COVID-19 Testing Among Out-of-Hospital Cardiac Arrest Patients: Implications for Public Health.

Objective: The objective of this study was to compare COVID-19 test positivity among out-of-hospital cardiac arrest patients whose resuscitative efforts were terminated in the field with the surrounding community.
Methods: This was a retrospective cohort study of out-of-hospital cardiac arrest patients for whom unsuccessful resuscitative efforts were terminated in the field. Emergency medical services (EMS) personnel obtained postmortem COVID-19 nasal swab specimens from these patients between July 1, 2020 and February 28, 2022 to facilitate patient contact tracing and awareness of potential occupational exposure. A chi-square (n-1) was used to compare test result proportions between cardiac arrest patients and the community at large. A Pearson correlation was used to correlate test positivity among the two groups.
Results: EMS personnel obtained postmortem specimens from 648 cardiac arrest patients; 20 (3.1%) were inconclusive. Of the 628 specimens successfully tested, 69 (11.0%) were positive, and 559 (89.0%) were negative. Monthly positivity ranged from 0.0% to 34.0%. For the community at large, overall test positivity during the same period was 5.1%, with a monthly range from 0.4% to 15.2%. Overall, expired and tested cardiac arrest patients had 5.9% (95%CI 3.68 - 8.59) greater COVID-19 test positivity than the general community. There was significant correlation in monthly positivity rates between the groups ( r  = 0.778, p  < .001, 95%CI0.51 - 0.91).
Conclusions: Compared to the general population, COVID-19 was over-represented among EMS cardiac arrest patients who died in the field. Postmortem testing by EMS personnel, not typical practice, identified infectious disease cases that would have otherwise gone undetected, indicating potential for future surveillance applications.