General anesthesia 1/9

Question 1

drugs which are not anesthetics

Answer 1

narcotics,sedatives,muscle relaxants

Question 2

properties of anesthesia

Answer 2

1) unconsciosuness and amnesia (benzos,NO)
2) analgesia (long and short-acting narcs)
3) blunting of protective reflexes (anesthetics)
4) reduced muscle tone (paralytics)

Question 3

inhaled anesthetics

Answer 3

NO(gas at room temp)

halogenated hydrocarbons(volatile liquids at room temp):

isoflurane,sevoflurane,desflurane,enflurane,halothane

Question 4

IV anesthetics

Answer 4

thiopental(used in capital punishment)

methohexit

etomidate(tolerated well in pts with shock)

propofol

ketamine

Question 5

depth of anesthesia

Answer 5

stage1: analgesia=pt conscious, pain tolerance increased(only NO and ketamine)
stage2: excitement=disinhibition,pt unresponsive to command,thrashing even without stimulation
stage3: surgical anesthesia=pt still,not responsive to command or surgical stimulation
stage4: medullary depression=life-threatening CV and resp depression

Question 6

basic concepts of inhaled anesthetics

Answer 6

effect is produced by partial pressure, not by concentration

agents that are highly soluble will require more dissolved molecules (more time) to produce anesthesia.

agenst with lower solubility produce faster induction and faster recovery

Question 7

how to measure solubility

Answer 7

blood:gas coefficient=ratio of blood concentration to gas concentration.

low B:G=low solubility=faster action

Question 8

minimal alveolar concentration MAC

Answer 8

alveolar concentration at which 50% of healthy pts do not move.

each pt respond differently

MAC is decreased in elderly,pregnancy and sickness

Question 9

factors influencing change of alveolar concentration

(during induction)

Answer 9

solubility of agent=lower–>faster rise

anesthetic concentration=higher–>faster rise

ventilation=normal is optimal for induction

cardiac output=lower CO–>faster rise

concentration in venous blood=hight–>faster rise

Question 10

factors influencing change of alveolar concentration

(during emergence)

Answer 10

same factors with exceptions

inspired concentration can’t be lower than zero

long anesthetic time–>higher venous concentration–>slower drop in alveolar concentration

Question 11

mechanism of action of inhaled anesthetics

Answer 11

unknown

Question 12

effects on cellular metabolism

Answer 12

metabolism decreases,O2 consumption decreases,myocardial O2 consumption decreases, O2 demand decreases,O2 supply decreases

Question 13

effects of sympathetic tone

Answer 13

decreases,arteries dilate,veins dilate,contractility and HR decrease

Question 14

effects on CV

Answer 14

some decrease in contractility,SA node changes, some directly dilate arteries

Question 15

effects on Resp

Answer 15

TV decreases,RR increases,alveolar ventilation decreases,response to hypercarbia and hypoxemia decreases,CO2 apnea threshold increases

Question 16

effects on brain

Answer 16

all functions decrease.cerebral blood flow increases (danger with ICP;exception NO and IV anesthetics)

Question 17

effects on other organs

Answer 17

renal GFR decreases with oliguria,not ARF

hepatic flow decreases with CO

Question 18

malignant hyperthermia

Answer 18

genetic predisposition to a hypermetabolic response to volatile anesthetics and or succs.See increased temp,acidosis,hyperkalemia,hypercarbia.

treat with dantroline

Question 19

IV anesthetics

Answer 19

concentration proportional to drug effect

rapid increase with bolus=rapid onset

rapid redistribution after bolus=short duration

large doses/long duration fill volume of distribution=prolonged effect

Question 20

pharmacodynamics of IV anesthetics

Answer 20

same as inhaled

Question 21

benzodiazepines

Answer 21

sedatives,produces amnesia and unconsciousness

antagonist is flumazenil

Question 22

narcotics

Answer 22

analgesics,pain relief,can reduce anesthetic agent required but cannot produce surgical anesthesia alone

all effects are reversible 100%

Question 23

propofol

Answer 23

anesthetic=unconsciousness and surgical anesthesia,cardiac and respiratory depression and death

high doses or long infusion fill volume of distribution

requires metabolism to end effect

Question 24

ketamine

Answer 24

dissociative anesthesia,pt remains responsive

low doses provide analgesia

simulates CV system

preserves airway reflexes

short elimination 1/2life

increases cerebral blood flow