Intrathecal clonidine added to small-dose bupivacaine prolongs postoperative analgesia in patients undergoing transurethral surgery

Abstract

Introduction: The aim of this prospective, double-blinded study was to investigate the effects of clonidine in co-administration with bupivacaine during spinal anesthesia, regarding the onset and regression of motor and sensory block, postoperative analgesia and possible side effects. Methods: We randomly selected 66 male patients (age 35 to 70), from the American Society of Anesthesiologists (ASA) class I-II; these patients were scheduled for transurethral surgical procedures. These patients were randomly allocated into two groups of 33 patients each: group B (bupivacaine) only received 0.5% isobaric bupivacaine 7.5 mg intrathecally and group BC (bupivacaine + clonidine) received bupivacaine 7.5 mg and clonidine 25 μg intrathecally. We performed the spinal anesthesia at a level of L3-L4 with a 25-gauge needle. We assessed the sensory block with a pinprick, the motor block using the Bromage scale, analgesia with the visual analog scale and sedation with the modified Wilson scale. We also recorded the hemodynamic and respiratory parameters. Results: The groups were demographically similar. The mean time of achievement of motor block (Bromage 3) and sensory block at level T9 was significantly shorter in the BC group compared with B group (p = 0.002, p = 0.000, respeectively). The motor block regression time was not significantly different between the two groups (p = 0.237). The postoperative analgesia requirement was significantly longer in group BC compared with group B (p = 0.000). No neurological deficit, sedation or other significant adverse effects were recorded. Conclusion: The intrathecal application of clonidine in combination with bupivacaine improves the duration and quality of spinal anesthesia; it also provides longer duration of postoperative analgesia, without significant side effects.