EXAM #3: GENERAL ANESTHESIA Flashcards Preview

Pharmacology > EXAM #3: GENERAL ANESTHESIA > Flashcards

Flashcards in EXAM #3: GENERAL ANESTHESIA Deck (64):
1

What are the advantages of general anesthesia?

Body wide anesthesia

2

What are the disadvantages of general anesthesia?

Disturbance of all organ systems

3

What are the advantages of local anesthesia?

Minimal system disturbance

4

What is the disadvantage of local anesthesia?

Anesthesia may not be adequate

5

What are the six characteristics of an ideal anesthetic agent?

1) Unconsciousness
2) Amnesia
3) Analgesia
4) Skeletal muscle relaxation
5) Areflexia
6) Good minute-to-minute control

6

What is the "Triad of Anesthesia?'

1) Asleep
2) Pain-free
3) Still

7

What is the pharmacologic synonym of unconsciousness?

Hypnosis

8

What are the four major things that you want to know about a patient as an anesthesiologist?

Patient history and/or blood relative history of:
1) Malignant hyperthermia
2) Cardiovascular disease
3) Respirator disease
4) Allergies

9

What is "balanced anesthesia?"

Use of a combination of drugs to produce all the effects of ideal anesthesia

****No anesthetic is ideal****

10

What are the PHASES of anesthesia?

1) Induction
2) Maintenance
3) Emergence
4) Recovery

11

What are the STAGES of anesthesia?

1) Analgesia
2) Excitement
- Body is "fighting" the anesthetic drug and patient can become combative
3) Surgical anesthesia
4) Medullary depression

12

What is the main purpose for inhalable anesthetics?

Maintenance of anesthesia

13

What is the main purpose of IV anesthetics?

Induction of anesthesia

14

What are the three general mechanisms of action of the general anesthetic agents?

1) Increased GABA-A channel activity
2) Activation of K+ channels
3) Inhibit glutamate NMDA receptors

15

What are the advantages of gaseous general anesthesia?

1) Easy to control depth of anesthesia
2) Minute-to-minute control

16

What is the disadvantage of gaseous anesthesia?

Anesthesia induction is not as fast or smooth as IV

17

Which "direction" do gas molecules move?

Down their partial pressure gradient

18

What factor results in a faster achievement of anesthetic concentration in the blood?

Higher initial concentration in air

-->leads to higher partial pressure in the lungs-->bloodd

19

What is the effect of alveolar ventilation on anesthesia onset?

Higher alveolar ventilation leads to more gas molecules/time and a faster rate of onset

20

What is the Otswald Coefficient?

Blood: gas partition coefficient i.e. the solubility of the anesthetic in the blood

21

What does a low Otswald Coefficient mean?

Low solubility

22

Otswald Coefficient is preferable for a fast rate of anesthesia onset, high or low? Why?

Low solubility i.e. low Otwald Coefficient, which translates to a faster buildup of the agent in the blood

23

What does the blood: brain partition coefficient translate into?

Solubility of the agent in lipid

24

What does a high lipid solubility of an anesthetic agent translate into?

More potent

25

What does a high pulmonary blood flow translate into in general anesthesia?

Slower onset

26

What does a low pulmonary blood flow translate into in general anesthesia?

Faster onset

27

How does the Otswald Coefficient effect elimination?

Low solubility equals faster elimination

28

What is the MAC value?

Minimum alveolar concentration i.e. the concentration of anesthetic in alveolar air at which there is no response to noxious stimuli in 50% of patients

29

What does a low MAC value translate into?

More potent anesthetic

30

What does a high MAC value translate into?

Less potent anesthetic

31

How are the MAC values of combinations of inhaled anesthetic described?

Additive

32

What important clinical factor will decrease the MAC value?

Presence of CNS depressants

33

What is the hallmark gaseous general anesthetic?

Nitrous Oxide

34

Why is NO described as almost an ideal anesthetic agent?

1) Good analgesia
2) Relatively nontoxic
3) Rapid onset and recovery

35

What is the major limitation of NO?

Incomplete anesthetic b/c MAC value is 110%

*****I.e. in 50% of patients, NO cannot be given in sufficient quantities to eliminate response to noxious stimuli*****

36

What is the common use for NO?

Carrier agent for another anesthetic gas

37

What is the second gas effect?

Utilizing the additive MAC of gaseous agents by combining two gases to reduce induction time

38

What are the advantages of the 2nd gas effect?

1) Reduced induction time
2) Reduced concentration of primary agent
3) Reduced toxicity of primary agent

39

What are the major disadvantages of NO?

1) Lack of potency
2) Diffusion hypoxia
3) Increased risk of spontaneous abortion and decreased probability of concenptoin

40

What is diffusion hypoxia?

- When d/c NO rapidly diffuses from the body into the alveoli
- Diffusion into the alveoli dilutes the gases in the alveoli i.e. oxygen
- PAO2 decreases leading to hypoxia

****Note that this is combated by progressive d/c of NO and administration of 100% oxygen*****

41

Clinically, what do you need to remember about NO?

Cannot be used as sole anesthetic agent for surgical anesthesia

42

List the halogenated anesthetic agents.

Halothane
Enfulrane
Isoflurane
Desflurane

43

Why are anesthetic agents halogenated?

1) Reduces flammability
2) Increased potency

44

What is the drawback to halogenation?

Increased toxicity and side effects

45

What are halogenated agents primarily used for in anesthesia?

Maintenance of anesthesia

46

What is the prototypical halogenated agent?

Halothane

47

What toxicity is associated with Halothane?

Hepatitis

48

What are the side effects associated with Enflurane?

CNS stimulant effects

49

What is the clinical utility of Isoflurane?

Primary anesthetic agent used for maintenance of anesthesia

****With lower toxicity compared to other halogenated agents****

50

What is Desflurane?

Second most common agent used for maintenance of anesthesia

51

What side effect is associated with Desflurane?

Respiratory irritant producing bronchioconstriction, cough, and laryngeal spasm

52

What is Sevoflurane?

Newest and most popular halogenated anesthetic agent

53

What is the advantage of Sevoflurane?

Low airway irritation vs. Desoflurane

54

What is malignant hyperthermia?

- Hypermetabolic crisis when an MH-susceptible (MHS) individual is exposed to a volatile anesthetic
- Exposure leads to elevated intracellular Ca++ in skeletal muscle, causing sustained contraction
- Sustained muscle contraction generates more body heat than can be dissipated

-->Result is marked hyperthermia (life-threatening)

55

What is Thiopental?

Barbiturate general anesthetic used for induction of anesthesia

56

What is Propofol?

- "Milk of Amnesia"
- Newer drug and most frequently used anesthesia induction agent

57

How does Propofol differ from Thiopental in terms of maintenance?

Propofol can be given as a continuous IV drip

58

What is the major advantage of Propofol clinically?

Excellent recovery from anesthesia

59

What type of anesthesia does Ketamine result in?

Dissociative anesthesia

60

What is the mechanism of action of Ketamine?

NMDA receptor antagonist i.e. glutamate antagonist

61

What is the side effect of Ketamine?

Emergence pheomenon

62

What is the mechanism of action of Midazolam?

Benzodiazepine that increases the frequency of GABA-A receptor opening

63

What are the role of Midazolam in general anesthesia?

Adjuvant agent

64

What are the indications for Midazolam?

1) Sedation for painful procedures
2) Induction agent in high risk patients

Decks in Pharmacology Class (64):