Comparison of intrathecal morphine and fentanyl in addition to ropivacaine for perioperative analgesia in lower segment caesarean section

Abstract

Aim: To compare the analgesic efficacy of intrathecal morphine and fentanyl as an adjuvant to isobaric ropivacaine in patients undergoing lower segment caesarean section under spinal anesthesia. Materials and Methods: A total of 120 parturients aged between 20 and 35 years of age, belonging to American Society of Anaesthesiologist (ASA) physical status I and II, were randomized into two groups: Group M received 15 mg of 0.75% isobaric ropivacaine (2 mL) and 100 μg of morphine (1 mL) intrathecally; and Group F received 15 mg of 0.75% isobaric ropivacaine (2 mL) and 25 μg of fentanyl (0.5 mL) and 0.5 mL of normal saline intrathecally. The primary outcome was the duration of postoperative analgesia. Block characteristics, hemodynamic variables, demand for rescue analgesia, and adverse effects were also assessed. Results: The demographic profiles and block characteristics were comparable in all groups. The mean duration of analgesia in Group M and Group F was 996.03 ± 25.3 and 203.88 ± 25.20 min, respectively; the difference between the groups was highly significant (P < 0.0001). Lesser visual analog scale pain scores were observed in Group M after the fourth postoperative hour and continued till 24 h (P < 0.05 at time interval of 4, 6, 8, 12, and 24 h). Conclusion: The addition of intrathecal morphine to isobaric ropivacaine resulted in a longer duration of postoperative analgesia as compared to intrathecal fentanyl in parturients undergoing caesarean section under spinal anesthesia.