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.