Continuous intravenous infusion anaesthesia with propofol in medetomidine and midazolam premedicated buffaloes: a quantitative electrocardiographic and haemato-biochemical study

Continuous intravenous infusion (CII) anaesthesia was studied in six male adult buffaloes used twice for P₁ and P₂ groups. In P₁ medetomidine (2.5 μg/kg) + butorphanol (0.05 mg/kg) and in P₂ midazolam (0.25 mg/kg) + butorphanol (0.05 mg/kg) i.v. were used as preanaesthetics. Induction by 5% thiopentone sodium and maintenance by 1% propofol as continuous infusion was done. Electrocardiographic and haematobiochemical parameters were recorded. ECG showed sinus bradycardia and a slight decrease in atrial depolarization area in group P₁ after premedication; whereas, sinus tachycardia and increase in atrial depolarization area was observed in P₂ after preanaesthetic administration. In group P₂ ventricular depolarization time and area increased significantly after preanaesthetic administration and remained so throughout the maintenance period. PR interval, however, did not show a definite pattern but it decreased in group P₂ after preanaesthetic administration. Increased QT interval was observed in P₁, whereas, P₂ showed decreased QT interval. The T wave amplitude remained non-significantly (P>0.05) different from the baseline throughout the observation period in group P₁ whereas, in P₂ a significant (P<0.05) decrease in the T wave amplitude was recorded. Slight neutrophilia, lymphocytopenia and an increase in plasma glucose level was observed in both groups. Plasma cortisol increased after the preanaesthetic administration but showed decreasing trend towards the end of observation period in both groups. Plasma creatinine, urea nitrogen and transaminases (AST and ALT) showed significant increase in both groups. It was concluded that neither of the combination induced serious electrocardiographic or haematobiochemical changes and are safe.