Analysis of physiologic alterations in intensive care unit patients and their relationship with mortality

Abstract

Purpose To analyze patient physiologic alterations (events) and multiple organ failure during intensive care unit (ICU) stay and examine their relationship with ICU mortality. Material and Methods A total of 17 598 consecutive patients were studied for 10 months (1997-1998) in 55 European ICUs (EURICUS-II). Hourly data were collected on critical and noncritical systolic blood pressure, heart rate, oxygen saturation, and urinary events throughout ICU stay. Sepsis-related Organ Failure Assessment (SOFA) score was collected daily (6409 patients). Results SAPS-II was 31.2 ± 18.4 and ICU mortality 13.9%. There were 3.4 ± 9.2 noncritical (duration, 3.9 ± 11.4 hours) and 2 ± 7.5 critical (3.8 ± 13.1 hours) systolic blood pressure events per patient. Heart rate, oxygen saturation, and urinary events had similar values. Nonsurvivors had significantly more and longer physiologic alterations vs survivors. Mortality was significantly related to mean daily duration of events and mean and maximum daily SOFA. Discrimination capacity to predict ICU mortality was measured using various models: with SAPS II, area under the receiver operating characteristic curve was 0.80; with APACHE III–classified diagnosis added, 0.84; with mean duration of events/ICU day, 0.91; and with mean and maximum SOFA scores, 0.95. Conclusion Routinely gathered ICU data on physiologic variables and multiple organ failure can offer considerable complementary information not provided by usual mortality prediction systems; and their weight in daily care policy decisions may need to be revisited.