Utility of the central venous-to-arterial CO₂ difference to predict adverse outcomes after liver transplantation

Objective: Test whether the development of abnormal venous-to arterial CO₂ difference (ΔPCO₂) during the early phases of postoperative care after a liver transplantation (LT) is related to multi-organ dysfunction and outcomes.

Materials and methods: Prospective cohort study accomplished in a mixed intensive care unit (ICU) at a university hospital. We included 150 eligible patients after a LT between 2015 and 2018. Patients were classified in four predefined groups according to the ΔPCO₂ evolution during the first 6 h of resuscitation: (1) persistently normal ΔPCO₂ (normal at T0 and T6); (2) decreasing ΔPCO₂ (high at T0, normal at T6); (3) increasing ΔPCO₂ (normal at T0, high at T6); and (4) persistently high ΔPCO₂ (high at T0 and T6). Multiorgan dysfunction at day-3 was compared for predefined groups and a Kaplan Meier curve was constructed to show the survival probabilities using a log-rank test to evaluate differences between groups. A Spearman-Rho was used to test the agreement between cardiac output and ΔPCO₂.

Results: There were no significant differences between the study groups regarding higher SOFA scores at day-3 (P = .86), Δ-SOFA (P = .088), as well as global mortality rates (χ² = 5.72; P = .126) and mortality rates at day-30 (χ² = 2.23; P = .5252). A significantly poor inverse agreement between cardiac output and ΔPCO₂ was observed (r2 -0,17; P = ,002) at different points of resuscitation.

Conclusions: After a LT, central venous-to-arterial CO2 difference was not associated with survival or postoperative adverse outcomes in a critical care patients population.