Propofol in rabbits. 2. Long-term anesthesia

The cardiopulmonary effects of propofol as the sole anesthetic agent administered as a continuous intravenous infusion over 8 hours were evaluated in ten ventilated New Zealand White rabbits. Heart rate, mean blood pressure, arterial oxygen and carbon dioxide tensions, arterial pH, hemoglobin's saturation with oxygen, packed cell volume, and temperature were continuously monitored and recorded at 0 (baseline), 30, 60, 120, 180, 240, 300, 360, 420, and 480 minutes and then hourly for up to 4 hours during recovery. Only light planes of anesthesia could be achieved with a mean propofol infusion rate of 0.876 mg/kg/min. Hypotension and hypoxemia were common features. Four rabbits did not survive the study period and recovery was slow in the surviving animals. With monitoring being the same, Intralipid 10%, the vehicle of propofol, infused into two rabbits (controls) had no adverse effects. Intravenous administration of propofol alone cannot be recommended for long-term anesthesia in the rabbit. Oxygen supplementation appears to be an important element in improving quality of anesthesia and outcome.