title: Impact of hemoglobin concentration and affinity for oxygen on tissue oxygenation: the case of hemoglobin-based oxygen carriers.
abstract: In patients undergoing exchange-transfusion with hemoglobin (Hb)-based oxygen (O₂) carriers (HBOC), native Hb coexists with newly transfused Hb. The two Hb types share the same arterial and venous PO₂, but their affinities for O₂ vary. A simple spreadsheet model is described aiming at evaluating the contribution of each Hb type to the overall O₂ transport characteristics as a function of the batch Hb concentration and O₂ affinity in the HBOC solution, of the fraction of exchange-transfused blood/HBOC, and of the arterial PO₂. This model helps to yield a quantitative estimate of how tissues with high or low O₂ extraction respond to the changes cited above. The results show that the higher the exchange-transfusion ratio, the O₂ transport to tissues becomes progressively impaired. However, this effect is more critical at low batch Hb concentration and high O₂ affinity of the HBOC, especially for tissues/organs with high O₂ extraction, whereas the arterial PO₂ does not appear as critical.
authors.affiliation: Dipartimento di Medicina, Chirurgia e Odontoiatria, Università di Milano-San Paolo, Milano, Italy. michele.samaja@unimi.it
authors.forename: Michele
authors.initials: M
authors.lastname: Samaja
authors.forename: Laura
authors.initials: L
authors.lastname: Terraneo
mesh_terms: D000465:Algorithms; D001692:Biological Transport; D001802:Blood Substitutes / Q000378:metabolism* / Q000494:pharmacology*; D005078:Exchange Transfusion, Whole Blood; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism*
chemical_list: D001802:Blood Substitutes; D006454:Hemoglobins; D010100:Oxygen