Comparison of anesthetic induction in cats by use of isoflurane in an anesthetic chamber with a conventional vapor or liquid injection technique.
OBJECTIVE
To compare 2 techniques for induction of cats by use of isoflurane in an anesthetic chamber.


METHODS
Prospective, randomized study.


METHODS
51 healthy cats.


METHODS
Cats were randomly allocated to 2 induction techniques. Cats were premedicated with acepromazine (0.1 mg/kg [0.045 mg/lb], SC) and buprenorphine (0.01 mg/kg [0.0045 mg/lb], SC) 30 minutes before induction. Cats were then placed into an induction chamber, and anesthetic induction was initiated. One technique involved a conventional flow-through system that used an oxygen flowmeter and an isoflurane vaporizer to flow vapors into the induction chamber. Alternatively, liquid isoflurane was injected into a vaporization tray that was mounted to the interior surface of the chamber lid. Inductions were videotaped for analysis. Five variables (head bobbing, head swinging side to side, paddling, rotating 180 degrees to 360 degrees, and rolling over or flipping) were scored to assess induction quality. Time variables recorded during induction corresponded to the interval until onset of excitatory motion, duration of excitatory motion, interval until recumbency, and interval until complete induction.


RESULTS
Compared with cats anesthetized by use of a conventional vapor chamber technique, cats anesthetized by use of the liquid injection technique had a significantly shorter interval until recumbency and interval until complete induction and lower scores for quality of induction, indicating a smoother induction.


CONCLUSIONS
Anesthetic induction in cats by use of a liquid injection technique was more rapid and provided a better quality of induction, compared with results for cats induced by use of a conventional vapor technique.
Schmid
Renee D
RD
Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
Hodgson
David S
DS
McMurphy
Rose M
RM
D000769:Anesthesia, Inhalation / Q000295:instrumentation / Q000379:methods / Q000592:standards / Q000662:veterinary*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D000818:Animals; D002415:Cats / Q000502:physiology*; D004867:Equipment Design; D005260:Female; D007530:Isoflurane / Q000008:administration & dosage*; D008297:Male; D009330:Nebulizers and Vaporizers / Q000662:veterinary*; D011446:Prospective Studies; D011897:Random Allocation; D013997:Time Factors
D018685:Anesthetics, Inhalation; D007530:Isoflurane