A Randomised Clinical Trial To Compare The Efficacy And Safety Of Dexmedetomidine-Ropivacaine Versus Fentanyl-Ropivacaine For Epidural Labor Analgesia

Abstract

Majority of women go through the most painful moments for human beings while giving birth. An epidural block is a superior potent approach of labor analgesia, which promotes painless delivery and is customised for each woman. Anesthesiologists have been looking for strategies to improve the effects of analgesia and to avoid the side effects associated with labor analgesia. Ropivacaine combined with fentanyl has been successfully used to provide epidural analgesia. Opioids may produce adverse effects, such as pruritus, nausea, vomiting, respiratory depression and urinary retention. The non-opioid Dexmedetomidine is characterized by its high selectivity and more significant analgesic effects without causing respiratory depression. The safety and benefits of Dexmedetomidine as an adjuvant to ropivacaine as a novel form of epidural labor analgesia must be researched more. The results of our study gives insight in the epidural block and come up with a pioneering approach for labor analgesia. OBJECTIVES OF THE STUDY: To compare the efficacy and safety of Dexmedetomidine- Ropivacaine versus Fentanyl- Ropivacaine for epidural labor analgesia. METHODS: Total 68 primigravida (34 in each group) at term gestation, with cephalic presentation between the age group of 19-35, with no known comorbidities or obstetric complications in the active phase of labor, willing for epidural analgesia were assigned with two groups using Computer Generated Randomisation Table. 1) Group RD : 34 were given 0.1% Ropivacaine + 0.5 mcg/ml Dexmedetomidine 2) Group RF : 34 were given 0.1% Ropivacaine + 2 mcg/ml Fentanyl After insertion of epidural catheter and administering a test dose of 3 ml 2% lignocaine with adrenaline, parturients received 10 ml of 0.5 mcg/ml Dexmedetomidine (Group RD) or 2 mcg/ml Fentanyl (Group RF) along with 0.1% Ropivacaine given as loading dose. After the loading dose was given, maintenance of epidural analgesia was done using a Patient Controlled Analgesia (PCA) pump. The PCA pump was adjusted at a pace of 7 ml/hr with a rescue dose of 7ml (with lockout period of 25 min and total limit of 25 ml/hr). A rescue bolus was administered when visual analog scale (VAS) score is ≥ 5 (0 = no pain, 10 = maximum pain) by a PCA pump. The primary objectives were to compare Dexmedetomidine and Fentanyl as adjuvants in epidural analgesia in terms of the time of onset of epidural analgesia, duration between epidural and delivery of baby, rescue analgesic dose requirement, Visual Analog Scale (VAS) score and maternal vitals. The secondary objectives were to observe Ramsay Sedation Scale (RSS) score, APGAR score of the baby and maternal side effects. RESULTS: Dexmedetomidine group displayed better analgesic effect compared to fentanyl group. Group RD showed shorter mean onset time of analgesia (RD – 12.50±1.31 min vs. RF - 15.26±1.46 min), less local anaesthetics requirement (RD –47.54±5.37 ml vs RF –59.05±6.62 ml), less number of bolus doses (RD– 0.15±0.36 vs RF– 1.21±0.95) and shorter duration from the administration of epidural to the delivery of baby (RD –312.97±42.40 min vs. RF 345.94±14.67 min) than group RF which was statistically significant and with p<0.001.VAS scores in group RD was significantly less than that of group RF at most time points after epidural administration. Maternal systolic blood pressure was high in group RF than group RD and it showed statistical significance at 4 hours. Diastolic blood pressure was high in group RF than group RD after epidural administration and did not show any statistical significance. Maternal heart rate was significantly low in group RD at 90 minute from baseline. There was no fall in room air oxygen saturation in both groups at any time. The study showed side effects in both the groups, which was not statistically significant. Maternal hypotension, nausea, vomiting, bradycardia and shivering was observed in group RD while pruritus, hypotension, nausea, vomiting and shivering was seen in group RF. Ramsay Sedation Scale score was comparably low in both groups and excessive sedation was not seen in both groups. Newborn Apgar scores were comparably high in both the groups. CONCLUSION: The results of the study indicate that with 0.1% Ropivacaine, 0.5 mcg/ml Dexmedetomidine shows more effectiveness than 2 mcg/ml Fentanyl during epidural labor and is a safe alternative for labor pain.