Single-dose intraoperative intravenous morphine for analgesia in children undergoing tonsillectomy: a double-blind randomized clinical trial

Introduction Children undergoing tonsillectomy have severe postoperative pain. One of the pharmacological options for analgesia are opioids, such as morphine. However, the risks of adverse effects, such as increased recovery time from anesthesia and respiratory depression, may limit its use. Goals To evaluate the use of intraoperative intravenous morphine to reduce immediate postoperative pain in children undergoing tonsillectomy. Method In this randomized blinded study, children aged 3 to 10 years underwent tonsillectomy, with or without adenoidectomy, and divided into two groups. Children in group M received 0.1 mg.kg-1 of intravenous morphine at induction of anesthesia, while children in the control group received conventional anesthesia without morphine. Postoperative pain perceptions were assessed at 30, 60, 120, 180 and 240 min after recovery from anesthesia, by the children themselves and also by their parents or guardians, using a facial pain scale. Results Fifty-seven children were included, 30 in the morphine group and 27 in the no-morphine group. According to the children themselves, postoperative pain was lower during evaluations performed at 30 minutes after awakening from anesthesia (p=0.023), while according to their parents/guardians, pain was less intense in evaluations performed at 30 (p=0.023). =0.002), 60 (p=0.006) and 180 minutes (p=0.007) after awakening. In addition, postoperative analgesics were less requested by children in the morphine group. There were no side effects associated with the use of morphine. Conclusion A single dose of intravenous morphine during anesthetic induction reduced the intensity of immediate postoperative pain in children undergoing tonsillectomy, without increasing anesthesia wake-up time and with lower consumption of rescue analgesics.