Abstract

Introduction: Pregnancy is accompanied by physiologic changes in multiple organ systems that may influence maternal responses to anaesthesia and the choice of anaesthetic techniques. The rate of caesarean sections is on the rise. Caesarean section in a conscious patient is a challenging test of regional anaesthesia. Spinal anaesthesia is perhaps the most efficient approach to this challenge. In modern scientific era, there has been a curiosity in using opioid analgesic adjuvants to subarachnoid local anaesthetics. Arrival of a new synthetic lipophilic opioid, fentanyl, has revolutionized its use in the past three decades. Fentanyl has a shorter duration of action and fast onset as compared to pethidine and morphine. Buprenorphine is a long acting, highly lipophilic opioid. It has proved to be a promising analgesic by intra thecal route^1,2. Buprenorphine is twenty five times more potent than morphine. In this study, an effort is made to compare the perioperative and postoperative analgesic efficiency of these two lipophilic opioid drugs along with bupivacaine  in caesarean section. 

Aim: To evaluate the efficacy of the combination of  intrathecal fentanyl 25 mcg  and 7.5 mg of 0.5% hyperbaric bupivacaine  in comparison with buprenorphine 60 mcg and 7.5 mg of 0.5% hyperbaric bupivacaine used  for  lower segment caesarean section

Materials and Methods: A total of 50 patients who underwent elective caesarean section were taken up for the study. Patients were randomised into two groups each. In group  A, patients recieved 1.5 ml of 0.5% hyperbaric bupivacaine (7.5mg) with 0.5ml of fentanyl (25 mcg) and in group B, patients received 1.5 ml of 0.5% hyperbaric bupivacaine (7.5mg) with 0.2 ml of buprenorphine (60 mcg) and 0.3 ml of normal saline. The final volume of the injected solution is 2 ml on both groups.

Results: In the current study, onset of analgesia was significantly earlier due to the addition of buprenorphine. This may be attributed  to high lipid solubility and highest affinity for opiate receptors of buprenorphine. Both the groups had the same mean time to achieve motor blockade. Both groups maintained hemodynamic stability which was statistically insignificant. The mean duration of effective analgesia was 200.32  minutes (3.33 hours)  in Group A  and  491.28  minutes ( 8.1 hours )   in group B which was highly significant statistically(p<0.01).

Conclusion: We observed that  anaesthesia was superior when buprenorphine is mixed with bupivacaine (0.5%) as compared to bupivacaine with fentanyl. Addition of buprenorphine to bupivacaine 0.5% augments the sensory blockade of local anaesthetics without affecting the sympathetic activity. Thus it is  concluded that intrathecal  buprenorphine is suitable drug for  post operative analgesia for caesarean section .

Keywords: Caesarean section, Spinal anaesthesia, bupivacaine, fentanyl, buprenorphine, post operative analgesia.