D. D. Eliezer1,2, M. Holmes1, G. Sullivan2,3, J. Gani1,2, P. Pockney1,2 1John Hunter Hospital,Department Of Surgery,Newcastle, NSW, Australia 2University of Newcastle,School Of Medicine And Public Health,Newcastle, NSW, Australia 3John Hunter Hospital,Department Of Anaesthesia,Newcastle, NSW, Australia
Introduction:
Emergency laparotomies performed in high risk patients can lead to significant morbidity and mortality. The National Emergency Laparotomy Audit (NELA) has highlighted the importance of identifying these high risk patients and providing them with the appropriate level of care. The NELA risk prediction calculator (NRPC) has been developed by data collected in England and Wales to look at 30-day mortality and morbidity risk and is one of several risk calculators, including P-POSSUM and ACS NSQIP. NRPC has not been tested outside of this context, though comparison has been made to P-POSSUM. In our study, we seek to validate NRPC in the Australian population and compare NRPC to P-POSSUM and ACS-NSQIP for predicting mortality in high risk patients.
Methods: A retrospective review of all emergency laparotomies undertaken at four different sized Australian surgical centres was performed between January 2016 and December 2017. Patient demographics, pre-operative clinical findings, haematology and biochemistry results, intra-operative data and post-operative course documentation were extracted from records. NRPC, ACS NSQIP and P-POSSUM calculators were used to estimate 30-day mortality risk. The previously established NELA high risk category score, ≥10% was chosen to assess the sensitivity of NRPC and compare its positive predictive value (PPV) to that of P-POSSUM and ACS NSQIP calculators. The McNemar test was used to identify statistical significance.
Results: There were 562 patient charts reviewed during the study period. Patient demographics included 261 males (46.4%), mean age: 66 years, median ASA: 3, average LOS: 13.65 days. There were 59 patients who died within 30 days (10.5%). NRPC was able to identify 52 (sensitivity = 88.1%) of these as being within the high risk group. Using the ≥10% risk level, NRPC identified 205 patients, P-POSSUM identified 228 patients and ACS NSQIP identified 201 as high risk. Fifty-two of 205 (25.4%) NRPC-scored patients died compared to 45 out of 228 (19.7%) for P-POSSUM and 46 out of 201 (22.9%) for ACS NSQIP. When using the McNemar test, there was no significant difference between NRPC and P-POSSUM (p=0.07) or NRPC and ACS NSQIP (p=0.18).
Conclusion: The NRPC is a sensitive test for predicting mortality in high risk emergency laparotomy patients within the Australian context which has a different healthcare model and population density when compared to England and Wales. When comparing the PPV of NRPC to that of P-POSSUM and ACS-NSQIP, no statistical difference was noted. Further validation in different populations, including more remote and regional areas of Australia and analysis of different risk categories is warranted.