Intravenous anesthetics Flashcards
Why are IV anesthetics the most widely used anesthetics for adults?
High lipophilicity and high perfusion into brain and spinal cord
Very rapid onset and short duration after a single bolus dose
What’s a downside to IV anesthetics?
They accumulate in fatty tissues leading to prolonged recovery especially after multiple doses or infusion
Termination of anesthetic effect is not due to metabolism. What is it due to?
Redistribution out of the CNS.
IV anesthetics quickly go into the brain and spinal cord, they slowly leave and enter the blood then the tissues.
Anesthesia goes away when they leave the CNS.
Elderly require _____ doses and children require ____ doses of IV anesthetics
Elderly require lower doses, children require higher doses
How long does thiopental take to cause unconsciousness?
20 seconds (high lipid solubility)
How strong is thiopental’s analgesic effect?
It has no analgesic effect
How long is thiopental’s duration?
5-10 minutes (quickly diffuses from the brain)
How is thiopental metabolized?
Nearly completely by the liver
How long is thiopental’s half-life?
Very long, it accumulates in fat and muscle
What effect does thiopental have on CV and respiratory?
Reduces BP and CO
Depresses respiratory center and blunts response to CO2 and hypoxia
Decreases cerebral metabolic rate, CBF, and ICP
Desirable for patients with cerebral edema, protects against ischemia
What is the most widely used IV anesthetic in the US?
Propofol
How long does propofol take to cause unconsciousness?
20 seconds
How long is propofol’s duration?
5-10 minutes (high clearance)
How fast is propofol metabolized?
10x faster than thiopental
Little accumulation too
Which IV anesthetic has anti-emetic properties as well?
Propofol
