Evaluation of the efficacy of MgSO4 as an adjunct to ropivacaine and fentanyl for labour analgesia

Background and Objective: Epidural analgesia is the most commonly practiced method for labor analgesia. It provides effective pain relief, less maternal stress response, better parturient satisfaction and the ability to provide anesthesia when required. We conducted this study to evaluate the efficacy of Magnesium Sulphate as an adjunct to ropivacaine and fentanyl for labor analgesia. Materials and Methods: 60 primi parturients, aged more than 18 years, ASA physical status class II, in active labor, requesting labor analgesia were included in this prospective randomised double blind study. Patients in Group F received 7.5 ml 0.2% Ropivacaine + 50 mcg Fentanyl + Normal Saline to make a total volume of 10 ml and in Group FM received 7.5 ml 0.2% ropivacaine + 50 mcg fentanyl + 50 mg MagnesiumSulphate + Normal Saline to make a total volume of 10 ml. Pain was assessed using Visual Analogue Scale (VAS). Time of onset, quality of analgesia and duration of analgesia of bolus dose were noted. Results: Epidural single dose Magnesium Sulphate added to ropivacaine and fentanyl resulted in significantly early onset (2.9 ± 0.7 min v/s 5.2 ± 1.1 min, P < 0.001) and longer duration of epidural analgesia (107.2 ± 20.1 min v/s 89.9 ± 21.3 min, P = 0.002) as compared to those patients who received ropivacaine and fentanyl only. There was no significant effect on neonatal outcome (assessed by APGAR Score) and no maternal side effects were recorded. Conclusion: Magnesium sulphate added to ropivacaine and fentanyl for labor analgesia resulted in early onset of analgesia and longer duration of action without any significant side effects.