NELA.03Laparoscopy in Emergency Surgery is Associated with Lower Risk-Adjusted Mortality

Aims To compare risk-adjusted outcomes after emergency intestinal surgery by operative approach. Methods Data from December 2013-November 2018 was retrieved from the NELA national database. Complete data on 102,154 patients with P-POSSUM was available, and 47,667 had NELA score. AUROC curves were calculated to assess model discrimination (c-statistic), and calibration plots to visualise agreement between predicted and observed mortality. Standardised Mortality Ratio's (SMR) were calculated for the total cohort and by operative approach. Operative approach was divided into: laparotomy, completed laparoscopically, converted to open and lap assisted. Results Both P-POSSUM and NELA score displayed good discrimination for total cohort and by operative approach (P-POSSUM c-statistic=0.801-0.815; NELA score c-statistic=0.851-0.880). Calibration plots demonstrated that P-POSSUM was highly accurate up to 20% mortality, after which it substantially over-predicted mortality. NELA score was highly accurate up to 25% mortality after which it slightly under-predicted. Overall SMR of observed vs expected deaths was 0.77 using P-POSSUM, 0.8 for laparotomy and 0.46 for laparoscopy. Restricting cases to < 10% predicted mortality (n = 65,000), overall SMR improved (0.9) and was considerably lower for cases completed laparoscopically (0.41) compared to open (0.97). Using NELA scores of < 10% predicted mortality (n = 27,000) had similar overall SMR (0.96), with cases completed laparoscopically displaying much lower SMR (0.61) compared to laparotomy (1.0). Conclusions SMR's calculated using P-POSSUM and NELA score have demonstrated that laparoscopy has significantly lower observed vs expected mortality rate compared to laparotomy. This raises the question of why laparoscopy is associated with reduced mortality and should operative approach be included in risk models?

SP4.1.2 Appendicitis during the COVID pandemic – Are we seeing more complicated presentations?

Aims Studies have suggested a decrease in emergency presentations of appendicitis during the COVID-pandemic along with a nationwide fall in non-COVID related presentations to A&E. We therefore hypothesised that those treated for appendicitis had later presentations resulting in increasing incidence of ‘complicated appendicitis’ and post-operative complications. Methods We retrospectively analysed all patients ≥16years, undergoing emergency appendicectomy during 3-month period of UK national lockdown (pandemic cohort). Data was compared to the same period one year previously (pre-pandemic cohort). Primary endpoint was nature of appendicitis (uncomplicated or complicated). Secondary endpoints were operative approach, LOS and post-operative complications. Statistical analysis was performed using Fisher’s Exact Test. Results A total of 31 patients (median age 35years) underwent emergency appendicectomy in the pre-pandemic cohort and 30 patients in the pandemic group (median age 37). 9/31 (29%) and 18/30 (60%) were found to have complicated appendicitis in each group respectively (p = 0.021). Open procedures took place in 2/31 pre-pandemic, and 12/29 (4 of which were converted from laparoscopic procedures) in the pandemic cohort (p = 0.002). Median LOS was 2 in each group, though the pandemic cohort had a much wider range (0-7 vs 0-25 days). Post-operative complications occurred in 1/31 and 5/30 patients respectively (p = 0.104) with 1 mortality within 30 days. Conclusions Despite overall volume and demographics of patients remaining the same, the COVID-19 pandemic has resulted in a statistically significant increase in complicated presentations of appendicitis to our hospital. Subsequently this has resulted in increasing incidence of open operations and post-operative complications.