Acellular hemoglobin solution enters compressed lung capillaries more readily than red blood cells

• Published in: Journal of applied physiology (1985) 2000-09, Vol.89 (3), p.1198-1204
• Main Authors: Conhaim, Robert L, Rodenkirch, Lance A, Watson, Kal E, Harms, Bruce A
• Format: Article
• Language: English
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Aspirin - analogs & derivatives; Aspirin - pharmacokinetics; Biological and medical sciences; Blood vessels; Blood. Blood and plasma substitutes. Blood products. Blood cells. Blood typing. Plasmapheresis. Apheresis; Capillaries - metabolism; Capillary Permeability; Cellular biology; Erythrocytes - physiology; Hemoglobin; Hemoglobins - pharmacokinetics; In Vitro Techniques; Lungs; Medical sciences; Microscopy, Confocal; Microscopy, Fluorescence; Pulmonary Alveoli - metabolism; Pulmonary Circulation; Rats; Rodents; Tissue Distribution; Transfusions. Complications. Transfusion reactions. Cell and gene therapy
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.2000.89.3.1198

Department of Surgery, University of Wisconsin-Madison, and William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin 53705 High lung inflation pressures compress alveolar septal capillaries, impede red cell transit, and interfere with oxygenation. However, recently introduced acellular hemoglobin solutions may enter compressed lung capillaries more easily than red blood cells. To test this hypothesis, we perfused isolated rat lungs with fluorescently labeled diaspirin cross-linked hemoglobin (DCLHb; 10%) and/ or autologous red cells (hematocrit, 20). Septal capillaries were compressed by setting lung inflation pressure above vascular pressures (zone 1). Examination by confocal microscopy showed that DCLHb was distributed throughout alveolar septa. Furthermore, this distribution was not affected by adding red blood cells to the perfusate. We estimated the maximum acellular hemoglobin mass within septa to be equivalent to that of 15 red blood cells. By comparison, we found an average of 2.7 ± 4.6 red cells per septum in zone 1.   These values increased to 30.4 ± 25.8 and 50.4 ± 22.1 cells per septum in zones 2 and 3, respectively. We conclude that perfusion in zone 1 with a 10% acellular hemoglobin solution may increase the hemoglobin concentration per septum up to fivefold compared with red cell perfusion. DCLHb; blood substitutes; plasma volume expanders; pulmonary microcirculation; pulmonary perfusion; zone I lung