Editor's Perspective What We Already Know about This Topic Children with obstructive sleep apnea are at greater risk for postoperative hypoxia and other respiratory events as compared with children without this disorder There is some reason to believe that children with obstructive sleep apnea may be at greater risk for opioid-induced respiratory depression due to increased sensitivity to the drugs What This Article Tells Us That Is New The authors hypothesized that children with obstructive sleep apnea would be more sensitive to the effects of an opioid (remifentanil) on pupil size- A very good indicator of opioid effects While remifentanil did reduce pupil size in the expected dose-related fashion, there were no differences between children with obstructive sleep apnea and those without While the authors did not observe any differences in the effect of remifentanil on respiration, the study was not designed to examine this factor in detail Background: Opioids are a mainstay of perioperative analgesia. Opioid use in children with obstructive sleep apnea is challenging because of assumptions for increased opioid sensitivity and assumed risk for opioid-induced respiratory depression compared to children without obstructive sleep apnea. These assumptions have not been rigorously tested. This investigation tested the hypothesis that children with obstructive sleep apnea have an increased pharmacodynamic sensitivity to the miotic and respiratory depressant effects of the prototypic μ-opioid agonist remifentanil. Methods: Children (8 to 14 yr) with or without obstructive sleep apnea were administered a 15-min, fixed-rate remifentanil infusion (0.05, 0.1, or 0.15 μg · kg-1 · min-1). Each dose group had five patients with and five without obstructive sleep apnea. Plasma remifentanil concentrations were measured by tandem liquid chromatography mass spectrometry. Remifentanil effects were measured via miosis, respiratory rate, and end-expired carbon dioxide. Remifentanil pharmacodynamics (miosis vs. plasma concentration) were compared in children with or without obstructive sleep apnea. Results: Remifentanil administration resulted in miosis in both non-obstructive sleep apnea and obstructive sleep apnea patients. No differences in the relationship between remifentanil concentration and miosis were seen between the two groups at any of the doses administered. The administered dose of remifentanil did not affect respiratory rate or end-expired carbon dioxide in either group. Conclusions: No differences in the remifentanil concentration-miosis relation were seen in children with or without obstructive sleep apnea. The dose and duration of remifentanil administered did not alter ventilatory parameters in either group.