Stratified outcome evaluation in peritonitis

Abstract

Background: The heterogeneity of disease severity in peritonitis often makes outcome prediction and treatment planning problematic. Disease severity stratification has been shown in studies elsewhere to relate with outcome. Risk evaluation in secondary peritonitis is of value in treatment planning, outcome prediction and conduction of surgical audits. This study evaluated outcome in peritonitis by stratifying patients according to disease severity using the Mannheim Peritonitis Index (MPI) at Kenyatta National IIospital. Objective: The main objective was to determine the usefulness of the MPI in predicting outcome of secondary peritonitis at KNI--I. Design: This was a prospective descriptive cross sectional survey. Materials and methods: Seventy patients meeting the inclusion criteria and admitted within the study period were consecutively enrolled into the study within 24 hours of operation. Data encompassing the risk factors under evaluation was collected comprising of age, sex, preoperative duration, organ failure, sepsis source, malignancy, character and extent of exudate from which the MPI was calculated. Patients were then followed up tiIJ discharge or death to record outcome (complications, hospital stay or death). Outcome evaluation was stratified in accordance with the MPI score. Data analysis was done with the aid of the SPSS version 12 computer programme. Results: A total of 56 males and 14 females (M:F =4:1) were recruited into the study. The age range was 13-59 years with a mean of 32.17 years. Forty six patients (65.7%) had generalised peritonitis, 15(21.4%) had 2-3 quadrant peritonitis while 9(12.9%) had focal peritonitis. The commonest source of sepsis was perforated appendicitis (31.4%), followed by perforated duodenal ulcer (22.9%) and ileal perforation (18.6%). Ileus was the most frequent organ dysfunction (48.6%). Source control was not achieved in 12.9% of patients with an attendant 100% morbidity. Males had a lower mean MPI score (23.17) compared to females (31). Patients with morbidity had a higher mean MPI (26.9) compared to those without morbidity (22.8) (p=0.0 18). Morbidity rates within group increased with rising MPI scores (31% for MPI <21,54.2% MPI 21-29,64% MPI >29). Nine (12.9%) patients died of which only 1(4.17%) had an MPI of<29. The mean MPI for non survivor,s was 33.8 (23.4 for survivors). Females had a higher mortality rate compared to males (21.43% vs 10.71%). The overall mean hospital stay was 14 days but 22 days for those who developed complications. Only 4 of 11(23.53%) patients with an MPI >29 had no recorded adverse outcome at discharge. Those with an MPI :::::26had x2.1 risk of in hospital death. ROC curve analysis showed a mortality predictive power of 0.916 with a sensitivity of88.9% and specificity of85.2% at MPl of 29 points. Conclusion: The findings of this study appear to be in keeping with others elsewhere in showing that increasing MPI score does relate with outcome. The MPI is therefore useful in prognosticating early outcome in patients with surgical peritonitis at KNH