Spinal analgesia with hyperbaric 0.5% bupivacaine: effects of different patient positions

A prospective randomised study of the effect when the patient remained sitting for 2, 10, 15, 20 or 25 min, was evaluated in 50 patients (10 in each group) given a spinal anesthesia, with 4 ml 0.5% bupivacaine in 8% glucose (hyperbaric). The first period of sitting was followed by a second period in the horizontal supine position; this period ended when there was the same level of pin-prick analgesia for 5 min. The patient was then placed in the Trendelenburg position until maximum spread was achieved. There was no difference in the spread of analgesia between the five groups at the end of each of the three periods. Between the five groups, there was no difference as to the duration of time from placing the patient in the supine horizontal position until maximum spread of analgesia (mean +/- s.e. mean 12 +/- 2-13 +/- 2 min) in this position, and from the start of the Trendelenburg position until maximum spread (mean +/- s.e. mean 7.5 +/- 1.2-9.5 +/- 1.7 min). All patients except one in the 25-min group had complete motor blockade of the lower limbs.