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In alignment with the latest ILCOR guidelines, CARES requires that all EMS-treated, non-traumatic cardiac 
arrests be entered into the registry. The etiology of arrest is identified by field providers and documented 
in the patient care record. Following the Utstein guidelines, an arrest is presumed to be of cardiac 
etiology unless it is clearly documented otherwise.
In 2025, 84% of adult (>18 years of age) OHCAs were presumed to be of a cardiac cause. Other causes 
of adult OHCA included: respiratory/asphyxia (9.7%), drug overdose (4.5%), exsanguination/hemorrhage 
(0.8%), drowning/submersion (0.5%), and other medical (0.5%) (Figure 3).
The etiology of arrest for pediatric patients (≤18 years of age) differed substantially from that of adults. In 
2025, 43% of pediatric arrests were presumed to be of a cardiac etiology. Other causes of pediatric OHCA 
included: respiratory/asphyxia (41%), drowning/submersion (9.2%), drug overdose (3.1%), SIDS/SUID 
(2.1%), and other medical (1.6%) (Figure 4).
Etiology
Figure 3. Etiology of arrest for adults.
Figure 4. Etiology of arrest for pediatric patients.

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