ABSITE Review - Anesthesia Flashcards
What is MAC?
Minimum alveolar concentration = smallest concentration of inhalational agent at which 50% of patients will not move with incision.
Explain the potency of MAC vs solubility.
Small MAC –> more lipid soluble = more potent
Nitrous is fastest but has high MAC (low potency)
Speed of induction is inversely proportional to solubility
Describe the potency and side effects of the following INHALATIONAL AGENTS: nitrous oxide, halothane, enflurane, isoflurane and sevoflurane.
Nitrous oxide - fast, minimal myocardial depression
Halothane - slow, highest degree of cardiac depression and arrhythmias
Enflurane - seizures
Isoflurane - good for NSG; higher cost
Sevoflurane - fast, less myocardial depression
Which induction agent is contraindicated in patients with head injury?
Ketamine
What are the side effects of sodium thiopental?
decrease cerebral blood flow and metabolic rate, decrease BP
What are the side effects of propofol? When is this contraindicated?
SEs: hypotension, respiratory depression
Do not use in patients with egg allergy
What are the side effects of ketamine?
SEs: hallucinations, catecholamines release (increase carbon monoxide, tachycardia), increase airway secretions and increase cerebral blood flow
Mention the indication for a rapid sequence intubation.
Recent oral intake, GERD, delayed gastric emptying, pregnancy, bowel obstruction
What is the last muscle to go down and 1st muscle to recover from paralytics?
Diaphragm
What is the 1st muscle to go down and the last to recover from paralytics?
Neck muscles and face
What is the only depolarizing agent? What are the side effects?
Succinylcholine
SEs: increase ICP, malignant hyperthermia
What is the 1st sign of malignant hyperthermia?
Increase end tidal CO2 then fever, tachycardia, rigidity, acidosis, hyperkalemia
Why malignant hyperthermia occurs?
Defect in calcium metabolism. Calcium released from sarcoplasmic reticulum causes muscle excitation –> contraction syndrome.
What is the treatment of malignant hyperthermia?
Dantrolene (10mg/kg) inhibits Ca release and decouples excitation complex, cooling blankets, HCO3, glucose, supportive care
In which patients, is succinylcholine contraindicated?
Do not use in burn patients, neurologic injury, neuromuscular disorders, spinal cord injury, massive trauma, acute renal failure
What is the MOA of nondepolarizing agents?
Inhibit neuromuscular junction by competing with acetylcholine. Can get prolongation of these agents with hypothermia, hypercarbia, certain antibiotics, electrolyte abnormalities, myasthenia gravis.
Which nondepolarizing agent can be used in liver and renal failure patients?
Cis-atracurium which undergoes Hoffman degradation
Which nondepolarizing agents cause histamine release?
Cis-atracutium and Mivacurium
Which nondepolarizing agent undergoes hepatic metabolism?
Rocuronium
Which nondepolarizing agent undergoes renal metabolism?
Pancuronium
Which nondepolarizing agent cause tachycardia?
Pancuronium
What is the MOA of neostigmine and edrophonium?
Counters non-depolarizing agents. Blocks AchE, increased Ach
Why atropine or glycopyrrolate should be given with neostigmine or edrophonium?
To counteract effects of generalized acetylcholine overdose
What is the maximum dose of lidocaine?
0.5cc/kg
What is the relation in lenght of action for lidocaine, bupivacaine and procaine?
bupivacaine > lidocaine > procaine
Which patients cannot have epinephrine in their local anesthetics?
Arrhythmias, unstable angina, uncontrolled HTN, poor collaterals (penis and ear), uteroplacental insufficiency
Mention the amides of local anesthetics.
Lidocaine, bupivacaine, mepivacaine (have “i” in first part of the name)
Mention the esters of local anesthetics.
Tetracaine, procaine, cocaine
What is the drug of choice for narcotic overdose?
Narcan
What is the drug of choice for benzodiazepine overdose?
Flumazenil
Which benzodiazepine is contrindicated in pregnancy because it cross the placenta?
Versed
What is the treatment for acute hypotension and bradycardia cause by epidural anesthesia?
Turn epidural down, fluids, phenylephrine, atropine
What is the treatment for spinal headaches?
Rest, increased fluids, caffeine, analgesics; blood patch to site if persists > 24 hrs.
Which patients need cardiology work up prior to surgery?
Angina, previous MI, SOB, CHF, walks 5/min, age > 70, pts undergoing major vascular surgery
Describe the ASA classes.
ASA I - Healthy
ASA II - Mild disease without limitation (controlled HTN, obesity, DM, significant smoking history, older age)
ASA III - Severe disease (angina, uncontrolled HTN, DM w complications, moderate COPD)
ASA IV - Severe constant threat to life (unstable angina, CHF, renal failure, liver failure, severe COPD)
ASA V - Moribund (ruptured AAA, saddle PE, ascending aortic dissection resulting in heart failure)
ASA VI - Donor
ASA E - Emergency
What are the biggest risk factors for postop MI?
age > 70, DM, previous MI, CHF, and unstable angina
What is the best determinant of esophageal vs tracheal intubation?
End tidal CO2
What is the adequate position for ETT?
Should be placed 2cm above the carina.
