SINGLE-SHOT SPINAL-ANESTHESIA WITH SMALL DOSES OF BUPIVACAINE

Background and objectives. The potential risks of spinal lidocaine hav e generated interest in an alternative local anesthetic solution, Feat ures of anesthetic block were therefore assessed in a double-blind ran domized prospective study following administration of spinal bupivacai ne in small doses. Methods. Ninety patients scheduled for lower limb s aphenous vein stripping were randomized to receive a 4-mL hyperbaric s olution containing 4, 6, or 8 mg bupivacaine in the subarachnoid space . Sensory and motor block and hemodynamic changes were assessed at reg ular intervals. Patients were also questioned regarding transient radi cular irritation symptoms. Results. The mean duration of sensory block increased with increasing dose (duration at L2: 56 +/- 27, 71 +/- 29, 79 +/- 25 minutes in groups 4, 6, and 8 mg, respectively, P < .05). M otor block was also dose dependent. The incidence of grade 3 motor blo ck increased from 0%, to 21%, and to 53%. No patient had symptoms of t ransient radicular irritation. Arterial pressure and heart rate were s table throughout the study. Conclusion. Hyperbaric bupivacaine 6-8 mg provides a suitable alternative to spinal lidocaine for surgical proce dures of short duration.