophthalmic
- Anticholinergic activity causes pupillary dilation, which could theoretically cause problems in patients with narrow angle glaucoma. It can also cause photophobia.
Neurologic
- Glycopyrrolate does not cross the blood brain barrier and therefore does not have any neurologic side effects. Other anticholinergics such as atropine and scopolamine, however, can lead to altered mental status and hallucinations.
What is a phase II block?
With increasing doses of succinylcholine (a large single dose, repeated doses, or a continuous infusion), a phase II block may occur. Continuous activation of acetylcholine receptors leads to ongoing shifts of sodium into the cell and potassium out of the cell. Despite this, the post-junctional membrane potential eventually moves in the direction of normal even in the continued presence of succinylcholine. This is due to increased activity of the sodium-potassium ATPase pump, which brings potassium into the cell in exchange for sodium. The receptor does not respond appropriately to acetylcholine, and the neuromuscular blockade is prolonged.
What is sux and how does it work?
It is effectively two ACh molecules joined at the acetate methyl groups. The two quaternary ammonium radicals bind to the two α-subunits of one nicotinic receptor, and depolarization occurs. When voltage-sensitive sodium channels sense membrane depolarization (as a result of activation of the ACh receptors), they first open and thereafter close and become inactivated. The membrane potential must be reset before the sodium channels can be reactivated. This is a very rapid process with ACh (1 ms), as it is hydrolyzed by acetylcholinesterase (AChE) within the synaptic cleft. However, succinylcholine is not metabolized by AChE, so a prolonged activation of the ACh receptors is produced. The sodium receptors at the end-plate and the peri-junctional zone remain inactivated and junctional transmission is blocked. The muscle becomes flaccid.
What is a phase I block?
Depolarization block is also called phase I or accommodation block and is often preceded by muscle fasciculation. This is probably the result of the prejunctional action of succinylcholine, stimulating ACh receptors on the motor nerve, causing repetitive firing and release of neurotransmitter. Recovery from phase I block occurs as succinylcholine diffuses away from the neuromuscular junction, down a concentration gradient as the plasma concentration decreases. It is metabolized by plasma cholinesterase (previously called pseudocholinesterase). Prolonged exposure of the neuromuscular junction to succinylcholine can result in a desensitization block or phase II block.
What is a phase II block?
Phase II block differs from desensitization block. It occurs after repeated boluses or a prolonged infusion of succinylcholine. In patients with atypical plasma cholinesterase, phase II block can develop after a single dose of the drug. The block is characterized by fade of the train-of-four (TOF) twitch response, tetanic fade, and post-tetanic potentiation, which are all features of a competitive block. After the initial depolarization, the membrane potential gradually returns towards the resting state, even though the neuromuscular junction is still exposed to the drug. Neurotransmission remains blocked throughout.
How are phase I and phase II blocks different?
With regard to nerve stimulation, a phase II block has features of a non-depolarizing block (e.g. fade is seen with tetanic and train-of-four stimulation; there is post-tetanic potentiation). This is in contrast to a phase I block in which no fade is seen with tetanic or train-of-four stimulation and there is no post-tetanic potentiation.
What are the three intial medical therapies for uncomplicated hypertension?
As per the JNC 8, thiazide diuretics, calcium channel blockers (amlodipine), angiotensin-converting enzyme inhibitors, or angiotensin receptor blockers are the recommended initial therapy in non-African American patients diagnosed with uncomplicated hypertension.
beta blockers are NOT first line
What is the right amount of pressure to not allow for gastric insuflation?
In the setting of appropriate NPO time, the threshold inspiratory pressure via facemask ventilation for reducing gastric insufflation while still allowing proper lung tidal volumes in an adult patient is 15 cm H2O. Gastric insufflation induces gastric adaptive relaxation and a transient LES relaxation increasing the risk for aspiration.
When is the right side of the heart perfused? What happens with pulmonary HTN?
The normal right ventricle is perfused throughout the cardiac cycle. Flow to the left ventricle (and the right ventricle in cases of chronic pulmonary hypertension) is largely confined to diastole.
WHat is PSV?
Pressure support ventilation (PSV) is a ventilatory mode that is triggered by the patient’s spontaneous effort and is assisted by a constant positive pressure. As such, PSV supports respiratory muscles and improves tidal volume for a given respiratory effort (the patient generates a greater volume than during spontaneous breathing). PSV can be either flow-triggered or pressure-triggered.
Must be spontaneously breathing. On Draegers, PSV is not a true PSV since it has a back-up rate.
What nerve proiveds sensation to the arm that can be a problem with tourniquets?
The intercostobrachial nerve provides sensory innervation to the medial brachium and does not originate from the brachial plexus. It originates from the T2 dermatome. Blockade of this nerve is required when an upper arm tourniquet is required and would not be successful with any brachial plexus block technique.
Inadequate analgesia in the lateral forearm after axillary block suggests sparing of the ______________ nerve which gives off the sensory lateral antebrachial cutaneous nerve of the forearm and can be supplemented by injecting local anesthetic into the coracobrachialis muscle.
Inadequate analgesia in the lateral forearm after axillary block suggests sparing of the MUSCULOCUTANEOUS nerve which gives off the sensory lateral antebrachial cutaneous nerve of the forearm and can be supplemented by injecting local anesthetic into the coracobrachialis muscle.
What is MAC-BAR?
The MAC-BAR is the MAC value at which the adrenergic response (e.g., hemodynamic, sudomotor) to noxious stimuli is blunted. This has been found to be approximately 50% higher than standard MAC (A). Some studies estimate this value as 1.7-2.0 MAC.
What is Cushing’s triad?
Brainstem manipulation or pressure on the brainstem can cause significant hemodynamic derangements. The Cushing triad of hypertension, bradycardia, and breathing alterations are due to brainstem compression (from either cerebral edema pushing down on the brainstem or from surgical manipulation intraoperatively).
What do carbonic anhydrase inhibitors do?
Carbonic anhydrase inhibitors blunt sodium bicarbonate reabsorption and cause diuresis.
What do Loop diurectics do?
Loop diuretics inhibit the activity of the Na+/Cl-/K+ symporter in the thick ascending limb of the loop of Henle.
How do K+ sparing diurectics work?
Potassium-sparing diuretics prevent K+ secretion by antagonizing the effects of aldosterone in collecting tubules.
Why is maintaining a neutral thermal environment for newborns important?
When neonates are hypothermic, nonshivering thermogenesis is the primary means to generate heat (oxidation of brown fat). This increases glucose consumption and increases the risk of hypoglycemia. Maintenance of a neutral thermal environment will help decrease the risk of hypothermia and thus decrease the risk of hypoglycemia.
____________________ injury results in weak voice, hoarseness, and paramedian (adduction) position of the ipsilateral vocal cord. _____________ results in airway obstruction requiring tracheostomy.
Unilateral recurrent laryngeal nerve injury results in weak voice, hoarseness, and paramedian (adduction) position of the ipsilateral vocal cord. Bilateral injury results in airway obstruction requiring tracheostomy.
What is the inital treatment of laryngospasm?
Unilateral recurrent laryngeal nerve injury results in weak voice, hoarseness, and paramedian (adduction) position of the ipsilateral vocal cord. Bilateral injury results in airway obstruction requiring tracheostomy.
What is covered by an axillary nerve block?
An axillary nerve block primarily targets the median nerve (sensation in medial forearm), radial nerve (sensation in dorsal hand), and ulnar nerve (sensation in palmar hand). The musculocutaneous nerve (sensation in lateral forearm) is often spared secondary to a proximal take-off from the brachial plexus and since the nerve does not travel within the axillary sheath.
Hepatopulmonary is caused how? What are the signs and symtpoms?
Hepatopulmonary syndrome is a syndrome of shortness of breath and hypoxemia (low oxygen levels in the blood of the arteries) caused by vasodilation (broadening of the blood vessels) in the lungs of patients with liver disease. Dyspnea and hypoxemia are worse in the upright position (which is called platypnea and orthodeoxia, respectively). Hepatopulmonary syndrome results from the formation of microscopic intrapulmonary arteriovenous dilatations in patients with chronic liver disease. The mechanism is incompletely understood but is thought to be due to increased hepatic production or decreased hepatic clearance of vasodilators, possibly involving nitric oxide. The dilation of these blood vessels causes over-perfusion relative to ventilation, leading to ventilation-perfusion mismatch and hypoxemia. There is an increased gradient between the partial pressure of oxygen in the alveoli of the lung and adjacent arteries while breathing room air.
What is the difference between CRPS I and II?
Complex regional pain syndrome is separated into types I and II according to the inciting event. Type I (formerly known as reflex sympathetic dystrophy or RSD) is usually caused by a trivial injury, sprain, crush injury, or burn. Type II (formerly known as causalgia) is caused by a traumatic injury to a major nerve trunk such as significant orthopedic trauma, gunshot injuries, or knife wounds. With either diagnosis, patients may develop burning pain and allodynia (pain to non-noxious stimuli). Both syndromes are also characterized by autonomic dysfunction, which presents with localized temperature changes, cyanosis, and/or edema. If the disease progresses without treatment, the skin can become glossy, smooth, and hairless.
The order for repair of hypoplastic left heart syndrome is “Not Gonna Fly”: _________________
The order for repair of hypoplastic left heart syndrome is “Not Gonna Fly”: Norwood, Glenn, Fontan.
What is obstructive shock?
The primary hemodynamic derangement in obstructive shock is decreased venous return. CVP is typically elevated, CO decreased, SVR increased, and PAOP may be increased or decreased depending on the underlying etiology of obstructive shock. he primary hemodynamic derangement in obstructive shock is decreased venous return. CVP is typically elevated, CO decreased, SVR increased, and PAOP may be increased or decreased depending on the underlying etiology of obstructive shock.
What HD changes are seen in cardiogenic shock?
Cardiogenic shock is a failure of the heart to generate enough cardiac output to provide adequate end organ perfusion. Similar to obstructive shock, in cardiogenic shock, CO is decreased, CVP is elevated, SVR is increased, and PAOP is increased.
What HD changes are seen in distributive shock?
Distributive shock is a failure of the vasculature to generate adequate SVR. In distributive shock, CVP is low, PAOP is low, SVR is low, and CO is high. Common causes of distributive shock are septic shock, anaphylactic shock, and neurogenic shock.
What changes are seen in hypoveolemic shock?
Hypovolemic shock results from intravascular volume depletion. The body has a decreased preload (CVP and PAOP) as the primary hemodynamic derangement. Hypovolemic shock results in decreased CO, increased SVR, decreased CVP, and decreased PAOP.
How is synthetic liver function best assessed?
Synthetic liver function is best assessed via the PT/INR, which most closely correlates with factor VIIa levels.
What EKG changes are seen with hypocalcemia?
Hypocalcemia prolongs phase 3 of the cardiac myocyte action potential which lengthens repolarization time. These effects can manifest as a prolongation of the QT interval on ECG.
Where is the obturator block palced?
The obturator block is performed by injecting local anesthetic between the adductor longus and brevis muscles.The mnemonic ALABAMa is used to remember the muscles from superficial to deep: Adductor Longus, Adductor Brevis, Adductor Magnus.
Does cyanide otxicity change oxygen delivery to tissue?
Cyanide toxicity does not lead to a decreased oxygen delivery. Instead, it affects the way that tissues can use oxygen. Cyanide is a toxin that inhibits cytochrome oxidase, leading to interference with oxidative metabolism and cellular use of oxygen. The delivery of oxygen usually increases in the acute phase of toxicity as the body tries to compensate for the cells’ inability to use the oxygen.
O2 delivery equation?
DO2 = CaO2 x CO x 10
CaO2 = arterial oxygen content CO = cardiac output (which is heart rate x stroke volume)
O2 content equation?
CaO2 = SaO2 x Hgb x 1.34 + (PaO2 x 0.003)
CaO2 = arterial oxygen content (mL/dL)
SaO2 = arterial oxygen saturation
Hgb = hemoglobin concentration (g/dL)
PaO2 = arterial partial pressure of oxygen (mm Hg)
1.34 is used because it is the oxygen carrying capacity of hemoglobin and 0.003 is used as it is the solubility coefficient of oxygen in plasma
Tell me about cyanide toxicity: cause, mechanism, tx
Cyanide toxicity can occur with the use of sodium nitroprusside. Sodium nitroprusside is used as a vasodilator, however its metabolism results in the release of cyanide ions. Usually the cyanide ions are metabolized and no side effects occur. When higher doses of nitroprusside are used for prolonged periods of time, cyanide can build up and toxicity occurs. Cyanide toxicity is characterized by metabolic acidosis and cardiac arrhythmias. Treatment is with hydroxocobalamin.
How does cardiogenic pulmonary edema occur?
Cardiogenic pulmonary edema occurs due to left ventricular failure, mitral stenosis, or left atrial obstruction. Increased hydrostatic pressures in the pulmonary vasculature lead to interstitial edema followed by increased alveolar fluid. Alveolar flooding occurs more in the dependent areas of the lung, which causes intrapulmonary shunting. This results in hypoxemia, hyperventilation, and hypocapnia, which can manifest in acute respiratory failure.
How is cardiogenic pulmonary edema treated?
Cardiogenic pulmonary edema is most appropriately treated by supplemental oxygen, diuresis (especially loop diuretics***not osmotic diuretics, though), vasodilators, inotropes, and positive end-expiratory pressure (PEEP).
_________ is the major extracellular cation while _________ is the major intracellular cation.
Sodium is the major extracellular cation while potassium is the major intracellular cation.
What causes a right shift?
Hyperthermia, acidosis, high pCO2, and high levels of 2,3-DPG cause a shift to the right.
What is lung protective ventilation?
The optimal tidal volume in acute respiratory distress syndrome (ARDS) is 6 mL/kg ideal body weight (IBW).
Tourniquet pain despite supraclavicular nere block?
A supraclavicular nerve block occurs at the level of the brachial plexus trunks and divisions, but misses the intercostobrachial fibers coming from T2 and T1 (not from the brachial plexus). The intercostobrachial nerve fibers supply the inner aspect of the upper arm and should be anesthetized in order to prevent tourniquet pain. Tourniquet pain usually begins after 45 minutes of inflation and is described as a dull aching pain and/or restlessness. The intercostobrachial nerve block is performed by subcutaneous injection of 3-5 mL of local anesthetic along the axillary crease. This is ideally performed prior to the surgery but could also be performed during surgery if the anesthesiologist is able to reach the upper arm crease, which should not be blocked by the upper arm tourniquet.
What distrubution is often spared in an intrascalene block?
Interscalene blocks can be associated with incomplete coverage in the ulnar distribution due to C8 and T1 sparing (50% of the time)
T/F:Patients undergoing laparoscopic procedures are at an increased risk of postoperative nausea and vomiting.
True
What CV and endocrine changes are seen with laparoscopy?
The cardiovascular changes of laparoscopy include an increase in systemic vascular resistance (SVR) and mean arterial pressure (MAP), which is caused by increased sympathetic output from CO2 absorption and a neuroendocrine response to pneumoperitoneum. Pneumoperitoneum-related increased intra-abdominal pressure (IAP) results in activation of the sympathetic system with catecholamine release and the renin-angiotensin system with vasopressin release.
Block of which ganglion is good in a FESS?
The sphenopalatine ganglion provides sensory innervation to the nasal mucosa and can be blocked by local anesthetic to reduce stimulation in patients undergoing FESS.
What happens to CBF during pH stat?
pH-stat management infuses extra CO2 into the blood, causing increased CBF and improved homogenous cerebral cooling during hypothermic cardiopulmonary bypass. pH-stat management adds CO2 to blood which causes a decrease in pH causing a Bohr shift with the rightward shift of the oxyhemoglobin dissociation curve (increased P50).
What is the difference between pH stat and alpha-stat?
Alpha-stat management maintains normocarbia and normal pH, based on the assumption that the patient is 37 degrees Celsius. pH-stat management maintains normocarbia and normal pH, based on the actual temperature of the patient. So if the patient is being cooled to 27 degrees Celsius, then the blood gas will be corrected for a body temperature of 27 degrees Celsius. As blood gets colder the partial pressures of CO2 and O2 decrease. So in pH-stat management, the CPB circuit infuses CO2 into the blood to maintain a normal pH at whatever the body temperature is at that point in the case.
What is the reduction in radiation exposure by doubling the distance?
Radiation exposure is inversely proportional to the square of the distance (1/radius^2). By doubling the radius from the source of radiation, the resultant incident radiation is 1/4th.
Myasthenia gravis risk factors increasing risk of reintubation?
- Duration of disease ≥ 72 months (≥ 6 years)
- History of a chronic respiratory disease (e.g. asthma and COPD)
- Pyridostigmine dose of > 750 mg/day
- Vital capacity < 2.9 liters (or < 40 mL/kg)
_______________bis associated with resistance to succinylcholine and sensitivity to nondepolarizing neuromuscular blocking agents.
_________ is associated with a sensitivity to both succinylcholine and nondepolarizing neuromuscular blockers.
Myasthenia gravis is associated with resistance to succinylcholine and sensitivity to nondepolarizing neuromuscular blocking agents. Eaton-Lambert syndrome, or myasthenic syndrome, is associated with a sensitivity to both succinylcholine and nondepolarizing neuromuscular blockers.
Efficacy of epidural steroid injections (ESIs) for lumbar radiculopathy is ____________ correlated with duration of symptoms.
Efficacy of epidural steroid injections (ESIs) for lumbar radiculopathy is inversely correlated with duration of symptoms.
What has a longer context-sensitive half-life: propofol or dexmeditomidine?
Context-sensitive halftime is the time required for the drug plasma concentration (rather than drug effect) to decrease by one half following discontinuation of a drug infusion. Dexmedetomidine has a longer context-sensitive half-time than propofol. After an 8 hour infusion, the context-sensitive half-time of dexmedetomidine is about six-fold that of propofol (250 min vs 40 min)
Early decelerations are caused by _________ and late decelerations caused by_____________.
Early decelerations are caused by head compression and late decelerations caused by hypoxemia.
What is the signfiicance of early decels?
Early decelerations occur simultaneously with uterine contractions and usually are less than 20 bpm below baseline. The onset, nadir, and offset of each deceleration coincides with the onset, nadir, and offset of the uterine contraction. Head compression can precipitate early decelerations which are believed to result from reflex vagal activity secondary to mild hypoxia. Early decelerations are not ominous.
What is the signficance of late decels?
Late decelerations lag 10 to 30 seconds behind the uterine contractions with their onset, nadir, and offset. Late decelerations are smooth and occur with every uterine contraction. Late decelerations represent a response to hypoxemia (e.g., uteroplacental insufficiency).
What are variable decels?
Variable decelerations, as the name suggests, vary in depth, shape, and duration. They often are abrupt in onset and offset without coinciding with uterine contractions. Variable decelerations result from baroreceptor or chemoreceptor-mediated vagal activity. Umbilical cord occlusion, either partial or complete, results in variable decelerations.
Where is a cuadal epidural placed?
Caudal epidurals are performed through the sacral hiatus at the level of S4-S5.
What is the target CPP in a TBI patient?
Maintenance of cerebral perfusion pressure is exquisitely important when caring for a patient with a traumatic brain injury. Even a single episode of hypotension decreases cerebral perfusion enough to affect outcomes. The CPP value to target lies within the range of 50-70 mm Hg according to current BTF guidelines.
___________ changes demonstrate a direct relationship with the force of contraction while ____________ changes demonstrate an indirect relationship with the velocity of fiber shortening.
Preload changes demonstrate a direct relationship with the force of contraction while afterload changes demonstrate an indirect relationship with the velocity of fiber shortening.
What does an occipital nerve block treat?
Occipital nerve block is both diagnostic and therapeutic in treating occipital neuralgia. If the patient has no relief of their headache after block trial, the diagnosis of occipital neuralgia becomes unlikely.
What are the most common side effects of thiazide diuretics?
Adverse effects unique to the use of thiazides include hypercalcemia and hyperuricemia
What are the side effects of triamterene and amiloride?
Triamterene and amiloride block the exchange between Na+ and both K+ and H+ in the late distal tubule and collecting duct. Excessive loss of K+ is prevented. Hyperkalemia and hyperkalemic, hyperchloremic metabolic acidoses are significant complications of the injudicious use of triamterene and amiloride.
What effect does mannitol have on the body?
As mannitol shifts water between fluid compartments, there can be effects on plasma and intracellular electrolyte concentrations, including hyponatremia and hypochloremia and intracellular increases in K+ and H+. Patients with normal renal function quickly correct these changes, but patients with renal impairment may develop significant circulatory overload with hemodilution and pulmonary edema, hyperkalemic metabolic acidosis, central nervous system depression, and even severe hyponatremia requiring urgent hemodialysis.
What are the loop diurtics and what are their side effects
Furosemide, bumetanide, torsemide, and ethacrynic acid are classified as loop diuretics because of their action in inhibiting the reabsorption of electrolytes in the thick ascending loop of Henle. All four drugs are rapidly absorbed from the gastrointestinal tract and are highly protein bound. Although loop diuretics have no proven mortality benefit, they reduce left ventricular filling pressures and very effectively relieve the symptoms of congestion, pulmonary edema, extremity swelling, and hepatic congestion. Adverse effects of loop diuretics include hypokalemia, hyponatremia, hyperuricemia, and also acute kidney injury.
WHat can be given to reduce epistaxis risk in nasal intubations?
Intranasal administration of vasoconstrictors such as oxymetazoline and phenylephrine can help prevent epistaxis during nasotracheal intubations. Oxymetazoline is an alpha-1 adrenergic receptor agonist and alpha-2 adrenergic receptor partial agonist. When used as a nasal spray, it causes vasoconstriction of the nasal mucosal vessels. This is used to treat rhinorrhea, but can also prevent epistaxis by decreasing blood flow. Beware pf hypertension.
What electrolyte changes are seen in chronic alcoholics?
Electrolyte and acid-base abnormalities including hypokalemia, hypomagnesemia, hyponatremia, hyperuricemia, metabolic acidosis, and respiratory alkalosis are common in alcoholics.
TACO or TRALI?
New onset or exacerbation of three or more
of the following within 6 hours of transfusion:
- Acute respiratory distress (dyspnea, cough, orthopnea)
- Increased brain natriuretic peptide (BNP)
- Increased central venous pressure (CVP)
- Evidence of left heart failure
- Evidence of positive fluid balance
- Radiographic evidence of pulmonary edema
TACO
TACO or TRALI?
1) Acute lung injury (ALI)
- Acute onset
- Hypoxemia (PaO2:FiO2 ≤ 300 mm Hg or SpO2 < 90%
on room air, or other clinical evidence of hypoxemia
- Bilateral infiltrates on frontal chest radiograph
- No evidence of left atrial hypertension as the sole
explanation for the clinical findings
2) No pre-existing ALI before transfusion
3) Onset during or within 6 hours of transfusion
4) No temporal relationship to an alternative
risk factor for ALI
TRALI
An otherwise healthy patient undergoing laparoscopic surgery under general endotracheal anesthesia develops asystole with abdominal insufflation.
Acute stretching of the peritoneum that occurs with abdominal insufflation may result in a huge vagal response. Bradycardia, bradyarrhythmias, and asystole can occur. Slow insufflation will help to avoid the vasovagal response that can occur. Additionally it will reduce the risk of gas embolism.
What is the greatest predictor of stroke in a pt with a SAH?
Morbidity and mortality after SAH most commonly occur secondary to rebleeding, cerebral ischemia, and hydrocephalus. Admission hemoglobin has been shown to be a predictor of cerebral infarction and outcomes in patients with SAH. Classic “triple H” therapy may contribute to complications after SAH.
How does sympathetic activity affect SA node firing?
Sympathetic activation leads to a sharper, or increased, slope of phase 4 which causes the triggering threshold of the membrane potential to be reached quicker thus leading to depolarization.
