Effect of intensive care after cardiac arrest on patient outcome: a database analysis

Abstract

Introduction: The study aimed to determine the impact of treatment frequency, hospital size, and capability on mortality of patients admitted after cardiac arrest for postresuscitation care to different intensive care units.

Methods: Prospectively recorded data from 242,588 adults consecutively admitted to 87 Austrian intensive care units over a period of 13 years (1998 to 2010) were analyzed retrospectively. Multivariate analysis was used to assess the effect of the frequency of postresuscitation care on mortality, correcting for baseline parameters, severity of illness, hospital size, and capability to perform coronary angiography and intervention.

Results: In total, 5,857 patients had had cardiac arrest and were admitted to an intensive care unit. Observed hospital mortality was 56% in the cardiac-arrest cohort (3,302 nonsurvivors). Patients treated in intensive care units with a high frequency of postresuscitation care generally had high severity of illness (median Simplified Acute Physiology Score (SAPS II), 65). Intensive care units with a higher frequency of care showed improved risk-adjusted mortality. The SAPS II adjusted, observed-to-expected mortality ratios (O/E-Ratios) in the three strata (<18; 18 to 26; >26 resuscitations per ICU per year) were 0.869 (95% confidence interval, 0.844 to 894), 0.876 (0.850 to 0.902), and 0.808 (0.784 to 0.833).

Conclusions: In this database analysis, a high frequency of post-cardiac arrest care at an intensive care unit seemed to be associated with improved outcome of cardiac-arrest patients. We were able to identify patients who seemed to profit more from high frequency of care, namely, those with an intermediate severity of illness. Considering these findings, cardiac-arrest care centers might be a reasonable step to improve outcome in this specific population of cardiac-arrest patients.

Figure 1

Association between mortality, severity of illness, and frequency of post-cardiac arrest intensive care provided in an ICU. x-axis: Frequency of patients treated after cardiac arrest, divided into tertiles. y-axis, Mortality ± 95% confidence intervals; SAPS II is divided into steps by 20: <20 (lowermost line), <40, <60, <80, <100, ≥100 (topmost line). Every second line (+CI) is shifted for improved identification of the confidence intervals.