Cardiopulmonary arrest and mortality trends, and their association with rapid response system expansion

To the Editor: Chen and colleagues associate the reduction in inhospital cardiopulmonary arrest (IHCA) incidence with the introduction of rapid response systems.1 Their population-based study of all patients aged ≥ 14 years in New South Wales found that hospital mortality decreased between 2002 and 2009. During this period, the age of the hospital population increased and patients aged ≥ 75 years were more likely to die in hospital (risk ratio [RR], 28.4), have an IHCA (RR, 8.6), die as a result of cardiac arrest (RR, 11.9), or die within 12 months of discharge (RR, 5.3).1

Australian statistics show that most deaths occur in hospital and that the background mortality rate of the population continued to decline from 1907 to 2012.2 However, there will be a background death rate that is not preventable and is a result of the natural end of life.

Studies show that up to 30% of rapid response team attendance results in limitation of care as a not-for-resuscitation order.3 If these patients continued to decline to death, they would not be considered in the IHCA figures because they are non-preventable deaths. Rather, they would be considered in the hospital mortality figures. This would result in a decrease in IHCA and an improvement in IHCA mortality from better management of end-of-life goals. This is suggested by the modest (1.8%) reduction in overall hospital mortality from the decreased mortality after IHCA.

This study provides excellent evidence for the need for advanced care planning and consideration of treatment goals at the end of life.