Comparison of Intrathecal Fentanyl with Bupivacaine and Intrathecal Dexmedetomidine with Bupivacaine in Patients Posted for Elective Caesarean Section: A Double-blinded Randomised Clinical Study

Introduction: Spinal anaesthesia is the preferred technique for elective caesarean section. However, the limited duration of postoperative analgesia with bupivacaine necessitates the use of intrathecal adjuvants. Opioids like fentanyl are commonly used but are associated with side-effects such as pruritus and nausea. Aim: To compare haemodynamics and postoperative analgesia of intrathecal adjuvants fentanyl and dexmedetomidine in patients undergoing caesarean section. Materials and Methods: This double-blinded randomised clinical study included 60 pregnant women posted for elective caesarean section with gestational age ≥37 weeks. The parturients were randomly divided into two groups of 30 each. Group-F received 0.5% 10 mg bupivacaine + 25 mcg fentanyl as an additive whereas Group-D received 0.5% 10 mg bupivacaine + 5 mcg dexmedetomidine as an additive. Haemodynamic parameters were recorded in the intraoperative period and postoperatively pain scores were recorded upto six hours. Onset of block, time to rescue analgesia, APGAR scores and any adverse events were also recorded and evaluated using independent student’s t-test, Mann-Whitney U test, Chi-square test, Fisher’s-exact test. The p-value <0.05 was considered as statistically significant. Results: Demographic characteristics age, height and weight were matched and they were comparable between the groups with p-value >0.05. DBP, MAP, RR were comparable between the groups suggesting both drugs provide comparable circulatory stability with p-value >0.05. Heart Rate (HR) with dexmedetomidine was statistically lower than fentanyl but did not cause bradycardia, with lowest mean score of 74.03±2.13. Onset of sensory blockade, time to T6 dermatomal level, was significant in Group D 92.4±5.01 in comparison to Group F 97.97±5.59, with p value <0.001. APGAR scores at 1st and 5th minute showed no statistical significance, Group D and Group F at 1st minute was at 8.47±0.51 with p value of 1.00, at 5th minute Group D and Group F were 8.93±0.45 and 9±0.53 respectively, with p value 0.599. Duration of motor blockade (in min) (regression to modified bromage grade 0) in Group D was 116.27±3.72 and in Group F it was 114.13±13.09 with p value 0.394 with no statistical significance. Conclusion: In parturients undergoing caesarean section, dexmedetomidine, as an additive, provides superior postoperative analgesia in comparison to fentanyl. Haemodynamic stability was comparable between the groups. Maternal HR is characteristically lower in the dexmedetomidine group but does not lead to bradycardia.