Prognostic factors for mortality in left colonic peritonitis: a new scoring system.

BACKGROUND: Perforating lesions of the colon affect a heterogeneous group of patients, often elderly, and usually present as abdominal emergencies, with high morbidity and mortality. The aims of this study were to assess the prognostic value of specific factors in patients with left colonic peritonitis and to evaluate the utility of a scoring method that allows one to define groups of patients with different mortality risks. STUDY
DESIGN: Between January 1994 and December 1999, 156 patients (77 men and 79 women), with a mean (SD) age of 63.2 years (15.5 years) (range 22 to 87 years), underwent emergency operation for a distal colonic perforation. Intraoperative colonic lavage was the first choice operation and it was performed in 74 patients (47.4%). There were three alternative procedures: the Hartmann operation was performed in 69 patients (44.2%), subtotal colectomy in 9, and colostomy in 4 patients. We analyzed specific variables for their possible relation to death including gender, age, American Society of Anesthesiologists (ASA) score, immunocompromised status, etiology, and degree of peritonitis, preoperative organ failure, time (hours) between hospital admission and surgical intervention, and degree of temperature elevation (38 degrees C). Univariate relations between predictors and outcomes (death) were analyzed using logistic regression. Multivariate logistic regression analysis was used to assess the prognostic value of combinations of the variables. Significant factors identified in univariate and multivariate logistic regression analyses were used to define a left colonic Peritonitis Severity Score (PSS). Factors that were significant only in univariate analysis scored 2 points if present and 1 if not. Variables significant in multivariate analysis were scored from 1 to 3 points. Patients were randomly split into two groups, one to calculate the scoring system and the other to validate it.
RESULTS: Overall postoperative mortality rate was 22.4%. Septic-related mortality was observed in 24 patients (15.4%). Age, peritonitis grade, ASA score, immunocompromised status, and ischemic colitis were significant for postoperative death in univariate analysis. But only ASA score and preoperative organ failure were significantly associated with postoperative mortality in multivariate logistic regression analysis. The PSS, as defined in this study, was related to outcomes of patients. Mortality rate increased from 0%, when PSS was 6 points (minimum possible score), to 100% in patients with a PSS of 13 (maximum possible PSS = 14).
CONCLUSIONS: Left colonic peritonitis continues to have a persistently high mortality in patients with septic complications. ASA score and preoperative organ failure are the only factors that are significantly associated with mortality in the multivariate analysis. The PSS classification may help uniformly define the mortality risk of patients with distal large bowel peritonitis, and may help to increase the comparability of studies carried out at different centers.