Discrepancy Between Pulmonary Artery Catheter and Co-Oximeter Value of Mixed Venous Oxygen Saturation After Graft Reperfusion During Living Donor Liver Transplantation

Abstract

Monitoring tissue oxygenation is critical in liver recipients. The pulmonary artery catheter (PAC) provides continuous monitoring of mixed venous oxygen saturation (SvO2) using fiberoptic reflectance spectrophotometry. Despite the need for in vivo calibration during liver transplantation, recalibration guidelines are absent, and we frequently observed a significant discrepancy between PAC and reference co-oximeter SvO2 values after graft reperfusion. This study aimed to assess the incidence and risk factors of a significant discrepancy after reperfusion during living donor liver transplantation. This retrospective study included 54 recipients who underwent living donor liver transplantation at our institution between October 2021 and April 2022. A PAC was inserted, and in vivo calibration was conducted using the co-oximeter SvO2 value. We defined a significant discrepancy as a drift was ≥ 3% at 1 hour after reperfusion. Logistic regression analysis was performed to determine the association between perioperative variables and the risk of significant discrepancy. PAC SvO2 was higher than co-oximeter SvO2 in 51 recipients. A significant discrepancy was observed in 37 recipients (68.5%). The risk of significant discrepancy decreased with a high preoperative hemoglobin concentration (odds ratio [OR] = 0.65 [0.47-0.91], P = .011) and a high arterial oxygen partial pressure (PaO2) at 1 hour after reperfusion (OR = 0.96 [0.94-0.99], P = .004) but increased with a high baseline co-oximeter SvO2 value (OR = 1.29 [1.05-1.59], P = .015). PAC SvO2 significantly drifted from the reference co-oximeter value in over two-thirds of recipients after reperfusion. Therefore, in vivo recalibration is required for the reliable measurement of PAC SvO2 during living donor liver transplantation.