THE LOGISTIC ORGAN DYSFUNCTION SYSTEM - A NEW WAY TO ASSESS ORGAN DYSFUNCTION IN THE INTENSIVE-CARE UNIT

Objective.-To develop an objective method for assessing organ dysfunct ion among intensive care unit (ICU) patients on the first day of the I CU stay. Design and Setting.-Physiological variables defined dysfuncti on in 6 organ systems, Logistic regression techniques were used to det ermine severity levels and relative weights for the Logistic Organ Dys function (LOD) score and for conversion of the LOD score to a probabil ity of mortality. Patients.-A total of 13152 consecutive admissions to 137 adult medical/surgical ICUs in 12 countries from the European/Nor th American Study of Severity Systems. Outcome Measure.-Patient vital status at hospital discharge. Results.-The LOD System identified from 1 to 3 levels of organ dysfunction for 6 organ systems: neurologic, ca rdiovascular, renal, pulmonary, hematologic, and hepatic, From 1 to 5 LOD points were assigned to the levels of severity, and the resulting LOD scores ranged from 0 to 22 points, Model calibration was very good in the developmental and validation samples (P=.21 and P=.50, respect ively), as was model discrimination (area under the receiver operating characteristic curves of 0.843 and 0.850, respectively). Conclusion.- The LOD System provides an objective tool for assessing severity level s for organ dysfunction in the ICU, a critical component in the conduc t of clinical trials. Neurologic, cardiovascular, and renal dysfunctio n were the most severe organ dysfunctions, followed by pulmonary and h ematologic dysfunction, with hepatic dysfunction the least severe. The LOD System takes into account both the relative severity among organ systems and the degree of severity within an organ system.