Symptoms reported in calls to emergency medical services within 24 hours prior to out-of-hospital cardiac arrest

AIM: There is limited evidence regarding prodromal symptoms of out-of-hospital cardiac arrest (OHCA). We aimed to describe patient characteristics, prodromal symptoms, and prognosis of patients contacting emergency medical services (EMS) within 24 hours before OHCA.METHODS: We identified all OHCA treated by Copenhagen EMS from 2016 through 2018 using the Danish Cardiac Arrest Registry and linked them to emergency calls. We included all pre-arrest calls by patients or bystanders if they were performed 1) within 24 hours before the OHCA call or 2) during the OHCA event for EMS-witnessed OHCA. Calls were reviewed by healthcare professionals using a survey guide.RESULTS: Among 4,071 patients, 481 patients (12%) had 539 calls within 24 hours prior to OHCA (60% male, median age 74 years of age). The patient spoke on the phone in 25% of calls. The most common symptoms were breathing problems (59%), confusion (23%), unconsciousness (20%), chest pain (20%), and paleness (19%). Patients with breathing problems compared to chest pain were more likely to be ≤75 years of age (55% versus 35%), less likely to be male (52% versus 73%), have shockable rhythm (10% versus 38%), receive bystander defibrillation (6% versus 19%) or EMS defibrillation (15% versus 65%), achieve return of spontaneous circulation (37% versus 68%) and survive 30 days following OHCA (10% versus 50%).CONCLUSION: More than 10% of patients with OHCA had a call to EMS within 24 hours before OHCA. The most common symptom was breathing problems which compared to chest pain had lower 30-day survival.