[Chronobiology of out-of-hospital cardiac arrest in Galicia with semi-automatic external defibrillators].

OBJECTIVE

To analyze the chronobiological variations of out-hospital cardiac arrest in which an automated external defibrillator was used in Galicia.

METHOD

Descriptive retrospective study of the cardiac arrest attended by the Emergency Medical Service in which an automated external defibrillator was in use during a period of 5 years (2007-2011). An Utstein style database was used. The sex, age, date and hour of the event, location, cardiac arrest attended, beginning of resuscitation by the professional, first monitored rhythm, emergency team activation time and care, endotracheal intubation, and recovery of spontaneous circulation were studied as independent variables.

RESULTS

A total of 2,005 cases (0.14/1,000 population-year) was recorded. Time slot with more frequency of cardiac arrest: between 09-11 hrs (18.4%). Months with more cases: January (10.4%) and December (9.8%). It was significantly more probable that the cardiac arrest occurred in the home between 00-08 hrs, and in the street between 08-16 hrs. Asystole was more frequent in the night period (00-08 hrs), whereas the shockable rhythm was in the evening (16-00 hrs). There is more probability of death after cardiac arrest between 00-08 hrs, with recovery of spontaneous circulation being more probable between 16-00 hrs. The time between the emergency team activation and time care was longer in night schedule.

CONCLUSIONS

In Galicia, cardiac arrest is more frequent in the winter months and in morning schedule. There is a circadian distribution of the cardiac arrest and the rhythm detected at the time of the first assistance, with asystole being more common in night schedule and the shockable rhythm in the evening. The chronobiology of the cardiac arrest should be taken into account in order to organize the distribution and the schedule of the healthcare resources.