Written by Andy Hogan
Spoon Feed
In contrast to yesterday’s paper, this retrospective study of more than 8,000 out-of-hospital cardiac arrest (OHCA) patients detected higher rates of ROSC and survival discharge among patients who received naloxone.
An antidote for cardiac arrest?
This retrospective observational study examined 8195 OHCA patients treated by 5 EMS agencies in Northern California, seeking to determine whether naloxone administration was associated with higher rates of ROSC or survival to hospital discharge. At the discretion of treating paramedics, 1165 patients received naloxone during resuscitation. Of these 1165 OHCA cases, 471 were presumed to be “drug-related.” The groups that did and did not receive naloxone differed significant in age, sex, comorbidities, and rate of suspected drug-related arrest.
To mitigate selection bias from imbalances between the exposure groups and the uncertain rationale underlying naloxone administration, the authors analyzed data using two different propensity score models. Results were reported in terms of absolute risk difference (ARD) between the groups. Both models yielded statistically significant increases in rates of ROSC (11.8%) and survival to hospital discharge (3.9% ARD) for patients who received naloxone. Assuming this association is correct, these figures translate to clinically significant NNTs of 9 for ROSC and 26 for survival to discharge.
A further complex regression analysis also suggested that naloxone administration was associated with improved survival to hospital discharge in both drug-related OHCA (OR 2.48) and non-drug-related OHCA (OR 1.35). Reversal of myocardial depression and catecholamine release by naloxone are discussed as possible explanations.
How will this change my practice?
In contrast to the recent report by Quinn et al, this investigation detected statistically and clinically significant associations between naloxone administration and multiple OHCA outcomes. Additionally, this study involved more than 10 times as many patients treated by multiple EMS agencies. Despite efforts to reduce the impact of selection bias on the results, this can’t be fully eliminated due to the study’s design. The authors reasonably conclude (as did Quinn et al.) that prospective, interventional studies are needed to clarify naloxone’s role in OHCA. As long as evidence-based resuscitative interventions are given priority, it is reasonable to consider giving naloxone during your next presumptive opioid-associated OHCA resuscitation.
Source
Naloxone and Patient Outcomes in Out-of-Hospital Cardiac Arrests in California. JAMA Netw Open. 2024 Aug 1;7(8):e2429154. doi: 10.1001/jamanetworkopen.2024.29154. PMID: 39163042; PMCID: PMC11337064.
