Slow recruitment due to covid-19 and organizational changes.

A prospective double-blind, randomized controlled trial investigating the effect of a single-dose of intraoperative methadone on postoperative pain and opioid consumption in 96 children undergoing open urological surgery.

Treatment of postoperative pain is a challenge in younger children undergoing outpatient surgery. After discharge parents must assess pain intensity and administer analgesics, including opioids, as per needed. It has been shown that parents often hesitate to administer analgesics. The result is unrelieved pain that negatively affects the whole family and increases the risk of unscheduled contacts with healthcare professionals.

In children, methadone has shown a half-life of 19,2 +/-13,6 hours. Regarding outpatient surgery, methadone is an opioid with unique pharmalogical properties that may be advantageous. A single-dose of this long acting opioid administered perioperatively could provide a stable analgesia and potentially reduce the need for shorter-acting opioids in the PACU and at home.

Inclusion Criteria:

Children scheduled for open urological surgery at the Outpatient Clinic at Aarhus University Hospital.

Exclusion Criteria:

• Age =/> 5 years at the date of operation
• Born preterm (Before gestational age of 37 weeks)
• Congenital heart disease
• Previous scrotal surgery
• Laparoscopic operation
• American Society of Anaesthesiologists (ASA) physical status lll, IV or V
• Allergy to study drugs
• Preoperative daily use of opioids
• Parents with inability to provide informed consent
• Severe respiratory insufficiency
• Acute abdominal pain
• Severe kidney insufficiency
• Treatment with rifampicin

Randomisation and study medication will be handled by the hospital pharmacy. All research team members, caregiving clinicians and enrolled patients will be blinded to the study allocation arms and the randomisation list will be concealed until all statistical analyses are made.