Outcomes of Out-of-Hospital Cardiac Arrest Patients Who Received Naloxone in an Emergency Medical Services System With a High Prevalence Of Opioid Overdose

Lung parenchymal and pleural findings on computed tomography after out-of-hospital cardiac arrest

INTRODUCTION

Lung injury and the acute respiratory distress syndrome (ARDS) are common after out-of-hospital cardiac arrest (OHCA), but the imaging characteristics of lung parenchymal and pleural abnormalities in these patients have not been well-characterized. We aimed to describe the incidence of lung parenchymal and pleural findings among patients who had return of spontaneous circulation (ROSC) and who underwent computed tomography (CT) of the chest after OHCA.

METHODS

This was a retrospective cohort study conducted at two academic hospitals from 2014 to 2019. We included adults successfully resuscitated from OHCA who received a head-to-pelvis or dedicated chest CT scan. The composite primary outcome was the incidence of lung parenchymal and pleural abnormalities. CT scans were overread by attending radiologists and lung parenchymal and pleural findings were categorized based on predefined criteria. Data are presented as absolute numbers and percentages. We examined the associations between CPR duration, time to successful intubation, and outcome using multivariable analyses.

RESULTS

We evaluated 204 eligible patients. Mean age was 54 years and 33 % were women. An initial shockable rhythm was found in 27 % and in 72 patients (36 %) the presumed etiology of OHCA was cardiac. A total of 133 patients underwent head-to-pelvis CT and 71 patients had dedicated chest CT. The median time from 911 call to CT scan was 2.5 (IQR 2.0-3.4) hours. A total of 160 (78 %) of patients had abnormal lung parenchyma or pleural findings. Patients with longer CPR duration or longer time to successful intubation had a higher incidence of abnormal lung findings on CT.

CONCLUSION

Over three-quarters of patients who survived to the hospital post OHCA and received a chest CT had lung parenchymal or pleural abnormalities, the most common of which were aspiration, pulmonary edema, and consolidation/pneumonia. Future planned research will characterize the clinical impact of these findings and whether early chest CT could identify patients at risk for ARDS or other pulmonary complications.

The association of early naloxone use with outcomes in non-shockable out-of-hospital cardiac arrest

STUDY OBJECTIVE

Evaluate the association between early naloxone use and outcomes after out-of-hospital cardiac arrest (OHCA) with initial non-shockable rhythms.

METHODS

This study was a secondary analysis of data collected in the Portland Cardiac Arrest Epidemiologic Registry, a database containing details of emergency medical services (EMS)-treated OHCA cases in the Portland, Oregon metropolitan region. Eligible patients had non-traumatic OHCA with an initial non-shockable rhythm and received naloxone by EMS or law enforcement prior to IV/IO access (exposure group). The primary outcome was ROSC at emergency department (ED) arrival. Secondary outcomes included survival to admission, survival to hospital discharge, and cerebral performance category score ≤2 at discharge (good neurologic outcome). We performed multivariable logistic regressions adjusting for age, sex, arrest location, witness status, bystander interventions, dispatch to EMS arrival time, initial rhythm, and county of arrest.

RESULTS

There were 1807 OHCA cases from 2018 to 2021 meeting eligibility criteria, with 57 receiving naloxone before vascular access. Patients receiving naloxone prior to vascular access attempts had higher adjusted odds (aOR [95% CI]) of ROSC at any time (2.14 [1.20-3.81]), ROSC at ED arrival (2.14 [1.18-3.88]), survival to admission (2.86 [1.60-5.09]), survival to discharge (4.41 [1.78-10.97]), and good neurologic outcome (4.61 [1.74-12.19]).

CONCLUSIONS

Patients with initial non-shockable OHCA who received law enforcement or EMS naloxone prior to IV/IO access attempts had higher adjusted odds of ROSC at any time, ROSC at ED arrival, survival to admission, survival to discharge, and good neurologic outcome.