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. 2025 Jun 2;8(6):e2516340.
doi: 10.1001/jamanetworkopen.2025.16340.

Bystander CPR Technique and Outcomes for Cardiac Arrest With and Without Opioid Toxicity

Brian Grunau  1   2   3   4   5 , May Lee  4 , Jane A Buxton  6 , Valerie Mok  1   2 , Jennie Helmer  1   5   6 , Andrew W Tu  7 , Sean van Diepen  1   8   9 , Frank Scheuermeyer  1   2   3   4 , Michael Asamoah-Boaheng  1   2   3   4 , Ian R Drennan  10   11   12 , Steven C Brooks  13   14 , Laurie J Morrison  10   15 , Katie N Dainty  12   16 , Jim Christenson  1   2   3   4
Affiliations

Bystander CPR Technique and Outcomes for Cardiac Arrest With and Without Opioid Toxicity

Brian Grunau et al. JAMA Netw Open. .

Abstract

Importance: Previous studies support bystander provision of chest compression-only cardiopulmonary resuscitation (CC-CPR) for out-of-hospital cardiac arrest (OHCA). However, it is unknown whether OHCA secondary to opioid toxicity may benefit from chest compression plus ventilation CPR (CCV-CPR).

Objective: To examine the association between bystander CPR technique and outcomes among both opioid-associated OHCA (OA-OHCA) and otherwise undifferentiated OHCA.

Design, setting, and participants: This cohort study (performed from August 1, 2023, to December 31, 2024) analyzed cases of adult emergency medical services-treated OHCA that occurred from December 1, 2014, to March 31, 2020, as identified through the British Columbia Cardiac Arrest Registry.

Exposures: Cases were classified as OA-OHCA based on positive postmortem toxicologic investigations, death certificates, or opioid-specific hospital-based diagnoses. All other cases were classified as undifferentiated OHCA.

Main outcomes and measures: Favorable neurologic outcome at hospital discharge (cerebral performance category ≤2). A multivariable Utstein-adjusted logistic regression model of complete cases was used to assess the association between bystander CPR technique (CC-CPR [reference] vs both CCV-CPR and no CPR individually) with outcomes. An interaction term between the OA-OHCA and bystander CPR technique was used to estimate associations among OA-OHCA and undifferentiated OHCA cases separately.

Results: The study included 10 923 OHCAs. After removing 24 cases only treated with ventilatory support, there were 1343 OA-OHCAs (median [IQR] patient age, 40 [31-50] years; 1015 [76%] male) and 9556 undifferentiated OHCAs (median [IQR] patient age, 70 [58-81] years; 6636 (69%) male). In the OA-OHCA group, bystander CCV-CPR was associated with an increased odds of a favorable neurologic outcome (adjusted odds ratio [AOR], 2.85; 95% CI, 1.21-6.75) when compared with CC-CPR. No association was detected with favorable neurologic outcome (AOR, 1.52; 95% CI, 0.82-2.82) when no CPR was compared with CC-CPR. Among undifferentiated OHCAs, no association was detected with a favorable neurologic outcome (AOR, 1.16; 95% CI, 0.80-1.67) when CCV-CPR was compared with CC-CPR. No CPR was associated with a decreased odds of a favorable neurologic outcome (AOR, 0.69; 95% CI, 0.55-0.87) when compared with CC-CPR. The interaction term was statistically significant (P for interaction = .04).

Conclusions and relevance: In this cohort study of OHCA, bystander CCV-CPR (compared with CC-CPR) was associated with improved outcomes in opioid-associated OHCA; however, this association was not observed among undifferentiated cardiac arrests. These results suggest that the optimal bystander CPR technique for OA-OHCA and undifferentiated OHCA may differ and that ventilations may improve outcomes in OA-OHCA resuscitation.

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Conflict of interest statement

Conflict of Interest Disclosures: Ms Lee reported receiving grants from Centre for Advancing Health Outcomes during the conduct of the study. Dr Drennan reported receiving grants and personal fees from ZOLL Medical Corp outside the submitted work. Dr Brooks reported receiving grants from Canadian Institutes of Health Research and Zoll Medical, personal fees from Rapid Response Revival, and discounted services from GoodSAM outside the submitted work and serving as a member of the Heart and Stroke Foundation Resuscitation Advisory Committee, Basic Life Support Task Force of the International Liaison Committee on Resuscitation and on the American Heart Association Emergency Cardiovascular Care Committee. Dr Dainty reported receiving personal fees from Philips Health Care outside the submitted work. Dr Christenson reported receiving grants from the Heart and Stroke Foundation during the conduct of the study. No other disclosures were reported.

Figures

Figure 1.
Figure 1.. Study Cohort Flow
EMS indicates emergency medical services; OA-OHCA, opioid-associated out-of-hospital cardiac arrest; OHCA, out-of-hospital cardiac arrest.
Figure 2.
Figure 2.. Association Between Bystander Cardiopulmonary Resuscitation (CPR) Technique and Favorable Neurologic Outcomes and Survival to Hospital Discharge Among OA-OHCA and Undifferentiated OHCA Cases (Complete Case Analysis)
Model adjusted for age, sex, location of arrest, time of day, arrest year, bystander witnessed status, and interval between dispatch call and first emergency medical services unit arrival. Error bars indicate 95% CIs. CC-CPR indicates chest compression–only cardiopulmonary resuscitation; CCV-CPR, chest compression plus ventilation cardiopulmonary resuscitation; NA, not applicable; OA-OHCA, opioid-associated out-of-hospital cardiac arrest; OR, odds ratio.
Figure 3.
Figure 3.. Multiple Imputation Models to Assess the Association Between Bystander Cardiopulmonary Resuscitation (CPR) Technique and Favorable Neurologic Outcomes at Hospital Discharge and Survival to Hospital Discharge Among OA-OHCA and Undifferentiated OHCA Cases
Models adjusted for age, sex, location of arrest, time of day, arrest year, bystander witnessed status, and interval between dispatch call and first emergency medical services unit arrival. Error bars indicate 95% CIs. CC-CPR indicates chest compression–only cardiopulmonary resuscitation; CCV-CPR, chest compression plus ventilation cardiopulmonary resuscitation; OA-OHCA, opioid-associated out-of-hospital cardiac arrest; OR, odds ratio.
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Comment in

  • doi: 10.1001/jamanetworkopen.2025.16348

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