CARDIOPULMONARY EFFECTS OF PROPOFOL INFUSION IN LLAMAS

Objective-To evaluate selected cardiopulmonary responses to propotol 2 infusion rates in nonpretreated llamas breathing room air. Animals-5 adult llamas (3 males, 2 females) with mean +/- SD body weight of 135 +/- 17.7 kg. Procedure-After anesthesia induction with propofol (2 mg/ kg of body weight, IV), llamas received either propofol infusion 0.2 m g/kg/min (group 1) or 0.4 mg/kg/min (group 2) for 60 minutes. Measurem ents, taken before anesthesia induction and at regular intervals durin g infusion were: direct blood pressures, heart and respiratory rates, cardiac output, and arterial blood gas tensions. Systemic and pulmonar y vascular resistance, cardiac and stroke indices, and plasma bicarbon ate and base excess concentrations were calculated. Results-At 3 to 60 minutes after either dosage of propofol, Pa-CO2, and heart rate incre ased in all llamas; at the same time, Pa-O2, and arterial pH decreased . Mean pulmonary artery and central venous pressures, and stroke index decreased at 3 to 60 minutes after either dosage of propofol. Mean ar terial pressure decreased at 30 to 60 minutes after infusion of 0.4 mg of propofol/kg/min; pulmonary arterial wedge pressure decreased at 20 to 40 minutes and 3 to 60 minutes after infusion of 0.2 and 0.4 mg of propofol/kg/min, respectively. Mean time from termination of infusion to sternal recumbency was 7 (group 1) and 13 (group 2) minutes. Stand ing was achieved in a mean 11 (group 1) and 22 (group 2) minutes. Conc lusion-Propofol infusion rate of 0.2 mg/kg/min was considered too low to maintain a suitable depth of anesthesia, but 0.4 mg/kg/min was cons idered sufficient for noninvasive procedures with minimal cardiopulmon ary depression.