Low dose intrathecal clonidine and fentanyl added to hyperbaric bupivacaine prolongs analgesia in gynecological surgery

Abstract

Background: We undertook this study to ascertain if a small dose of clonidine (30 μg) when added to a bupivacaine-fentanyl mixture improves spinal analgesia, without producing side effects, as compared to a bupivacaine-fentanyl or a bupivacaine-clonidine mixture.

Materials and methods: In this prospective, randomized, double-blind study, 75 (American Society of Anesthesiologists) ASA grade I-II patients, aged between 45 and 65 years, who were scheduled for vaginal hysterectomy with pelvic floor repair or non-descent vaginal hysterectomy under spinal anesthesia were recruited. The patients received hyperbaric bupivacaine (2.3 ml) with fentanyl 15 μg (Group BF) or clonidine 30 μg (Group BC) or both fentanyl (15 μg) and clonidine (30 μg) (Group BCF). The total amount of intrathecal mixture was constant (2.8 ml) in all the groups. Duration of sensory, motor block and effective analgesia, hemodynamic profile, postoperative pain score and analgesic requirements were recorded.

Results: The duration of effective analgesia, mean time till two-segment regression, and duration of sensory and motor block were significantly longer in group BCF as compared to group BC (P ~ 0.002), and in group BC as compared to group BF (P ~ 0.01). The incidence of intraoperative pain and requirement of postoperative analgesics in the first 24 hours was significantly more in group BF as compared to the other groups (P ~ 0.01). There was no difference in the hemodynamic profile between the groups.

Conclusion: Low-dose clonidine (30 μg) when added to a bupivacaine-fentanyl mixture increased the duration of effective analgesia and the duration of sensory and motor block in gynecological surgery. The incidence of intraoperative pain and requirement of postoperative analgesics was significantly less when clonidine was added to intrathecal bupivacaine with or without fentanyl.

Keywords: Anesthetic; analgesia; bupivacaine; clonidine; fentanyl; postoperative; spinal.

Figure 1

Comparison of mean heart rate between groups during the intraoperative period MAP = Mean arterial pressure, Group BF = Intrathecal bupivacaine-fentanyl, Group BC = Intrathecal bupivacaine-clonidine, Group BCF = Intrathecal bupivacaine-clonidine-fentanyl)

Figure 2

Comparison of mean arterial pressure between groups during the intraoperative period (MAP = Mean arterial pressure, Group BF = Intrathecal bupivacaine-fentanyl, Group BC = Intrathecal bupivacaine-clonidine, Group BCF = Intrathecal bupivacaine-clonidine-fentanyl)