SPINAL ANESTHESIA FOR ENDOSCOPIC UROLOGICAL SURGERY - Low dose vs. Varying doses of Hyperbaric Bupivacaine

Background and objective: The aim of this study is to compare the efficiency of low dose vs. varying doses of hyperbaric bupivacaine in spinal anesthesia for endoscopic urological procedures.Methods: Sixty consecutive patients were studied in a randomized prospective manner. They received either of 5 (Gr I), 7.5 (Gr II) or 10 mg (Gr III) of hyperbaric bupivacaine 0.5% combined with 25 μg of fentanyl, through a 25-gauge W hitacre spinal needle placed in the L3-L4 interspace. Characteristics of sensory and motor block, dose of ephedrine required, secondary effects, the patients, and the surgeons. satisfaction, were noted. Results: The maximum number of blocked segments was 14 ± 1 (Gr I), 15 ±2 (Gr II) and 16  2 (Gr III). Time to T12 regression was significantly shorter for Gr I (53 ± 13 min) than for Gr II (69 ±20 min) or Gr III (94 ±14 min). Bromage 3 block was not found in Gr I compared to 4 patients in Gr II and 15 patients in Gr III. The duration of motor block was shorter in Gr I(51 ±18 min) than in Gr II (86 ± 19 min) and in Gr III(138 ± 21 min). Ephedrine was used for 16 patients in Gr III (9.8 ±12.2 mg), 5 patients in Gr II (3.7 ±7.8 mg) and 2 patients in Gr I (0.5 ± 1.5 mg). The difference is statistically significant between Gr III and the other groups. Conclusions: These results suggest that the use of a low dose of bupivacaine (5 mg) added to fentanyl (25 μg) for endoscopic urological surgery, resulted in short-acting sensory block, without motor block and a lower incidence of cardiovascular side effects, as compared to either of 7.5 or 10 mg bupivacaine with 25 μg fentanyl.