Evaluation of bupivacaine alone and in combination with hyaluronidase for epidural analgesia in dogs

Bupivacaine HCl (0.5%) alone and with hyaluronidase 150 I.U./100 mL of bupivacaine HCl was administered epidurally in six dogs each. Increase in rectal temperature, heart rate, respiratory rate and pulse rate were recorded at initial intervals in the animals of both groups. However, these values decreased at later intervals of observation and reached to near normal level by 120 min of observation. The decrease in clinical parameters was sharper in the animals receiving bupivacaine with hyaluronidase as compared to animals receiving bupivacaine alone. Addition of hyaluronidase significantly decreased the time of onset, duration, standing on its own and ambulation after standing. Maximum analgesia could be recorded at 15 min and 30 min, respectively after administration of bupivacaine with and without hyaluronidase. The cutaneous and pedal reflexes were absent at 60 min of observation in both groups. The extent of spread of anaesthesia was observed up to the level of T₁₃ and T₁₁ vertebrae in the animals receiving bupivacaine alone and in combination with hyaluronidase, respectively.