Cardiopulmonary and Anesthetic Effects of Isoflurane and Propofol in Hispaniolan Amazon Parrots (Amazona ventralis)

The cardiopulmonary and anesthetic effects of isoflurane and propofol were determined in 10 healthy, adult Hispaniolan Amazon parrots (Amazona ventralis). Anesthesia was induced and maintained with isoflurane in oxygen for 30 minutes. Cardiopulmonary parameters including heart rate, respiratory rate, relative arterial oxygen hemoglobin saturation (SpO2), and esophageal temperature were recorded at 1, 2, 3, 4, 5, 10, 15, 20, 25, and 30 minutes. End-tidal CO2 (EtCO2) concentrations and inspired and expired end-tidal isoflurane concentrations were recorded continuously. Before the study continued, birds were allowed to recover from isoflurane anesthesia for at least 2 hours. In a second trial, anesthesia was induced by intravenous administration of propofol (5 mg/kg) and maintained for 30 minutes by constant rate infusion of propofol (1 mg/kg per min IV). No supplemental oxygen was provided. Cardiopulmonary parameters and EtCO2 concentrations were recorded as in the isoflurane trial. Induction times with propofol (51 ± 40 sec; mean ± SD) and isoflurane (58 ± 15 sec) were rapid and not significantly different. No significant changes in heart rates and SpO2 values over time were seen with isoflurane anesthesia, but the respiratory rate decreased significantly from 41 ± 17 breaths/min at 1 minute to 25 ± 15 breaths/min at 10 minutes following induction. A significant decrease in respiratory rate was noted only at 2 (26 ± 10 breaths/min) and 3 (29 ± 12 breaths/min) minutes following induction with propofol. A significant increase in EtCO2 concentrations was recorded at 3 (37% ± 4%) minutes and thereafter with propofol anesthesia. No significant change in heart rate was observed over time. The SpO2 values significantly decreased below 90% at 2 minutes after induction with propofol and remained significantly decreased for the remainder of the anesthetic event. No significant differences in partial pressure of oxygen (PaO2) values were observed over time. SpO2 values were significantly higher with isoflurane compared with propofol at any given time during anesthesia. No significant differences in EtCO2 concentrations and heart rates were observed between groups throughout the study. Propofol recovery times (15.4 ± 15.2 min) were prolonged when compared with isoflurane (4.6 ± 1.6 min), and 6 birds had agitated recoveries from propofol anesthesia. A constant rate infusion of propofol at 1 mg/kg per minute resulted in a light anesthesic plane in 8 Hispaniolan Amazon parrots (Amazona ventralis) and a surgical plane in 2 birds. Supplemental oxygen is recommended during propofol anesthesia. Propofol can be useful for brief, noninvasive procedures or as an induction agent to facilitate endotracheal intubation prior to inhalational anesthesia.