Study of clinical course of organ dysfunction in intensive care.

OBJECTIVE: Multiple organ dysfunction is a common cause of death in intensive care units. We describe the daily course of multiple organ dysfunction measured by the Sequential Organ Failure Assessment score in a population-based cohort of critically ill patients.

DESIGN: Prospective cohort study.

SETTING: Adult multisystem intensive care units in the Calgary Health Region.

PATIENTS: A total of 1,436 patients admitted from May 1, 2000 to April 30, 2001.

MEASUREMENTS: Temporal change in Sequential Organ Failure Assessment score.

INTERVENTIONS: None; observational study.

MAIN RESULTS: The mean age was 58 yrs (range, 14-100). The mean +/- sd intensive care unit admission Acute Physiology and Chronic Health Evaluation II score was 25 +/- 9. The median intensive care unit length of stay was 4 days (interquartile range, 2-8), and the median hospital length of stay was 15 days (interquartile range, 7-32). A total of 20.5% of patients were infected at admission, and 26.0% were immediately postoperative. Intensive care unit mortality was 27.0%, and hospital mortality was 35.1%. The daily Sequential Organ Failure Assessment score was significantly higher in nonsurvivors than survivors. A population-averaged model determined a mean rate of change of Sequential Organ Failure Assessment score to be -0.29 per day (95% confidence interval, -0.32 to -0.25) for survivors and -0.03 per day (95% confidence interval, -0.08 to 0.03) for nonsurvivors (overall regression, p <.0001). Patients with infection had higher admission Sequential Organ Failure Assessment scores compared with patients without infection (difference, 1.8; p <.001), but a similar rate of daily change.

CONCLUSIONS: Multiple organ dysfunction, does not follow a course of progressive and sequential failure. Evidence of differential daily change should further inform the use of organ failure scores as surrogate outcomes in clinical trials.