Association between fentanyl test results and rescue morphine requirements in children after adenotonsillectomy

Abstract

Preoperative sleep study helps to predict post-adenotonsillectomy morphine requirements. However, in some institutions, many suspected children with obstructive sleep apnoea syndrome have an adenotonsillectomy without polysomnography assessments. This study investigated the relationship between the results of a fentanyl test performed before extubation and the postoperative morphine requirements in children after adenotonsillectomy. Intravenous fentanyl (1µg/kg) was given as a test before extubation when spontaneous ventilation was restored in 80 children aged 3-7years who underwent adenotonsillectomy. The result was considered positive if the patient's respiratory rate decreased >50% after the test. In the recovery room, pain was assessed every 10min using the Children's Hospital of Eastern Ontario Pain Scale. Rescue morphine (10µg/kg) was given when the score was≥6. The median [IQR (range)] cumulative morphine consumption rates for children with a positive result (n=25) and a negative result (n=52) were 30 (20, 40) and 50 (40, 50)µg/kg, respectively (P=0.002). Eighty-eight percent of the positive-result patients and 48% of the negative-result patients were light consumers of morphine (cumulative dose<50µg/kg) (P=0.001). We conclude that children with a positive result after a fentanyl test require less morphine to achieve comfort than those with a negative result. CLINICALTRIALS. NCT02484222.