Abstract

Total or partial intravenous anesthesia (TIVA, PIVA) has been advocated in human and veterinary medicine as a potential means to improve hemodynamics and recovery times when compared to conventional inhalant anesthetic agents. In terms of great ape anesthesia, most veterinarians use a cyclohexanone/benzodiazepine or a cyclohexanone/α-2 agonist combination for induction followed by intubation and maintenance on either isoflurane or sevoflurane anesthesia. The use and benefits of TIVA and PIVA protocols in great apes have only been modestly described. Great ape anesthesia reports (n=12) from two zoological institutions were evaluated for their TIVA/PIVA drug protocols and various simple indices. Species included gorilla (Gorilla gorilla, n=8), bonobo (Pan paniscus, n=1), and orangutan (Pongo pygmaeus, n=1). Following induction with a cyclohexanone/benzodiazepine combination intramuscularly, patients were intubated and maintained on isoflurane (0.2–3%) and sevoflurane (0.5–2%) in 100% oxygen (n=11 PIVA procedures), while one procedure was a complete TIVA procedure. Anesthesia was effectively and safely maintained using constant-rate infusions of a single agent or combinations of the following agents: fentanyl at 0.5–2.0 µg/kg/h, remifentanil at 0.10–0.50 µg/kg/min, and propofol at 20–150 µg/kg/min. Heart rates were variable from 50–145 bpm. The longest procedure was a PIVA protocol that lasted 337 min with 135 min of intravenous infusion for anesthesia maintenance. Hypotension (systolic pressure less than 90 mm Hg) was the most common complication and was managed with increased fluid rates, the administration of glycopyrrolate, and vasopressor agents (dopamine or ephedrine) as needed. TIVA/PIVA provides an option for the maintenance of general anesthesia in great apes.