Treatment of diaphragmatic hernia in buffaloes

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.

Evolution and Functional Differentiation of the Diaphragm Muscle of Mammals

Symmorphosis is a concept of economy of biological design, whereby structural properties are matched to functional demands. According to symmorphosis, biological structures are never over designed to exceed functional demands. Based on this concept, the evolution of the diaphragm muscle (DIAm) in mammals is a tale of two structures, a membrane that separates and partitions the primitive coelomic cavity into separate abdominal and thoracic cavities and a muscle that serves as a pump to generate intra-abdominal (Pab ) and intrathoracic (Pth ) pressures. The DIAm partition evolved in reptiles from folds of the pleural and peritoneal membranes that was driven by the biological advantage of separating organs in the larger coelomic cavity into separate thoracic and abdominal cavities, especially with the evolution of aspiration breathing. The DIAm pump evolved from the advantage afforded by more effective generation of both a negative Pth for ventilation of the lungs and a positive Pab for venous return of blood to the heart and expulsive behaviors such as airway clearance, defecation, micturition, and child birth. © 2019 American Physiological Society. Compr Physiol 9:715-766, 2019.

Haemodynamic and blood gas changes in buffaloes (Bubalus bubalis) in the supine position following thiopentone anaesthesia with premedication

Studies were undertaken on seven adult female buffaloes (Bubalus bubalis) premedicated with triflupromazine hydrochloride (0.3 mg/kg) and chloral hydrate (30 mg/kg). Anaesthesia was induced with thiopentone sodium (10 mg/kg) and animals were kept under intermittent positive pressure ventilation. Measurements were made for 30 min in the lateral position, for 20 min in the supine position and subsequently for 40 min again in the lateral position. Regurgitation during anaesthesia was avoided by evacuation of the rumen by rumenotomy two days prior to the experiment. When animals were in the lateral position there were minimal changes in arterial pressure and heart rate but central venous pressure rose. These changes were related to intermittent positive pressure ventilation. In the supine position, increase in heart rate (28%) was associated with profound hypotension (56%) and decrease in central venous pressure (171%) in these animals. There was a fall in venous oxygen tension and a marked increase (91%) in oxygen extraction ratio. Restoration to the lateral position ameliorated all these changes rapidly. It was suggested that a 'low pressure-low flow' circulatory state exists in anaesthetised adult buffaloes in the supine position.