Hemoglobin based oxygen carrying solution stability in extracorporeal circulation: an in vitro evaluation and implications for clinical use.
This study evaluated the stability of a hemoglobin based oxygen carrying (HBOC) solution during extracorporeal circulation. HBOC solution was diluted 1:1 with normal saline, 2 L of the resulting solution was oxygenated in either a bubble oxygenator (n=5) or membrane oxygenator (n=5), and it was placed in extracorporeal circulation at a rate of 2 L/min for 5 hr at 37 degrees C. To assess the effect of added human blood, 500 ml of fresh human whole blood was added to 1.5 L of diluted HBOC solution, and circulated as described. Methemoglobin level, hemoglobin integrity (percent of HBOC solution tetramer), and oxygen affinity (PO2 at 50% hemoglobin saturation) were measured. Extracorporeal circulation using the bubble oxygenator slightly altered (<1%) hemoglobin integrity compared with controls. Oxygen affinity decreased during extracorporeal circulation with both the membrane and bubble oxygenators; there was no significant difference between the oxygenators. Methemoglobin formation in controls and in extracorporeal circulation with either oxygenator was significant, with a slight advantage of the membrane compared with the bubble oxygenator; however, the presence of blood significantly decreased the rate of methemoglobin formation. In the presence of blood, HBOC solution remains structurally stable and efficacious for oxygen delivery during extracorporeal circulation.
Neya
K
K
Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston 02114-2696, USA.
Lee
R
R
Vlahakes
G J
GJ
D001769:Blood; D001802:Blood Substitutes / Q000737:chemistry*; D015199:Extracorporeal Membrane Oxygenation; D006454:Hemoglobins / Q000737:chemistry*; D006801:Humans; D008706:Methemoglobin / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D010101:Oxygen Consumption / Q000502:physiology; D010106:Oxygenators; D010313:Partial Pressure; D012996:Solutions
D001802:Blood Substitutes; D006454:Hemoglobins; D012996:Solutions; D008706:Methemoglobin; D010100:Oxygen