I appreciate the interest that Drs. Webber and Karan showed in our study of opioid sensitivity in children with sleep apnea1 and welcomed their comments. They note that opioid-induced miosis and opioid-induced respiratory depression are distinct effects. I agree and explicitly stated as much in the abstract, noting that although remifentanil administration resulted in miosis, “the administered dose of remifentanil did not affect respiratory rate or end-expired carbon dioxide in either group.” Nowhere in the article do I make the claim that my study addresses the paramount concern of respiratory depression in children with or without obstructive sleep apnea. However, our study failed to find a difference in opioid-induced miosis between patients with and without a clinical diagnosis of obstructive sleep apnea. This was surprising and raises the need to assess other opioid-mediated effects in patients with and without obstructive sleep apnea, especially respiratory depression.
Regarding the concern that Drs. Webber and Karan raise about obstructive sleep apnea diagnosis, many patients do not have a formal sleep study before presenting to the operating room for tonsillectomy. We sought to replicate real-world diagnostic practices and used surgeon diagnosis to determine whether a patient carried an obstructive sleep apnea clinical diagnosis. We assessed sleep studies in patients where one was available, just as would be performed in a real-world environment. Of note, 60% of our obstructive sleep apnea patients did have a sleep study, and the remainder had at least two of the following symptoms: snoring, witnessed breathing pauses or gasping for breath, restless sleep, or daytime somnolence. The editorialists’ concerns regarding a perceived failure to assess obstructive sleep apnea severity are addressed in table 1.1 Only two of the patients who underwent polysomnography had mild obstructive sleep apnea; the others had either moderate or severe obstructive sleep apnea.
I agree that much remains to be discovered regarding opioid sensitivity in children with and without obstructive sleep apnea. As Drs. Webber and Karan point out, the relationship between pupillary miosis, ventilation, oxygenation, and obstructive sleep apnea status are all areas ripe for further research.
Supported by a Faculty Development Award from the Pharmaceutical Research and Manufacturers of America Foundation and the Washington University in St. Louis Department of Anesthesiology, St. Louis, Missouri.
The author declares no competing interests.