Acquired organ system derangements and hospital mortality: are all organ systems created equally?

Abstract

BACKGROUND: Acquired organ system derangements are common among patients who require intensive care, but the relative importance of different derangements as determinants of patients' outcomes is unclear. OBJECTIVES: To determine organ system derangements that occur in patients who require intensive care and the relative importance of different derangements to hospital mortality. METHODS: A prospective cohort study design was used to evaluate the occurrence of organ system derangements and hospital mortality in 617 adults admitted to the medical and surgical intensive care units of a university-affiliated teaching hospital. RESULTS: Eighty-three patients (13.5%) died while hospitalized. Patients who died had significantly more derangements than did patients who survived (3.3 +/- 1.2 vs 0.9 +/- 0.9; P < .001). The crude hospital mortality rate varied with the specific organ system involved (pulmonary, 23.6%; gastrointestinal, 25.0%; hepatic, 42.4%; hematological, 47.9%; cardiac, 54.0%; renal, 54.8%; neurological, 65.9%). Derangements of neurological function (adjusted odds ratio, 3.20; 95% CI, 2.0-5.3; P = .019) and cardiac function (adjusted odds ratio, 3.96; 95% CI, 2.63-5.99; P < .001) were independently associated with hospital mortality. Additionally, derangements occurred later during the stay in the intensive care unit in patients who died in the hospital than in patients who survived, especially for derangements of pulmonary, neurological, and renal function. CONCLUSION: Among critically ill patients, neurological and cardiac dysfunction are the acquired organ system derangements most closely associated with hospital mortality. These data suggest that hospital mortality depends on both the specific types of derangements that occur and the total number of such derangements. Interventions to prevent cardiac and neurological dysfunction have the greatest potential for improving outcomes for patients in the intensive care unit.