# Improving the Identification of Opioid-Associated Out-of-Hospital Cardiac Arrest

> **NIH NIH K38** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2024 · $106,164

## Abstract

PROJECT SUMMARY/ABSTRACT
Over 356,000 cases of out-of-hospital cardiac arrest (OHCA) occur in the US each year, nearly 90% of which
are fatal.2 While 99.7% of OHCA in patients over age 60 are cardiac in etiology, a meaningful proportion of OHCA
for patients between 20 and 59 years of age are drug-related.3 We previously used data from the NHLBI-funded
Postmortem Systematic Investigation of Sudden Cardiac Death (POST SCD)4 to investigate the prevalence of
occult drug-related cardiac arrest. We found that 10.3% of OHCA in San Francisco between 2011-2016 were
due to occult opioid overdose5 – cases without a history or evidence of drug use that would otherwise have been
attributed to a non-overdose cause, such as sudden cardiac death. While it is currently unknown whether
naloxone – an opioid receptor competitive antagonist – is beneficial to patients experiencing opioid-associated
(OA)-OHCA, a recent American Heart Association scientific statement identified the rigorous evaluation of
naloxone’s efficacy in OA-OHCA as an important knowledge gap.1 However, no evidenced-based method to
identify OA-OHCA in real-time currently exists, making the targeted-evaluation of naloxone’s efficacy in this
group difficult. Our study team leveraged data from the POST SCD study to develop the NAloxone Cardiac
ARrest Decision Instrument (NACARDI) – two exam-based criteria that improve the pre-test probability of occult
OA-OHCA from 10.3% to 20.6%.6 These criteria were derived from patients in San Francisco County who died
of OHCA in the field. The objective of this K38 grant is to answer two outstanding questions: 1) Are the NACARDI
criteria valid in OHCA patients who survive to the emergency department (ED), and 2) Are the NACARDI criteria
externally generalizable outside of San Francisco? My central hypothesis is that the NACARDI criteria are
externally valid and generalizable for identifying patients at risk for occult OA-OHCA. My long-term goal is to use
the results of this K38 to develop validated inclusion criteria for a future multi-center NACARDI-enriched clinical
trial of naloxone in suspected OA-OHCA. Aim 1 of this proposal will validate the NACARDI criteria in OHCA
patients who survived to the ED by calculating screening characteristics for NACARDI in a retrospective cohort
of all OHCA patients who were transported to two major hospitals in San Francisco between 2011-2021, using
blood and urine toxicology screens to identify OA-OHCA. Aim 2 will refine and externally validate the NACARDI
criteria using data from the Canadian Sudden Cardiac Arrest Network (C-SCAN), an EMS- and coroner-based
dataset of OHCA patients who died in the field in Toronto, Canada between 2018-2022. Occult opioid overdose
will be identified in the C-SCAN dataset through medical examiner adjudication. The NACARDI criteria are
innovative because they allow for evidence-based real-time identification of patients at risk for occult OA-OHCA,
instead of relying on the current practices of ...

## Key facts

- **NIH application ID:** 10909294
- **Project number:** 5K38HL165363-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** David G Dillon
- **Activity code:** K38 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $106,164
- **Award type:** 5
- **Project period:** 2023-09-01 → 2025-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10909294

## Citation

> US National Institutes of Health, RePORTER application 10909294, Improving the Identification of Opioid-Associated Out-of-Hospital Cardiac Arrest (5K38HL165363-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10909294. Licensed CC0.

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