30-Day mortality risk predictors for emergency laparotomy: a comparative study

INTRODUCTION: Morbidity and mortality are significant risks associated with emergency laparotomies. A risk calculation tool facilitates the identification of high-risk patients and provides clinicians with information to help them make informed decisions. In search of an ideal scoring system that yields accurate results, we compared 30-day mortality predictions using the National Emergency Laparotomy Audit (NELA), the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (P-POSSUM), the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP), and the Surgical Outcome Risk Tool (SORT) risk calculators. METHODS: This retrospective study analysed data collected from adult patients who underwent emergency laparotomies between July 2018 to October 2019 at Maidstone and Tunbridge Wells NHS Trust. Each patient's median preoperative mortality risk was calculated using the four risk calculators: NELA, P-POSSUM, ACS-NSQIP and SORT. RESULTS: During the study period, 227 patients were eligible for inclusion, with a mean (sd) age of 65 (±16) years and a median American Society of Anesthesiologists score of 2. NELA and P-POSSUM identified 11 patients (sensitivity 73.3%) who died in the high-risk group, which was higher than the identification rates of ACS-NSQIP (53.3%) and SORT (40.0%). The average 30-day mortality risk for the 15 patients who died was 25.8% for NELA, 39.6% for P-POSSUM, 17.9% for ACS-NSQIP and 15.7% for SORT. NELA and ACS-NSQIP had the highest area under the curve at 0.869 and 0.877, respectively. Although NELA exhibited higher sensitivity (73.3%), ACS-NSQIP demonstrated greater specificity (88.7%). CONCLUSIONS: Overall, the NELA score demonstrated the highest performance in predicting mortality in emergency laparotomy.