We read with great interest a recent position statement on the physiology and presentation of a means of unambiguous identification of native lung and membrane lung blood flow occurring in patients supported by venoarterial extracorporeal membrane oxygenation (VA-ECMO).¹ In their work, Badulak et al. provide nomenclature for three main concepts that occur as a result of the dual circulation present in patients undergoing VA-ECMO support: cannula configuration, blood flow, and the attendant effects of the presence of two areas of gas exchange (the native lung and membrane lung zones).¹ Newly defined terms are proposed for concepts important to VA-ECMO physiology, including the “native lung zone,” “membrane lung zone,” “mixing point,” “differential oxygenation,” “differential carbon dioxide,” and “CO₂ removal.”¹ Endorsed by the Extracorporeal Life Support Organization (ELSO), this work represents an important and necessary step toward a consistent method of describing key aspects of VA-ECMO physiology in clinical practice, academics, and educational settings.¹ We congratulate the author’s effort and would like to discuss the nomenclature assigned to certain oxygen saturation measurements, as further clarification on this matter is needed.¹