Seasonal variation in cardiac arrest, is there any connection with incidence and surviving rate?
Background: Previous studies have showed seasonal variation in the incidence of cardiac arrest as well as temporal variation, demonstrating that these variations are probably associated with different patterns of activities. It is well established for example the increase in incidence myocardial infarction during winter months. 
Methods: We conducted a retrospective observational study during 2 years (2017-2018) on the incidence and etiology of OHCA and IHCA. We analyzed the cases of cardiac arrest in adults presented to our services from pre-hospital and hospital (our ED include a pre-hospital team who responds to code red cases). We followed the location, age, witnessed and/or assisted cardiac arrest, time between first call and start of ALS, first rhythm, etiology, ROSC, surviving in first 24 hours. We used for the statistical analysis IBM SPSS v25.
Results: From the total of 430 cases, 64,7% were males. The mean age of the patients was 66,96 +/- 14,83 years. The percentage of OHCA was 36,3% vs 63,7% IHCA. The initial rhythm   was asistola in 54,4%, PEA in 35,3%, VF in 6,5% and VT in 3,7%. The mean time for initiating ALS was 4,65 minutes. ROSC during first CPR attempt was 37,9% (OHCA 36,5% and IHCA 38,6%), and survival rate at 24 hours was 31,6%. We found bigger incidence of cardiac arrest cases in December (12,6%) and February (10,7%), and the lower incidence in August (5,1%). The most frequent cause was medical (43,7%), followed by the cardiac etiology (31,2%). In 15,8% of cases nobody perform CPR until medical team arrived, and 63,7 was assisted from the beginning by a physician.
Conclusion: We did not find any correlation between month or seasons and o surviving rate of cardiac arrest but we found that the incidence of cardiac arrest in winter months is higher. We did not found also any connection between months and etiology.

7 - Seasonal variation in cardiac arrest, is there any connection with incidence and surviving rate?