THE EFFECTS OF CONSECUTIVE DAY PROPOFOL ANESTHESIA ON FELINE RED-BLOOD-CELLS

This study investigated the potential for multiple exposures of propof ol to induce oxidative injury, in the form of Heinz body production, t o feline red blood cells. Anesthesia was induced in six healthy cats w ith propofol (6 mg/kg, intravenous [IV]) and maintained for 30 minutes with a propofol infusion (0.20 to 0.30 mg/kg/min, IV). The initial pr otocol was designed for each cat to receive 10 consecutive days of pro pofol anesthesia. All cats spontaneously breathed room air. Heart rate , respiratory rate, and indirect blood pressure were measured and reco rded before and during anesthesia. Time to complete recovery after eac h infusion was measured and recorded. Heinz body analysis was performe d before and after each day of propofol anesthesia. Based on predeterm ined criteria for discontinuing daily infusions, the mean number of co nsecutive days of propofol anesthesia was six and propofol administrat ion did not continue beyond 7 days in any cat. Heart rate, respiratory rate, and indirect blood pressure did not change significantly during propofol anesthesia compared with awake values. Following the third c onsecutive day of propofol anesthesia, there was a significant increas e from baseline in the mean percentage of Heinz bodies. Hemolysis was not detected in any cat. Recovery time significantly increased after t he second consecutive day of propofol anesthesia compared with the fir st day. Five of six cats developed generalized malaise, anorexia, and diarrhea on day 5, 6, or 7, and two cats developed facial edema. All c linical signs resolved without treatment 24 to 48 hours after disconti nuing propofol anesthesia. This study suggests that consecutive day pr opofol anesthesia in normal cats can induce oxidative injury to feline red blood cells in the form of excessive Heinz body formation, result in increased recovery times, and result in clinical signs of illness. (C)Copyright 1995 by The American College of Veterinary Surgeons