Analysis of Prognostic Factors for Return of Spontaneous Circulation and Survival in Elderly Patients with Cardiac Arrest

ABSTRACT

BACKGROUND: Recently the incidence of cardiac arrest in the elderly has been on the rise due to aging and the rapid increase in cardiovascular disease. Nevertheless, there has been only a few studies done regarding the factors affecting return of spontaneous circulation (ROSC) and survival in this population within Korea. We investigated the prognostic factors for ROSC and survival in cardiac arrest patients over 65 years visiting a single local emergency center. METHODS: We conducted a single center retrospective observational study, and 87 elderly patients with cardiac arrest were enrolled. They visited the emergency medical care center via ambulance from November 2013 to October 2014. Primary outcomes were ROSC and survival and the secondary outcome was 100 days cumulative survival rate. RESULTS: The level of potassium was the only significant factor for ROSC. The increase in potassium level reduced the rate of ROSC (odds ratio, 0.64; 95% confidence interval [CI], 0.44-0.92; p=0.01). However, higher potassium level was not related to survival (p=1.00). For the 100 days cumulative survival rate, neither hypokalemia (hazard ratio [HR], 1.1; 95% CI, 0.57-2.38; p=0.66) nor hyperkalemia (HR, 1.5; 95% CI, 0.89-2.59; p=0.11) was related to survival compared to normokalemia. CONCLUSION: The potassium level may be considered a valid prognostic factor for ROSC in elderly patients with cardiac arrest. However, it was unrelated to survival.