HPB P08 Exploring Carbon-13 breath delta value and other biomarkers of infection following Liver Transplantation and Hepatopancreatobiliary Surgery

Abstract

Abstract Background Sepsis and infection are the leading cause of morbidity and mortality after surgery, but the inflammatory response to the trauma of surgery can make diagnosis challenging. Carbon-13 breath delta value (13C BDV) has been shown to be discriminant as a novel diagnostic marker for sepsis and infection. We aim to assess biomarkers including BDV following major hepatopancreatobiliary (HPB) surgery to diagnose postoperative infection/sepsis. Methods 20 participants undergoing HPB surgery were recruited prospectively. Breath samples were collected from baseline preoperatively, and on postoperative days (POD) 1–9, with plasma and peripheral blood mononuclear cell (PBMC) samples preoperatively, POD1, 4 and 8. Breath samples were analysed using infrared laser spectroscopy to generate BDV (per mil). Plasma was analysed for cytokines using MesoScale Discovery immunoassay, Procalcitonin (PCT) using ELISA, and Cell surface marker expression on monocytes was phenotyped using flow cytometry. Differences between groups who did and did not develop infective complications was analysed using two-way ANOVA and Mann Whitney U test. Results 5/20 participants developed infective complications, with a mean day of diagnosis POD5. There was no difference between BDV in patients with or without infection. Monocyte count was increased in infected participants at all timepoints, and monocyte expression of PD-L1 on POD1, and CD155 and HLA-DR on POD4 was upregulated, +13.09% (95%CI 1.59 to 24.61, p<0.05), +422.5 MFI (95% CI -770.9 to -73.68, p<0.05), and +19.02% (95% CI 37.58 to 0.45, p<0.05) respectively. Conclusions Monocyte expression of PD-L1, HLA-DR and CD155 is associated with infection, +13.09% (p<0.05), +422.5 MFI (p<0.05), and +19.02% (p<0.05) respectively. The innate immune system is dysregulated in infection following major HPB surgery. In this cohort BDV did not predict infection. Further investigation of novel biomarkers including BDV and soluble monocyte markers is required.