-
The effect site for injectable anesthesia?
Brain
-
Rout of admin for wildlife/zoo animals, usually suboptimal?
IM
-
Route of admin for very small animals?
IP
-
Relative to IV, drawbacks of using IM for anasthetics (6):
- Slow Onset
- Higher dose required
- Less Predictable
- No secure Venous Access
- Must use small volume
- Must be non-irritant
-
What factors affect the seed of onset (5)?
- Drug
- Dose
- Rate of admin
- Route
- P factors
-
What drug properties affect the speed of onset (4)?
- Lipid Solubility
- Molecular Weight
- Protein Binding
- Ionisation
-
What P factors affect the speed of onset?
- Acid-Base balance
- Electrolyte Balance
- Plasma Protein Concentration
- CO
-
What influence does lipid solubility have on drug?*
+lipid solubility-> crosses membranes faster
-
What influence does molecular weight have on drug?
Smaller MW -> Cross BB faster
-
What influence does Protein binding have on drug?*
Determines how much drug can leave vascular space and exert effects (hypoalbuminaemia= greater Fx)
-
What influence does Ionization have on drug?*
- Ionized drugs cannot cross membrane
- (pH changes can cause ionization of drug)
-
What factors influence Distribution?
- Organ Perfusion
- Protein Binding
- Lipid Solubility
-
After Admin, plasma concentrations fall b/c of... (3)
- Redistribution (to vessel rich tissues, muscle, fats)
- Elimination (through metab and excretion)
-
What factors affect recovery?
- Duration of admin
- Distribution to other tissues
- Elimination 1/2 Life
-
How are barbiturates categorized?
Duration
-
What is Thiopental classified as?
Ultra-Short
-
Thiopental, not in solution, is classified as..... (pH)
Weak Organic Acid
-
Thiopental, IN solution, is classified as ... (pH)
10.5, HIGHLY ALKALI
-
Once injected, what happens to Thiopental?
The pH falls (blood is 7.4) and becomes UN-IONIZED
-
One reconstituted, what is the shelf life of Thiopental?
7 Days (High pH = bactericidal)
-
Thiopental concentrations greater than ____%, can cause sloughing, pain and self trauma
- >2.5%
- (Dilute w/ SQ ++NaCl if accidental peri-vascular injection)
-
Thiopental Mechanisms of Action (3):
- Interacts with GABA to increase the duration of GABAa dependent Cl channel in the CNS= Hyperpolarzation and Neurolnal Inhibition
- Depresses the reticular activating system in the brainstem => sleepy
- Depresses transmission in sympathetic ganglia
-
Thiopental...
Speed of onset:
Speed of Redistribution:
Recovery:
- Onset: VERY rapid (<30 sec)
- Redistribution: Rapid
- recovery: Slow
-
What increases the effects of barbiturates?
- Acidosis
- Hypoproteinaemia (active form unbound)
-
Ionized VS Unionize
Which is in plasma?
Which is Active?
- Both are in plasma
- Un-ionized is active (highly lipid soluble, crosses BB)
-
What technique can increase the rate of induction and recovery?
Rapid Inj using Minimal Effective Dose
-
Why isnt thiopental used for maintenance?
It is cumulative
-
Two determinants of thiopental induction dose requirements:
-
Avoid Thiopental in...
- Sight Hounds
- Thin Animals (little depot)
- Use caution in hypovolemia/shock/cardio Dz
-
Thiopental CNS Fx (3):
- Rapidly Crosses BBB
- Splenomegaly
- No alangesia
-
Thiopental Cardio Fx (4):
- Vasodilation
- Hypotension
- Drop CO
- Arrythmogenic
-
Thiopental Respiratory Fx:
- Depression
- Post-induction Apnea
- Laryngospasm
-
Advantages of Thiopental (2):
- Potent & Short Acting
- Long history of use in many species
-
Disadvantages of Thiopental (7):
- CVS and Resp Depression
- Fx depend of admin technique
- Cumulative
- Hyperalgesic
- Tissue Irritation
- Splenomegaly
- Solutions dont mix with other drugs
-
Barbiturate used for ET:
Pentobarbital +/- Phenytoin
-
Propofol is classified as a...
Steroid Anasthetic
-
Lipid Solubility of Propofol:
HIGHLY lipid Soluble
-
Protein Binding of Propofol
High Protein Binding
-
Shelf life of Propofol:
- 12-24 hrs, in fridge
- (NO PRESERVATIVES)
-
Propofol is available as...
- 1% or 2% emulsion in
- 10% soybean oil
- 2.2% glycerol
- 1.25 purified egg phosphatide
-
-
Propoclear is a _____ formulation of propofol
Microemulsion
-
Propoclear...
Redistribution:
Metabolism:
Clearance:
Recovery:
- Redistribution: Rapid
- Metabolised: Rapid
- Clearance: Exceeds Hepatic Flow
- Recovery: Rapid (except in cats) & No hangover
-
Propoclear should be administered____
Slowly
-
Proprclear CNS Fx (4):
- GABA-ergic
- Inhibits NMDA
- Anti-convulsant (give w/ Propofol)
- Central Anti-Emetic
-
Propoclear Cardiovascular Fx(4):
- Depress CO
- Vasodilation= hypotension
- Inhibit/Reset Baroreceptor Reflex
- Splenic Engorgement
-
Propoclear Respiratory Fx(2):
- Depressant
- Post-Induction Apnea
-
Important Propoclear Side Fx(4):
- CVS Depression
- Respiratory Depreassion
- Pain on Injection
- Shakes
-
Administration of Propofol slowly => (2)
- Min hypotension
- Min Respiratory Depression
-
Tx for persistant Propofol Shakes
Ketamine
-
Which is used for epileptic dogs that don't respond to Valium?
Propofol
-
Cats should not anesthetized on consecutive days with...
Propofol
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