Postoperative Respiratory Depression: A Review and Call to Action

Postoperative Respiratory Depression: A Review and Call to Action

Background: Postoperative respiratory depression (PORD) is associated with an increased risk of mortality, postoperative pulmonary complications (PPC), greater resource utilization and healthcare costs, and prolonged length of stay. Nonetheless without a systematic way to identify and track its occurrence, PORD remains a problem. 

Purpose/Objectives: Our aim was to review the literature on PORD/PPC and begin to develop working definitions and guidelines to support identification and clinical response.

Method: Review of the current literature on postoperative respiratory depression (PORD).

Results: In the post-procedural setting, it is not possible to predict which patient will develop PORD. PORD can be the result of a number of risk factors such as advanced age, procedure type, concomitant medications, underlying pulmonary or CNS disease and sleep apnea. The long-term consequences of PORD could be increases in morbidity and mortality associated with PPCs.  One underlying cause of PORD is opioid-induced respiratory depression.  Opioid-induced respiratory depression is the result of opioid receptor activation in the brainstem leading to hypoxia and hypercapnia.  Cardiorespiratory arrest is the most common form of death in opioid-induced respiratory depression.¹ Risk factors for opioid-induced respiratory depression include a history of cardiac or pulmonary disease or obstructive sleep apnea.² A systematic review of opioid-induced respiratory depression studies found 5.0 cases per 1000 anesthetics delivered and 85% of all cases of opioid-induced respiratory depression occurred in the initial 24 hours² with the greatest risk during the initial 12 hours after surgery.³ While clinicians monitor patients closely in the post-anesthesia care unit, opioid-induced respiratory depression can occur when the patient is in the ward.¹
Opioid-induced respiratory depression can be largely prevented with prompt identification and timely intervention.⁴ Despite national differences in opioid use, POIRD remains a common problem worldwide.⁵ While there is an abundance of peer-reviewed literature about PORD in general and opioid-induced respiratory depression specifically, guidance tends to be highly specific to patient group, treatment, or type of surgery. Quantification has been challenged because of different surrogates and endpoints (naloxone administration, hypoxemia, bradypnea, etc.).

Conclusions: PORD are common but under diagnosed due to a lack of awareness and guidance for its treatment. Consensus definitions and standardized study endpoints are lacking. PORD is a major medical challenge and one that warrants more intensive expert study. The authors propose that better management of PORD will avoid direct healthcare costs as well as subsequent PPC.

References: 1. Ayad S, Khanna AK, Iqbal SU, Singla N. Characterisation and monitoring of postoperative respiratory depression: current approaches and future considerations. Br J Anaesth. 2019;123(3):378-391.
2. Gupta K, Nagappa M, Prasad A, et al. Risk factors for opioid-induced respiratory depression in surgical patients: a systematic review and meta-analyses. BMJ Open. 2018;8(12):e024086.
3. Weingarten TN, Warner LL, Sprung J. Timing of postoperative respiratory emergencies: when do they really occur? Curr Opin Anaesthesiol. 2017;30(1):156-162.
4. Lee LA, Caplan RA, Stephens LS, et al. Postoperative opioid-induced respiratory depression: a closed claims analysis. Anesthesiology. 2015;122(3):659-665.
5. Urman RD, Khanna AK, Bergese SD, et al. Postoperative opioid administration characteristics associated with opioid-induced respiratory depression: Results from the PRODIGY trial. J Clin Anesth. 2021;70:110167.