Induction agents Flashcards
What are induction agents?
General anaesthetics administered through IV
What do induction agents do?
Induce RAPID and SHORT LASTING unconsciousness
Why aren’t induction agents used as sedatives?
- You can control inhalant anaesthetics
- You skip the stage of excitement
What is the stage of excitement?
A stage in the induction process that has a ton of negative attributes (vomiting, pissing, shitting, delirium)
What are the properties of an ideal induction agent?
Painless
Compatible with other medication
Rapid onset and metabolism
Inhibits gag reflex
Most modern induction agents…
last for 40-90 seconds
have adverse effects based on rate of injection
Premedication reduces the amount of induction agent needed to put a patient under by approx…
50%
The first induction agents were ____ but were abandoned due to a ____
barbituates which were abandoned due to a high fatality rate
Modern induction agents include…
propofol and phencyclidines (ex. ketamine)
What are the 3 problems with using barbituates as induction agents?
- Barbs can open GABAa channels in the absence of GABA (low therapeutic index)
- Barbs are metabolized slowly by p450 (long effect duration (30-60min)
- Partial doses can have intense CNS excitation effects
What is the method of action of propofol?
Facilitates the effect of GABA at GABAa receptors (cant work without GABA)
What is the main adverse effect of propofol?
Dose-dependent depression of respiration and blood pressure
What are phencyclidines like ketamine?
These are dissociative anaesthetics
Dissociative anaesthesia is…
a dream-like state of pseudo-unconsciousness
Phencyclidines are NMDA receptor ____
blockers
