Association Between Higher Intraoperative Oxygen Exposure and Worse Patient and Organ Outcomes in Liver Transplantation

Objectives: Hemodynamic instability (postreperfusion syndrome) at reperfusion of the liver graft during transplant is common and represents the acute phase of ischemia-reperfusion injury. Both phenomena involve reactive oxygen species generation and are associated with worse patient and graft outcomes. Unwarranted hyperoxia is increasingly recognized as a harmful intervention among different clinical settings. We sought to determine the association between intraoperative oxygen exposure, during liver transplant, and patient and graft outcomes to inform clinical management strategies. Materials and Methods: We conducted a retrospective, observational cohort study of 185 adult patients undergoing deceased donor liver transplant at a single UK transplant center between February 2017 and June 2019. Primary endpoints were severity of postreper-fusion syndrome and early allograft dysfunction. Secondary endpoints were critical care and hospital length of stay. We calculated time-weighted oxygen exposure by the area under the curve method from serial blood gas measurements. Univariate and multivariate associations between donors, patients, and process risk factors, as well as oxygen exposures, were calculated for the predefined endpoints. Results: Among 185 included patients, 93 (51.4%) had postreperfusion syndrome and 26.0% had early allograft dysfunction. Total anhepatic oxygen exposure (kPa.h) was shown to independently increase the risk of moderate to severe postreperfusion syndrome (odds ratio = 1.041; P = .007). Total oxygen exposure (kPa.h) throughout surgery was shown to independently increase the severity of postoperative early allograft dysfunction (coefficient 0.174; P = .011). Early allograft dysfunction was independently associated with prolonged intensive care unit (odds ratio = 3.045; P = .005) and hospital stay (odds ratio = 7.738; P < .001). Conclusions: Hyperoxia during liver transplant was independently associated with increased risk of adverse patient and graft outcomes, similar to data from other clinical settings. Intraoperative oxyge-nation strategies to minimize unnecessary hyperoxia may lead to clinical benefits and cost savings.