Spinal anaesthesia with hyperbaric bupivacaine: effects of concentration and volume administered
Chambers, W.A.; Littlewood, D.G.; Edstrom, H.H.; Scott, D.B.
British Journal of Anaesthesia 54(1): 75-80
1982
ISSN/ISBN: 0007-0912 PMID: 7034758 Document Number: 190157
A double-blind study was carried out on 57 patients using hyperbaric solutions of bupivacaine to compare the effects of varying the concentration of bupivacaine and the volume of solution administered intrathecally. Patients (57) were studied. Ten patients received each volume of each concentration: 0.5% bupivacaine in 8% dextrose, 2 ml, 3 ml, or 4 ml and 0.75% bupivacaine in 8% dextrose, 1.3 ml or 2 ml. A further 7 patients received 3 ml of the 0.75% solution. Both solutions consistently produced good nerve blockade. With the 0.5% solution, increases in the volume administered had no effect on the spread of sensory loss, whereas with the 0.75% solution, increasing the volume administered resulted in a significantly greater cephalad spread. The use of 3 ml of this solution was abandoned after 7 patients had received it because of the excessive spread. With both solutions, increasing the volume produced a longer duration of action. The use of a 0.75% solution of hyperbaric bupivacaine for spinal anesthesia apparently did not confer any advantage over the 0.5% solution.