Abstract

In a double-blind study, solutions of bupivacaine 0.5% in 8% glucose (15 mg) and lidocaine 5% in 7.5% glucose (90 mg), were compared in 40 patients who had urologic surgery under spinal anesthesia. After the injection, the patients remained in the sitting position for 2 minutes before they were placed in a supine position. After 10 minutes, the patients were placed in the lithotomy position. Maximum cephalad level of analgesia (T9-T10) was achieved within approximatsly 20 minutes with both drugs. Total duration of analgesia was significantly longer for bupivacaine. Onset time to complete motor blockade of the lower limbs was significantly shorter for lidocaine, and more patients achieved complete motor blockade with lidocaine (18 of 20 patients vs. 11 of 20 patients). Duration of complete motor blockade was 87 ± 15.0 minutes (mean ± SEM) for bupivacaine and 69 ± 5.8 minutes for lidocaine. Reduction of systolic blood pressure by 30% was seen in five patients in the lidocaine group but in no patients in the bupivacaine group. Hypotension that required administration of ephedrine was seen in three patients in the bupivacaine group and in six patients in the lidocaine group. Bradycardia was also observed in two of the three patients in the bupivacaine group and in three of the six patients in the lidocaine group. One patient had mild postspinal headache.