Decreasing Magnitude of Multiple Organ Dysfunction Syndrome Despite Increasingly Severe Critical Surgical Illness: A 17-Year Longitudinal Study

Abstract

Multiple organ dysfunction syndrome (MODS) remains prevalent and the leading cause of mortality in the surgical intensive care unit (ICU). Improvements in ICU care in the last 10 years (e.g., tight glycemic control, activated protein C, fewer transfusions causing fewer nosocomial infections) may have decreased the incidence, magnitude, and mortality of MODS, as hypothesized in this study. Longitudinal 17-year prospective study of 11,314 ICU patients (academic/tertiary unit, Level I trauma center), 5,157 (45.5%) of whom developed any degree of MODS (Marshall score, cumulative). Data collected included Admission Acute Physiology and Chronic Health Evaluation (APACHE)-II and APACHE-III scores, MOD score (MODsc), hospital mortality, and the incidence and magnitude of MODS. The ratio of MODsc: APACHE III was calculated. Analyses (X +/- SEM, chi2, repeated-measures ANOVA, linear and polynomial regression, c-statistic) were performed for calendar-year intervals beginning in 1990 through 2006. Among MODS patients, the mean MODsc was 6.3 +/- 0.1 points, and the mortality rate was 22%. The APACHE III score increased significantly (p < 0.0001) over time, but the mortality rate was unchanged (r2 = 0.02). Adjusted for illness severity (MODsc:A3), the magnitude of MODS decreased significantly (p < 0.0001) during the time period. Despite significant increases in admission APACHE III score over 17 years, the adjusted magnitude of MODS (MODsc:A3) decreased. Given the strong association between MODS and mortality for critically ill surgical patients, it is likely that the unchanged risk-adjusted mortality observed over time is due to the reduced magnitude of MODS.