Effect of theatre temperature on body temperature during anaesthesia for routine neutering of domestic rabbits (Oryctolagus cuniculus)

Abstract

Objective: To investigate the effect of theatre temperature on body temperature in rabbits undergoing castration or ovariohysterectomy surgery during general anaesthesia.

Study design: Prospective, clinical study.

Animals: A group of 88 rabbits presented for elective neutering.

Methods: Rabbits were divided into male (31/54) and female (23/54) groups and assigned to one of two theatre temperatures via coin toss. Theatre temperature was 23 °C (±2 °C) for group A (n = 37/54) and 28 °C (±2 °C) for group B (n = 17/54). During anaesthesia and recovery, theatre temperature and rectal temperature were recorded every 5 minutes. Time to resumption of feeding and passing faeces were recorded. Data are presented as median (interquartile range) or mean (± standard deviation). Statistical analyses comprised a mixed-effects model, with Sidak's multiple comparison test for post-hoc testing and Fisher's exact test; p < 0.05.

Results: A total of 54 rabbits completed the study, with median age 6 (4-9) months and median weight 1.53 (1.30-1.79) kg. In rabbits undergoing castration, theatre temperature did not significantly affect body temperature. Mean temperatures immediately after induction were 38.6 °C and 38.7 °C and at the end of the procedure 38.5 °C and 38.5 °C for group A and group B, respectively. In rabbits undergoing ovariohysterectomy, mean temperatures immediately after induction were 38.3 °C and 38.8 °C and at the end of the procedure 38.1 °C and 39.2 °C for group A and group B, respectively. Rabbits undergoing ovariohysterectomy at an ambient temperature of 28 °C had a significantly higher final temperature, mean ± 1.15 °C (95% confidence interval, 0.47-1.83), compared with 23 °C (p = 0.001). Theatre temperature did not affect return to feeding or defaecating.

Conclusions and clinical relevance: During anaesthesia an ambient theatre temperature of 28 °C may reduce the risk of hypothermia in rabbits undergoing ovariohysterectomy or similarly invasive surgery.

Keywords: anaesthesia; hypothermia; rabbit; temperature; theatre.