Caudal Morphine in Pediatric Patients: A Comparison of Two Different Doses in Children Undergoing Infraumbilical Surgery - A Prospective, Randomized, Double-Blind Study.

Background: One of the most feared symptoms of any disease is PAIN. It is a complex phenomenal experience, especially in children. Various methods and medications have been administered through different routes. Regional anesthesia produces marvelous postoperative analgesia and cessation of stress response in infants and children. Caudal epidural analgesia is the most acceptable and popular method of providing intra- and postoperative analgesia for abdominal, perineal, and lower limb surgeries in children. The use of preservative-free morphine as an adjunct to ropivacaine increases the quality and duration of analgesia despite the various side effects. Various articles use various doses of morphine as an adjuvant in caudal epidural analgesia. Hence, we conducted the study to compare the two dosages of morphine that is 20 μg.kg^-1 and 30 μg.kg^-1 of caudal epidural morphine for infraumblical surgeries with regard to its efficacy and safety and side effect profiles.

Materials and methods: The study is a prospective, randomized, double-blinded study. Sixty patients were divided into two groups. Group A: 20 μg.kg^-1 of morphine was added to 0.2% ropivacaine 1 mL.kg^-1 and the solution was made. Group B: 30 μg.kg^-1 of morphine was added to 1 mL.kg^-1 of 0.2% ropivacaine. Heart rate, systolic blood pressure, diastolic blood pressure, SPO₂, pain score, and sedation score were recorded immediately, after 15 min, 30 min, 45 min, 1 h, 2 h, 4 h, 8 h, 12 h, 16 h, 18 h, and 24 h were recorded.

Results: The mean duration of analgesia is similar in both groups (P = 0.011). The mean duration was 20.517 ± 1.9143 h in Group A and 22.233 ± 1.6853 h in Group B. Children with the requirement of one dose of rescue analgesia in Group A was 83.3% which was higher than Group B being 66.7%. Children with no analgesic requirement were 16.7% in Group A and 33.3% in Group B. The incidence of side effects was more in Group B (8 [26.7%] children with nausea and vomiting; 1 [3.3%] children with urinary retention) than in Group A (2 [6.6%] children with nausea and vomiting.

Conclusion: From the above observations, it can be concluded that morphine of less dosage (20 μg.kg^-1) when added to 0.2% ropivacaine for the caudal epidural block has better efficacy than morphine of higher dosage (30 μg.kg^-1) as the duration of analgesia is similar with decreased incidence of side effects.