Inhalation anestheics Flashcards

1
Q

Inspired gas concentration determined by

A

Fresh gas flow rate
breathing circuit volume
circuit absorption

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2
Q

Alveolar gas concentration determined by

A

uptake of anesthetic into blood
ventilation
the concentration effect and second gas effect

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3
Q

Arterial gas concentration determined by

A

ventilation/perfusion mismatching (bronchial intubation, R–>L intra cardiac shunts

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4
Q

Definition of MAC

A

alveolar concentration that prevents movement in 50% of pts in response to a standardized stimulus

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5
Q

MAC ~ ? prevents movement in 95% of pts

A

1.3

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6
Q

MAC ~? awake MAC

A

0.3

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7
Q

MAC of N20

A

105

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8
Q

MAC of Halothane

A

0.75

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9
Q

MAC of Isoflurane

A

1.2

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10
Q

MAC of Desflurane

A

6.0

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11
Q

MAC of Sevoflurane

A

2.0

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12
Q

Blood: Gas partition coefficient of NO

A

0.47

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13
Q

Blood: Gas partition coefficient of Des

A

0.42 (fastest onset)

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14
Q

Blood: Gas partition coefficient of Sevo

A

0.7

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15
Q

Blood: Gas partition coefficient of Halothane

A

2.3 (slowest onset)

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16
Q

Blood: Gas partition coefficient of Iso

A

1.4

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17
Q

Partial pressure of NO

A

39,000

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18
Q

Partial pressure of Des

A

670

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19
Q

Partial pressure of Iso

A

240

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20
Q

Partial pressure of Halothane

A

240

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21
Q

Partial pressure of Sevo

A

160

22
Q

Partial pressure of enflurane

A

175

23
Q

Factors affecting MAC: hyperthermia

A

decreased (increased above 42 degrees Celsius)

24
Q

Factors affecting MAC: hypothermia

A

decreased

25
Q

Factors affecting MAC: young

A

increased

26
Q

Factors affecting MAC: old

A

decreased

27
Q

Factors affecting MAC: acute etoh intox

A

decreased (depressant of central nervous system)

28
Q

Factors affecting MAC: chronic etoh abuse

A

increased

29
Q

Factors affecting MAC: hct less than 40%

A

decreased

30
Q

Factors affecting MAC: PaCO2 > 40mmHg

A

decreased (caused by lower ph in CSF)

31
Q

Factors affecting MAC: hyperthyroid

A

no change (same with hypothyroid)

32
Q

Factors affecting MAC: MAP < 40mmHg

A

decreased

33
Q

Factors affecting MAC: hyper Ca++

A

decreased (decreased excitability)

34
Q

Factors affecting MAC: hyper Na+

A

increased

35
Q

Factors affecting MAC: hypo Na+

A

decreased

36
Q

Factors affecting MAC: Pregnancy

A

decreased (MAC dec by 1/3 at 8 weeks)

37
Q

Factors affecting MAC: local anesthetics

A

decreased

38
Q

Factors affecting MAC: lithium

A

decreased

39
Q

Factors affecting MAC: sympatholytics (clonidine, dexamedetomidine)

A

decreased

40
Q

Factors affecting MAC: sympathomymetics - cocaine

A

increased

41
Q

Factors affecting MAC: sympathomymetics - ephedrine

A

increased

42
Q

Factors affecting MAC: amphetamine, acute

A

increased

43
Q

Factors affecting MAC: amphetamine, chronic

A

decreased

44
Q

affect on breathing of volatile anesthetics

A

dec minute ventilation: dec TV and small inc RR; rapid shallow breathing (MV = TV x RR)

45
Q

NO toxicity is due to

A

impaired methionine synthesis and results in neurologic sequelae.
concern in substance abusers, pts with vit b12 def, and possibly unborn fetuses

46
Q

inhalational agents ______ (inc/dec?) hypoxic pulmonary vasoconstriction response

A

decrease the HPV response (HPV response = pulmonary vasculature constricts in response to decreased alveolar oxygen tension in an attempt to match ventilation and perfusion)

47
Q

which anesthetic agent is most associated with cardiac dysrhythmias?

A

halothane. halothane increases sensitivity of myocardium to epinephrine and results in PVC and tachydysrhythmias.

48
Q

volatile anesthetics affect on intracranial blood flow

A

increases blood flow and may increase ICP

49
Q

what is the toxic metabolic by-product of sevo?
which organ does it affect?
minimal flow rates to reduce risk?

A

compound A - sevo degraded by soda lime produces compound A which is nephrotoxic.
2-3L/min

50
Q

What by-product of CO2 absorbent degradation is desflurane associated with?

A

CO. most often occurs with absorbent is dry.
incidence is highest in first case of the day when machines have not been used for some time.
KOH containing absorbents produce greatest CO