An update on postoperative respiratory depression

Postoperative Sedation in General Care Wards: A Retrospective Cohort Study

BACKGROUND

We hypothesized that deeper sedation in the postanesthesia care unit (PACU) increases the risk of subsequent sedation in general care wards (ward sedation) and that patients with ward sedation have more postoperative adverse events than those without ward sedation.

METHODS

We reviewed the health records of adult patients who underwent procedures with general anesthesia at Mayo Clinic from May 5, 2018, through December 31, 2020, and were discharged from the PACU to the general care ward. Patient groups were dichotomized as with ward sedation (Richmond Agitation-Sedation Scale [RASS], ≤-2) and without ward sedation (RASS, ≥-1) within the first 24 hours after PACU discharge. Multivariable logistic regression was used to assess the association between clinical variables and ward sedation.

RESULTS

A total of 23,766 patients were included in our analysis, of whom 1131 had ward sedation (incidence, 4.8 [Poisson 95% confidence interval, CI, 4.5-5.0]) per 100 patients after general anesthesia. Half of the ward sedation episodes occurred within 32 minutes after PACU discharge. The risk of ward sedation increased with the depth of PACU sedation. The odds ratios (95% CI) of ward sedation for patients with a PACU RASS score of -1 was 0.98 (0.75-1.27); -2, 1.87 (1.44-2.43); -3, 2.98 (2.26-3.93); and ≤-4, 3.97 (2.91-5.42). Adverse events requiring an emergency intervention occurred more often for patients with ward sedation (n = 92, 8.1%) than for those without ward sedation (n = 326, 1.4%; P < .001).

CONCLUSIONS

Among patients who met our criteria for PACU discharge, deeper sedation during anesthesia recovery was associated with an increased risk of ward sedation. Patients who had ward sedation had worse outcomes than those without ward sedation.

Respiratory Depression Following Intraoperative Methadone: A Retrospective Cohort Study

BACKGROUND

Methadone is used as a perioperative analgesic in the management of postoperative pain. Despite positive outcomes from randomized trials favoring methadone, concerns about its safety persist, particularly regarding respiratory depression (RD) and excessive sedation. In this study, we compared the incidence of naloxone administration between patients administered intraoperative methadone and those administered intraoperative morphine as a measure of severe RD. Time spent at the postanesthesia care unit (PACU) was used as a proxy variable for excessive sedation.

METHODS

This was a retrospective cohort study including all patients aged ≥18 years who underwent surgery between March 2019 and March 2023 at Aarhus University Hospital, Denmark. We assessed the association between intraoperative administration of either methadone or morphine and postoperative naloxone administration within the first 24 hours using logistic regression (primary outcome). An analogous linear regression model was used for the secondary outcome of time spent in the PACU after surgery. Patients were weighted using propensity scores to adjust for potential confounding variables.

RESULTS

A total of 14,522 patients were included in the analysis. Among the 2437 patients who received intraoperative methadone, 15 (0.62%) patients received naloxone within the first 24 hours after surgery compared to 68 of 12,0885 (0.56%) who received intraoperative morphine. No statistical difference was observed in the odds of naloxone administration between patients administered methadone or morphine (adjusted odds ratio 95% confidence interval [CI], 1.21 [0.40-2.02]). Patients who were administered intraoperative methadone had a mean PACU length of stay (LOS) of 334 minutes (standard deviation [SD], 382) compared to 195 minutes (SD, 228) for those administered intraoperative morphine. The adjusted PACU LOS of patients administered intraoperative methadone was 26% longer compared to those administered intraoperative morphine (adjusted ratio of the geometric means 95% CI, 1.26 [1.22-1.31]).

CONCLUSIONS

The incidence of naloxone administration to treat severe RD was low. No difference was observed in the odds of naloxone administration to treat severe RD between patients administered intraoperative methadone or intraoperative morphine. Intraoperative methadone was associated with longer stays at the PACU; however, this result should be interpreted with care. Our findings suggest that intraoperative methadone has a safety profile comparable to that of morphine with regard to severe RD.

Pro-Con Debate: Universal Versus Selective Continuous Monitoring of Postoperative Patients

In this Pro-Con commentary article, we discuss use of continuous physiologic monitoring for clinical deterioration, specifically respiratory depression in the postoperative population. The Pro position advocates for 24/7 continuous surveillance monitoring of all patients starting in the postanesthesia care unit until discharge from the hospital. The strongest arguments for universal monitoring relate to inadequate assessment and algorithms for patient risk. We argue that the need for hospitalization in and of itself is a sufficient predictor of an individual's risk for unexpected respiratory deterioration. In addition, general care units carry the added risk that even the most severe respiratory events will not be recognized in a timely fashion, largely due to higher patient to nurse staffing ratios and limited intermittent vital signs assessments (e.g., every 4 hours). Continuous monitoring configured properly using a "surveillance model" can adequately detect patients' respiratory deterioration while minimizing alarm fatigue and the costs of the surveillance systems. The Con position advocates for a mixed approach of time-limited continuous pulse oximetry monitoring for all patients receiving opioids, with additional remote pulse oximetry monitoring for patients identified as having a high risk of respiratory depression. Alarm fatigue, clinical resource limitations, and cost are the strongest arguments for selective monitoring, which is a more targeted approach. The proponents of the con position acknowledge that postoperative respiratory monitoring is certainly indicated for all patients, but not all patients need the same level of monitoring. The analysis and discussion of each point of view describes who, when, where, and how continuous monitoring should be implemented. Consideration of various system-level factors are addressed, including clinical resource availability, alarm design, system costs, patient and staff acceptance, risk-assessment algorithms, and respiratory event detection. Literature is reviewed, findings are described, and recommendations for design of monitoring systems and implementation of monitoring are described for the pro and con positions.

Postoperative opioid-induced respiratory depression or oversedation requiring naloxone treatment in a community hospital: a case series

Background

Postoperative opioid-induced respiratory depression and oversedation can lead to fatal events and increase perioperative mortality. In reports from major academic centers, naloxone administration has been used as a proxy for severe opioid overdose. Herein, we studied the incidence, clinical characteristics, and outcomes of postoperative naloxone use in a mid-size community hospital.

Methods

This was a retrospective review of adult patients who received naloxone within 48 postoperative hours between July 9, 2017, and May 31, 2022.

Results

During the study timeframe, a total of 23,362 surgical procedures were performed and a total of 19 patients received naloxone (8 in the recovery room, 11 on hospital wards), with an incidence of 8.1 [95% confidence interval 4.9-12.7] per 10,000 anesthetics. In 12 cases (63%), naloxone was indicated for oversedation, and in 7 cases (37%), for opioid-induced respiratory depression. All patients received naloxone within the first 24 postoperative hours. While all patients survived the opioid-related adverse event, 2 patients were intubated, 1 developed stress-induced cardiomyopathy, and 5 required intensive care unit admission.

Conclusion

The rate of early postoperative opioid-induced respiratory depression or oversedation in our community hospital was low; however, these patients often require a substantial escalation of medical management.

Review of Postoperative Respiratory Depression: From Recovery Room to General Care Unit

Contemporary evidence suggests that episodes of respiratory depression during anesthesia recovery are associated with subsequent respiratory complications in general care units.

Perioperative considerations for adult patients with obstructive sleep apnea

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA) is a common, but often undiagnosed, sleep breathing disorder affecting approximately a third of adult surgical patients. OSA patients have increased sensitivity to anesthetic agents, sedatives, and opioid analgesics.

RECENT FINDINGS

Newer technologies (e.g., bedside capnography) have demonstrated that OSA patients have repetitive apneic spells, beginning in the immediate postoperative period and peaking in frequency during the first postoperative night. Compared to patients without OSA, OSA patients have double the risk for postoperative pulmonary as well as other complications, and OSA has been linked to critical postoperative respiratory events leading to anoxic brain injury or death. Patients with OSA who have respiratory depression during anesthesia recovery have been found to be high-risk for subsequent pulmonary complications. Gabapentinoids have been linked to respiratory depression in these patients.

SUMMARY

Surgical patients should be screened for OSA and patients with OSA should continue using positive airway pressure devices postoperatively. Use of shorter acting and less sedating agents and opioid sparing anesthetic techniques should be encouraged. In particular, OSA patients exhibiting signs of respiratory depression in postanesthesia recovery unit should receive enhancer respiratory monitoring following discharge to wards.