Cardiopulmonary effects of anaesthesia maintained by propofol infusion versus isoflurane inhalation in cheetah (Acinonyx jubatus)

Abstract

Objective To compare the cardiopulmonary function of cheetahs (Acinonyx jubatus) undergoing propofol total intravenous anaesthesia (TIVA) to isoflurane maintenance in order to evaluate their feasibility for field use. Study design Prospective clinical study Animals 24 adult cheetahs Materials and Methods Cheetahs were immobilised with tiletamine-zolazepam (1.2 mg kg-1) and medetomidine (40 ?g kg-1) intramuscular by darting. A maintenance protocol of propofol TIVA (Group-P) or isoflurane inhalation (Group-I) was randomly assigned to each cheetah. Anaesthesia was maintained for at least 60 minutes. Cheetah breathed spontaneously throughout anaesthesia. Oxygen was supplemented at 3 L minute-1. Cardiopulmonary parameters were recorded at five minute intervals and three arterial blood gas samples analysed. Following maintenance, atipamezole was administered intramuscular (200 ?g kg-1) and recovery observed. Data is reported as mean ±SD; variables over time were compared using a linear mixed model (fixed: time, treatment; random: cheetah). Results Lack of response to manipulations was maintained in all cases (end-tidal isoflurane 1.1 ± 0.1%, propofol infusion rate maintained at 0.1 mg kg-1 minute-1). The heart rate and respiratory rate were 82 ± 10 beats minute-1 and 14 ± 4 breaths minute-1, respectively for both groups overall. The end-tidal carbon dioxide tension increased slowly (to 44.0 ± 5.0 mmHg at the end of maintenance) with no differences between groups. All cheetahs were initially markedly hypertensive (mean arterial pressure (MAP) 163.3 ± 17 mmHg); MAP normalised for Group-I (125 ± 30 mmHg) but remained high for Group-P (161.0 ± 17 mmHg) (p < 0.001). The arterial carbon dioxide tension (48.9 ± 14.6 mmHg) never differed between groups. Recovery time was 10.8 ± 5.0 and 51.9 ± 23.5 minutes for Group-I and Group-P, respectively. Conclusions and clinical relevance Both protocols provided acceptable cardiopulmonary values. Propofol may be an alternative to isoflurane for field use, but the prolonged recovery requires investigation.