In hospital cardiac arrest: the danger comes from the night and the weekend

A large US study confirms a previous British study: survival after an in-hospital arrest is reduced if the event occurs at night or on the weekend, even if the trend of recent years appears to be improving.

31 January Jan 2018 0000 6 years ago

Time course of survival rate after an episode of intra-hospital cardiac arrest (IHCA) has constantly improved in the last years. However, the results of a study, recently published in JACC (Journal of the American College of Cardiology),1 show that for patients in whom IHCA has occurred at night or on weekends, the survival rate continues to be worse than for patients who have had IHCA during daylight hours on weekdays.

The studied population consisted of 151,071 patients ≥18 years who experienced in-hospital cardiac arrest between 2000 and 2014, more than half of wich experienced cardiac arrest during off-hours. Overall, 62.4% of patients survived acute resuscitation efforts, – according to Uchenna Ofoma by Geisinger Health System in Danville, Pennsylvania USA, leading author of the study, – and 18.6% survived to hospital discharge.

The progressive increase, observed over the years, of the effective resuscitation rate for patients revived at night or at weekends, has allowed to reduce the "gap" existing between this population and that of patients resuscitated during the daytime hours of weekdays. This, however, did not translate into a similar increase in the survival rate following effective resuscitation, which still remains significantly lower in patients resuscitated at night or on weekend (see graphs below ) .

The graphs show unadjusted (A) acute resuscitation survival and (B) post-resuscitation survival in patients who arrested during on-hours (blue) and off-hours (orange).

The same conclusions had been reached in 2016 by another study from the UK,2 according to which, – analysing NCAA data from 27,700 patients aged ≥16 years receiving chest compressions and/or defibrillation, – IHCA attended by the hospital-based resuscitation team during nights and weekends have substantially worse outcomes than during weekday daytimes.

According to the researchers, poor survival during off-hours is likely due to several factors:

  • changes to hospital staffing patterns and nurse-to-patient ratios are lower during off-hours during nights and weekends;
  • physicians workings nights and weekends provide coverage to patients they may be less familiar with;
  • the impact of shift work, particularly during night time, has been shown to impact psychomotor skills and performance of skilled activities, such as cardiopulmonary resuscitation.

The observed results are likely related, at least partially, to the type of the IHCA the medical staff had to face during the night hours or at the weekend (higher prevalance of unwitnessed IHCA; non-shockable rhythm, higher prevalence of asystole) at the time of recognition of the event.

Case studies from monodisciplinary and highly specialized structures may differ from that of the present study. But the persistent difference in patients survival in the studied populations, faced with an observed improvement in the effectiveness of resuscitation manoeuvres, stresses the absolute importance of all those therapeutic support strategies that can be fully implemented only in dedicated structures. Having said that, whatever the causes, the standards of care in a hospital should of course be maintained at optimal levels regardless of the working time or day of the week

Dr. Emilio Maria Assanelli, Head OU ER and Emergency Cardiology of Monzino


  1. Ofoma UR, Basnet S, Berger A et al. Trends in Survival After In-Hospital Cardiac Arrest During Nights and Weekends. 2018;71(4).
  2. Robinson EJ, Smith GB, Power GS et al. Risk-adjusted survival for adults following in-hospital cardiac arrest by day of week and time of day: observational cohort study. BMJ Qual Saf 2016;25(11):832-841.