Week 5- Induction Agents Flashcards
1
Q
Primary MOA of propofol
A
GABA- A receptor agonist (enhance GABA inhibition)
2
Q
Chemical name for propofol
A
2-6-diisopropylphenol
3
Q
Protein binding of propofol
A
98%
4
Q
Make up of propofol
A
1% propofol
10% soybean oil
2.25% glycerol
1.2% egg phospholipid emulsifier
5
Q
What is added to propofol to decrease microbial growth
A
EDTA
6
Q
T or F: propofol has an unpredictable CSS
A
False- predictable
7
Q
T or F: propofol causes PONV
A
F- antiemetic properties
8
Q
What component of propofol causes veno irritation
A
The glycerol
9
Q
CNS effects of propofol
A
CNS depressant
- neuroprotective
- anticonvulsant
- decrease CMRO2, CBF, and ICP
10
Q
CV effects of Propofol
A
Significant decrease in SVR, SV, and CO
11
Q
Pulmonary reactions to propofol
A
Respiratory depressant and potent bronchodilator
12
Q
Major side effects of propofol
A
Pain with injection
Propofol infusion syndrome
13
Q
sign of propfol infusion syndrome
A
Green urine
14
Q
Clinical uses of propofol
A
- general, induction, maintenance
- TIVA
- Conscious/deep sedation including ambulatory centers
- ICU
- PONV prevention
- safe for MH patients
15
Q
Propofol is metabolized in
A
Liver
inactive/water soluble metabolites excreted by kidneys
16
Q
Most common extra hepatic site of metabolism of Propofol. How much metabolism occurs here
A
Kidney and lungs
30%
17
Q
Which model explains elimination of propfol
A
3-compartment model
18
Q
What causes unconscious states of propofol
A
Enhancement of GABA inhibitory pathways and central cholinergic transmission, NMDA, or a- adrenergic sites
19
Q
What does low dose propofol produce
A
- sedation
-possible paradoxical excitation at higher doses
20
Q
T or f: propfol can be used to treat status epilepticus
A
T
21
Q
Why would you use propofol for ECT
A
Shorten seizure duration
22
Q
When are you more likely to have a CV response to Propofol?
A
Induction dosing compared to continuous
*drop in BP without increased HR (decreased CO, SV, SVR)
23
Q
What can maintenance doses of propfol do to tidal volume and RR
A
Decrease Tv and increased RR
24
Q
Why is propofol a good bronchodilator
A
Direct effect on intracellular calcium
25
IV and infusion dose of Propofol to prevent PONV
Why does this seem to prevent PONV
IV = 10-15 mg
Infusion = 10 mcg/kg/min
direct effect on chemoreceptor trigger zone
26
What can you use to effectively treat opioid-induced pruritus, what dose, and what mechanism is this related to
Propofol
10 mg IV
Spinal cord suppression
27
Induction of anesthesia with propofol:
- dose
- produces unconsciousness in ____
- 2 mg/kg
- 30 seconds
28
Intravenous sedation of propofol (MAC)
Maintenance dose of propofol (GA)
25-75 mcg/kg/min
100-200 mcg/kg/min
29
Usual concentration of propofol
200 mg/20 mL --> 10 mg/mL
30
What cause cause propofol allergies?
- phenyl nucleus and di-isopropyl side chain (anaphylaxis reported)
- generic brand have sodium metabisulfite —> contrainidicated with sulfite sensitivity
- eggs or soy
31
Cautious using propofol in (5 examples)
- elderly —> increased sensitivity d/t decreased CO and clearance
- children —> large Vd and faster clearance
- chronic alcoholics —> require more
- CV disease
- trauma/ hypotension/ bleeding
32
How long is propofol good for?
12 hours in opened vial, 6 hours in syringe
**read the vial** IT CAN SUPPORT BACTERIA
33
What doses can cause propofol infusion syndrome
4 mg/kg/hr > 48 hours
34
Most important side effects of propofol infusion syndrome
Bradycardia/ asystole
35
Etomidate is __________ stable.
It also can cause post-operative __________.
Hemodynamically ;
PONV
36
MOA of etomidate
GABA-A receptor agonist
37
T or F: etomidate should be avoided in elderly
F- good for cardiac, trauma, elderly
38
Critically ill patients administered etomidate should be monitored for
Adrenocortical supression
39
Chemical makeup of etomidate
Carboxylated imidazole derivative
40
Why is the continuous infusion of etomidate limited?
Due to possible adrenal suppression.
41
T or F: etomidate follows 1 compartment model
F- 3 compartment model
**Fast resolution of effect secondary to redistribution
42
Etomidate (_________)
Amidate
43
Metabolization and excretion of etomidate
Liver and plasma esterases
Excreted by kidney (80%) and bile (20%)
44
Protein binding of etomidate
75% (Highly protein bound)
45
Etomidate
Initial distribution half-life:
Redistribution of half-life:
Elimination half-life:
Volume of distribution:
2.7 minutes
29 minutes
3-6 hours.
2.5-4.5L/kg
46
Induction dose of etomidate
the usual concentration of etomidate
0.2-0.3 mg/kg
2 mg/cc
47
CNS effects of etomidate
- potent vasoconstrictor that reduces CBF, ICP, CMRO2
- seizure like, myoclonic movements on induction --versed/opioid
- proconvulsant and lowers seizure threshold
48
CV effects of etomidate
- hemodynamically stable on induction
- minimal to no side effects on CV
49
Why does etomidate cause adrenocortisol suppression
Inhibit activity of 11B-hydroxylase and prevents conversion of cholesterol to cortisol
50
Ketamine (_________)
Ketalar
51
Ketamine's active metabolite
Norketamine
52
Ketamine is a _________ anesthetic. Emergence was associated with __________.
Dissociative;
Delirium and hallucinations.
53
Ketamine is a __________ derivative.
Phenylcyclohexyl piperidine(PCP)
54
T or F- ketamine is a racemic mixture with a chiral compound
T
55
Bioavailability of routes of administration of ketamine
IM (93%)
Transnasal (25-50%)
Rectal or oral (16%)
56
Protein binding of Ketamine
20%
** it has a high lipid solubility/ rapid redistribution
57
How is ketamine metabolized
by Cytochrome p450 enzymes
58
where is Ketamine metabolized and what is the metabolite of Ketamine
Liver
Demethylation to norketamine (1/3-1/5 as active)
59
Ketamine
Onset:
Duration:
Induction dose:
K-dart dose:
Usual concentration
O: 30-60 sec
D: 10-20 min (dose depedent)
ID: 0.5-2 mg/kg IV
4-5 mg/kg IM (K dart)
Usual conc: 10 mg/cc
60
Ketamine's CNS effect are primarily related to its _______ activity at the NMDA receptor
antagonistic
61
MOA of Ketamine
- function dissociation between thalamocortical and limbic systems
- CNS effects primarily related to antagonistic activity of NMDA receptor
62
Where else does Ketamine bind
- non NMDA glutamate receptor
- Nicotinic receptors
- cholinergic receptors
- monoaminergic receptors
- mu, delta, and kappa-opioid receptors
- inhibit neuronal NA+ channel and Ca2+
63
Ketamine uses:
- Sedation
- Analgesia and acute post- op pain (part of non-opioid protocol)
- ERAS protocol (enhanced recovery after surgery.
- Opioid abuse patients
- Acute and CHRONIC pain.
- Depression
64
Why Ketamine clinically
- dissociative amnestic state
- unconscious with eyes open, maintain RR and do not react to painful stimulus
- good choice for hemo stable (induction dose associated with increased HR and BP)
- OB
- acute/chronic pain
- depression
65
In what pt should you be cautious of using Ketamine
Cardiac, cardiac cripple, and severe right heart dysfunction (increases PVR)
66
CNS effects of Ketamine
- POTENT CEREBRAL VASODILATOR
- increased CBF 60-80% during normocapnia (attenuated with hyperventilation)
- relatively contraindicated in elevated ICP
67
Why is there increase of secreations in Ketamine use
Effect of muscarinic receptors
**can give glycopyrollate
68
T or F: Ketamine is a good bronchodilator
T
**maintains protective airways/ does not produce significant depression of ventilation.
69
Ketamine resembles _________ on the CV system
SNS stimulation
70
CV effects of Ketamine
Everything up
- MAP, CO, myocardial O2 requirements, SVR
71
Why should Ketamine be avoided in critically ill or shock like pt
Due to chatecholomine depletion leading to unopposed direct myocardial depression
72
How to medically prevent Ketamine emergence delerium
Midazolam preoperative and awake in calm and quiet environment
** becareful in pt's with PTSD
73
Incidence of emergence delerium in Ketamine and what is the dose at which it occurs
5-30%
>2 mg/kg
74
MOA of dexmedetomidine
Highly selective, specific, potent a2-adrenergic agonist
75
Dexmotidine produces dose-dependent sedation and analgesia with _________ respiratory depression.
MILD
76
dexmedetomidine is ______ times more selective for a2 receptors than clonidine
7-8
77
Protein binding of dexmedetomidine
94%
**highly protein bound
78
Metabolism of dexmedetomidine
Rapid hepatic metabolism involving conjugation, N-methylation, and hydroxylation
79
Excretion of dexmedetomidine
Urine and feces
80
rapid redistribution: with distribution half life of dexmedetomidine
6 minutes
81
Short elimination half life of dexmedetomidine
2 hours
82
dexmedetomidine could cause increased plasma concentration of ________
and why?
Opioids
precedex has weak inhibitory properties in the CYP-450 system
83
CNS effects of dexmedetomidine
- sedative, anxiolytic, analgesic (spinal cord and brain)
- sedated but easily arousable
- Analgesic effects reduce opioid requirement
84
Respiratory effects of dexmedetomidine
- less ventilator depression compared to others.
- bolus dose reduces minute ventilation
85
CV effects of dexmedetomidine
- increase potential hypotension and bradycardia (esp in kids)
- blunt effects of hemo dynamic effects of direct laryngoscopy and improves hemo dynamic stability when given as anesthetic adjunct
86
Sedation and infusion dose of dexmedetomidine
typical syringe concentration
Sedation: 0.5- 1 mcg/kg over 10 minutes
Infusion: 0.2-0.7 mcg/kg/hr
Conc: 4 mcg/mL
87
Side effects of dexmedetomidine
- hypotension
- bradyacardia
- dry mouth and nausea
- rebound hypertension
88
Benefits of using benzodiazepines
- amnesia
- minimal CV and respiratory depression
- anticonvulsant
- anxiolysis and sedation
- skeletal muscle relaxant
89
MOA of benzodiazepines
Effect central inhibitory GABA-A
Bind to alpha subunits increasing chloride conductance --> hyperpolarization of cell
90
Benzodiazepine have rapid absorption from the gut, with _________% first- pass hepatic extraction.
>50%
** watch for patients with kidney and liver dysfunction, age, cormobidities,
91
T or F: benzodiazepines burn on injection
False- does not burn d/t being water soluble in bottle
92
Protein binding of benzodiazepines
94-98%
**high lipid solubility
93
benzodiazepines effects (5)
- descrease CMRO2, CBF, little effect on ICP
- decreased upper airway reflexes
- decreased central Resp drive
- decrease SVR and BP
- anterograde amnesia (OB)
94
Reversal dose of benzodiazepine with flumazenil (_________):
Romazicon
0.2 mg IV over 15 seconds
If after 45 seconds, no response, give 0.2 mg
Can repeat at 1 min intervals (not exceed 4 doses)
95
Oral dose of benzodiazepines in kids and adults
Kids: 0.5 mg/kg 30 min before OR
Adults: 1-2 mg in preoperative (IV)
96
3 most common benzodiazepines
- midazolam, lorazepam, diazepam
97
Which of the benzodiazepines is water soluble
a. midazolam
b. lorazepam
c. diazepam
Midazolam
***undergoes conformational change in the bloodstream becoming more lipophilic
98
Barbiturates 2 classes
- oxybabrbiturates
- thiobarbiturates
99
Why is methohexital a oxybarbiturate
Retains an O2 atom on the #2 carbon atom
100
Why is thiopental a thiobarbiturates
Replacement of the O2 atom with sulfur on the #2 carbon atom
101
Primary metabolism Barbiturates
Hepatic, inactive metabolites excreted in urine and bile
102
What accounts for rapid termination after a single dose of Barbiturates
Rapid distribution of highly perfused compartments
103
MOA of Barbiturates
Cortical and brain stem GABA inhibitory pathways
104
Concerning side effects of Barbiturates
- LOC, respiratory and CV depression
105
What causes hypnotic effects of Barbiturates
Inhibiton of central excitatory pathway
** mediated by glutamate via the NMDA receptors and acetylcholine
106
Thiopental may be used for induction of anesthesia in patients with ________, as well as the treatment of _______ that is resistant to hyperventilation.
increase ICP
Increase ICP
107
Thiopental is generally considered an ___________ and used to treat ___________.
anticonvulsant;
status epilepticus
108
Elimination 1/2 life of thiopental
12 Hours
109
thiopental precipitates with (3)
- SCh
- rocuronium
- lidocaine
110
Thiopental stimulates the release of histamine from:
mast cells
111
T or F: thiopental is neuroprotective
T
*** by drug induced cerebrovascular vasoconstriction.
- This leads to decreased cerebral blood flow.
- subsequent decrease in intracranial pressure
- decreased cerebral metabolic O2 consumption.
112
Barbiturates should be avoided in patients with what disorder:
AIP ( acute intermittent porphyria )
113
Other name for methohexital
Brevital
114
Elimination half life of Brevital
4 hours
** more efficient hepatic extraction
115
Drug of choice for Electroconvulsive therapy
Methohexital (brevital)
**proconvulsant activity
116
Methohexital (brevital)
IV dose
Rectal dose
IV: 1-2 mg/kg
Rectal: 20-30 mg/kg
***may cause pain on injection
117
Induction dose of thiopental
2.5-5 mg/kg
***reduce dose by 30-35% in elderly
118
low dose of IV anesthetics produce ______ and high doses produce ______
sedation
unconsciousness
119
T or F: all IV anesthetics are sedative-hypnotics and produce dose-dependent CNS depression
T
120
uses for IV induction medications
- induction of anesthesia
- TIVA
- MAC
- sedation during local and regional anesthesia
121
the time it takes for the plasma concentration of a drug to decreas to 50% of its original concentration (after 1 bolus dose)
elimination half-time (t 1/2)
122
T or F: elimination half-time can describe a three-compartment model for a drug only in the blood phase or a drug administered only once (bolus)
F- one-compartment model
123
the time to achieve a 50% reduction in concentration after stopping a continuous infusion
context-sensitive half time
124
describes the transfer of drug out of the plasma into the peripheral compartments followed by the reverse process once the infusion is stopped back into the central compartment
context-sensitive half time
125
the best example of Css
remifentanil
126
which induction agent can cause an increase in "sexual tendencies"
propofol
127
T or F: Ketamine is a bronchodilator
T
128
other name for etomidate
amidate
129
T or F: etomidate can cause PONV
T
130
what contributes to the veno-irritation and phlebitis of etomidate
solvents in the formation (propylene glycol)
131
etomidate has a _______ onset of action
quick
**(vein to brain)
132
the initial distribution half-life of etomidate
2.7 minutes
133
redistribution half-life of etomidate
29 minutes
134
elimination half life of etomidate
3-6 hours
135
volume of distribtuion of etomidate
2.5-4.5 L/kg
136
T or F: Ketamine is a phencyclidine derivative
T
137
T or F: Ketamine is also known as Vitamin K
T
138
T or F: ketmine can cause emergence delerium and hallucinationsn
t
139
t or f: ketamine only has anesthetic effects, not analgesic effects
F, has both
140
Ketamine has ____________ effects
a. associative
b. dissociative
dissociative
141
why would ketamine be used in a pt with acute or chronic pain
NMDA receptor is associated with central sensitization and winds up at the spinal cord associated with chronic pain. studies suggest ketamine analgesia occurs by prevention of hyperalgesia and decreases in CNS sensitization that occurs with acute pain
142
T or F: Ketamine produces significant depresison of ventilation
F - does NOT produce ... maintain protective airway reflexes
143
t or F: Precedex produces dose-dependent sedation and analgesia with mild respiratory depression
T
144
Why is precedex a good IV adjunct during induction or maintenance of general anesthesia `
will blunt acute SNS response to laryngoscopy
145
uses of dexmedetomidine
- procedural sedation (awake fiberoptic)
- rigid bronchs
- used as adjuvant during local and regional anesthesia
146
how can you decrease the incidence of bradycardia with precedex use and how can you treat it?
- ommit loading dose
- treat with atropine, ephedrine, or volume
147
rapid absorption in the gut with ________ first-pass hepatic extraction of benzos
>50%
148
rapid absorption in the gut with ________ first-pass hepatic extraction of benzos
>50%
149
which barbiturate is associated with accumulation in poorly perfused compartments and slow elimination (prolonged Css and delayed recovery)
Thiopental
150
may be used for induction of anesthesia in patients with increased ICP as well as the treatment of increased ICP that is resistant to hyperventilation alone
Thiopental
151
CNS effects of thiopental
- cerebrovascular vasoconstriction
- decrease cerebral blood flow
- decreased intracranial pressure
- decreased cerebral metabolic O2 consumption
**anticonvulsant
152
T or F: thiopental stimulates the release of histamine from mast cells
T
