Developments in buffalo anaesthesia with special reference to diaphragmatic herniorrhaphy

Ruminants are poor subject for general anaesthesia. Diaphragmatic hernia (DH) is a common digestive disorder in buffaloes requiring balanced general anaesthesia for surgical repair. For premedication, initially, a combination of phenothiazine/chloralhydrate was used which was later replaced by alpha2 agonist like xylazine. Anticholinergics like atropine or glycopyrrolate were included in balanced anaesthetic protocols to reduce cardiac depression by alpha2 agonists. Thiobarbiturates historically were used for induction and maintenance but late recovery and cardiorepiratory depression lead to switch over to propofol. Maintenance of anaesthesia by top-up or continuous rate infusion (CRI) of propofol was not economical. The inclusion of opioids like butorphanol improved the analgesia as well as has dose sparing effect on induction and maintenance agent. The introduction of inhalants for maintenance significantly improved outcomes with the ease of change of depth of anaesthesia. It has also been observed that adrenocortical suppression by etomidate and mechanical intermittent positive pressure ventilation (IPPV) resulted in poor outcomes whereas maintaining the homeostasis and functional adreno-cortical axis of buffaloes under anaesthesia improves the success rate of DH surgeries. The balanced anaesthetic combination of Atropine/xylazine/ butorphanol/propofol/isoflurane has been found to be most satisfactory till date in buffaloes undergoing DH surgery. The studies on muscle relaxants, blood gas analysis and end tidal carbon dioxide (EtCO2) in buffaloes are scarce. Moreover, many drugs have been used in combinations in clinical cases on the basis of extrapolation from other species; but in buffaloes the effect of individual drug (like dose sparing effect of analgesics, minimum alveolar concentration (MAC) of inhalants) has to be still studied.