Propofol versus thiopental: effects on peri-induction intraocular pressures in normal dogs.
OBJECTIVE
To determine the effects of propofol or thiopental induction on intraocular pressures (IOP) in normal dogs.


METHODS
Prospective randomized experimental study.


METHODS
Twenty-two random-source dogs weighing 19.5 +/- 5.3 kg.


METHODS
Dogs were randomly assigned to receive propofol 8 mg kg(-1) IV (group P) or thiopental 18 mg kg(-1) IV (group T) until loss of jaw tone. Direct arterial blood pressure, arterial blood gasses, and IOP were measured at baseline, after pre-oxygenation but before induction, before endotracheal intubation, and after intubation.


RESULTS
There were no significant differences between groups with regard to weight, body condition score, breed group, or baseline or before-induction IOP, arterial blood pressure, or blood gases. The baseline IOP was 12.9 mmHg. Before endotracheal intubation, IOP was significantly higher compared to baseline and before induction in dogs receiving propofol. After intubation with propofol, IOP was significantly higher compared to thiopental and was significantly higher compared to before induction. After intubation, IOP was significantly lower compared to before intubation in dogs receiving thiopental. Propofol increased IOP before intubation by 26% over the before-induction score and thiopental increased IOP by 6% at the same interval. The IOP in group P remained 24% over the before induction score whereas thiopental ultimately decreased IOP 9% below baseline after intubation. There was no significant relationship between any cardiovascular or blood gas parameter and IOP at any time. There was no significant relationship between the changes in any cardiovascular or blood gas parameter and the changes in IOP between time points. CONCLUSIONS AND CLINICAL RELEVANCE Propofol caused a significant increase in IOP compared to baseline and thiopental. Thiopental caused an insignificant increase in IOP which decreased after intubation. Propofol should be avoided when possible in induction of anesthesia in animals where a moderate increase in IOP could be harmful.
Hofmeister
Erik H
EH
Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA. erikh@vet.uga.edu
Williams
Clara O
CO
Braun
Christina
C
Moore
Phillip Anthony
PA
D018686:Anesthetics, Intravenous / Q000009:adverse effects / Q000494:pharmacology*; D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs / Q000502:physiology*; D007429:Intraocular Pressure / Q000187:drug effects*; D007442:Intubation, Intratracheal / Q000662:veterinary; D015742:Propofol / Q000009:adverse effects / Q000494:pharmacology*; D011446:Prospective Studies; D013874:Thiopental / Q000494:pharmacology*
D018686:Anesthetics, Intravenous; D013874:Thiopental; D015742:Propofol