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

Toby N. Weingarten, M.D.; Juraj Sprung, M.D., Ph.D.


Anesthesiology. 2022;137(6):735-741. 

In This Article

Abstract and Introduction


Postoperative respiratory failure secondary to opioid-induced respiratory depression (hereafter termed respiratory depression) can result in permanent morbidity, such as anoxic brain injury, or even death.[1,2] In many cases, the respiratory failure seems to develop acutely and without warning, often shortly after seemingly reassuring nursing assessments.[2] Severe respiratory depression on general care units, however, is rare (3.7 to 53.3 opioid naloxone reversals per 10,000 general anesthetics),[3] and this infrequency of events has presented a barrier for healthcare organizations to invest in the equipment and personnel required for universal continuous monitoring.

To address the dual concerns that these events can be catastrophic but are rare, medical societies have published several guidelines. These guidelines, however, are primarily focused on perioperative management in patients who have obstructive sleep apnea (OSA) or are at risk for undiagnosed OSA.[4–6] In general, these guidelines focus on preoperative assessment of OSA in several ways: (1) obtaining a sleep-disordered breathing history; (2) using a validated OSA screening tool (e.g., STOP-Bang [Snore loudly; daytime Tiredness; Observed apneas; high blood Pressure; Body mass index greater than 35; Age more than 50 yr; Neck circumference more than 40 cm; G, male sex]; Table 1);[7] (3) continuation of perioperative OSA therapy (e.g., using positive airway pressure devices); and (4) tailoring perioperative care to reduce the risk of respiratory depression by choosing appropriate anesthetic management and introducing heightened surveillance for respiratory depressive episodes. Although useful, these guidelines focus on OSA and do not provide guidance for other patients who may be at increased risk for respiratory depression.

Emerging evidence regarding the phenotypic presentation and temporal course of postoperative respiratory depression has provided new insights that may help anesthesiologists to identify patients with increased risk of respiratory depression and intervene more effectively. One important aspect of these developments is a better understanding of the relationship between early respiratory depression, in the postanesthesia care unit (PACU), as a warning sign for risk of respiratory failure in general care units. Major themes of this review are summarized in Box 1.