Abstract : Background and Aims: 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.
Materials and Methods: 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.
Conclusion: Fractionated dose of SA provides greater haemodynamic stability and longer duration of
analgesia compared to bolus dose.
Keywords: Bupivacaine, Spinal anaesthesia, Dose fraction, Hypotension.