A Comparative Study of 0.15 mg and 0.2 mg Intrathecal Morphine for Post-Cesarean Analgesia: A Quasi-Experimental Study with Historical Control versus New Intervention

Abstract

The intrathecal administration of morphine in combination with local anesthetics is the standard analgesic technique for cesarean section. However, intrathecal morphine can cause side effects, including pruritus, nausea, vomiting, and respiratory depression. The incidence of these side effects is dose dependent. This was a quasi-experimental study employing a historical control versus new intervention design. The study involved 80 pregnant women who underwent cesarean section at Pathumthani Hospital. All participants received an intrathecal injection of 0.5% hyperbaric bupivacaine. They were then divided into two groups: the study group received 0.15 mg intrathecal morphine, while the control group received 0.2 mg intrathecal morphine. This study aimed to compare the effectiveness of a lower dose of intrathecal morphine 0.15 mg with that of a 0.2 mg. The objective was to determine whether the lower dose provided equivalent pain relief while reducing the incidence of side effects within the first 24 hours.

The results revealed no significant difference between the two groups in pain intensity at 6, 12, 18, and 24 hours post-surgery, the number of patients requesting tramadol, the total amount of tramadol administered in the first 24 hours, and the time to the first dose of tramadol, and the incidence of nausea and vomiting. Pruritus, however, was significantly lower in the 0.15 mg morphine group compared to the 0.2 mg group at 12 hours post-surgery (p-value = 0.021). All patients in both groups regained consciousness without experiencing opioid-induced respiratory depression.

The administration of 0.15 mg of intrathecal morphine during cesarean section provided similar pain control efficacy comparable to 0.2 mg withing the first 24 hours post-surgery, while resulting in a lower incidence of pruritus.