IV Anesthetics Flashcards
(99 cards)
1
Q
How is propofol cleared?
A
mostly hepatic with some extra hepatic in the lungs
2
Q
what is gren urine from propofol caused by?
A
phenol excretion
3
Q
what is clouding urine from propofol caused by?
A
uric acid excretion
4
Q
How does propofol affect baroreceptor reflex?
A
impairs it
accoridng to one thing in apex…
5
Q
Propofol affects on sezuires?
A
It has anticonvulsant properties, but can cause myoclonus. There are rare reports of propofol causing seizures.
6
Q
PIS tx:
A
dc prop, pacing, PDE inhibitors, glucagon, ECMO, CRRT
7
Q
waht is PIS?
A
Propofols long chain triglycerides (LCTs) impair oxidative phosphorylation and fatty acid metabolism. This starves cells of oxygen, particuarly skeletal muscle and cardiac muscle.
8
Q
PIS symptoms
A
metabolic acidosis (base deficit >10)
rhabdomyolysis
enlarged for fatty liver
renal failure
hyperlipidemia
lipemia (cloudy plasma or blood may be an early sign)
9
Q
Which anesthetics incease the time GABA-A channel is open?
A
most of them:
propofol
etomidate
etc.
10
Q
which drugs increase frequency of GABA-A channel opening?
A
Midazolam
11
Q
A
propofol
12
Q
Fospropofol inductiondose
A
6.5mg/kg
13
Q
fospropofol maintence dose
A
1.6mg/kg no sooner than every 4 min
14
Q
fospropofol onset
A
5-13min
15
Q
fospropofol doa
A
15-45min
16
Q
fospropofol SE
A
genital and anal burning
17
Q
A
fospropofol
18
Q
Ketamine 2ndry mechs of action
A
binds to opioid, mao, serotnoni, NE, muscarinic receptors and Na channels
19
Q
what is the normal agonist at ketamines primary site of action?
A
glutamate
20
Q
ketamine induction dose
A
1-2mg/kg IV
21
Q
opioid sparing ketamine dose
A
1-3mcg/kg/min
22
Q
ketamine analgesia dose
A
0.1-0.5mcg/kg/min
23
Q
IM and PO ketamine doses
A
IM 4-8mg/kg
PO 10mg/kg
24
Q
ketamine doa
A
10-20min but may take 60-90min to return to full orientation
25
ketamine active metaboliste and is potency
norketamine
1/3 - 1/5 as potent as ketamine
26
when does keatmine usually not activate the SNS
doses less than 0.5mg/kg
27
how does ketamine affect RR after induction dose?
can cause breif period of apnea
28
how does ketamine affect cerebral blood flow and oxygen use?
^ CMRO2 and ^ CBF
29
Why should you be careful with ketamine in patients with hixtory of seizures?
it can raise EEG activity so it could cause a seizure
30
risk factors for emergence delirium from ketamine
>15yrs age
female gender
dose >2mg/kg
hx personality disorder
31
what kind of pain does ketamine treat?
somatic > visceral
32
what is esketamine?
levorotaroy enatntiomer
nasal spray used for treatment resistant depression
33
keatmine protein binding
12% which is an outlier from other anesthetics which are all in uppper 90s
34
ketamine
35
etomidate
36
etomidate induction dose
0.2-0.4mg/kg
37
how does etomidate affect hemodynamics
"cardiac stable"
does have small decrease in BP
38
what drugs have an imidazole ring?
etomidate
versed
precedex?
39
consideration with etomidate and intubation?
it wont blunt the SNS response to laryngoscopy
40
etomidate on RR
mild resp depression
41
etomidate effect on CPP
CPP remains stable
42
what are the two formulation of etomidate?
propylene glycole - burns on injection
lipophilic one - no burning
43
does etomidate cause seizures?
Not in a patient without any history of seizures.
it does cause myoclonus
if pt has hx of seizures it can increase risk of seizure
44
how does etomidate cause adrenal cortical supression?
11-betahydroxylase and 17-alphahydroxylase supression
45
how long does a single dose of etomidate cause adrenal corticol supression?
5-8hrs
some texts say up to 24hrs
46
when should you avoid etomidate?
if pt is reliant on SNS
i.E sepsis and adrenal failure
47
PONV risk with etomidate
30-40%
48
sodium thiopental
49
sodium thiopental dose
adult: 2.5-5mg/kg
child: 5-6mg/kg
50
does sodium thiopental release histamine?
yes be careful in asthmatics
51
how does sodium thiopental affect baro receptor reflex?
it doesnt so you get reflex tachycardia from the HoTN
52
what happens with intrarterial injection of sodium thiopental? how do you treat it?
intense vasoconstrction and crystal formation
tx: vasodilator like phentolamine or phenoxybenzamine. or stellate ganglion block which will cause sympathectomy of uppper extremity
53
what are thiobarbituurates?
thiopental
have sulfur in the 2nd position
54
what are oxybarbiturates?
oxygen in 2nd position
methohexital
55
what does adding a methyl to the nitrogen on a barbiiturate do?
decreases seizure threshold and ^ potency. I.E. methohexital
56
what does adding a phenyl to 5th position of barbiturate do?
increase anticonvulsant effects I.E (phenobarbital)
57
sodium thiopental mech of action
low dose: ^ affinty for GABA at GABA - A Recptor
High dose: directly bind GABA-A Receptor
58
does sodium thiopental have an active metabolite?
yes, pentobarbital after high doses
59
what causes the decreased BP from sodium thiopental?
primarily from venodilation. 2ndary to myocardial depression
60
what caues more HoTN propofol or sodium thiopental?
propofol
61
when does thiopental provide neuroprotection?
only during focal ischemia
NOT global ischemia
62
how are barbiturates metabolised?
all by p450 system
Except: phenobarbital is excreted unchanged in the urine
63
sodium methohexital induction dose
1-1.5mg/kg
64
how does sodium methohexital affect seizures?
decrease the seizure threshold for better quality seizures
65
what drugs should be avoided in actue intermitent porphyria?
Why should they be avoided?
ketamine
etomidate
barbiiturates
ketorolac
amiodorone
birth control pills
many but not all CCBs
lidocaine (contraversial)
They induce ALA synthase
66
are non-inducible forms of porphyria affected by drugs?
no
67
what are the two types of intermitent porphyria?
acute (inducible) and
chronic (non-inducible)
68
what is acute intermitent porphyria?
defect in heme synthesis > accumulation of heme precursors
69
what are the s/s of acute intermittent porphyria?
severe admonial pain > N/V
anxiety, confusion, seizure, psyschosis, coma,
skeletal muscle weakness > resp failure
bulbar m. weakness > aspiration risk
70
describe anesthetic management for acute intermittent porphyria
liberal hydration
glucose supplementation ( decrease ala synthase activity)
heme arginate ( decrease ala synthase activity)
prevent hypothermia
VA, nitrous oxide, nmbs, nmb reversals, narcotics, versed, pressors, zofran, BB, are all safe
regional is not CI but many avoid becaseu may be hard to distinguish block related symptoms from acute porphyria attack
71
precedex onset of action?
10-20min
72
precedex doa?
10-30min... really??
73
precedex dosing?
loading dose 1mcg/kg over 10min
drip 0.4-0.7mcg/kg/hr
74
how does precedex affect cerebral blood flow?
decrease CBF but no chagnge in CMRO2 so it does cause cerebral uncoupling
75
does precedex provide reliable amnesia?
no
76
how does precedex affect body's thermoregulation?
it impairs it so patient that should shiver wont
77
mech of action for analgesia from precedex?
alpha 2 stimulation in dorsal horn of spinal cord > decreased substance P and glutamate release
78
how does precedex affect evoked potentials?
it does not impair them
79
why is nasal/ buccal precedex useful in preop peds sedation? what is the dose?
nasal and buccal routes have high degree of availability.
3-4mcg/kg 1 hour before surgery
80
versed doa?
20-60min
81
what is this?
precedex
82
what is this?
versed
83
versed active metabolite? potency? what happens to this active metabolite?
1-hydroxymidazolam 0.5 as potent
it is rapidly conjugated to an inactive compound
84
versed sedation and induction doses?
sedation 0.01-0.1mg/kg
induction dose:
85
CV/resp affects of induction dose versed?
decreased BP SVR and resp depression
86
what medications potentiate resp depression when given with benzos?
opioids
87
How does versed affect EEG compared to other common IV anesthetics?
cannot produce isoelectric EEG and propofol and barbituates can
88
does versed cause any muscle relaxation? if so, how? When is this useful?
yes spinally mediated skeletal muscle relaxation. antispasmodic effect useful for patients with cerebral palsy
89
does versed have an imidazole ring? What does this mean?
yes. makes it hydrophilic in the vial and liophilic once injected
90
what to know about lorazepam?
amnesia for up to 6 hours, slow onset so its usefullness as an anticonvulsant is limited
91
indication for remimazolam?
induction and maintence of procedural sedation in adults for less than 30min
92
remimazolam doses
induction 2.5-5mg over 1 min
M: 2.5mg IV/15/15sec q 2 min
93
when should remimazolam dose be decreased?
hepatic dysfunction
94
remimazolam profile compared to propofol?
less resp depression, and more CV stability
95
when is remimazolam contraindicated?
dextran 40 allergy
96
flumazenil dose
0.2mg IV and repeat 0.1mg Q 1 min as needed
97
does flumazenil reverse sedation or amnesia more?
sedation
98
side effects of flumazenil
seizure in benzo dependent patient
99
flumazenil doa?
30-60min so may need to re-dose as Doa is shorter than benzo doa
