Inhalational Agents: Individual Agents Flashcards

1
Q

halothane was introduced into practice in

A

1956

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2
Q

halothane odor

A

sweet, nonpungent

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3
Q

halothane is stable in __ but decomposes __

A

soda lime

rubber products and most metals

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4
Q

halothane requires storage in

A

dark bottles and preservative to prevent spontaneous oxidative decomposition

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5
Q

halothane perservative it is stored in

A

thymol

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6
Q

halothane breaks down to

A
  1. hydrochloic acid
  2. hydrobromic acid
  3. chloride
  4. bromide
  5. phosgene
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7
Q

halothane causes ___ myocardial depression

A

dose-dependent

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8
Q

halothane dose-dependent myocardial depression causes

A

decreased cardiac output and decreased blood pressure

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9
Q

2 MAC of halothane causes __ reduction in BP, CO

A

50%

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10
Q

halothane slows conduction of the heart through the

A

AV node to cause junctional rhythms, wandering pacemaker, and bradycardia

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11
Q

halothane inhibits (cardiac related)

A

baroreceptor reflex

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12
Q

halothane myocadial depression comes from

A

the interference with Na-Ca exchange and intracellular calcium utilization

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13
Q

halothane myocardial depression is accentuated with

A

b-blocking agent, propanolol, and CCB

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14
Q

combining halothane with aminophylline results in

A

serious ventricular arrhythmias

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15
Q

halothane sensitizes the myocardium to

A

catecholamines

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16
Q

halothane adults max dose of epi

A

1.5 mcg/kg subq

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17
Q

halothane lidocaine 0.5% added essentially

A

doubles dose of epi allowed

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18
Q

halothane children max dose of epi

A

7.8-10 mcg/kg with and without lido

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19
Q

__ enhances sensitization of catecholamines from halothane

A

hypercarbia

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20
Q

halothane sensitization of catecholamines is thought to be due to

A

effect on the transmission rate of cardiac impulses through the conduction system

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21
Q

halothane is an excellent broncho___

A

dilator- reverses asthma-induced bronchospasm

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22
Q

halothane respiratory effects work by

A

inhibiting intracellular calcium mobilization- bronchial smooth muscle

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23
Q

halothane is used for __ induction

A

inhalation

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24
Q

halothane causes direct cerebral ___ and decreases __

A

vasodilation

CMRO2

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25
Q

with halothane __ is attenuated so you must __ prior to initiation of halothane

A

cerebral autoregulation

hyperventilate

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26
Q

at 1.1 MAC and MAP of 80, halothane increases CBF by

A

190% (more than iso)

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27
Q

halothane is the most potent trigger for

A

MH

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28
Q

halothane metabolism

A

15-40%

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29
Q

halothane hepatitis mechanism

A

not clear but likely an antibody that binds to hepatocytes previously exposed to halothane has been isolated from 70% patients with halothane-induced hepatic dysfunction

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30
Q

the antibody response from halothane may involve

A

liver microsomal proteins that have been modified by trifluoroacetic acid as the triggering antigens

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31
Q

incidence of halothane hepatitis

A

1 in 35,000 fatal, hepatic necrosis (1 in 10,000 jaundice)

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32
Q

incidence of halothane hepatitis is higher if

A

halotahne exposure repeats within 28 days

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33
Q

risk factors for halothane hepatitis

A
  1. sepsis
  2. obesity
  3. age > 40 years
  4. female
  5. enhanced metabolism/induced enzymes
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34
Q

halothane hepatitis has rarely been reported in

A

prepubescent children, even with preexisting liver disease

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35
Q

hepatitis similar to halothane hepatitis can be induced by

A

other volatile agents but rarely (**potential trick question, can happen with all the other agents but not sevo)

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36
Q

halothane effect on hematology

A

may cause a decrease in platelet aggregation and increased bleeding time (like sevo)

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37
Q

halothane effect on immune system

A

depresses the defense against infection, the oxidative burst response of neutrophils (unlike the other three potent agents)

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38
Q

isoflurane was introduced into clinical practice in

A

1981

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39
Q

isoflurane odor

A

pungent, ether-type

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40
Q

isoflurane is an isomer of

A

enflurane

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41
Q

isoflurane flammability

A

stable, nonflammable

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42
Q

isoflurane preservative

A

not necessary

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43
Q

isoflurane __ myocardial depression

A

minimal

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44
Q

isoflurane ___ oxygen demand more in heart than other organs

A

decreased

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45
Q

with isoflurane, CO is preserved by

A

increased HR related to baroreflexes

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46
Q

isoflurane __ decreases (cardiac related)

A

stroke volume (CO remains nearly constant due to compensation)

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47
Q

rapid increase in isoflurane concentration causes

A

increases in HR, BP, and norepinephrine

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48
Q

isoflurane is different from other agents due to __ properties (cardiac related)

A

mild beta-adrenergic agonist test question

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49
Q

can prevent HR increases at lower concentration of isoflurane with

A

small dose of opioid, MSO4 or fentanyl, and anxiolytic

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50
Q

increased HR with isoflurane is not seen in

A

neonates with decreased BP or elderly; more likely seen in healthy younger patients

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51
Q

CO is not affected by __ MAC of isoflurane

A

1-1.8

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52
Q

RA pressure can __ with isoflurane but is unchanged by __ MAC

A

increase

0.9-1.4

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53
Q

heart remains efficient even up to __ MAC isoflurane

A

1.4-1.9

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54
Q

mild beta stimulation from beta 1 with isoflurane causes

A

maintenance of CO, increased HR

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55
Q

mild beta stimulation from beta 2 with isoflurane causes

A

vasodilation, decreased SVR and lower BP

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56
Q

isoflurane causes __ coronary vascular resistance with ___ increased or unchanged

A

decreased

coronary blood flow

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57
Q

isoflurane dilates

A

small endocardial coronary arteries within the heart muscle (unlike nitroglycerin)

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58
Q

isoflurane causes ___ steal according to some studies

A

coronary artery (blood flow goes to areas that already have good blood flow versus the ischemic areas)

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59
Q

cardioprotection from isoflurane

A

0.25 MAC

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60
Q

coronary artery steal with isoflurane is only when MAP was allowed

A

to go below 60

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61
Q

with isoflurane BP is decreased based on

A

dose which is mainly due to SVR reduction

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62
Q

__ patients may not tolerate BP decrease seen with isoflurane

A

hypovolemic

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63
Q

with isoflurane, carotid sinus baroreceptor reflex is maintained at __ MAC but depressed at __ MAC

A

1

2

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64
Q

isoflurane increases the refractoriness of

A

accessory pathways and the AV conduction system

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65
Q

isoflurane’s effect on the accessory pathway conduction interferes with

A

interpretation of confirming success of ablation procedures (suppression of SVT re-entry tachycardia)

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66
Q

isoflurane effect on ablations

A
  1. prolong action-potential duration, delay atrial and vent repolarization, decrease tachyarrhythmia inducibility
  2. enhance automaticity of secondary atrial pacemakers causing ectopic atrial rhythms
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67
Q

isoflurane cause __ prolongation in healthy patients

A

QT; may not be seen in patients with idiopathic long QTc

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68
Q

isoflurane causes __ respiratory depression than halothane

A

greater

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69
Q

with isoflurane, tachypnea is less pronounced resulting in

A

enhanced reduction in minute ventilation

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70
Q

isoflurane is __ and __ to airways but a good broncho__

A

pungent and irritating

dilator

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71
Q

concentration greater than 1 MAC, isoflurane increases __ and __ pressure

A

CBF and intracranial

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72
Q

__ that accompanies the introduction of isoflurane can minimize the effect on ICP

A

hyperventilation

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73
Q

when isoflurane is used for deliberate hypotension, it decreases

A

cerebral oxygen demand

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74
Q

at 2 MAC, isoflurane results in

A

an isoelectric EEG; this provides brain protection during episodes of cerebral ischemia

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75
Q

isoflurane hepatic oxygenation is better maintained because

A

hepatic artery perfusion and hepatic venous oxygen saturation are preserved

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76
Q

isoflurane is metabolized to

A
  1. flouride ions
  2. trifluoroacetic acid
  3. formic acid

no real concerns for inorganic fluoride levels

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77
Q

isoflurane metabolism

A

0-0.2%

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78
Q

desflurane was introduced to practice in

A

1992

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79
Q

desflurane differs from isoflurane only in

A

the substiution of a fluorine atom for a chlorine atom on the alpha ethyl carbon

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80
Q

desflurane __ boiling point, __ vapor pressure requiring __

A

low

high

temperature-controlled vaporizer

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81
Q

desflurane is stable in

A

moist absorbent

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82
Q

desflurane preservative

A

none required

83
Q

desflurane pungency

A

the worst

84
Q

fluorination of desflurane

A
  1. increases vapor pressure
  2. enhances molecular stability
  3. decreased potency
85
Q

__ results from degradation of desflurane with strong base of dried or desiccated CO2 absorbents

A

carbon monoxide

86
Q

pungency of desflurane causes __ with 6% is exceeded on induction

A
  1. increased airway irritation
  2. increases salvation
  3. breath-holding
  4. coughing
  5. laryngospasm
87
Q

blood gas solubility of desflurane is __ compared to __

A

0.42

nitrous oxide 0.46

so faster recovery

88
Q

fat: gas solubility of desflurane

A

13 compared to 70 for iso

quick in and quick out for bariatric patients

89
Q

with desflurane, rapid increase in the concentration above 6% can cause

A

sympathetic stimulation with increased HR and BP

90
Q

a change in desflurane from 4% to 8% in less than one minute can

A

double HR and BP

91
Q

the sympathetic stimulation from desflurane is accompanied by

A

a significant increase in plasma epinephrine suggesting enhanced release from the adrenal gland

92
Q

the sympathetic stimulation from desflurane is most commonly seen in

A

young healthy patients with little opioid

93
Q

the sympathetic stimulation from desflurane occur both

A

with nitrous oxide and without

94
Q

the sympathetic stimulation from desflurane returns to normal with

A

5 min

95
Q

limiting the change in HR and BP from the sympathetic stimulation from desflurane

A
  1. fentanyl 1.5 mcg/kg prior to increasing concentration
  2. dont exceed 6% desflurane
  3. increase (even above 6%) slowly minimizes changes
  4. alfentanil, sufentanil, clonidine, beta blockers
  5. lidocaine 1.5 mg/kg minimizes HR response, but not BP
96
Q

esmolol effect on the sympathetic stimulation from desflurane

A

decreases HR but doesnt change the BP

97
Q

__ and __ have no effect on the sympathetic stimulation from desflurane

A

propofol and nitrous oxide

98
Q

desflurane __ SVR

A

decreases (related to Ca in the vasculature) but to a lesser extent than with iso

99
Q

desflurane effects on coronary vascular resistance

A
  1. decreased resistance to coronary blood flow
  2. redistribution (coronary steal) not seen when CAD present
100
Q

desflurane respiratory depression is similar to

A

iso up to 1.24 MAC of desflurane

101
Q

desflurane causes profound depression to apnea at

A

1.5-2 MAC

102
Q

with desflurane, __ is preserved

A

HPV as it is with sevo and iso

103
Q

desflurane has __ effect on hypoxic drive than other agents

A

less; 0.1 MAC of des decreased response by 30% with hypercapnia (other volatiles 50-70% decrease)

104
Q

desflurane causes __ in smokers

A

increased bronchial resistance (less than 6% is less irritating)

105
Q

desflurane causes fade with tetanus at

A

3% to 12%

106
Q

desflurane NM effects potentiated

A

pancuronium, vecuronium, rocuronium, and succ in a dose dependent manner

107
Q

some studies say __ has the greatest effect on NMB

A

des

108
Q

desflurane causes burst suppression at

A

1.24 MAC; no seizure activity

109
Q

desflurane causes isoelectric EEG at

A

1.5 to 2.0 MAC

110
Q

desflurane effects on CBF

A

similar to iso during 1 and 1.5 MAC

111
Q

with desflurane, consider use during dilberate hypotension due to

A

rapid titratability and reduction of CMRO2 and CPP

112
Q

desflurane maintains autoregulation at

A

1MAC

113
Q

desflurane metabolism

A

least metabolized at 0.02%

114
Q

desflurane produces a minute amount of

A

trifluoroacetic acid

115
Q

desflurane causes no increased in serum

A

inorganic fluoride

116
Q

desflurane greenhouse effect

A

58-116 days worth of auto emission

117
Q

sevoflurane greenhouse effect

A

4.3 days

118
Q

isoflurane greenhouse effect

A

4.8-9.6 days

119
Q

sevoflurane was introduced into practice in

A

1990 Japan
1995 USA

120
Q

sevoflurane odor

A

nonpungent, sweet

121
Q

sevoflurane stability

A

unstable and can spontaneously degrade, must have water added as a preservative, bottle changed to plastic

122
Q

sevoflurane is reactive with CO2 absorbent to

A

produce Compound A (lowest risk with CaOH)

123
Q

sevoflurane is potential for

A

fire with dry absorbent

124
Q

sevoflurane myocaridal depression comparable to

A

isoflurane at equal MAC concentrations

125
Q

with sevoflurane, CO decreased at __ MAC and recovered at __ MAC

A

1-1.5

2

126
Q

with sevoflurane, HR is

A

increased at >1.5 MAC

127
Q

sevoflurane rarely causes __ and treat with __

A

bradycardia

decreasing concentration

128
Q

sevoflurane causes __ prolonagtion so use caution with __

A

QT interval

patients with previously prolonged QT

129
Q

sevoflurane cardiac conduction effects

A
  1. minimal effect on conduction of AV, SA & accessory pathway
  2. autonomic suppression
  3. prolongs QT and action potential- may affect arrhythmogenicity
130
Q

sevoflurane effect on SVR

A

reduces in slightly less magnitude than iso

131
Q

SVR reduction mechanism

A

reduces resistance through the aortic arch (arterioles at higher concentrations and abruptly) versus isoflurane that reduces arteriolar resistance graudally and dose-dependently

sevo is more central so it has a quicker reduction compared to iso that is more in periphery

132
Q

with sevoflurane, the baroreceptor reflex is

A

preserved to a greater extent than with other agents

133
Q

sevoflurane is a broncho__

A

dilator; Stoelting states it causes the least degree of airway irritation among available agents

134
Q

compared to halothane for inhalation induction, studies show sevoflurane better:

A
  1. slightly faster
  2. less patient movement
  3. quicker onset of immbolity
  4. fewer airway problems
135
Q

at high concentration, sevoflurane causes __ than halothane

A

less myocardial depression

136
Q

inhalation induction on an adult, healthy, unpremedicated, given vital capcity breaths of up to 7% sevoflurane will have

A
  1. loss of lash reflex in 1 min
  2. acceptance of LMA in 1.7 min
  3. laryngoscopy, intubation in 4.7 min
137
Q

with sevoflurane, HPV is

A

preserved as with des and sio at clinically used concentrations

138
Q

sevoflurane NM effects

A

similar to other agents, enhaced intensity and duration of NMB

139
Q

sevoflurane may ___ slightly longer than iso

A

prolong duration of roc

140
Q

with sevoflurane, autoregulation is preserved up to

A

1.5 MAC

141
Q

sevoflurane cerebral vasodilation is similar to

A

iso

142
Q

sevoflurane EEG

A

may have evidence of seizure activity (7% conc)

143
Q

sevoflurane effects on platelet aggregation

A

inhibited more strongly than with halotane, due to the suppression of arachadonic acid, probably due to inhibition of cyclooxygenase

144
Q

sevoflurane metabolism- __ is metabolized by __ to produce __

A

5-8%

cytochrome P450

inorganic fluoride

145
Q

with sevoflurane, levels of serum flouride ___ but __

A

> 50 mcmol/L in 7% of patients

no evidence of clinically significant renal dysfunction

146
Q

sevoflurane is metaboized by

A

liver enzymes and kidney

147
Q

sevoflurane is different from other agents in that it is not metabolized to form

A

trifluoroacetic acid which can stimulate the immune response resulting in hepatitis

148
Q

nitrous oxide was discovered by __ in __ and used for analgesia/anesthesia in __

A

Priestly

1772

1840s

149
Q

nitrous oxide odor

A

odorless (sweet-smelling)

150
Q

nitrous oxide has a low solubility so it

A

equilibrates rapidly

151
Q

nitrous oxide potency

A

low

152
Q

nitrous oxide flammability

A

nonflammable but supports combustion

153
Q

nitrous oxide is stored in

A

a liquid-gas equilibrium in blue cylinders

154
Q

nitrous oxide __ psi liquid in equilibrium with gas

A

745

155
Q

nitrous is inorganic meaning

A

no carbons test question

156
Q

nitrous oxide is stable in

A

soda lime

157
Q

impurities in nitrous oxide

A

N2, NO, NO2, water vapor

158
Q

nitrous oxide does not combine with

A

hemoglobin, carried in solution in blood

159
Q

__ are induced by nitrous oxide

A

hepatic enzymes

160
Q

less than 0.004% of nitrous oxide is metabolized by

A

intestinal flora; not metbaolized by the human body, liver

161
Q

nitrous oxide effect on myocardial depression

A

direct

162
Q

young healthy patients cardaic effects from nitrous oxide

A

sympathetic stimulation and increased SVR due to increased endogenous catecholamines

163
Q

nitrous oxide causes __ PVR

A

increased, especially if PRVR already slightly elevated

164
Q

nitrous oxide can inhibit uptake of

A

norepinephrine in the lungs

165
Q

nitrous oxide effects __ receptors

A

NMDA

166
Q

nitrous oxide with preexisting CV disease, myocardial depression (less than MAC equivalent of potent agents)

A
  1. 40% nitrous oxide procudes myocardial depression
  2. added to opioid anesthetic
167
Q

if only opioids and nitrous oxide, the opioids seemingly block the effect on __ and __ is revealed

A

NMDA receptors (no sypathetic stim)

myocardial depression

168
Q

nitrous oxide, at concentrations < 50%, no increase in

A

PaCO2, it increased the RR more than other agents

169
Q

with nitrous oxide, the response to __ is reduced even with small amount of nitrous oxide

A

hypoxia

170
Q

nitrous oxide does not potentiate

A

nondepolarizing NMB

171
Q

nitrous oxide does potentiate

A

succ

172
Q

nitrous oxide increased __ with opioids

A

muscle rigidity

173
Q

chest wall rigidity with opioids risk factor

A

the use of nitrous

174
Q

nitrous oxide produces __ and __

A

analgesia and amnesia

175
Q

nitrous oxide produces analgesia due to

A

increase in enkephalins produced

176
Q

with nitrous oxide, __ occurs with 50%

A

nystagmus

177
Q

nitrous oxide EEG effects

A

similar to volatile (slowing frequency and higher voltage)

178
Q

nitrous oxide cerebral vasodilation

A

less than potent agents

179
Q

nitrous oxide __ CMRO2

A

increases

180
Q

withdrawal seizures seen with cessation of nitrous oxide may reflect

A

acute nitrous dependence

181
Q

nitrous oxide causes sensorimotor polyneuropathy related to

A

oxidizing effect on cobalt atom of B12

182
Q

nitrous oxide causes increase in size of

A

gas in the bowel

183
Q

nitrous oxide causes increased incidence of

A

PONV

184
Q

nitrous oxide affect on uterine tone

A

no effect

185
Q

nitrous oxide is a weak __ when used in high concentrations for prolonged time frame

A

teratogen

186
Q

nitrous oxide (related to vitamine B12 dependent enzymes) inhibits

A

methionine synthetase and thymidylate synthetase

187
Q

methionine synthetase is necessary for

A

myelin formation

188
Q

thymidylate synthetase is necessary for

A

DNA synthesis

189
Q

nitrous oxide (related to vitamine B12 dependent enzymes) prolonged exposure can result in

A

bone marrow depression- megaloblastic anemia, and even neurologic deficiences, peripheral neuropathies and pernicious anemia

190
Q

Evaluation of Nitrous oxide In the Gas Mixture of Anaesthesia (ENIGMA): prospective, randomized, multination found that nitrous free led to

A

decreased PONV, wound infection, fever, PNA, atelectasis

191
Q

homocysteine levels in the nitrous group

A

59% increase in long term risk of MI; increased homocysteine levels (post op strokes or death not increased)

192
Q

nitrous oxide is __ more soluble than nitrogen in the blood

A

34 times

193
Q

nitrous oxide is absorbed into

A

air-filled spaces faster than nitrogen moves back inot the blood causing expansion of the “bubble”

194
Q

nitrous oxide can diffuse into

A

ear, pneumothorax, gastric/intestinal air, retinal detachment (intraocular gas bubble that serves as tamponade or splint)

195
Q

nitrous oxide immunologic affects

A

chemotaxins and motility of polymorphonuclear leukocytes for phagocytosis, which is necessary for the inflammatory respone to infection

196
Q

expansion of volume or pressure of nitrous oxide depends on

A
  1. partial pressure of nitrous oxide
  2. blood flow to air-filled cavity
  3. duration of nitrous oxide admin
197
Q

diffusion hypoxia with nitrous oxide

A

nitrous is so insoluble that it returns to alveoli so rapidly in such volumes that it dilutes other gases including oxygen

198
Q

diffusion hypoxia with nitrous oxide can be avoided if

A

supplemental oxygen is administered for the frist 5-10 minutes after nitrous discontinued

199
Q

nitrous oxide second gas effect

A

administering high concentration of nitrous oxide will cause an increase of the alveolar concentration of a second gas

200
Q

when nitrous oxide is utilized, __ must be decreased

A

oxygen concentration

201
Q

nitrous oxide in C-section

A

common practice to deliver no more than 50% prior to the delivery of the infant

202
Q

nitrous oxide occupational risks- recent studies with scavenging and limited exposrue failed to show

A

difference in fertility and birth defects with general population

203
Q

if nitrous oxide is substituted for a portion of a volatile agent

A
  1. decreases the magnitude of BP decrease
  2. less depression of ventilation (does not increase PaCO2)
  3. MAC portion related to nitrous oxide is not reduced due to decrease in temperature

test question- substitute a portion of MAC with nitrous these would be the benefits