COMPARISON OF 3 INJECTABLE ANESTHETIC TECHNIQUES IN PIGS

Forty-six near-adult pigs (mean age 10 months, mean weight 156 kg) wer e anaesthetised for laparoscopy. After intramuscular azaperone (1.0 mg /kg) and ketamine (2.5 mg/kg), 14 of the pigs received intravenous eto midate (200 mu g/kg) and midazolam (100 mu g/kg) and 17 were given ket amine (2 mg/kg) and midazolam (100 mu g/kg). The other 15 pigs were an aesthetised with pentobarbitone (15 to 20 mg/kg) without pre-anaesthet ic medication. The duration and adequacy of anaesthesia, recovery rate , and seven physiological variables (ECG, heart rate, indirect arteria l blood pressure, respiratory rate, minute volume, mean end-tidal carb on dioxide concentration and percentage oxygen saturation of haemoglob in) were compared. Repeated injections were needed in 29 of the 46 cas es. Pentobarbitone was the least satisfactory drug because although th e haemodynamic variables were greater, it caused more respiratory depr ession and a higher overall complication rate than the other methods. Apnoea occurred in two pigs, and was fatal in one, and positive pressu re ventilation with oxygen was needed in three others. Intubation cond itions were poorer and the times to standing, walking and rooting were longer in the pigs anaesthetised with pentobarbitone.