Injectable Anesthesia Flashcards
Safe therapeutic indices
Etomidate, Ketamine, Alfaxalone
not so safe thereapeutic indices
propofol 3
thiopental 5
high therapeutic index means
if you overdose its less likely to be lethal
Compartment theory
when give blood iv it moves first to high blood flow areas and then organs with low blood flow
Time of awakening for all injectable anesthetics is due to the _______ phase
redistribution
continuous infusion can lead to
accumulation and saturate the compartments.
Context sensitive half life
time it takes to wake up once CRI is discontinued (for plasma to drop 50%)
The lower the protein the
less drug you should give!!
drop in serum protein will lead to increase in ______
free portion of anesthetic analgesic drug (non protein bound drug)
also increase in drug effect and side effect
Barbiturates
- not used in human med so super expensive for us now.
- includes thiopental(short acting)
Mechanism of action for thiopental
- GABA, Allows chloride in when binds to barbituric site
- negative ions make the cell lazy
thiopental is one of the best drugs to prevent
oxygen consumption of brain, intracranial pressure
thiopental not recommended for
repeated bolus, takes forever to be eliminated (especially bad for liver patients/portosystemic shunts)
propofol problems
sleep apnea
respiratory/cardiovascular depression but its ok because short lived
propofol benefits
- so easy, people get less vigilant with it (smooth induction and recovery)
- fast in fast out
- recovery due to redistribution
- short context sensitive half life -> great for infusion rate
mechanism of action propofol
GABA
best for liver patients (PSS)
propofol
because doesn’t rely on liver metabolism
prefer not to use propofol with
heart patients
high oil/triglycerides/fat in ?
So don’t?
- Propofol vehicle
- Don’t mix with other drugs. May cause fat embolism.
Cats produce heinz body and methemoglobinemia when
long term use of propofol
Etomidate
GIVE YOUR HEART A BREAK
(Murmur, DCM, ASD) Doesn’t drop BP, CO, not bad for respiratory depression either
Etomidate adverse effects?
shuts down adrenal gland, can no longer perform stress functions (bad in trauma cases that you wan’t to use etomidate in)
Bleeding, Septic, ICU patients use etomidate?
nah bro
Ketamine
“Swimming in a bowl of jello” Dissociative drug. Disconnects cortex from limbic system.
Can’t be used as solo agent, need to add high sedation(Benzdiazepam alpha agonist)
Ketamine drawbacks
controlled (date rape, Special K)
Ketamagic
can give IM to feral cats
only anesthetic drug for analgesia
because?
ketamine
because works nMDA receptor
increases sympathetic tone, good for ICU patients
ketamine
Alfaxalone
safe for heart, smooth induction, doesnt stop breathing, can give IM, no analgesia
alfaxalone drawback
super expensive
Alfaxalone is good for patients
with heart issues that we don’t want to mess up the adrenal gland.
Heart disease
Etomidate>Alfaxalone
kidney disease
Alfaxalone»»> Ketamine
Liver disease
Propofol»_space;Alfaxalone
Trauma - hypovolemic shock
Ketamine>Alfaxalone
Trauma - Head injury
Propofol»_space;> Alfaxalone
Trauma - Septic shock
Ketamine» Alfaxalone
