Use of Caudal Analgesia Supplemented with Low Dose of Morphine in Children Who Undergo Renal Surgery

Introduction: To test the efficacy and safety of caudal anesthesia (CA) supplemented by low dose morphine in children who undergo renal surgery.

Materials and methods: Forty patients aged 2 months-14 years were enrolled and randomly divided into two groups of 20 patients each: Group A (bupivacaine 0.2% with fentanyl); Group B (bupivacaine with morphine). The duration of surgery and hospitalization time were recorded. Postoperative pain score was measured by Face Legs Activity Cry Consolability scale and Wong-Baker Faces scale for those who are older. Overall use of rescue analgesics was calculated.

Results: There was no statistical difference in the length of surgery, incidence of pruritus, postoperative nausea, vomiting and urinary retention between the two groups. However the postoperative opioid requirements were significantly higher in Group A 1.03 ± 0.9 mg/kg compared to Group B, in which only one patient required opioid therapy (p < 0.0001). Moreover the need for non-opioid rescue analgesic was higher in Group A, (36 ± 5.7 mg/kg of paracetamol) compared to morphine CA group there only 26 ± 3.6 mg/kg required during first 24 h of the postoperative period (p = 0.0312). The Face Legs Activity Cry Consolability pain score (1, 4, and 24 h after surgery) and Wong-Baker Faces scale were significantly higher in Group A. The hospitalization period was shorter in the CA morphine group, but the difference did not reach statistical significance. None developed hemodynamic instability or respiratory depression.

Conclusions: Our data show that CA supplemented with low dose morphine provides a longer duration of analgesia without significant side-effects in children undergoing renal surgery.