It would seem reasonable to assume that, if your heart were to stop, the best place for it to happen would be in a hospital. According to a recent study published in the Journal of the American Medical Association, cardiac arrest survival in the hospital seems to vary depending on the time of day. Investigators found that patients who go into cardiac arrest during the night or on the weekend are more likely to die.

In the United States, in-hospital cardiac arrest occurs about twice as often as out-of-hospital cardiac arrest, and past studies have found that 80-85% of patients who suffer a cardiac arrest in the hospital die in the hospital. In this study of survival from in-hospital cardiac arrest during nights and weekends, an analysis of more than 86,000 cardiac arrests in over 500 hospitals was performed. Of the 58,593 patients who suffered a cardiac arrest during the day or evening, 20% survived to be discharged from the hospital. However, of the 28,155 patients who suffered a cardiac arrest during the shift that began at 11 p.m., less than 15% survived. The only locations where survival from in-hospital cardiac arrest did not significantly differ between day and night were the emergency room and trauma services.

Although the researchers did not examine the reasons behind the differences in in-hospital cardiac arrest survival, a possible explanation may be delayed detection and treatment of cardiac arrest at night due to lower staffing, slower response times, and an increased number of medical errors. An article published in the New England Journal of Medicine showed that, even in the hospital, delayed defibrillation (a potentially lifesaving shock) after in-hospital cardiac arrest was common. The findings of this study should urge hospitals to evaluate their processes for performing resuscitation, especially because the Institute of Medicine estimates that as many as 98,000 preventable in-hospital deaths occur every year.