Fig. 2. Mean ± SEM of total analgesic morphine dose (  A ), morphine dose per injection  (B ), and number of morphine injections  (C ) in children with obstructive sleep apnea after adenotonsillectomy. The results are grouped by severity of obstructive sleep apnea into those in children who had a preoperative oxygen saturation nadir of < 85% or ≥ 85%. Within each group, children who received the calculated morphine regimen for analgesia are designated by the  hatched bar , and those who received the standard pediatric morphine regimen are designated by the  filled bar . *Post hoc differences between groups.