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.
Written informed consent
Adults ≥18 years of age and ≤85 years of age
Patients planned for general anesthesia with an expected anesthetic time of at least 2 hours
Patients expected to receive postoperative opioid analgesia
Non-operative procedure (imaging)
Patients not admitted to the PACU postoperatively
Use of patient-controlled analgesia systems
Female patients who are pregnant or breastfeeding