Postop Respiratory Depression: Recovery Room to General Care

Abstract and Introduction

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.

Table 1. STOP-Bang Score for Obstructive Sleep Apnea*
Characteristic	Points
Snore loudly	1
Daytime tiredness	1
Observed apneas	1
High blood pressure	1
Body mass index > 35 kg/m²	1
Age > 50 yr	1
Neck circumference > 40 cm	1
Male sex	1
Total STOP-Bang score

Data from Chung et al. ⁷
*A STOP-Bang score or greater is considered high.
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 2. PRODIGY Score for Risk of Postoperative Opioid-induced Respiratory Depression*
Risk Factor	Points
Age, yr
< 60	0
60–69	8
70–79	12
≥ 80	16
Male sex	8
Opioid naïve	3
Known sleep-disordered breathing or high STOP-Bang score†	5
Coexisting congestive heart failure	7
Total PRODIGY score

Data from Khanna et al.⁹
*Risk level for respiratory depression is low with a total PRODIGY score less than 8, intermediate with a score of 8 to 14, and high with a score ≥ 15 or greater. †See table 1 for STOP-Bang score calculation.
PRODIGY, PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY; 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.

Box 1. Emerging Concepts Regarding Postoperative Opioid-induced Respiratory Depression
Phenotypic presentation Most common presentation is intermittent apneas or partial apneas^8,9 Isolated bradypnea is a rare presentation^8,9 Routine monitoring* fails to detect most events^2,8,10,11 Temporal distribution Most life-threatening events† occur in the late afternoon and early evening^12–14 The greatest number of overall events occur during early morning hours⁸ PACU to general care unit relationship Patients who have events in the PACU are at several-fold increased risk for critical events in general care units^13–15 Depressed ventilation detected in the PACU persists for hours in general care units¹⁶ Risk factors Sleep-disordered breathing and obstructive sleep apnea are important risk factors^17,18 Advancing age and greater disease burden are equally important risk factors^9,12,14,19 PRODIGY score (see table 2) can be used to calculate risk⁹ General anesthesia has higher risk than regional anesthesia²⁰ Longer-acting anesthetics increase risk^21,22 Sedating nonopioid analgesics (e.g., gabapentinoids) increase risk^20,23
*Routine monitoring refers to intermittent vital sign checks. †Defined as administration of naloxone to reverse opioid toxicity. PACU, postanesthesia care unit; PRODIGY, PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY.

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

Abstract and Introduction

Introduction

Tables

Tables

Tables

References

Authors and Disclosures

Authors and Disclosures

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