Abstract: Dependent on timing of assessment, anesthetic agents and specifically medetomidine negatively impact cardiac function in great apes. The aim of this study was to determine the influence of tiletamine-zolazepam with and without medetomidine on cardiac structure and function in healthy chimpanzees (Pan troglodytes) during a period of relative blood pressure stability. Twenty-four chimpanzees living in an African wildlife sanctuary undergoing routine health assessments were stratified by age, sex and body mass and randomized to be anesthetized using either tiletamine-zolazepam (6 mg/kg; TZ; n=13; seven males and six females) or a combination of tiletamine-zolazepam (2 mg/kg) and medetomidine (0.02 mg/kg; TZM; n= 11; five males and six females). During the health checks, regular heart rate and blood pressure readings were taken and a standardized echocardiogram was performed 20-30 minutes post-induction. Data were compared between the two anesthetic groups using independent samples T or Mann Whitney U tests. While heart rate (Mean ± S.D; TZ: 76 ± 10 bpm; TZM: 65 ± 14 bpm, P = 0.027), cardiac output (TZ: 3.0 ± 0.7 L/min; TZM: 2.4 ± 0.7 L/min, P = 0.032) and mitral A wave velocities (TZ: 0.51 ± 0.16 cm/s; TZM: 0.36 ± 0.10 cm/s, P = 0.013) were lower in the TZM group, there were no statistically significant differences in cardiac structure or the remaining functional variables between groups. Furthermore, there were no statistical differences in systolic (TZ 114.6 ± 14.9 mmHg; TZM: 123.0 ± 28.1 mmHg; P = 0.289) or diastolic blood pressure (TZ: 81.8 ± 22.3 mmHg, TZM: 83.8 ± 20.1 mmHg; P = 0.827) between the groups during the echocardiogram. This study has shown that during a period of relative blood pressure stability there are few differences in measures of cardiac structure and function between protocols using tiletamine-zolazepam with or without medetomidine in healthy chimpanzees.
|Journal||Journal of Zoo and Wildlife Medicine|
|Publication status||Accepted/In press - 7 Apr 2021|