Postanaesthetic effects of ketamine–midazolam and ketamine–medetomidine on gastrointestinal transit time in rabbits anaesthetised with isoflurane

Abstract

BackgroundGastrointestinal stasis is a common perianaesthetic complication in rabbits. The objective of this study was to assess the impact on gastrointestinal transit time of ketamine–midazolam (KMZ) versus ketamine–medetomidine (later antagonised by atipamezole) (KMT-A) in rabbits anaesthetised with isoflurane.MethodsThis was a cross-over, randomised, single-blinded, controlled, experimental trial. Seven healthy adult New Zealand White rabbits were used. Gastrointestinal transit time was assessed by contrast radiography in awake rabbits. Presence of contrast medium in the small intestine (gastric transit time), in the caecum (small intestinal transit time) and in faeces in the colon was assessed. One week later, 55 minutes isoflurane anaesthesia was induced with ketamine (15 mg/kg) and either midazolam (3 mg/kg) or medetomidine (0.25 mg/kg) by intramuscular injection. Thirty minutes after discontinuation of isoflurane, atipamezole (0.5 mg/kg) was administered only to rabbits in KMT-A treatment. Gastrointestinal transit time was then assessed in both treatment groups, beginning 30 minutes after cessation of isoflurane administration. Two weeks later, the treatment groups were interchanged.ResultsGastric and small intestinal transit times were significantly longer with KMT-A (92±109 minutes and 214±119 minutes, respectively) than with KMZ (1±0 minutes and 103±6 minutes, respectively) and in the awake state (7±7 minutes and 94±32 minutes, respectively).ConclusionClinicians should therefore be aware of the potential gastrointestinal side effects of KMT-A, particularly in rabbits at risk for gastrointestinal stasis.

Comparison between Carprofen and Meloxicam for Post-Neutering Pain Management in Pet Rabbits

“…In addition, it is noteworthy that the chosen anesthesiological protocol may impact the restoration of normal gastrointestinal functionality. It has been reported that a protocol based on ketamine and medetomidine prior to anesthesia induction with isoflurane is more likely to induce a reduction in gastric and intestinal peristalsis, compared to the use of ketamine and midazolam [ 36 ]. In the present study, in addition to ketamine and medetomidine, butorphanol was utilized as part of the anesthesiological protocol.…”

Effects of a Single Opioid Dose on Gastrointestinal Motility in Rabbits (Oryctolagus cuniculus): Comparisons among Morphine, Butorphanol, and Tramadol

“…Medetomidine is an alpha-2-agonist molecule often used in rabbit anaesthesia. Its use in conjunction with ketamine has been postulated to be responsible for perianaesthetic mortality in rabbits and with post anaesthetic gastrointestinal complications [5,34] but also with potential gastrointestinal side effects [35]. Lidocaine, on the contrary, has been proven to elicit higher gastrointestinal motility in rabbits following ovariohysterectomy when administered through an intravenous constant rate infusion [3].…”