A proposed classification of intra-abdominal infections. Stratification of etiology and risk for future therapeutic trials.

Serious studies of ultra-abdominal infections have yielded a mortality that ranges from 3.5% (a composite of antibiotic studies evaluating 1,275 patients) to more than 60% in studies of multiple-organ failure. In reviewing these studies, it is apparent that under the umbrella of "serious intra-abdominal infection," different diseases, processes, and patients are being studied. We define a binomial classification incorporating both an anatomic and a functional approach to intra-abdominal infection. There are ten etiologic classifications of intra-abdominal infections combined with an acute physiologic score (APS), measuring severity of illness, in three gradations. In the patient with undifferentiated intra-abdominal sepsis, the patient will be in class I, II, III, or IV, with a score, A, B, or C, added. Each of the groups V-X, defining a specific infectious category, can also use the APS, which has been verified in patients in intensive care and in those with intra-abdominal infection. It is anticipated that using this approach will provide a technique to evaluate patient groups uniformly in which drug or technical approaches to the management of intra-abdominal infections are being studied. The patients being studied will be more clearly defined, and studies will be comparable from one center to another.