Opioid Induced Respiratory Depression

The goal of this study is to determine if a relationship can be detected between the administration of an opioid and quantitative respiratory depression in spontaneously breathing non-intubated patients who have undergone general anesthesia and have received perioperative opioids. The primary aim is to determine the temporal effect of opioid administration on respiratory depression as assessed by minute ventilation with a reduction of at least 20% in the percent of predicted minute ventilation. A secondary aim is to determine a dose response of opioid administration and its effect on minute ventilation. The investigators aim to determine the influence of opioid administration on minute ventilation on spontaneously breathing patients during post-anesthesia care unit (PACU) stay.

This study will evaluate whether quantitative pupillometry measurements can be used to identify children at risk for postoperative opioid-induced respiratory depression (OIRD) following tonsillectomy. Opioid-induced respiratory depression is a serious and potentially life-threatening complication that can occur after surgery, and current monitoring approaches are limited in their ability to predict which patients are at highest risk. In this prospective observational cohort study, approximately 300 pediatric patients undergoing tonsillectomy will undergo non-invasive pupillometry measurements at defined perioperative time points, including preoperative, intraoperative, and postoperative periods. Pupillometry measurements will be collected using a commercially available, FDA-regulated infrared pupillometer. These measurements will include pupil size, constriction and dilation velocities, and latency in response to light stimulation. Pupillometry data will be collected for research purposes only and will not be used to guide clinical care or treatment decisions. Standard clinical care will not be altered as part of this study. Clinical outcomes, including the occurrence of postoperative opioid-induced respiratory depression, opioid use, sedation levels, pain scores, and other postoperative events, will be recorded from the medical record. The goal of this study is to evaluate the relationship between pupillary response patterns and the occurrence of postoperative respiratory depression, and to support the development of predictive models that may improve early identification of patients at risk for opioid-related adverse events.