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. 2021 Sep 1;36(36):e255. doi: 10.3346/jkms.2021.36.e255

Fig. 1. Definition of the study cohort. (A) Study cohort during the pre-COVID-19 period. (B) Study cohort during COVID-19 period.

Fig. 1

OHCA = out-of-hospital cardiac arrest, EMS = emergency medical service, ED = emergency department, DNR = do not resuscitate.

aPrehospital emergency medical service data exist, but no record of patients visiting the ED exists.