Quiz 1 Flashcards
What are the 3 elements of anesthesia?
akinesia, amnesia, analgesia
Define akinesia
immobility, motionless
Define analgesia
deadening or absence of the sense of pain without loss of consciousness
Define amnesia
loss of memory (anterograde- loss of memory moving forward)
Define anesthesia
total or partial loss of sensation, especially tactile
Chemical name of propofol
2,6-diisopropylphenol (think “prop”)
Chemical name of etomidate
R-1-methyl-1-(a-methylbenzyl) imidazole- 5 carboxylate (carboxylate rhymes with etomidate)
Chemical name of ketamine
2-(o-chlorophenyl)-2 (methylamino) cyclohexanone HCl (ketaMINE rhymes with methaylaMINo)
Chemical name of benzodiazepines
8-chloro-6-(2-flurophenyl)-1-methyl-4 H-imidazo [1,5-a][1,4] benzodiazepine
Induction dose of propofol
1-2 mg/kg
induction dose of etomidate
0.2-0.3 mg/kg
induction dose of Versed
0.1-0.2 mg/kg (clinical is 1-2 mg)
Induction dose of ketamine
2-4 mg/kg (clinical is 10-50 mg)
Induction dose of thiopental
5 mg/kg
What drugs are GABA agonists?
benzos, barbiturates, propofol, etomidate
Benefits of propofol
rapid induction and awakening, amnestic, antipruritic, antiemetic, antiepileptic
Propofol and egg allergy?
most people are allergic to protein in egg whites- propofol has egg lecithin from egg yolk
How long can you use a propofol syringe vs tubing?
syringe- 6 hours tubing- 12 hours
What drug causes pain on injection?
propofol- can premedicate with lidocaine
Where is propofol metabolizes and does it have active metabolites?
liver, lungs- no
Symptoms of propofol infusion syndrome?
metabolic acidosis, hypertriglyceridemia, hypotension, rhabdo, acute renal failure, hepatomegaly
risk factors for propofol infusion syndrome
dose >4 mg/kg/hr, infusion >48 hours, pressors, steroids, low glycogen stores, mitochondrial disorders, neuro compromise
Effects of propofol on organ systems
CV- tachycardia on induction, negative inotrope respiratory- apnea, depress normal response to hypercarbia, lower incidence of wheezing Cerebral- decreased CBF and ICP
CNS effect that may occur with induction by propofol?
excitatory phenomena- muscle twitching, spontaneous movement, opisthotonus, hiccupping
Mechanism of action for etomidate
depresses RAS and mimics GABA
Potential consequence of using etomidate?
adrenal corticoid suppression with long term infusions
What is common with induction by etomidate?
myoclonus
Will a standard induction dose of etomidate fully inhibit ventilation?
no
Effects of etomidate on organ systems
CV- minimal effects (good for HD unstable patients) Respiratory- may induce apnea when used with opioids cerebral- decreased CMR, CBF, ICP
Relationship of fentanyl with etomidate
fentanyl inreases plasma levels and prolongs elimination half life but decreases myoclonus
MoA of barbiturates
depress RAS, enhance GABA, suppress Ach
Duration of action of most induction drugs is determined by?
redistribution, not metabolism/elimination
Effects of barbiturates on organ systems
CV- increased HR, decreased BP, vasodilation (effects vary depending on volume status, autonomic tone, CV disease) Respiratory- depresses Cerebral- decreased CBF, ICP renal- decreased RBF and GFR Hepatic- decreased hepatic BF, can trigger porphyria
Barbiturates are highly ? and are incompatible with opioids and NMBs because…
alkaline; they will precipitate
What SE is associated with ketamine at high doses?
nausea
What is the MoA for ketamine?
NMDA receptor antagonist (blocks glycine and glutamate)
Metabolite of ketamine
norketamine- ACTIVE!
Effects of ketamine on organ systems
CV- increased BP, HR, CO (avoid in those with cardiac disease respiratory- bronchodilator (good for asthma), increased salivation, does not depress ventilatory drive cerebral- increased CMRO2, CBF, ICP
Psychedelic effects of ketamine
emergence delirium- visual, auditory, proprioceptive illusions dreams and hallucinations can occur up to 24 hours
Drug interactions with ketamine
-NMBA are potentiated -valium attenuates CV effects and prolongs elimination -versed and prop can decrease psychedelic effects
Benzo reversal
romazicon (flumazenil)
Which benzos are oil based and which are water based?
oil based- valium and ativan water- versed
5 effects of benzos
anxiolysis, sedation, anticonvulsant, anterograde amnesia, spinal cord mediated muscle relaxant
MoA of benzos
enhances inhibitory effects of various NTs, especially GABA
elimination half life of benzos
versed- 2 hours ativan- 15 hours valium- 30 hours
Effect of benzos on organ systems
CV- minimal, slight drop in BP and increase in HR Respiratory- depress vent response to CO2 cerebral- prevents seizures, amnesia
Characteristics of thiopental (from study guide)
anterograde amnesia, 2 hour elim 1/2 life, minimal CV and resp effects, raises seizure threshold, potentiated by other CNS depressants
How soon does awakening occur from propofol and what is its eliminatino half time?
2-8 minutes; 0.5-1.5 h
Elimination half time of etomidate
2-5 hours
elimination half time of ketamine
2-3 hours
The “perfect induction process”
“pleasant loss of sensation”, from awake to level of surgical anesthesia -uses Versed, fentanyl, lidocaine, propofol, NMB
