RESUMEN
PURPOSE: One disadvantage of spinal anesthesia using bupivacaine is the relatively short duration of action. Combining it with opioids can increase its analgesic effects. It was aimed to analyze the effectiveness and the side effects of bupivacaine alone and in combination with sufentanil in arthroscopic knee surgery during unilateral spinal anesthesia. METHODS: This is a prospective, randomized, double-blind trial. Fifty patients undergoing unilateral arthroscopic knee surgery were enrolled in this study. The patients were assigned into two groups to receive either 10 mg of 0.5% hyperbaric bupivacaine (Group I) or 5 mg of 0.5% hyperbaric bupivacaine combined with 2.5 µg sufentanil (Group II) to obtain unilateral spinal anesthesia. RESULTS: The time for sensorial block to reach level T10 was 6.3 ± 1.7 min in Group I and 4.8 ± 1.6 min in Group II (P < 0.05). Complete motor block was obtained at the 10th min in 16 patients in Group I (P < 0.005), and the duration of the motor block was lower in Group II (4.9 ± 2.2 h and 2.0 ± 1.1 h, P < 0.001). Bradycardia was encountered in 8 patients in Group I and in 1 patient in Group II (P < 0.05). No differences were encountered regarding other side effects. During the postoperative 24 h, 5 patients in Group I and 3 patients in Group II required analgesic drugs (n.s.). There was not any significant difference between groups with regard to first analgesic request time (8.3 ± 2.4 and 9.0 ± 2.3 h, n.s.). CONCLUSIONS: This study showed that combining lower dose bupivacaine with sufentanil provided faster onset of sensorial block and lower risk of motor block in unilateral spinal anesthesia for arthroscopic knee surgery.