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ADVANCED PHARMACOLOGY I > CH 4 Inhaled Anesthetics Comparative Pharmacology > Flashcards

CH 4 Inhaled Anesthetics Comparative Pharmacology Flashcards

1
Q

Which two inhaled anesthetics have a low blood and tissue solubility that permits more precise control over the induction of anesthesia and more rapid recovery when the drug is discontinued?

A

Desflurane and Sevoflurane

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2
Q

Reaction to N2O does not occur until ____% to ____% is inhaled

A

10% to 20% nitrous oxide is inhaled

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3
Q

Mental impairment is not detectable in volunteers breathing __________ of nitrous oxide or __________halothane

A

1,600 ppm (0.16%) nitrous oxide or 16 ppm (0.0016%) halothane

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4
Q

Drug-induced increases in CBF may ____________ intracranial pressure (ICP) in patients with space-occupying lesions

A

increase

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5
Q

Cerebral metabolic oxygen requirements are _______________ in parallel with drug-induced ______________in cerebral activity

A

decreases
decreases

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6
Q

What concentration of MAC increase the frequency and voltage on the EEG? (Excitement stage)

A

Volatile anesthetics in concentrations of <0.4 MAC

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7
Q

Cerebral metabolic oxygen requirements begin to decrease abruptly at about _______ MAC

A

0.4

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8
Q

What happens when volatile anesthetic approaches 1 MAC?

A

The frequency on the EEG decreases and maximum voltage occurs.

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9
Q

During administration of isoflurane, burst suppression appears on the EEG at about ________MAC, and at ________ MAC, electrical silence predominates

A

During administration of isoflurane, burst suppression appears on the EEG at about 1.5 MAC, and at 2 MAC, electrical silence predominates

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10
Q

____________ and _____________ cause dose-related changes in the EEG similar to those that occur with isoflurane

A

Desflurane and sevoflurane

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11
Q

1.5 MAC of isoflurane will cause

A

burst suppression

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12
Q

2 MAC of Isoflurane will cause

A

electric silence(isoelectric line)

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13
Q

What is the patients state on EEG when the MAC is 0?

A

WAKEFUL

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14
Q

What is the patients state on EEG when the MAC is 0.4

A

SEDATED

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15
Q

What is the patients state on EEG when the MAC is 0.8?

A

Unresponsive

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16
Q

What is the patients state on EEG when the MAC is 1.3?

A

Surgically anesthetized

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17
Q

What is the patients state on EEG when the MAC is 2?

A

Deeply anesthetized

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18
Q

How can volatile anesthetics affect evoked potentials?

A

Dose-related decreases in the amplitude and increases in the latency of the cortical component of median nerve somatosensory evoked potentials, visual evoked potentials, and auditory evoked potentials.

The decrease in amplitude is more marked than increase in latency

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19
Q

Mental Function and Awareness

A

Gaseous anesthetics may not be equally effective in preventing awareness.

0.4 MAC isoflurane prevents recall and responses to commands, whereas nitrous oxide requires greater than 0.5 to 0.6 MAC to produce similar effects.

Surgical stimulation may increase the anesthetic requirement to prevent awareness.

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20
Q

Volatile anesthetics administered during normocapnia in concentrations of >0.6 MAC produce

A

cerebral vasodilation, decreased cerebral vascular resistance, and resulting dose-dependent increases in CBF

Increase in CBF occurs despite concomitant decreases in cerebral metabolic requirements.

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21
Q

Which inhaled anesthetics increases the CBF?

A

Isoflurane = Desflurane> Sevoflurane

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22
Q

Which inhaled anesthetics do not affect CBF autoregulation?

A

ISO,DES & SEVO

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23
Q

What can counteract increases in ICP by volatile anesthetics?

A

Hyperventilation to decrease PaCO2 to about 30mmHg

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24
Q

Which inhaled anesthetic offers a degree of cerebral proctetion? from transient incomplete cerebral ischemia during carotid endarterectomy?

A

Isoflurane

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25
Q

Circulatory effects of inhaled anesthetics may be different in the presence of

A

(1) controlled ventilation of the lungs compared with spontaneous breathing,

(2) preexisting cardiac disease, or

(3) drugs that act directly or indirectly on the heart.

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26
Q

The mechanisms of circulatory effects are diverse but often reflect the effects of inhaled anesthetics on

A

(1) myocardial contractility,

(2) peripheral vascular smooth muscle tone

(3) autonomic nervous system activity

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27
Q

Which inhaled anesthetics cause a decrease in MAP?

A

Halothane, isoflurane, desflurane, and sevoflurane

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28
Q

In contrast with volatile anesthetics, nitrous oxide produces either _________or _________ in systemic blood pressure

A

In contrast with volatile anesthetics, nitrous oxide produces either no change or modest increases in systemic blood pressure

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29
Q

Substitution of nitrous oxide for a portion of the volatile anesthetic ___________the magnitude of blood pressure decrease produced by the same MAC of the volatile anesthetic alone

A

DECREASES

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30
Q

The decrease in blood pressure produced by halothane is, in part or in whole, a consequence of

A

decreases in myocardial contractility and cardiac output

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31
Q

The decrease in blood pressure produced by isoflurane, desflurane, and sevoflurane is due

A

the decrease in systemic blood pressure results principally from a decrease in systemic vascular resistance

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32
Q

Which inhaled anesthetics increase HR?

A

Isoflurane, desflurane, and sevoflurane, but not halothane, increase heart rate when administered

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33
Q

TRUE OF FALSE: A small dose of opioid (morphine in the preoperative medication or fentanyl intravenously immediately before induction of anesthesia) can prevent the heart rate increase associated with isoflurane and presumably the other volatile anesthetics

A

TRUE

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34
Q

Unchanged heart rate despite a decrease in blood pressure during the administration of halothane may reflect

A

Depression of the carotid sinus (baroreceptor reflex response) by halothane as well as drug-induced decreases in the rate of sinus node depolarization.

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35
Q

When using Halothane, the Junctional rhythm and associated decreases in systemic blood pressure most likely reflect

A

suppression of sinus node activity by halothane

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36
Q

Halothane _________ the speed of conduction of cardiac impulses through the atrioventricular node and His-Purkinje system

A

decreases

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37
Q

In neonates, administration of isoflurane is associated with

A

attenuation of the carotid sinus reflex response, as reflected by drug-induced decreases in blood pressure that are not accompanied by increases in heart rate

Heart rate responses during administration of isoflurane also seem to be blunted in elderly patients

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38
Q

Which inhaled anesthetic produces dose-dependent decreases in cardiac output when administered?

A

Halothane

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39
Q

Sevoflurane did decrease cardiac output at __ and __ MAC, but at 2 MAC, cardiac output had recovered to nearly awake values.

A

1 and 1.5

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40
Q

Which inhaled anesthetics increase right atrial pressure (central venous pressure) when administered ?

A

Halothane, isoflurane, and desflurane, but not sevoflurane,

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41
Q

Increased right atrial pressure during administration of nitrous oxide most likely reflects

A

increased pulmonary vascular resistance due to the sympathomimetic effects of this drug.

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42
Q

which inhaled anesthetics decreases the systemic vascular resistance?

A

Isoflurane, desflurane, and sevoflurane, but not halothane,

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43
Q

Decreases in systemic vascular resistance during administration of isoflurane principally reflect

A

substantial (up to fourfold) increases in skeletal muscle blood flow

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44
Q

implications of alterations in blood flow when administering inhaled anesthetics may include

A

(1) excess (wasted) perfusion relative to oxygen needs, (2) loss of body heat due to increased cutaneous blood flow, and (3) enhanced delivery of drugs, such as muscle relaxants, to the neuromuscular junction.

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45
Q

Which is the inhaled anesthetic that only causes dose-dependent CO decrease?

A

Halothane

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46
Q

Which inhaled anesthetic has better maintenance of HR and minimal depressant effects on CO?

A

Isoflurane

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47
Q

True or False: All volatile anesthetics, including Isofluranedepress myocardial contractility to some degree

A

true

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48
Q

Which inhaled anesthetic increases right atrial pressure (CVP)?

A

Halothane, Desflurane and Isoflurane but not sevoflurane

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49
Q

Which inhaled anesthetic decreases SVR?

A

ISO
DES
SEVO
But not halothane

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50
Q

Halothane decreases BP principally by decreasing______

A

CO

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51
Q

A decrease of SVR during the administration of Isoflurane reflect

A

Increases in skeletal muscle blood flow x4

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52
Q

True or False: Volatile anesthetics appear to exert little or no predictable effect on pulmonary vascular smooth muscle

A

true

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53
Q

Nitrous oxide may produce
_______________in pulmonary vascular resistance that is exaggerated in patients with preexisting pulmonary hypertension

A

increases

the neonate with or without preexisting pulmonary hypertension may also be uniquely vulnerable to the pulmonary vascular vasoconstricting effects of nitrous oxide

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54
Q

In patients with congenital heart disease, increases in pulmonary vascular resistance may increase the magnitude of _______________intracardiac shunting of blood and further jeopardize arterial oxygenation.

A

of right-to-left

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55
Q

The ability of volatile anesthetics to decrease the dose of epinephrine necessary to evoke ventricular cardiac dysrhythmias is greatest with
____________

Minimal to non existent with___________

A

the alkane derivative halothane and minimal to nonexistent with the ether derivatives isoflurane, desflurane, and sevoflurane

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56
Q

Which inhaled anesthetics prolong QTc interval?

A

Halothane, enflurane, and isoflurane prolong the QTc interval on the electrocardiogram in healthy patients

similar changes may not occur in patients with idiopathic long QTc interval syndrome suggesting that generalizations from healthy patients to patients with long QTc interval syndrome may not be valid.

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57
Q

CO2 accumulation causes __________ of vascular muscle, which can produce ____ in HR and _______ in SVR

A

RELAXATION
INCREASES
DECREASES

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58
Q

Volatile anesthetics induce coronary vasodilation by preferentially acting on vessels with diameters from ___ TO ____ microns

A

20 to 50

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59
Q

Which inhaled anesthetic produce coronary steal syndrome?

A

Isoflurane

as well as other coronary vasodilators (adenosine, dipyridamole, nitroprusside) that preferentially dilate the small coronary resistance coronary vessels would be capable of redistributing blood from ischemic to nonischemic areas

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60
Q

________ is a good inhaled anesthetic choice to treat increases in BP & HR in response to surgical stimulus

A

Desflurane

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61
Q

Abrupt increases of which volatile anesthetics increase SNS activity & renin-angiotensin activity? increase BP and HR

A

Abrupt increases in Isoflurane and Desflurane

More desflurane than Isoflurane

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62
Q

Decreased contractility by inhaled anesthetic may be detrimental for patients with hx of

A

CHF

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63
Q

Abrupt increases in desflurane may be detrimental in patients with hx of

A

CAD

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64
Q

Peripheral vasodilation by inhaled anesthetics might be detrimental in

A

Patients with aortic stenosis

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65
Q

Peripheral vasodilation by inhaled anesthetics might be beneficial in

A

patients with aortic regurgitation

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66
Q

Which medications that alters SNS activity may influence in the magnitude of inhaled anesthetics changes?

A

Calcium channel blockers

beta blockers

Ace inhibitors

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67
Q

The proposed mechanisms of cardiovascular depressant effects by volatile anesthetics include

A

1) direct myocardial depression,

(2) inhibition of CNS sympathetic activity,

(3) peripheral autonomic ganglion blockade,

(4) attenuated carotid sinus reflex activity,

(5) decreased formation of cyclic adenosine monophosphate, (

6) decreased release of catecholamines,

(7) decreased influx of calcium ions through slow channels.

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68
Q

negative inotropic, vasodilating, and depressant effects on the sinoatrial node produced by volatile anesthetics are similar to the effects produced by _________________

A

calcium entry blockers.

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69
Q

______________may be unique among the volatile anesthetics in possessing mild β-adrenergic agonist properties.

A

Isoflurane

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70
Q

The increase in blood pressure that is associated with rapid increases in desflurane concentration is accompanied by a significant increase in

A

plasma epinephrine suggesting enhanced release from the adrenal gland.

71
Q

Nitrous oxide administered alone or added to unchanging concentrations of volatile anesthetics produces signs of mild sympathomimetic stimulation characterized by

A

(1) increases in the plasma concentrations of catecholamines, (2) mydriasis, (3) increases in body temperature, (4) diaphoresis, (5) increases in right atrial pressure, and (6) evidence of vasoconstriction in the systemic and pulmonary circulations

72
Q

What is ischemic preconditioning?

A

cardiac protection (anesthetic preconditioning)

” In theory inhaled gases protect from ischemia insults”

Brief episodes of myocardial ischemia occurring before a subsequent longer period of myocardial ischemia provide protection against myocardial dysfunction and necrosis

73
Q

Which inhaled anesthetics increases in the frequency of breathing?

A

All Inhaled anesthetics, except for isoflurane,

74
Q

Isoflurane increases the frequency of breathing similarly to other inhaled anesthetics up to a dose of _____MAC

A

1 MAC

At a concentration of >1 MAC, however, isoflurane does not produce a further increase in the frequency of breathing.

75
Q

Nitrous oxide increases the frequency of breathing more than other inhaled anesthetics at concentrations of ___MAC

A

> 1

76
Q

Effects on the pattern of breathing by inhaled

A

Increase in the frequency of breathing.

CNS stimulation

Reduction of tidal volume

Decrease in Minute ventilation.

77
Q

Ventilatory response to CO2

A

dose-dependent depression (medullary resp center)

N2O does not increase CO2 (used as an attenuator)

78
Q

Inhaled anesthetics produce dose-dependent and drug-specific effects on the

A

(1) pattern of breathing, (2) ventilatory response to carbon dioxide, (3) ventilatory response to arterial hypoxemia, and (4) airway resistance.

79
Q

Volatile anesthetics stimulate central respiratory chemoreceptor neurons likely through activation of

A

THIK-1 (potassium channel subfamily K member 13; K2p13.1) receptors, a two-pore potassium channel that is responsible for a background potassium current

80
Q

Surgical stimulation increases minute ventilation by about
_____ because of increases in tidal volume and frequency of breathing.

A

40%

81
Q

Anesthetic-induced depression of ventilation as reflected by increases in the ________ most likely reflects the direct depressant effects of these drugs on the _______________________

A

PaCO2

medullary ventilatory center.

82
Q

The predictable ventilatory depressant effects of volatile anesthetics are most often managed by institution of __________________ ventilation of the patient’s lung

A

mechanical (controlled)

83
Q

______________ is useful during thoracic surgery as it is a potent bronchodilator, its low blood-gas solubility permits rapid adjustment of the depth of anesthesia, and effects on hypoxic pulmonary vasoconstriction are small

A

Sevoflurane

84
Q

Risk factors for developing bronchospasm during anesthesia include

A

young age (<10 years),

perioperative respiratory infection,

endotracheal intubation,

the presence of COPD.2

85
Q

Which inhaled anesthetic produces bronchodilation in patients with COPD?

A

isoflurane and sevoflurane

86
Q

Which inhaled anesthetic produces bronchocosntriction?

A

Desflurane

specially in smoker pts and COPD

87
Q

Which inhaled anesthetic has the greater risk for irritability?

A

Desflurane

88
Q

Which inhaled anesthetic has the least risk of irritability?

A

Sevoflurane

89
Q

Which inhaled anesthetic is a vasodilator of the hepatic circulation?

A

isoflurane is a vasodilator of the hepatic circulation providing beneficial effects on hepatic oxygen delivery

90
Q

Which inhaled anesthetic is a vasoconstrictor of the hepatic circulation?

A

halothane acts as a vasoconstrictor on the hepatic circulation

91
Q

True or False: Volatile anesthetics may interfere with clearance of drugs from the plasma.

A

True

92
Q

Which drug is greatly affected due to intrinsic clearence of hepatic metabolism?

A

Propanolol

Intrinsic clearance by hepatic metabolism of drugs such as propranolol is decreased by 54% to 68% by inhaled anesthetics

93
Q

Which Inhale anesthetic transiently increases the plasma alanine aminotransferase activity?

A

Desflurane

Transient increases in the plasma alanine aminotransferase activity follow administration of desflurane,

94
Q

Which Inhale anesthetic transiently increases the plasma concentrations of α-glutathione transferase (sensitive indicator of hepatocellular injury)?

A

Transient increases in plasma concentrations of α-glutathione transferase (sensitive indicator of hepatocellular injury) follow administration of isoflurane or desflurane for surgical anesthesia.

95
Q

How does administration of isoflurane and surgical stimulation affect liver function test?

A

In the presence of surgical stimulation, bromsulphalein retention and increases in liver enzymes follow transiently the administration of even isoflurane, suggesting that changes in hepatic blood flow evoked by painful stimulation can adversely alter hepatic function independent of the volatile anesthetic.

96
Q

Which inhaled anesthetic causes the most clinical and relevant hepatotoxicity?

A

Halothane

However, post op liver dysfunction has been associated with most volatile anesthetics

97
Q

How does the metabolism of halothane affects the liver?

A

Metabolism of halothane can produce free radicals that can alter hepatic proteins, creating antigens that stimulates the immune system

98
Q

you should avoid halothane on patients with liver disease such as hepatic cirrhosis because

A

Preexisting liver disease, such as hepatic cirrhosis, may be associated with marginal hepatocyte oxygenation, which would be further jeopardized by the depressant effects of anesthetics on hepatic blood flow and/or arterial oxygenation.

99
Q

Hypothermia ___________ hepatic oxygen demand

A

decreased

Hypothermia may protect the liver from drug-induced events that decrease hepatic oxygen delivery.

100
Q

Halothane produces ___ types of hepatotoxicity

A

2

101
Q

An estimated 20% of the patients that develop a mild sel-limited post operative hepatoxicity will experience

A

Nausea
Lethargy
Fever
Minor increases in plasma concentrations of liver transaminase enzymes

102
Q

Halothane Hepatitis is estimated to occur in ___ in ____ to ____ in _______ adult patients

A

The other and rarer type of hepatotoxicity (halothane hepatitis) is estimated to occur in 1 in 10,000 to 1 in 30,000 adult patients

103
Q

Halothane Hepatitis may lead to

A

massive hepatic necrosis and death

104
Q

Which patient
(age ) population is more susceptible to experiencing halothane hepatoxicity?

A

Adults. Children are less susceptible

105
Q

Halothane Hepatitis/Hepatoxicity is

A

Rare
Life-threatening form of hepatic dysfunction
Most likely to be an immune-mediated hepatoxicity

106
Q

What are the clinical manifestations of halothane hepatitis suggesting an immune-related response?

A

eosinophilia, fever, rash, arthralgia, and prior exposure to halothane

107
Q

Risk factors commonly associated with halothane hepatitis include

A

female gender, middle age, obesity, and multiple exposures to halothane

108
Q
A
109
Q

The predominant histologic feature of halothane hepatitis is

A

Acute hepatitis

110
Q

The most compelling evidence for a Halothane hepatitis immune-mediated mechanism is the presence of

A

circulatory immunoglobulin G antibodies in at least 70% of those patients with the diagnosis of halothane hepatitis

111
Q

Halothane Metabolism

A
112
Q

This chemical structures belongs to

A

desflurane

113
Q

This chemical structures belongs to

A

Isoflurane

114
Q

This chemical structures belongs to

A

Halothane

115
Q

The mild, self-limited postoperative hepatic dysfunction that is associated with all the volatile anesthetics most likely reflect anesthetic-induced alterations in hepatic oxygen delivery relative to demand that results in

A

inadequate hepatocyte oxygenation.

116
Q

Halothane is metabolized to

A

a trifluoroacetylated (TFA) adduct (altered protein) that binds to liver proteins.

In susceptible patients, this adduct (altered protein) is seen as nonself (neoantigen), generating an immune response (production of antibodies).

Subsequent exposure to halothane may result in hepatotoxicity.

117
Q

enflurane, isoflurane, and desflurane are oxidatively metabolized by

A

liver cytochrome P450 enzymes to form acetylated liver protein adducts by mechanisms similar to that of halothane

118
Q

Which inhaled anesthetic could possibly produce hepatoxicity by a similar mechanism to that of halothane?

A

Enflurane, isoflurane, and desflurane could produce hepatotoxicity by a mechanism similar to that of halothane ,but at a lower incidence because the degree of anesthetic metabolism appears to be directly related to the potential for hepatic injury.

119
Q

The incidence of anesthetic-induced hepatitis would be greatest with

A

Halothane

120
Q

the incidence of anesthetic-induced hepatitis would be intermediate with

A

Enflurane

121
Q

the incidence of anesthetic-induced hepatitis would be rare to occur with

A

Isoflurane

122
Q

Which inhaled anesthetic “should be very safe to administer to a liver/hepatic patient?

A

Desflurane should be very safe because it would have the lowest level of adduct formation.

123
Q

True or False:

Environmental exposure of operating room personnel to trace concentrations of volatile anesthetics could stimulate antibody production.

It is presumed that pediatric anesthesiologists experience greater occupational exposure to trace concentrations of volatile anesthetics due to the frequent use of nonrebreathing anesthesia delivery systems and use of uncuffed endotracheal tubes.

Despite these higher antibody levels, pediatric anesthesiologists did not have increased liver transaminase enzymes compared with general anesthesiologists, suggesting these antibodies may be insufficient to cause appreciable damage to normal hepatic cells

A

true!!!

very scary

124
Q

Does sevoflurane undergo metabolism to an acetyl halide?

A

NO

The chemical structure of sevoflurane, unlike that of other fluorinated volatile anesthetics, dictates that it cannot undergo metabolism to an acetyl halide

125
Q

______________metabolism does not result in the formation of trifluoroacetylated liver proteins and therefore cannot stimulate the formation of antitrifluoroacetylated protein antibodies.

A

SEVOFLURANE

Therefore, unlike all the other fluorinated volatile anesthetics, sevoflurane would not be expected to produce immune-mediated hepatotoxicity or to cause cross-sensitivity in patients previously exposed to halothane

126
Q

Which inhaled anesthetics are metabolized to reactive acetyl halide metabolites?

A

metabolism does not result in the formation of trifluoroacetylated liver proteins and therefore cannot stimulate the formation of antitrifluoroacetylated protein antibodies.

127
Q

Which inhaled anesthetic unlike all the other fluorinated volatile anesthetics, would not be expected to produce immune-mediated hepatotoxicity or to cause cross-sensitivity in patients previously exposed to halothane?

A

Sevoflurane

128
Q

What are the renal effects of volatile anesthetics

A

Volatile anesthetics produce similar dose-related decreases in renal blood flow, glomerular filtration rate, and urine output

129
Q

Changes in renal system by volatile anesthetics are due to

A

The effects of volatile anesthetics on systemic blood pressure and cardiac output

130
Q

What can be done preoperatively to attenuate or abolish changes in renal function associated with volatile anesthetics?

A

Preoperative hydration attenuates or abolishes many of the changes in renal function associated with volatile anesthetics.

131
Q

S/S of Fluoride-induced nephrotoxicity

A

polyuria, hypernatremia, hyperosmolarity, increased plasma creatinine, inability to concentrate urine)

132
Q

Fluoride-induced nephrotoxicity quick facts

A

first recognized in patients after the administration of methoxyflurane, which undergoes extensive metabolism (70% of the absorbed dose) to inorganic fluoride, which acts as a renal toxin.

133
Q

Sevoflurane causes the following transient changes in the renal system:

A

transient impairment of renal concentrating ability

increased urinary excretion of β-N-acetylglucosaminidase in patients exposed to sevoflurane

developing peak plasma inorganic fluoride concentrations >50 μmol/L

134
Q

What is considered to be the indicator of acute proximal renal tubular injury?

A

Urinary excretion of β-N-acetylglucosaminidase is considered an indicator of acute proximal renal tubular injury.

135
Q

_____________ undergoes greater hepatic metabolism, thus accounting for the higher plasma concentrations of fluoride

A

Sevoflurane

136
Q

Carbon dioxide absorbents containing potassium and sodium hydroxide react with _____________ and eliminate hydrogen fluoride from its isopropyl moiety to form a breakdown product

A

sevoflurane

137
Q

The degradation product produced in greatest amount by sevoflurane is

A

The degradation product produced in greatest amounts is fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether (compound A).

138
Q

What is another name for this degradation product?

A

Compound A

139
Q

carbon dioxide production _________ the absorbent temperature and thus the production of compound A

A

increases

140
Q

The rationale for the limitation of gas flow to at least 2 L per minute when administering sevoflurane is

A

to minimize the concentration of compound A that may accumulate in the anesthesia breathing circuit.

141
Q

Which inhaled anesthetic shows maintenance of total hepatic blood flow and hepatic arterial blood flow?

A

Isoflurane

142
Q

Risk factors for halothane hepatitis

A

Female
Middle Age
Obese
Prior exposure to Halothane

143
Q

True or False: Sevoflurane undergoes metabolism to acetyl halide

A

False

144
Q

Which inhaled anesthetic has the greatest metabolite recovery?

A

Halothane with a 15-20%

145
Q

Factors that increase the production of Compound A

A

Higher concentrations of Baralyme (not available anymore)

Higher temperatures

Longer exposure of sevoflurane (4-8 hrs)

Low flows <2L/min

146
Q

Which inhaled anesthetics produce skeletal muscle relaxation twofold that of halothane?

A

Ether derivative fluorinated volatile anesthetics (isoflurane, sevoflurane, and desflurane)

produce skeletal muscle relaxation that is about twofold greater than that associated with a comparable dose of halothane.

147
Q

What are the skeletal muscle effects of N2O ?

A

Nitrous oxide does not relax skeletal muscles

in doses of >1 MAC (delivered in a hyperbaric chamber), it may produce skeletal muscle rigidity

148
Q

The ability of skeletal muscles to sustain contractions in response to continuous stimulation (such as with a nerve-muscle stimulator) is impaired in the presence of

A

increasing concentrations of ether derivative volatile anesthetics but not in the presence of halothane or nitrous oxide

149
Q

True or False All volatile anesthetics including desflurane and sevoflurane can trigger malignant hyperthermia in genetically susceptible patients even in the absence of concomitant administration of succinylcholine

A

True

150
Q

Which volatile anesthetics is the most potent trigger for malignant hyperthermia?

A

Halothane

151
Q

Which inhaled anesthetics does not trigger malignant hyperthermia?

A

N20
Xenon

152
Q

What are the obstetric effects caused by inhaled anesthetics?

A

Volatile anesthetics produce similar and dose-dependent decreases in uterine smooth muscle contractility and blood flow

These changes are modest at 0.5 MAC (analgesic concentrations) and become substantial at concentrations of >1 MAC

153
Q

Which inhale anesthetic is useful in obstetrical anesthesia to help reduce concentration of volatile anesthetics, benzos and opioids?

A

nitrous oxide is particularly useful in obstetrical anesthesia to reduce the need to volatile anesthetic that promotes uterine atony while avoiding opioids and benzodiazepines that may cause prolonged depression of the newborn.

154
Q

_________ reduce the need to volatile anesthetic that promotes uterine atony

A

N2O

155
Q

uterine relaxation produced by volatile anesthetics may contribute to

A

blood loss due to uterine atony

FYI uterine atony refers to a soft and weak uterus after childbirth. It happens when the uterine muscles don’t contract enough to clamp the placental blood vessels shut after childbirth. This can lead to life-threatening blood loss after delivery.

156
Q

Inhaled anesthetics and immune system effects

A

normal functions of the immune system are depressed after patient exposure to the combination of anesthesia and surgery

inhaled anesthetics, particularly nitrous oxide, produce dose-dependent inhibition of polymorphonuclear leukocytes and their subsequent migration (chemotaxis) for phagocytosis, which is necessary for the inflammatory response to infection.

157
Q

Which inhaled anesthetics produce a dose dependent inhibition of leukocytes?

A

N20

158
Q

How is compound A formed?

A

Compound A, which is formed from sevoflurane degradation by carbon dioxide absorbent

159
Q

which inhaled anesthetic irreversibly oxidizes the cobalt atom of vitamin B12 such that the activity of vitamin B12–dependent enzymes is decreased?

A

N20

160
Q

methionine synthetase is neccesary for the formation of

A

myelin

161
Q

thymidylate synthetase is important for

A

DNA synthesis

162
Q

Which inhaled gas could lead to spontaneous abortion, bone marrow depression, and neurologic disturbances?

A

N20

163
Q

Chronically Inhalation of N2O causes

A

neuropathy characterized by sensorimotor polyneuropathy which is associated with Vit B12 enzyme interference

164
Q

The oxygen requirements of the __________decrease more than those of other organs

A

heart

165
Q

Decreased oxygen requirements would protect tissues from _________ that might result from decreased oxygen delivery due to drug-induced decreases in perfusion pressure.

A

ischemia

166
Q

Decreases in total body oxygen requirements reflects a

A

depressed metabolism

167
Q

alveolar ventilation is principally responsible for the elimination of

A

enflurane and isoflurane (presumably also desflurane and sevoflurane)

168
Q

Which gases are known to participate in the chlorine-mediated catalytic destruction of the ozone layer?

A

isoflurane, enflurane, and halothane

169
Q

Which gases produce CF3O2 radicals?

A

Desflurane and sevoflurane

170
Q

Which gas is a prominent contributor to both ozone destruction as well as the greenhouse effect?

A

N2O

171
Q

The gas with the greatest green house effect is

A

Desflurane

desflurane run at 1 to 2 L of fresh gas flow produces 58 to 116 days’ worth of average auto emissions.

Desflurane demonstrates roughly 26 and 13 times the global warming potential of sevoflurane and isoflurane, respectively.

172
Q

The gas with the lowest green house effect is

A

sevoflurane (2 L fresh gas flow) and isoflurane (1-2 L fresh gas flow) produce the equivalents of 4.3 and 4.8 to 9.6 days of average auto emissions

173
Q

Proposed mechanisms for limiting the environmental impact of inhalational agents include

A

closed-circuit anesthetics,

low-flow administration of the less environmentally detrimental inhalational agents

total intravenous anesthetic techniques.

The use of propofol in place of inhalational agents

ADVANCED PHARMACOLOGY I (2 decks)

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