ELAyashy M, et al. - Researchers sought to determine the value of central and pulmonary veno-arterial CO₂ gradients in prognosticating fluid responsiveness and in guiding fluid management during liver transplantation. Based on pulse pressure variations (PPV), intraoperative fluid management was done in adult recipients (ASA III to IV) scheduled for liver transplantation. PPV of ≥15% (Fluid Responding Status-FRS) was suggestive of fluid resuscitation with 250 ml albumin 5% boluses; this was repeated as required to restore PPV to < 15% (Fluid non-Responding Status-FnRS). They calculated central venous to arterial CO₂ gap [C(v-a) CO₂ gap] and pulmonary venous to arterial CO₂ gap [Pulm(p-a) CO₂ gap] in simultaneous blood samples from central venous and pulmonary artery catheters (PAC). In addition, they measured CO and lactate. Record of 67 data points was made (20 FRS and 47 FnRS). Findings provide no support for the utility of central and the pulmonary CO₂ gaps as tools for predicting fluid responsiveness or to guide fluid management during liver transplantation. Also, CO₂ gaps did not show good correlation with the changes in PPV or CO.