EVALUATING ECHOCARDIOGRAM AND INDIRECT BLOOD PRESSURE RESULTS IN MALE WESTERN LOWLAND GORILLAS (GORILLA GORILLA GORILLA) DURING THREE PHASES OF AN ANESTHETIC PROTOCOL

Abstract

Until the majority of the great ape population is trained for conscious cardiac evaluations, most individuals will require general anesthesia to perform echocardiograms. Within the veterinary community, concern exists that certain anesthetic protocols may exacerbate or artificially induce signs of cardiac disease. Because of potential cardiovascular effects, medetomidine has generally been used cautiously in patients with cardiac disease. The combination of ketamine and medetomidine is frequently used by many institutions because of its reversibility. To date, no published studies have obtained physiologic or echocardiographic parameters comparing different anesthetic protocols. In this study, with the use of seven adult male gorillas (Gorilla gorilla gorilla) with and without cardiac disease, echocardiographic and indirect blood pressure data during three phases of an anesthetic protocol were collected. The initial echocardiographic study was completed with ketamine/ medetomidine alone (5-7 mg/kg, i.m., and 0.05-0.07 mg/kg, i.m., respectively); the second study was completed after the addition of sevoflurane inhalant anesthesia to this procedure; and the third study was completed after reversal of medetomidine by administration of atipamezole (5:1 with the medetomidine dose given at induction). Without exception, ejection fractions were 15-25% lower under anesthesia with medetomidine as compared to ejection fractions after administration of atipamezole. Indirect blood pressures were higher on ketamine/ medetomidine, lower with addition of sevoflurane, and considerably lower after administration of atipamezole.