Flashcards in Chapter 8 - Anesthesia Deck (53):
MAC (minimum alveolar concentration) equals what?
Smallest concentration of inhalation agent at which 50% of patients will not move with incision
Small MAC means what?
More lipid soluble = more potent = slow speed of induction
Effects of inhalational agents?
Unconsciousness, amnesia, some degree of analgesia
Side effects of inhalational agents?
Blunted hypoxic drive, myocardial depression, increased cerebral blood flow, decreased renal blood flow
Characteristics of NO2?
Fast, minimal myocardial depression
Characteristics of halothane?
Slow, highest degree of cardiac depression and arrhythmias, least pungent (good for kiddies)
What is halothane hepatitis?
Fever, eosinophilia, jaundice, increased LFTs
Side effect of enflurane?
Characteristics of sevoflurane?
Less myocardial depression, fast on/off, less laryngospasm, higher cost
Side effects of sodium thiopental (barbiturate)?
Decreased cerebral blood flow and metabolic rate, decreased blood pressure
Characteristics of propofol?
Very rapid distribution and on/off, amnesia, sedative; NOT an analgesic
Side effects of propafol?
Hypotension, respiratory depression; do not sure in pts with egg allergy
Characteristics of ketamine?
Dissociation of thalamic/limbic systems, places pts in cataleptic state (amnesia, analgesia); no respiratory depression
Side effects of ketamine?
Hallucinations, catecholamine release (inc. CO and tachycardia), inc. airway secretions, inc. cerebral blood flow (contraindicated in head injuries)
Characteristics of etomidate?
Fewer hemodynamic changes, fast acting
Side effect of etomidate?
Continuous infusions can lead to adrenocortical suppression
What is the last muscle to go down and 1st to recover from paralytics?
What is the 1st muscles to go down and last to recover from paralytics?
Neck and face muscles
What is the only depolarizing agent?
Characteristics of succinylcholine?
Fast, short acting; causes fasciculations
Side effects of succinylcholine?
Malignant hyperthermia, inc. ICP, incraed end-tidal CO2 then fever, tachycardia, rigidity, acidosis, hyperkalemia
Treatment of malignant hyperthermia?
Dantrolene: inhibits Ca release and decouples excitation complex; cooling blankets, HCO3, glucose, supportive care
What patients do you NOT use succinycholine in?
Burn patients, neurologic injury, neuromuscular disorders, spinal cord injury, massive trauma, acute renal failure
Nondepolarizing agents MOA?
Inhibit neuromuscular junction by competing with ACh
What can cause prolongation of nondepolarizing agents?
Hypothermia, hypercarbia, certain abx, electrolyte abnormalities, myasthenia gravis
Which nondepolarizing agent can be used in liver and renal failure?
Cis-atracurium (because it undergoes Hoffman degradation)
Where is rocuronium metabolised?
How does neostigmine reverse nondepolarizing agents?
Blocks AChE, increasing ACh
How does edrophonium reverse nondepolarizing agents?
Blocks AChe, increasing ACh
What should be given with nondepolarizing reveral agents to counteract effects of generalized ACh overdose?
Atropine or glycopyrrolate
How do local anesthetics work?
By increasing action potential threshold, preventing Na influx
What is the max dose of 1% lidocaine?
Why are infected tissues hard to anesthetize?
When should you not use epinephrine with local anesthetics?
Patients with arrhythmias, unstable angina, uncontrolled hypertension, poor collaterals, uteroplacental insufficiency
What type of local anesthetic has a higher rate of allergic reaction?
Esters (secondary to PABA analogue)
What happens when you mix narcotics in patients on MAOIs?
Can cause hyperpyrexic coma
Effects of narcotics?
Profound analgesia, respiratory depression (dec. CO2 drive), no cardiac effects, blunted sympathetic response
Unique side effects of morphine?
Decreased cough, constipation, histamine release
Unique side effects of demerol?
Tremors, fasciculations, convulsions, NO histamine release
In which patients should you avoid the use of demerol?
Renal failure - can get buildup of normeperidine analogue and result in seizures
Morphine in epidural can cause what?
Lidocaine in epidural can cause what?
Decreased heart rate and blood pressure
Treatment for acute hypotension and bradycardia in patient with epidural?
Turn epidural down, fluids, phenylephrine, atropine
Treatment for spinal headaches?
Rest, increased fluids, caffeine, analgesics; blood patch if persists >24h
Contraindications for spinal anesthesia?
Hypertrophic cardiomyopathy, cyanotic heart disease
What two conditions are associated with the most postoperative hospital mortality?
CHF and renal failure
Presentation of post-op MI?
May have no pain or EKG changes; hypotension, arrhythmias, increased filling pressures, oliguria, bradycardia
Which patients need a cardiology workup?
Angina, previous MI, SOB, CHF, FEV1 5/min, age >70, patients undergoing major vascular surgery
Biggest risk factors for postop MI?
Age >70, DM, previous MI, CHF, unstable angina
What is the best determinant of esophageal vs. tracheal intubation?
End tidal CO2
What causes an intubated patient to have sudden transient rise in ETCO2?
Alveolar hypoventilation; increase TV or RR