Anesthesia in sheep with propofol or with xylazine-ketamine followed by halothane

This study evaluates the clinical usefulness and anesthetic effect of propofol, and compares these effects with those of xylazine-ketamine-halothane anesthesia in sheep.

Prospective, randomized, clinical trial.

Fourteen healthy adult male sheep.

Sheep were randomly assigned to two different drug regimens: (1) Bolus injection of propofol (3 mg/kg, intravenously [i.v.]) followed by continuous intravenous infusion and (2) xylazine (0.11 mg/kg, i.v.) and ketamine (2.2 mg/kg, i.v.) for induction followed by halothane anesthesia. Heart rate, respiratory rate, and arterial blood pressures were monitored during anesthesia. Venous blood samples were collected for blood gas analysis. Quality of induction and recovery were also recorded.

The average dose of propofol used to induce and maintain anesthesia was 6.63 +/- 2.06 mg/kg and 29.3 +/- 11.7 mg/kg/hr (0.49 +/- 0.20 mg/kg/min), respectively. The duration of propofol anesthesia was 45.3 +/- 13.2 minutes and recovery to standing occurred in 14.7 +/- 5.7 minutes. Sheep receiving xylazine-ketamine-halothane were anesthetized for 35.9 +/- 4.0 minutes and recovery to standing occurred within 28.5 +/- 7.5 minutes. Sheep anesthetized with propofol had a significantly higher heart rate, diastolic blood pressure and Pvo2, and a lower Pvco2 at 30 minutes and lower BE at 15 and 30 minutes than sheep anesthetized with xylazine-ketamine-halothane.

Propofol anesthesia was characterized by a smooth induction, effective surgical anesthesia and rapid recovery which was comparable to anesthesia with xylazine-ketamine-halothane.

Propofol may be indicated in situations when it is desirable to maintain anesthesia with an intravenous infusion followed by a rapid recovery in healthy sheep.