Effect of different baricities of intrathecal bupivacaine on the quality of spinal block in elderly patients undergoing transurethral resection of the prostate

Abstract

Background Elderly patients undergoing spinal anesthesia require restricted block with a low dose of a local anesthetic. Considering that the baricity of local anesthetic solutions is the primary determinant of the level of motor and sensory block in nonobstetric patients, the aim of this study was to evaluate the effect of baricity of bupivacaine on the quality of spinal block and on hemodynamics in elderly patients undergoing transurethral resection of the prostate (TURP). Materials and methods Ninety-nine patients undergoing TURP were randomized into three groups. Patients of the first group (33 patients) received intrathecal 10 mg hyperbaric bupivacaine 0.5%. The second group of patients (34 patients) received 5 mg isobaric bupivacaine added to 5 mg hyperbaric bupivacaine, resulting in what was called 'slightly hyperbaric solution'. The third group of patients (32 patients) received 10 mg isobaric bupivacaine 0.5%. All patients were injected below L2 level in the sitting position. Sensory and motor blockade was assessed, as well as the first request for analgesic, rescue analgesics, and the overall incidence of side effects. Results Onset of sensory block was comparable in the three studied groups, but motor block set earlier in the hyperbaric group and the 'slightly hyperbaric' group compared with the isobaric group. Higher sensory block was observed in the isobaric group. Recovery from sensory and motor block was earlier in the hyperbaric group. First need for analgesics was earlier in the hyperbaric group than in the 'slightly hyperbaric' and isobaric groups. Postoperative analgesia and tolerance to urinary catheter were prolonged in the isobaric and 'slightly hyperbaric' group as compared with the hyperbaric group. Conclusion Use of slightly hyperbaric bupivacaine (density = 1.013) than the traditional hyperbaric bupivacaine (density = 1.028) and the isobaric one (density = 1.007) results in good quality spinal block with fewer side effects in patients undergoing TURP.