Vinod Cherian1, Sunilkumar T.S.2, Shamsad Beegum T.S.3, Satheedevi P.4
BACKGROUND
This study compared the characteristics of hyperbaric and hypobaric bupivacaine
in patients undergoing unilateral lower limb surgeries under lumbar subarachnoid
block with regard to their onset and level of sensory and motor blockades,
haemodynamic stability, and recovery profile in terms of analgesic duration and
motor recovery.
METHODS
This is a comparative study. Two groups, each of 36 patients who satisfied
American society of Anaesthesiologist (ASA) I & II aged 18 – 65 years, were
observed intra operatively and during immediate post-operative period. Group 1
received 2.4 ml of 0.5 % bupivacaine (heavy) with operated limb in dependent
position. Group 2 received 4 ml of reconstituted hypobaric bupivacaine 0.3 %, with
the operated limb positioned in non-dependent position. Onset, level and duration
of motor and sensory block, hemodynamic changes and duration of surgical
analgesia were compared between groups.
RESULTS
The level of sensory block attained in the hypobaric group was at T12 with
maximum at T9, in the hyperbaric group it is variable and at higher level. Duration
of sensory blockade was less with hypobaric. Motor block of modified Bromage
scale 3 after 10 minutes was none in group 2 and 91.7 % in group 1. Significant
fall in systolic blood pressure at 15 to 30 minutes and diastolic BP at 15 and 20
minutes was noted in hyperbaric group after subarachnoid block. There was
significant percentage of change in systolic blood pressure from 4 to 70 minutes
and mean arterial pressure (MAP) from 4 to 90 minutes in hyperbaric group.
Duration of surgical analgesia in hypobaric group was longer compared to hyper
baric
CONCLUSIONS
Intrathecal hypobaric bupivacaine showed better haemodynamic stability and
longer duration of analgesia in comparison with hyperbaric bupivacaine in lower
limb surgeries.
