Risk Stratification for Postoperative Opioid Induced Respiratory Depression: A Retrospective Case-Control Analysis of Existing Validated Tools.

Purpose: Postoperative opioid-induced respiratory depression (POIRD) is a preventable perioperative cause of morbidity and mortality. A validated POIRD risk stratification tool could reduce these complications. 3 pre-existing validated opioid tools; and specific risk factors identified from these tools; were examined in this retrospective case-control study to determine if they could assess POIRD risk in patients discharged to hospital floors from the Post-Anesthesia Care Unit (PACU).

Patients and methods: Our dataset includes 126 matched patients who underwent surgery at the University of Tennessee Medical Center from January 2019 to December 2021. All patients that were related to active traumas or burns were excluded from this study. Escalation of care secondary to respiratory failure (an increase in respiratory support with movement to an intensive care unit/stepdown unit or patient expiration secondary to respiratory failure) with and without naloxone administration was the primary endpoint; with the subgroup that received naloxone being the surrogate POIRD endpoint. Escalation of care secondary to respiratory failure; regardless of naloxone use; was a secondary endpoint.

Results: There was no association between the 3 opioid tools evaluated with the POIRD surrogate endpoint or escalation of care. Bipolar disorder (OR 3.68; 95% CI 1.11-9.56) and a history of substance abuse (OR 26.33; 95% CI 5.18-119.02) were significant risk factors that contributed to escalation of care secondary to respiratory failure. A history of substance abuse was found to have a significant association with escalation of care secondary to respiratory failure with naloxone administration (OR=6.886; 95% CI 2.02-23.56).

Conclusion: While we were unable to identify a tool to stratify POIRD risk; patients with bipolar disorder and a history of substance abuse are at an increased risk of postoperative respiratory failure requiring escalation of care; with a history of substance abuse being associated with POIRD.