Objective assessment methods are essential to assess the effects of anaesthesia on rabbits’ gastrointestinal function. In this prospective case series, the digestive function of four pet rabbits undergoing general anaesthesia for elective orchiectomy was assessed using both abdominal ultrasonography (60 minutes pre-anaesthesia and 45-75 minutes post-anaesthesia) and quantification of their food intake and faecal output. The ultrasonographic outcome measures were duodenal and pyloric contractions, counted from a three-minute video recording for each site. A peristaltic contraction was defined as either unidirectional motion of luminal contents (sagittal plane) or a single rhythmic dilation and contraction of the lumen (transverse plane) lasting one to two seconds. Postoperative food intake was calculated by weighing the offered food using a precision scale. The faeces collected during the observation period were also weighed. Only one out of the four rabbits ate during the elapsed observation period from the end of the anaesthetic to abdominal ultrasonography, and none of them produced any faeces during this time. Abdominal ultrasonographic assessment could be completed within 15 minutes and was feasible with gentle restraint of the rabbits in sternal recumbency. Duodenal contractions were subjectively found to be more consistent and easier to detect and monitor than pyloric contractions. Based on the pilot findings of this case series, ultrasonographic assessment of duodenal contractions, together with monitoring of postoperative food intake and faecal output, may be a useful tool for the early detection of post-anaesthetic digestive dysfunction in rabbits, and potential identification of rabbits at higher risk of developing postoperative ileus.
Fitzmaurice et al. (Mon,) studied this question.