Physiological responses of sheep to two hours anaesthesia with diazepam-ketamine

The cardiopulmonary effects of repeated intravenous injections of a combination of diazepam and ketamine for anaesthesia were evaluated in six domestic sheep. Induction doses of 0.375 mg/kg and 7.5 mg/kg were followed by maintenance doses of 0.188 mg/kg and 3.75 mg/kg every 15 minutes for 105 minutes. Although this dosing regimen produced the desired anaesthetic effects, it caused untoward cardiopulmonary effects. Salient features of multiple dosing with diazepam and ketamine were hypoventilation, respiratory acidosis and an increase in both systemic and pulmonary vascular resistance.