Induction Agents Flashcards
1
Q
Barbiturates (Thiopental)
A
- thiopental, methohexital, pentobarbital and phenobarbital
- ultrashort acting (10-15mins) IV
- rapid, smooth and excitement free induction
- excitment and hypertonus can occur if an inadequate dose is administered to an unsedated or poorly sedated animal.
- Thiopental
- dose dependent decrease in cerebral metabolic oxygen requirements, cerebral blood flow and intra-cranial pressure
- good for head trauma, brain tumors, hydrocephalus and possible seizures
2
Q
What are the precautions in barbituate use?
A
- Can cause peripheral vasodilation which can lead to hypotension
- Usually a compensatory increase in heart rate to offset vasodilation
- Hypotension usually not an issue in normal healthy patients
- Avoid drug in CHF, hypovolemic and pre-existing hypotension patients
- Bigeminy (normal ECG followed by a VPC)
- common at induction and no Tx needed
- Must use IV
- strong alkalinity can cause sloughing and necrosis if injected perivascular
- infuse with 0.5-2mL of lidocaine
- dilute drug with saline if perivascular
- highly protein bound
- hence will enhance effect if given concurrently with NSAIDs and benzodiazepines
- hypoproteinemia will greatly prolong the duration and effect
- Sight hounds or any skinny patient lack the body fat and muscle for redistribution of drug and hence prolonged effects seen
- cummulative in the body, therefore don’t use CRI or repeated doses