Comparison of Subarachnoid Block Characteristics with Levobupivacaine at 24°C and 37°C for Infra-Umbilical Surgeries-a Randomized Controlled Trial.

Abstract

Background & Aim: The temperature of a local anaesthetic solution influences its pKa and molecular kinetic activity, thereby affecting baricity. We evaluated the effects of 0.5% Levobupivacaine preheated at 37ºC on sensory and motor block characteristics and haemodynamic in patients undergoing infra-umbilical surgeries. Methods: This was a prospective, randomised, double blinded study, in which 70 patients were allocated into two groups [Group A (n=35) and Group B (n=35)]. In Group A, patients were administered 3 mL of levobupivacaine 0.5% solution at room temperature (24-28ºC) and patients in Group B were administered with 3 mL of levobupivacaine 0.5% solution at 37°C (Thermostatically controlled digitalized hot bath machine) into the subarachnoid space. Our primary objective was to determine the time of onset of sensory blockade at T10. Time of onset and duration of motor blockade, duration of analgesia, time to two segment regression and other adverse events after spinal anaesthesia were secondary objectives. Results: The time to reach a sensory block of T10 was significantly shorter in group B (Mean ±SD 2.7±2.9 min, P 0.005) compared to that in group A (Mean ±SD 4.8±4.5 min). The mean duration of sensory block was longer in group B (Mean ±SD 155.5±25.9 min, P 0.048). Time to onset of motor block, duration of motor block and time to regression of two dermatomal level were not found statistically significant among the two groups. Conclusion: Spinal anaesthesia with 0.5% levobupivacaine heated to 37ºC shortens sensory block onset time and provides longer block duration.