Spinal anaesthesia with 0.5% hyperbaric bupivacaine in elderly patients: effects of duration spent in the sitting position

Sixty patients, aged 65-84 yr, undergoing minor urological surgery under sp inal anaesthesia remained sitting for 2 (group 1, n=15), 5 (group 2, n=15), 10 (group 3, n=15), or 20 (group 4, n=15) min after completion of the suba rachnoid administration of 3 ml of a 0.5% hyperbaric bupivacaine solution. They were then placed in the supine position. Analgesia levels were assesse d bilaterally using pinprick. Motor block was scored using a 12-point scale . Systolic and diastolic arterial pressures and heart rate were also record ed. Twenty minutes after the injection the upper analgesia levels were lowe r (P<0.05) in group 4 (median T9.0) than in the groups 1-3 (medians T6.6-T8 .5). The highest obtained levels (medians T5.7-T8.0) did not differ between the groups, but occurred later (P<0.05) in group 4 (median 35 min) than in groups 1-3 (medians 19-24 min). There were no significant differences in t he maximum degree of motor block or haemodynamic changes between the four s tudy groups.