A Prospective Study of Possum Scoring System in Patients Undergoing Emergency Laparotomy for Non-Traumatic Peritonitis in a Tertiary Care Center

Abstract

BACKGROUND Peritonitis is a life-threatening condition; a uniform scoring system is a must to judge the efficacy in hospital care. It aids in selecting patients at high risk who require intensive management and also to provide a reliable objective classification of severity and operative risk. With 12 clinical and basic biochemical parameters and 6 operative parameters as the basis, POSSUM is the scoring system, which has proven ability to assess morbidity and mortality risk, especially in the health care center where only basic investigations are available. Application of POSSUM in developing countries with different population and limited resources is done. In the present prospective study, POSSUM and p-POSSUM scoring systems applied to determine how they performed in predicting complication or death in patients undergoing emergency laparotomy. METHODS A total of 150 cases diagnosed to be peritonitis who underwent laparotomy at a tertiary care centre were enrolled. The parameters for calculating POSSUM score were retrieved and O:E Ratio for Mortality and Morbidity calculated using linear and exponential analysis. Data was entered using EPIDATA software and statistical analysis was performed using SPSS 25.0. RESULTS Using Linear Analysis, Mean Morbidity Risk calculated by POSSUM was 73.3%. Expected and observed morbidity was 110 and 102, with O:E Ratio 0.92 ‫א(‬ 2 test-not significant) showing POSSUM morbidity equation as a good predictor of morbidity in cases of peritonitis. Mean Mortality Risk as calculated by POSSUM was 32.39%. Expected and observed mortality was 49 and 21, with O:E Ratio 0.43 ‫א(‬ 2 test-significant) showing POSSUM Mortality equation over predicts Mortality in cases of peritonitis especially in low risk patients. Mortality risk prediction by p-POSSUM by linear analysis was 19.47%. Expected and observed mortality was 30 and 21, with O:E Ratio 0.72 ‫א(‬ 2 test-non significant). Using exponential analysis POSSUM Morbidity equation could predict morbidity accurately for risk strata 51-100 where O:E Ratio 0.99 (ℵ 2 test-not significant), but ‫א‬ 2 test showed significant difference for risk strata 21-40 showing that POSSUM Morbidity equation over predicts morbidity especially in low risk group. Using exponential analysis POSSUM and p-POSSUM Mortality equations could better predict mortality with O: E Ratio. 1.04 ‫א(‬ 2 testnot significant) and 1.05 ‫א(‬ 2 test-not significant) respectively. CONCLUSIONS POSSUM SCORING SYSTEM is a good predictor of morbidity using linear analysis whereas using exponential analysis it over predicts morbidity in low risk group (<60). POSSUM SCORE over predicts mortality using linear analysis, while the results are significantly better when exponential analysis is used. Whereas mortality risk prediction by p-POSSUM score is better compared to POSSUM score by linear and exponential analysis.