Bolus dose versus fractionated dose injection of hyperbaric bupivacaine in spinal anaesthesia among adult patients undergoing lower limb surgery: A prospective study

Abstract

Spinal anaesthesia (SA) with bolus dose has rapid onset but rapid onset may precipitate hypotension. If local anaesthetic is injected in fractions with some time gap, it may provide dense block with haemodynamic stability and prolonged duration of analgesia. We aimed to compare bolus dose with fractionated dose in SA for haemodynamic stability and duration of analgesia in patients undergoing lower limb surgery. After the Institutional Ethics Committee clearance, the study was carried out in sixty patients undergoing lower limb surgery. Patients were divided into two groups. Group B patients received single bolus SA with injection bupivacaine heavy (0.5%), 3 ml and Group F patients fractionated dose with two-third (2ml) of the total dose of injection bupivacaine heavy (0.5%) given initially followed by one- third (1ml) dose after 90s. Time of onset and regression of sensory and motor blockage, intraoperative haemodynamics and duration of analgesia were recorded and analysed with Student’s unpaired t-test. Result: Patients were more haemodynamically stable in Group F as compared to Group B. Five patients in Group F and ten patients in Group B required vasopressor. Duration of sensory and motor block and duration of analgesia were longer in Group F compared to Group B. Fractionated dose of SA provides greater haemodynamic stability and longer duration of analgesia compared to bolus dose.