[Spinal anesthesia with isobaric 0.5% bupivacaine. Effect of age]

The effects of age on the characteristics of spinal anaesthesia with plain bupivacaine were investigated in 29 adult patients (less than 50 yr : group I), and 37 older patients (greater than or equal to 80 yr : group II). Three millilitres of 0.5% solution (15 mg) were injected at the L3-L4 interspace in the lateral position; the patients were turned supine immediately afterwards. The onset, extent and duration of sensory and motor blockade, the cardiovascular effects and the quality of anaesthesia were evaluated. Anaesthesia was unsatisfactory in one patient in group I and two patients in group II; they required a supplement with intravenous inhalation anaesthesia. These patients were not included in the analysis of the variables studied. The time to maximum spread was significantly shorter in the group I : 7.3 min versus 9.9 min in group II. A higher sensory spinal blockade was obtained in the older age group (T 10.4 versus T 11.2). There were no significant difference between the two groups in the mean time from the injection to recovery from analgesia in the two uppermost segments (121 min versus 107 min). The mean duration of analgesia at the L2 level did not differ significantly (149 min versus 164 min). All the patients had complete motor blockade of lower limbs. Only the Bromage's degrees 2 and 1 were greater in the elderly's group. In the older group, there was a tendency to a greater decrease in systolic arterial pressure from the preanaesthetic values (-20.9% versus -13%). But moderate falls in mean and diastolic arterial pressures were observed.(ABSTRACT TRUNCATED AT 250 WORDS)