Epidemiology of intensive care unit cardiac arrest: characteristics, comorbidities, and post-cardiac arrest organ failure - a prospective observational study

BACKGROUND: Critically ill patients in intensive care units can frequently suffer from cardiac arrest (ICU-CA), the incidence of ICU-CA is associated with high mortality. Most studies on ICU-CA focused on risk factors and intra-arrest determinants. However, there is a lack of data on organ failure after ICU-CA and its clinical implications for outcome. This study aimed to investigate ICU-CA incidence, outcome and the occurrence of organ failure after ICU-CA.

METHODS: We conducted a prospective observational study over a 1-year at 12 intensive care units of a tertiary care university hospital. We included all consecutive adult patients suffering cardiac arrest (CA) during the ICU stay. Incidence, clinical and neurological outcome, as well as organ failure and support were assessed.

RESULTS: Out of 7690 patients, 176 (2%) with ICU-CA were identified during the study period. Male patients comprised 63% and the median age was 70 (58-78) years. The median ICU stay before ICU-CA was 3 (1-8) days. The initial cardiac rhythm was shockable (VT/VF) in 23% of patients; defibrillation during CPR was performed in 19%. The presumed cause of CA was cardiac in 24%, and sustained ROSC was observed in 80% of patients. Before CA 57% (n = 100) of patients were sedated, 63% (n = 110) mechanically ventilated, 70% needed vasopressor therapy and renal replacement therapy was necessary in 27% (n = 48) of patients. Organ failure after ICU-CA was common, 70% suffered from post-CA cardiac failure, renal replacement therapy was newly initiated in 26% of patients and liver failure occurred in 24% of patients. Mortality at ICU-discharge and at hospital discharge was 66 % and 68 %, respectively. Multivariate regression analysis identified the SOFA score [HR 1.09, 95% CI (0.92-3.18); p < 0.05] and liver failure [HR 2.44, 95% CI (1.39-4.26); p < 0.001] after ICU-CA as independent predictors of mortality.

CONCLUSION: The incidence of ICU-CA is rare in critically ill patients. Organ failure before and after ICU-CA is common; liver failure incidence and severity of illness after ICU-CA are independent predictors of mortality and should be considered in further decisions on ICU therapy.