678 Can patients have their old life back? Using PM:L3 ratio to predict discharge destination of emergency laparotomy survivors

Aim Psoas muscle:L3 vertebra (PM:L3) ratio is a relatively new risk assessment tool for emergency laparotomy(1,2) based upon the proven concept that sarcopenia – as diagnosed by low skeletal muscle index(3–6), psoas muscle density(7–9) or total psoas area(10–13) in a single axial slice CT image – correlates with increasing risks of bad outcomes in surgery. This study looks into the association between PM:L3 ratio of emergency laparotomy patients from home and their discharge destination. Method We performed an analysis on patients in the Hunter Emergency Laparotomy Audit (HELA) database, from January 2016 to December 2017. HELA is a retrospective review of all emergency laparotomy undertaken in a discrete area in NSW, Australia. All patients admitted from home, survived to be discharged from hospital and had an available CT abdomen were included (N = 433/562). A single slice axial CT image at the L3 endplate level was analysed using ImageJ® software to measure the area of L3 and bilateral psoas muscles. Results PM:L3 ratio is significantly lower in the group of patient discharged to a care facility than the group discharging back to their previous home residence (mean 0.951 vs. mean 1.128, p < 0.001). Upon further analysis, the PM:L3s are divided into quartiles and stratified by sex. There is an association between lower PM:L3 and risk of discharging into a care facility (Q1 22.45%, Q2 19.59%, Q3 19.10%, Q4 5.71%). Conclusions PM:L3 ratio can predict the discharge destination of patients undergoing emergency laparotomy.