Jonckheer J, et al. - In this study involving patients (n=10) receiving standard continuous veno-venous hemofiltration (CVVH) under citrate anticoagulation, researchers analyzed carbon dioxide (CO₂) and oxygen (O₂) behavior at various sample points of CVVH in a prospective manner, as well as, they developed a model to calculate CO₂ removal bedside. Findings revealed a significant correlation of CO₂ flow (V̇CO₂) in the effluent (26.0 ml/min) with transmembrane V̇CO₂ (24.2 ml/min). This signifies 14% of the average expired V̇CO₂ in ventilated patients. No statistical difference was observed in tCO₂ values in effluent, before, and following the filter. No significant difference was found for transmembrane total CO₂ (tCO₂) under citrate or NaCl 0.9% predilution. Throughout the CVVH circuit, O₂ flow (V̇O₂) remained unaltered. To enable bedside assessment of CVVH-attributable CO₂ removal, they formed formulas on the basis of recorded data. Overall, CVVH removed a relevant amount of CO₂, which can be quantified by one simple blood gas analysis within the circuit.