General anesthesia

Question 1

what does general anesthesia do to respiration and BP?

Answer 1

lowers respiration and BP

Question 2

what is the triad of anesthesia?

Answer 2

asleep, pain free, still

Question 3

which anesthesia adjuvants relieve anxiety?

Answer 3

benzodiazepines (midolazam)

Question 4

which anesthesia adjuvants prevent allergic reactions?

Answer 4

antihistamines (diphenhydramine, ranitidine)

Question 5

which anesthesia adjuvants prevent nausea and vomiting?

Answer 5

antiemetics (dexamethasone, scopolamine)

Question 6

which anesthesia adjuvants provide analgesia?

Answer 6

opiods (fentanyl, morphine, hydromorphone)

Question 7

which anesthesia adjuvants prevent bradycardia and secretion?

Answer 7

atropine, glycopyrrolate

Question 8

what kind of clinical conditions might be important to know about when a patient is to undergo anesthesia?

Answer 8

prior anesthetic history of patient and blood relatives:

malignant hyperthermia
CV problems
respiratory disease
allergies

Question 9

what are the four phases of general anesthesia?

Answer 9

1. induction
2. maintenance
3. emergence
4. recovery

Question 10

which route of anesthesia is usually used for maintenance?

Answer 10

inhalable

Question 11

which route of anesthesia is usually used for induction in pediatric patients?

Answer 11

inhalable

Question 12

which route of anesthesia is usually used for induction and short surgical procedures in adults?

Answer 12

IV

Question 13

what are the general mechanisms of action for general anesthetics?

Answer 13

1. depress spontaneous and evoked neuronal activity

2. alter ion channel function

Question 14

how do general anesthetics depress spontaneous and evoked neuronal activity?

Answer 14

1. induce neuronal hyperpolarization
2. increase firing threshold (lessen activity)
3. inhibit synaptic transmission and response to released NTs

Question 15

which ion channels are altered under general anesthetics?

Answer 15

1. increase GABAa receptor chloride activity
2. activate voltage gated potassium channels
3. inhibit glutamate NMDA receptors

Question 16

what are the stages of general anesthesia with respect to effects on the brain?

Answer 16

1. analgesia
2. excitement
3. surgical anesthesia
4. medullary depression

Question 17

which stage of general anesthesia do anesthesiologists want to avoid?

Answer 17

stage 2 (excitement)

Question 18

what does ketamine do?

Answer 18

inhibits glutamate NMDA receptors - decreases excitatory neurotransmission

Question 19

what are the advantages to inhalable anesthetic agents?

Answer 19

1. easy to control depth of anesthesia
2. readily reversible
3. minute to minute control

Question 20

what are the disadvantages to inhalable anesthetic agents?

Answer 20

induction not as fast or smooth as with fixed agents

Question 21

which pharmacokinetic factors affect the rate of anesthetic onset and recovery?

Answer 21

1. concentration in inspired air
2. ventilation rate
3. solubility in blood and lipid
4. lung blood flow
5. arteriovenous concentration gradient
6. elimination

Question 22

the partial pressure of anesthetic with higher solubility are affected by what physiological process?

Answer 22

ventilation rate

Question 23

what is the ostwald coefficient?

Answer 23

blood - gas partition coefficient - solubility in blood

lower coefficient means lower solubility

Question 24

how does low solubility in blood affect equilibration with brain and induction?

Answer 24

less solubility leads to a rapid rise in partial pressure in blood and a faster equilibration with brain and induction

Question 25

what does the brain-blood partition coefficient describe? what is it related to?

Answer 25

solubility in lipid related to anesthetic potency

Question 26

which solubility factor relates to anesthetic potency?

Answer 26

solubility in lipid

Question 27

how does high blood flow affect onset? low flow?

Answer 27

high flow - slow onset low flow - fast onset

Question 28

how does alveolar and arterial concentration affect onset?

Answer 28

the greater the uptake of agent, the difference between inspired and alveolar concentrations - slower rate of induction

Question 29

elimination is dependent on what solubility coefficient? why?

Answer 29

blood - gas partition coefficient: ostwald less soluble - faster elimination

Question 30

what is the minimum alveolar concentration? what does a low MAC value mean? high MAC value?

Answer 30

concentration of anesthetic (%) in inspired air at equilibrium when there is no response to noxious stimulus in 50% of patients low MAC - more potent high MAC - less potent

Question 31

how does lipid solubility related to minimum alveolar concentration (MAC)?

Answer 31

high lipid solubility - more potent (lower MAC)

Question 32

when is anesthesia produced, as related to partial pressure in brain and MAC?

Answer 32

when partial pressure of drug is equal to or exceeds the MAC

Question 33

is MAC affected by age, height, sex, or weight?

Answer 33

no

Question 34

MAC values for inhaled anesthetics have what property?

Answer 34

additive

Question 35

what is the gaseous inhalable anesthetic?

Answer 35

nitrous oxide

Question 36

what is the major limitation of nitrous oxide?

Answer 36

incomplete anesthetic insufficient potency for surgical anesthesia due to low potency (110% MAC value)

Question 37

what is the second gas effect?

Answer 37

reduces induction time for primary agents - carrier agent reduced induction time reduced requirement concentration of primary agent reduced toxicity of primary agent

Question 38

what are the advantages of nitrous oxide?

Answer 38

1. 2nd gas effect 2. minimal effects on CVS, respiratory, liver, kidney, GI 3. minimal toxicity

Question 39

what are the disadvantages of nitrous oxide?

Answer 39

1. lack of potency 2. diffuse hypoxia 3. increased risk of spontaneous abortion

Question 40

what are the uses for nitrous oxide?

Answer 40

1. general anesthesia | 2. analgesic for minor procedures

Question 41

can nitrous oxide be used as sole anesthetic agent?

Answer 41

no

Question 42

what is the general use for halogenated agents?

Answer 42

maintenance of anesthesia

Question 43

what are the properties of halothane?

Answer 43

1. complete anesthetic 2. poor analgesia 3. muscle relaxant

Question 44

what is the toxicity of halothane?

Answer 44

post-op hepatitis

Question 45

what are the systemic effects of halothane?

Answer 45

decreased CO and hypotension

Question 46

why is enflurane not as popular?

Answer 46

CNS stimulation effects - EEG convulsion pattern, jerking, twitching

Question 47

isoflurane is used for what phase of anesthesia?

Answer 47

maintenance

Question 48

what are the primary advantages of desflurane?

Answer 48

fastest onset and recovery, excellent minute to minute control

Question 49

what are the advantages of sevoflurane?

Answer 49

1. rapid onset and recovery 2. very potent 3. excellent controllability due to low solubility and high potency 4. low airway irritation - USED FOR MASK INDUCTION AND THOSE WITH AIRWAY IRRITATION

Question 50

thiopental is used for what phase of anesthesia?

Answer 50

induction

Question 51

propofol is what class of anesthetic?

Answer 51

barbiturate

Question 52

what are the advantages of propofol?

Answer 52

1. can be used as IV drip | 2. excellent quality of recovery

Question 53

propofol is used for what phase of anesthesia?

Answer 53

induction

Question 54

ketamine produces what type of anesthesia?

Answer 54

dissociative anesthesia

Question 55

what is dissociative anesthesia?

Answer 55

intense analgesia, catalepsy, and amnesia

Question 56

what is the MOA of ketamine?

Answer 56

NMDA receptor antagonist

Question 57

what is an adverse effect of ketamine?

Answer 57

emergence phenomenon

Question 58

what is emergence phenomenon?

Answer 58

unpleasant dreams, hallucinations, disorientation

Question 59

ketamine is ideal for what situation?

Answer 59

compromised cardiac status - tamponade, bleeding GSW, GI bleed

Question 60

midazolam is used for what adjunctive purposes?

Answer 60

sedation for painful procedures, induction