Mortality in out-of-hospital cardiac arrest patients has decreased in the era of therapeutic hypothermia

Abstract

Background: Mild therapeutic hypothermia (TH) improves survival after out-of-hospital cardiac arrest (OHCA). This treatment was implemented in most Finnish intensive care units (ICUs) in 2003. The aim of this study was to find out whether hospital mortality of ICU-treated OHCA patients has changed in the era of TH.

Methods: This was a retrospective study of data collected prospectively into the database of the Finnish Intensive Care Consortium during the years 2000-2008. The study population consisted of 3958 patients for whom cardiac arrest was registered as the reason for ICU admission and who were transferred to the ICU from the emergency department. We divided the patients into those treated in the pre-hypothermia era (2000-2002) and those treated in the hypothermia era (2003-2008). We investigated whether the treatment period had any impact on hospital mortality.

Results: There were no differences between the periods regarding the age or initial Glasgow Coma Scores of the patients. Mean severity of illness was higher in the latter period. Despite this, mortality decreased: the hospital mortality rate was 57.9% in 2000-2002 and 51.1% in 2003-2008, P < 0.001. In a multivariate logistic regression analysis, treatment in 2003-2008 was associated with a reduced risk of in-hospital death (adjusted odds ratio 0.54, 95% confidence interval 0.45-0.64 and P < 0.001). Survival improved markedly between the years 2002 and 2003. This improvement has persisted, but there has been no further improvement.

Conclusion: Concurrently with the implementation of TH, hospital mortality of OHCA patients treated in Finnish ICUs decreased.