Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

National Board Exam > Volatile Anesthetics > Flashcards

Volatile Anesthetics Flashcards

1
Q

The depth of general anesthesia depends on partial pressure exerted by inhalational agent in the patient’s brain. This brain P depends on _______ partial pressure which depends on _________ partial pressure which depends on partial pressure of agent in the inspired gas.

A

Arterial

Alveolar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the path an inhalational agent takes from the vaporizer to the brain?

A

Vaporizor->circuit->Lungs->Blood->Brain

and then it goes back out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is Relative affinity of an anesthetic for two phases and therfore the Partitioning of that anesthetic between the two phases is called…

A

Solubility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In a mixture of gases, each gas has a ______ ______ which is the pressure which the gas would have if it alone occupied the volume.

A

Partial pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What factors can we change to influence the amount of Inspired agent?

A

increase concentration
Increase FGF
(decrease the volume of the circuit and decrease the absorption by the machine are also listed but these are difficult to change)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a formula that describes alveolar partial pressure?

A

Input into alveoli - uptake into blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How can we increase PA?

A

Increase ventilation

Increase concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are two ways to increase initial concentration and uptake?

A

Concentration effect

Second gas effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the definition of concentration effect?

A

Impact of the inspired partial pressure of the agent increases the rate of rise of the partial pressure of the alveolus
(the higher the concentration of gas used the faster the alveolar concentration of that gas….or…. At 100 percent inspired concentration, the uptake of anesthetic creates a void, which draws gas down the trachea. This additional inspiration replaces the gas taken up.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the second gas effect

A

High volume of uptake of one gas accelerates the rate of increase of the PA of the companion gas
(During induction of general anesthesia when a large volume of nitrous oxide is taken up from alveoli into pulmonary capillary blood, the concentration of gases remaining in the alveoli is increased.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What three factors affect anesthetic uptake?

A

Solubility, cardiac output, alveolar-venous difference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the formula for uptake?

A

Uptake = soulbility x CO x (PA-PV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

RElative affinity of inhale anesthetic for two phases at equilibrium?

A

Solubility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens to ithe PA/PI rise if soulbility is increased? How would this affect induction?

A

decreases PA/PI making induction slower, Halothane is given as the example for this

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Rank the Partition coefficients from lowest to highest of Halothane, Sevoflurane, Desflurane, Nitrous Oxide and Isoflurane.

A

Desflurane (0.42)<Halothane (2.4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The more soluble an anethesthetic agent is in the blood, the _____ the drug goes into the body, and the ________ the patient becomes anesthetised.

A

Faster

Slower

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How can you compensate for a more soluble agent to speed induction?

A

YOu can increase concentration, but it there are limits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Increased cardiac output has what effect on the rate of rise in PA/PI?

A

decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Increased cardiac output is more a concern for (soluble/insoluble) agents.

A

soluble. ON insoluble agents there is less of an effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does cardiac output influence its effect on uptake?

A

greater pulmonary blood flow remove more anesthetic and lowers PA. the alveoli will saturate faster if it is seeing less blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is responsible for alveolar venous difference?

A

absorption by the tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

If gases were not absorbed by tissue what would the arterial venous difference be?

A

0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why do muscle and fat take longer for uptake and washout of gases compared to VRG?

A

Less blood flow

VRG is 10% of body mass and receives 75% of bf, whereas fat is 20% and receives only 6% of bf

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How do we get rid of anesthetic gases?

A

biotransformation (small amount)
transcutaneous loss
EXHALATION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Which agent is the most metabolized?

A

Halothane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Which agent is the least metabolized?

A

Nitrous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Is there a concentration effect for elimination?

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the partial pressures in the tissue during recovery?

A

All tissues have varying amounts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What changes pharmacokinetics of inhalational agents?

A 
Age
Lean muscle
Body fat
Hepatic function
Pulmonary gas exchang
Cardiac output
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What MAC prevents movement in 95% of the population?

A

1.3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

how does MAC change per decade?

A

6% decrease per decade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the definiton of MAC awake?

A

end tidal concentration of an anesthetic agent at which 50% of patients appropriately respond to verbal commands. It only applies to inhalation agents. ~10% of MAC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What may affect MAC awake?

A

Adjuctive needs
age
hypothermia
Sedatives

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is MAC bar?

A

concentration required to block autonomic reflexes to nociceptive stimuli.
1.3 MAC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What factors increase mac?

A

Hyperthermia
Drug-induced increase in catecholamines
Hypernatremia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How does chronic alcohol abuse affect MAC?

A

no change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are some factors that may decrease MAC?

A 
OPIOIDS
Acute alcohol intoxication
Pregnancy
Lithium
Neuraxial opioids
Others:
Pre op meds
increased age
Hypothermia
A-2 agonists
PaO2<40
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Which inhaled anesthetics were available in 1840s?

A

Nitrous oxide
Ether
Chloroform

39
Q

Which anesthetics became available in 1951?

A

Halothane

floroxene

40
Q

When did isoflurane become available? Des? Sevo?

A

1981, 1992 and 1994

41
Q

how do anesthetic gases affect cerebral blood flow?

A

Increase vasodilation, decrease vascular resistance, increase CBF and ICP

42
Q

Which causes more CBF, halothane or isoflourane?

A

Halothane can increase CBF by 166%d

43
Q

What are inhaled anesthetics effect on siezures?

A

They will block siezure activity

44
Q

What is burst suppression for isoflorane?

A

1.5 MAC. This will sacrifice blood pressure. all volatile agents cause burst supression at >2 MAC

45
Q

what effect do inhaled anesthetics have on CSF production?

A

Sevo at 1 MAC may depress CSF production by up to 40%

46
Q

Which hair color is associated with an increased mac?

A

red

47
Q

what is the maximum for inhaled anesthetics for Evoked potential?

A

.5 MAC

48
Q

How do inhaled anesthetics affect EEG

A

all may abolish EEG activity

49
Q

How do inhaled anesthetics affect Cerebral blood flow?

A

All cause it to increase

50
Q

What affects the tissue uptake of anesthetic gases?

A

Tissue solubility
Tissue blood flow
Difference between partial pressure of blood and the specific tissue

51
Q

HOw do Inhaled anesthestics affect Cerebral perfusion pressure?

A

All decrease

51
Q

HOw do Inhaled anesthestics affect Intercranial pressure?

A

Increased in all. Halogenated agents may increase it or remain the same

52
Q

HOw do Inhaled anesthestics affect cerebral metabolic demands?

A

Nitrous increase all others decrease

53
Q

HOw do Inhaled anesthestics affect CO2 reactivity?

A

No change

54
Q

What effects do volatiles have on SVR and BP

A

Decrease SVR and BP

55
Q

What effect do nitrous have on BP?

A

No change or slight increase

56
Q

What effect do desflurane have on HR?

A

Causes tachycardia (and may cause HTN) due to stimulation of SNS

57
Q

How do Iso and Sevo cause an increase in HR?

A

baroreceptor mediated

58
Q

What effects do volatile have on CO?

A

decrease

59
Q

What effect does Nitrous have on CO?

A

slight increase due to sympathomimetic activity

60
Q

HOw do volatiles affect PVR?

A

decrease

61
Q

what is coranary steal? which agent is associated with it and why?

A

Coronary steal is the diversion of blood from a myocardial bed with limited or inadequate perfusion to a bed with more adequate perfusion. Isoflurane has been associated with this because it is a potent coronary vasodilator (why the others are weak coronary vasodilators). However, no studies demonstrate an increas in ischemia with the use of ISO

62
Q

what happens with administering halothane with epinephrine?

A

May cause arrhythmias

63
Q

How do inhaled anesthetics affect MAP?

A

Nitrous remains the same or increases. All others decrease

64
Q

How do inhaled anesthetics affect systemic vascular resistance?

A

Nitrous increases. Other decrease, except sevo stays the same

65
Q

How do inhaled anesthetics affect Heart rate?.

A

Increase

66
Q

How do inhaled anesthetics affect Miocardial function?

A

all decrease

67
Q

How do volatile agents affect Vt, RR and MV?

A

RR increases, Vt and MV decrease–rapid shallow breathing

68
Q

at what MAC do des and Sevo produce apnea?

A

1.5-2 MAC

69
Q

How do volatile drugs affect AW resistance? Which is the exception?

A

Decrease AW resistance, except Des

70
Q

HOw does anesthesia affect FRC?

A

decreases

71
Q

HOw do inhaled anesthetics affect the kidneys?

A

decrease renal blood flow, GFR and urine output. May also lead to nephrotoxicity

72
Q

How do the inhaled anesthetics affect the liver?

A

decrease hepatic blood flow and clearance, and can cause hepatic toxicity

73
Q

What effects do inhaled drugs have the uterus?

A

decrease uterine smooth muscle contractility and blood flow.
helpful to remove retained placenta
May increase blood loss during delivery

74
Q

Can inhaled drugs cross the placenta?

A

Yes

75
Q

What effects do inhaled drugs have on skeletal muscle?

A

Ether derived drugs pruduce muscle relaxation and potentiate paralytics
Nitrous does not produce relaxation and may produce rigidity

76
Q

How do volatile anesthetics lower body temp?

A

Lower the core temp set point at which thermoregulatory vasoconstriction is activated
Vasodilation redistributes blood flow from central to peripheral compartments
Metcabolic oxygen consumption is decreased-decreases heat generation

77
Q

Which produces more compound A? baralyme or soda lime?

A

Baralyme

78
Q

Which volatile agent leads to carbon monoxide?

A

Des–from dry dessicated absorber

79
Q

What leads to nephrotoxicity from volatiles/

A

an inactive flouride metabolite–methoxyflurane

80
Q

What are the two types of halothane hepatitis?

A

Mild self limiting form and a more rare life threatening hepatic necrosis

81
Q

what % of halothane is metabolized by liver?

A

20%

82
Q

What is the preservative used with halothane?

A

thymol

83
Q

how much of Isoflurane is metabolized?

A

0.2%

84
Q

Isoflurane has ____ cardiovascular changes at 1 MAC

A

minimal

85
Q

Why is isoflurane a good choice for EEG?

A

2 MAC = isoelectric EEG

86
Q

What patient should you avoid use of Des?

A

reactive Airways

87
Q

Is des used with LMA?

A

No–AW irritant

88
Q

Which volatile agent is least AW irritant?

A

Sevo

89
Q

HOw much is Sevo metabolized?

A

2-5%. Associated with Compound A formation and renal tubular injury

90
Q

How does nitrous affect PVR?

A

increases

91
Q

How does Nitrous affect CMRO2?

A

Increases

92
Q

When shoudl nitrous be avoided?

A 
enclosed air spaces--34x as soluble as nitrogen
Avoid with:
 laparoscopic surgery
Working on bowels
Eye surgery with the gas buble
93
Q

What is the rule for sevo at low flows?

A

you can use low flows for 2 MAC hours

National Board Exam (36 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions