Effect of nimodipine on regression of spinal analgesia

We have investigated the effect of infusion of nimodipine on the spread of spinal anaesthesia in 50 patients undergoing transurethral procedures. Patients were allocated randomly to receive during operation continuous infusion of nimodipine 10 ml h(-1) (group N, n=25) or normal saline (group C, n=25) in a double-blind manner. All patients received hyperbaric lidocaine 100 mg (5% in 8% dextrose) intrathecally and were then placed in the lithotomy position. Twenty minutes after intrathecal injection the level of spinal anaesthesia was tested with a pressure palpator and a baseline was established. Assessments were repeated 5, 10 and 15 min thereafter. Five minutes after establishing baseline, mean regression of sensory analgesia did not differ between groups. Analgesia had regressed by 1.3 (SD 1.4) and 1.0 (1.9) cm, respectively. After 10 min, sensory block in group N regressed by 1.7 (1.7) cm and in group C by 1.5 (1.6) cm. After 15 min these values were 1.1 (1.7) cm and 2.2 (1.9) cm, respectively (P<0.035). Similar results were found after normalizing the changes by dividing the change by patient height.