Cardiac arrest & resuscitation
Evaluating the accuracy of surrogate markers for identifying opioid-associated out-of-hospital cardiac arrests
Authors' conclusion
EMS naloxone administration and EMS- impression overdose had limited sensitivity for identifying OA-OHCA in expired patients in this large urban EMS system.
Study context
- Population
- Adult (≥18) non-traumatic OHCA patients treated by Milwaukee County emergency medical services (EMS), 2015–2016, who died
- Participants
- 1,654 OHCA cases
- Exposure
- EMS naloxone administration and EMS-impression overdose as surrogate markers vs medical examiner opioid toxicology
- Outcome
- Sensitivity (SN), specificity (SP), PPV and NPV of surrogate markers for identifying OA-OHCA
Methodological detailsdiagnostic accuracy, medical examiner toxicology reference standard
- Diagnostic accuracy
- Medical examiner toxicology reference standard
Main finding
As reported in the abstract
Accuracy for identifying OA-OHCA in expired patients
| Group | Sensitivity | Specificity | PPV | NPV |
|---|---|---|---|---|
| EMS naloxone administration | 39% | 96% | 52% | 94% |
| EMS-impression overdose | 27% | 99% | 68% | 93% |
Sensitivity
EMS naloxone administration39%
EMS-impression overdose27%
Specificity
EMS naloxone administration96%
EMS-impression overdose99%
PPV
EMS naloxone administration52%
EMS-impression overdose68%
NPV
EMS naloxone administration94%
EMS-impression overdose93%
Observational data: associations, not effects.
Further findings
Marker distribution and OA-OHCA cases
- Received ≥1 Naloxone
- 112 (6.8%)
- No Naloxone
- 1,542 (93.2%)
- EMS-impression overdose
- 60 (3.6%)
- Not EMS-impression overdose
- 1,594 (96.4%)
- OA-OHCA cases treated by EMS, of 525 opioid-associated deaths in Milwaukee County Medical Examiner (MCME) database
- 150 (28.6%)
Original publication
Evaluating the accuracy of surrogate markers for identifying opioid-associated out-of-hospital cardiac arrests. Resuscitation. Published 5 March 2025. doi:10.
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