Reversing Effect of Insulin on Analgesic and Motor-Blocking Action of Epidural Bupivacaine in Dogs

Abstract

Epidural anesthesia is a common technique in veterinary medicine despites lack of specific reversal agent for local anesthetics pose unique set of challenges. This study evaluated insulin as a reversal agent for epidural bupivacaine in dogs. Study involved two phases (phase 1&2). Phase 1: conducted on three dogs to determine the neurotoxic effect of epidurally administered insulin and to elaborate the effective reversal dose. Phase 2: involved six dogs receiving two epidural treatments at one-week interval. Two groups were assessed: BUP (epidural bupivacaine 1mg/kg + saline & saline infusion) and BUP/INS (epidural bupivacaine 1mg/kg + insulin 1IU/kg & dextrose infusion). Both groups were assessed for sedation, analgesia, motor blockade, plasma glucose and potassium concentrations, and serum bupivacaine concentrations. Phase 1 revealed no clinical neurological sequelae following epidural insulin and proposed 1IU/kg of insulin as a reversal dose. Phase 2 revealed comparable duration and degree of sedation in both groups. Analgesia and motor blockade durations were longer in BUP group than BUP/INS group. Significant changes in blood glucose concentrations were detected in both groups relative to baseline and even in between groups. Potassium concentrations significantly changed from baseline only in BUP group. Epidural insulin effectively reversed sensory and motor blocking action of epidural bupivacaine in dogs.