Inhalational Agents: Individual Agents Flashcards
(203 cards)
1
Q
halothane was introduced into practice in
A
1956
2
Q
halothane odor
A
sweet, nonpungent
3
Q
halothane is stable in __ but decomposes __
A
soda lime
rubber products and most metals
4
Q
halothane requires storage in
A
dark bottles and preservative to prevent spontaneous oxidative decomposition
5
Q
halothane perservative it is stored in
A
thymol
6
Q
halothane breaks down to
A
- hydrochloic acid
- hydrobromic acid
- chloride
- bromide
- phosgene
7
Q
halothane causes ___ myocardial depression
A
dose-dependent
8
Q
halothane dose-dependent myocardial depression causes
A
decreased cardiac output and decreased blood pressure
9
Q
2 MAC of halothane causes __ reduction in BP, CO
A
50%
10
Q
halothane slows conduction of the heart through the
A
AV node to cause junctional rhythms, wandering pacemaker, and bradycardia
11
Q
halothane inhibits (cardiac related)
A
baroreceptor reflex
12
Q
halothane myocadial depression comes from
A
the interference with Na-Ca exchange and intracellular calcium utilization
13
Q
halothane myocardial depression is accentuated with
A
b-blocking agent, propanolol, and CCB
14
Q
combining halothane with aminophylline results in
A
serious ventricular arrhythmias
15
Q
halothane sensitizes the myocardium to
A
catecholamines
16
Q
halothane adults max dose of epi
A
1.5 mcg/kg subq
17
Q
halothane lidocaine 0.5% added essentially
A
doubles dose of epi allowed
18
Q
halothane children max dose of epi
A
7.8-10 mcg/kg with and without lido
19
Q
__ enhances sensitization of catecholamines from halothane
A
hypercarbia
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
21
Q
halothane is an excellent broncho___
A
dilator- reverses asthma-induced bronchospasm
22
Q
halothane respiratory effects work by
A
inhibiting intracellular calcium mobilization- bronchial smooth muscle
23
Q
halothane is used for __ induction
A
inhalation
24
Q
halothane causes direct cerebral ___ and decreases __
A
vasodilation
CMRO2
25
with halothane __ is attenuated so you must __ prior to initiation of halothane
cerebral autoregulation
hyperventilate
26
at 1.1 MAC and MAP of 80, halothane increases CBF by
190% (more than iso)
27
halothane is the most potent trigger for
MH
28
halothane metabolism
15-40%
29
halothane hepatitis mechanism
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
30
the antibody response from halothane may involve
liver microsomal proteins that have been modified by trifluoroacetic acid as the triggering antigens
31
incidence of halothane hepatitis
1 in 35,000 fatal, hepatic necrosis (1 in 10,000 jaundice)
32
incidence of halothane hepatitis is higher if
halotahne exposure repeats within 28 days
33
risk factors for halothane hepatitis
1. sepsis
2. obesity
3. age > 40 years
4. female
5. enhanced metabolism/induced enzymes
34
halothane hepatitis has rarely been reported in
prepubescent children, even with preexisting liver disease
35
hepatitis similar to halothane hepatitis can be induced by
other volatile agents but rarely (**potential trick question, can happen with all the other agents but not sevo)
36
halothane effect on hematology
may cause a decrease in platelet aggregation and increased bleeding time (like sevo)
37
halothane effect on immune system
depresses the defense against infection, the oxidative burst response of neutrophils (unlike the other three potent agents)
38
isoflurane was introduced into clinical practice in
1981
39
isoflurane odor
pungent, ether-type
40
isoflurane is an isomer of
enflurane
41
isoflurane flammability
stable, nonflammable
42
isoflurane preservative
not necessary
43
isoflurane __ myocardial depression
minimal
44
isoflurane ___ oxygen demand more in heart than other organs
decreased
45
with isoflurane, CO is preserved by
increased HR related to baroreflexes
46
isoflurane __ decreases (cardiac related)
stroke volume (CO remains nearly constant due to compensation)
47
rapid increase in isoflurane concentration causes
increases in HR, BP, and norepinephrine
48
isoflurane is different from other agents due to __ properties (cardiac related)
mild beta-adrenergic agonist **test question**
49
can prevent HR increases at lower concentration of isoflurane with
small dose of opioid, MSO4 or fentanyl, and anxiolytic
50
increased HR with isoflurane is not seen in
neonates with decreased BP or elderly; more likely seen in healthy younger patients
51
CO is not affected by __ MAC of isoflurane
1-1.8
52
RA pressure can __ with isoflurane but is unchanged by __ MAC
increase
0.9-1.4
53
heart remains efficient even up to __ MAC isoflurane
1.4-1.9
54
mild beta stimulation from beta 1 with isoflurane causes
maintenance of CO, increased HR
55
mild beta stimulation from beta 2 with isoflurane causes
vasodilation, decreased SVR and lower BP
56
isoflurane causes __ coronary vascular resistance with ___ increased or unchanged
decreased
coronary blood flow
57
isoflurane dilates
small endocardial coronary arteries within the heart muscle (unlike nitroglycerin)
58
isoflurane causes ___ steal according to some studies
coronary artery (blood flow goes to areas that already have good blood flow versus the ischemic areas)
59
cardioprotection from isoflurane
0.25 MAC
60
coronary artery steal with isoflurane is only when MAP was allowed
to go below 60
61
with isoflurane BP is decreased based on
dose which is mainly due to SVR reduction
62
__ patients may not tolerate BP decrease seen with isoflurane
hypovolemic
63
with isoflurane, carotid sinus baroreceptor reflex is maintained at __ MAC but depressed at __ MAC
1
2
64
isoflurane increases the refractoriness of
accessory pathways and the AV conduction system
65
isoflurane's effect on the accessory pathway conduction interferes with
interpretation of confirming success of ablation procedures (suppression of SVT re-entry tachycardia)
66
isoflurane effect on ablations
1. prolong action-potential duration, delay atrial and vent repolarization, decrease tachyarrhythmia inducibility
2. enhance automaticity of secondary atrial pacemakers causing ectopic atrial rhythms
67
isoflurane cause __ prolongation in healthy patients
QT; may not be seen in patients with idiopathic long QTc
68
isoflurane causes __ respiratory depression than halothane
greater
69
with isoflurane, tachypnea is less pronounced resulting in
enhanced reduction in minute ventilation
70
isoflurane is __ and __ to airways but a good broncho__
pungent and irritating
dilator
71
concentration greater than 1 MAC, isoflurane increases __ and __ pressure
CBF and intracranial
72
__ that accompanies the introduction of isoflurane can minimize the effect on ICP
hyperventilation
73
when isoflurane is used for deliberate hypotension, it decreases
cerebral oxygen demand
74
at 2 MAC, isoflurane results in
an isoelectric EEG; this provides brain protection during episodes of cerebral ischemia
75
isoflurane hepatic oxygenation is better maintained because
hepatic artery perfusion and hepatic venous oxygen saturation are preserved
76
isoflurane is metabolized to
1. flouride ions
2. trifluoroacetic acid
3. formic acid
no real concerns for inorganic fluoride levels
77
isoflurane metabolism
0-0.2%
78
desflurane was introduced to practice in
1992
79
desflurane differs from isoflurane only in
the substiution of a fluorine atom for a chlorine atom on the alpha ethyl carbon
80
desflurane __ boiling point, __ vapor pressure requiring __
low
high
temperature-controlled vaporizer
81
desflurane is stable in
moist absorbent
82
desflurane preservative
none required
83
desflurane pungency
the worst
84
fluorination of desflurane
1. increases vapor pressure
2. enhances molecular stability
3. decreased potency
85
__ results from degradation of desflurane with strong base of dried or desiccated CO2 absorbents
carbon monoxide
86
pungency of desflurane causes __ with 6% is exceeded on induction
1. increased airway irritation
2. increases salvation
3. breath-holding
4. coughing
5. laryngospasm
87
blood gas solubility of desflurane is __ compared to __
0.42
nitrous oxide 0.46
so faster recovery
88
fat: gas solubility of desflurane
13 compared to 70 for iso
quick in and quick out for bariatric patients
89
with desflurane, rapid increase in the concentration above 6% can cause
sympathetic stimulation with increased HR and BP
90
a change in desflurane from 4% to 8% in less than one minute can
double HR and BP
91
the sympathetic stimulation from desflurane is accompanied by
a significant increase in plasma epinephrine suggesting enhanced release from the adrenal gland
92
the sympathetic stimulation from desflurane is most commonly seen in
young healthy patients with little opioid
93
the sympathetic stimulation from desflurane occur both
with nitrous oxide and without
94
the sympathetic stimulation from desflurane returns to normal with
5 min
95
limiting the change in HR and BP from the sympathetic stimulation from desflurane
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
esmolol effect on the sympathetic stimulation from desflurane
decreases HR but doesnt change the BP
97
__ and __ have no effect on the sympathetic stimulation from desflurane
propofol and nitrous oxide
98
desflurane __ SVR
decreases (related to Ca in the vasculature) but to a lesser extent than with iso
99
desflurane effects on coronary vascular resistance
1. decreased resistance to coronary blood flow
2. redistribution (coronary steal) not seen when CAD present
100
desflurane respiratory depression is similar to
iso up to 1.24 MAC of desflurane
101
desflurane causes profound depression to apnea at
1.5-2 MAC
102
with desflurane, __ is preserved
HPV as it is with sevo and iso
103
desflurane has __ effect on hypoxic drive than other agents
less; 0.1 MAC of des decreased response by 30% with hypercapnia (other volatiles 50-70% decrease)
104
desflurane causes __ in smokers
increased bronchial resistance (less than 6% is less irritating)
105
desflurane causes fade with tetanus at
3% to 12%
106
desflurane NM effects potentiated
pancuronium, vecuronium, rocuronium, and succ in a dose dependent manner
107
some studies say __ has the greatest effect on NMB
des
108
desflurane causes burst suppression at
1.24 MAC; no seizure activity
109
desflurane causes isoelectric EEG at
1.5 to 2.0 MAC
110
desflurane effects on CBF
similar to iso during 1 and 1.5 MAC
111
with desflurane, consider use during dilberate hypotension due to
rapid titratability and reduction of CMRO2 and CPP
112
desflurane maintains autoregulation at
1MAC
113
desflurane metabolism
least metabolized at 0.02%
114
desflurane produces a minute amount of
trifluoroacetic acid
115
desflurane causes no increased in serum
inorganic fluoride
116
desflurane greenhouse effect
58-116 days worth of auto emission
117
sevoflurane greenhouse effect
4.3 days
118
isoflurane greenhouse effect
4.8-9.6 days
119
sevoflurane was introduced into practice in
1990 Japan
1995 USA
120
sevoflurane odor
nonpungent, sweet
121
sevoflurane stability
unstable and can spontaneously degrade, must have water added as a preservative, bottle changed to plastic
122
sevoflurane is reactive with CO2 absorbent to
produce Compound A (lowest risk with CaOH)
123
sevoflurane is potential for
fire with dry absorbent
124
sevoflurane myocaridal depression comparable to
isoflurane at equal MAC concentrations
125
with sevoflurane, CO decreased at __ MAC and recovered at __ MAC
1-1.5
2
126
with sevoflurane, HR is
increased at >1.5 MAC
127
sevoflurane rarely causes __ and treat with __
bradycardia
decreasing concentration
128
sevoflurane causes __ prolonagtion so use caution with __
QT interval
patients with previously prolonged QT
129
sevoflurane cardiac conduction effects
1. minimal effect on conduction of AV, SA & accessory pathway
2. autonomic suppression
3. prolongs QT and action potential- may affect arrhythmogenicity
130
sevoflurane effect on SVR
reduces in slightly less magnitude than iso
131
SVR reduction mechanism
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
with sevoflurane, the baroreceptor reflex is
preserved to a greater extent than with other agents
133
sevoflurane is a broncho__
dilator; Stoelting states it causes the least degree of airway irritation among available agents
134
compared to halothane for inhalation induction, studies show sevoflurane better:
1. slightly faster
2. less patient movement
3. quicker onset of immbolity
4. fewer airway problems
135
at high concentration, sevoflurane causes __ than halothane
less myocardial depression
136
inhalation induction on an adult, healthy, unpremedicated, given vital capcity breaths of up to 7% sevoflurane will have
1. loss of lash reflex in 1 min
2. acceptance of LMA in 1.7 min
3. laryngoscopy, intubation in 4.7 min
137
with sevoflurane, HPV is
preserved as with des and sio at clinically used concentrations
138
sevoflurane NM effects
similar to other agents, enhaced intensity and duration of NMB
139
sevoflurane may ___ slightly longer than iso
prolong duration of roc
140
with sevoflurane, autoregulation is preserved up to
1.5 MAC
141
sevoflurane cerebral vasodilation is similar to
iso
142
sevoflurane EEG
may have evidence of seizure activity (7% conc)
143
sevoflurane effects on platelet aggregation
inhibited more strongly than with halotane, due to the suppression of arachadonic acid, probably due to inhibition of cyclooxygenase
144
sevoflurane metabolism- __ is metabolized by __ to produce __
5-8%
cytochrome P450
inorganic fluoride
145
with sevoflurane, levels of serum flouride ___ but __
> 50 mcmol/L in 7% of patients
no evidence of clinically significant renal dysfunction
146
sevoflurane is metaboized by
liver enzymes and kidney
147
sevoflurane is different from other agents in that it is not metabolized to form
trifluoroacetic acid which can stimulate the immune response resulting in hepatitis
148
nitrous oxide was discovered by __ in __ and used for analgesia/anesthesia in __
Priestly
1772
1840s
149
nitrous oxide odor
odorless (sweet-smelling)
150
nitrous oxide has a low solubility so it
equilibrates rapidly
151
nitrous oxide potency
low
152
nitrous oxide flammability
nonflammable but supports combustion
153
nitrous oxide is stored in
a liquid-gas equilibrium in blue cylinders
154
nitrous oxide __ psi liquid in equilibrium with gas
745
155
nitrous is inorganic meaning
no carbons **test question**
156
nitrous oxide is stable in
soda lime
157
impurities in nitrous oxide
N2, NO, NO2, water vapor
158
nitrous oxide does not combine with
hemoglobin, carried in solution in blood
159
__ are induced by nitrous oxide
hepatic enzymes
160
less than 0.004% of nitrous oxide is metabolized by
intestinal flora; not metbaolized by the human body, liver
161
nitrous oxide effect on myocardial depression
direct
162
young healthy patients cardaic effects from nitrous oxide
sympathetic stimulation and increased SVR due to increased endogenous catecholamines
163
nitrous oxide causes __ PVR
increased, especially if PRVR already slightly elevated
164
nitrous oxide can inhibit uptake of
norepinephrine in the lungs
165
nitrous oxide effects __ receptors
NMDA
166
nitrous oxide with preexisting CV disease, myocardial depression (less than MAC equivalent of potent agents)
1. 40% nitrous oxide procudes myocardial depression
2. added to opioid anesthetic
167
if only opioids and nitrous oxide, the opioids seemingly block the effect on __ and __ is revealed
NMDA receptors (no sypathetic stim)
myocardial depression
168
nitrous oxide, at concentrations < 50%, no increase in
PaCO2, it increased the RR more than other agents
169
with nitrous oxide, the response to __ is reduced even with small amount of nitrous oxide
hypoxia
170
nitrous oxide does not potentiate
nondepolarizing NMB
171
nitrous oxide does potentiate
succ
172
nitrous oxide increased __ with opioids
muscle rigidity
173
chest wall rigidity with opioids risk factor
the use of nitrous
174
nitrous oxide produces __ and __
analgesia and amnesia
175
nitrous oxide produces analgesia due to
increase in enkephalins produced
176
with nitrous oxide, __ occurs with 50%
nystagmus
177
nitrous oxide EEG effects
similar to volatile (slowing frequency and higher voltage)
178
nitrous oxide cerebral vasodilation
less than potent agents
179
nitrous oxide __ CMRO2
increases
180
withdrawal seizures seen with cessation of nitrous oxide may reflect
acute nitrous dependence
181
nitrous oxide causes sensorimotor polyneuropathy related to
oxidizing effect on cobalt atom of B12
182
nitrous oxide causes increase in size of
gas in the bowel
183
nitrous oxide causes increased incidence of
PONV
184
nitrous oxide affect on uterine tone
no effect
185
nitrous oxide is a weak __ when used in high concentrations for prolonged time frame
teratogen
186
nitrous oxide (related to vitamine B12 dependent enzymes) inhibits
methionine synthetase and thymidylate synthetase
187
methionine synthetase is necessary for
myelin formation
188
thymidylate synthetase is necessary for
DNA synthesis
189
nitrous oxide (related to vitamine B12 dependent enzymes) prolonged exposure can result in
bone marrow depression- megaloblastic anemia, and even neurologic deficiences, peripheral neuropathies and pernicious anemia
190
Evaluation of Nitrous oxide In the Gas Mixture of Anaesthesia (ENIGMA): prospective, randomized, multination found that nitrous free led to
decreased PONV, wound infection, fever, PNA, atelectasis
191
homocysteine levels in the nitrous group
59% increase in long term risk of MI; increased homocysteine levels (post op strokes or death not increased)
192
nitrous oxide is __ more soluble than nitrogen in the blood
34 times
193
nitrous oxide is absorbed into
air-filled spaces faster than nitrogen moves back inot the blood causing expansion of the "bubble"
194
nitrous oxide can diffuse into
ear, pneumothorax, gastric/intestinal air, retinal detachment (intraocular gas bubble that serves as tamponade or splint)
195
nitrous oxide immunologic affects
chemotaxins and motility of polymorphonuclear leukocytes for phagocytosis, which is necessary for the inflammatory respone to infection
196
expansion of volume or pressure of nitrous oxide depends on
1. partial pressure of nitrous oxide
2. blood flow to air-filled cavity
3. duration of nitrous oxide admin
197
diffusion hypoxia with nitrous oxide
nitrous is so insoluble that it returns to alveoli so rapidly in such volumes that it dilutes other gases including oxygen
198
diffusion hypoxia with nitrous oxide can be avoided if
supplemental oxygen is administered for the frist 5-10 minutes after nitrous discontinued
199
nitrous oxide second gas effect
administering high concentration of nitrous oxide will cause an increase of the alveolar concentration of a second gas
200
when nitrous oxide is utilized, __ must be decreased
oxygen concentration
201
nitrous oxide in C-section
common practice to deliver no more than 50% prior to the delivery of the infant
202
nitrous oxide occupational risks- recent studies with scavenging and limited exposrue failed to show
difference in fertility and birth defects with general population
203
if nitrous oxide is substituted for a portion of a volatile agent
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**
