Critically ill patients sometimes require tandem application of extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT) which is easier and cheaper. We aimed to transform the kidney membrane into a lung membrane by adding hydrogen peroxide (H₂O₂) to the dialysate as the oxygen source. A solution containing H₂O₂ and a dialysate fluid mixture was used as the final dialysate. Starting with 100% H₂O₂ solution and gradually reducing the volume of H₂O₂, respectively: 50%, 10%, 5%, 4%, 3%, 2%, and 1%. PRISMAFLEX system, Prismaflex M60 set and a bag of packed red blood cells (pRBCs) were the prototype. blood flow rate was about 40 ml/minute and the dialysis rate was about 200 ml/m²/minute/1.73 m². blood sampling times were; at the beginning (T₀), at 15th (T₁), 30th (T₂), 60th (T₃) minutes. Amongst eight attempts H₂O₂ concentration that increased the partial oxygen pressure (pO₂) level significantly in a reasonable period, without any bubbles, was 3%. Methemoglobinemia was not observed in any trial. After the test with 3%, H₂O₂ in the dialysate fluid decreased progressively without any H₂O₂ detection at post-membrane blood. Three percent H₂O₂ solution is sufficient and safe for oxygenation in CRRT systems. With this new oxy-dialysate solution, both pulmonary and renal replacement can be possible viaa single membrane in a simpler manner.