We reported previously that 8ml/kg B. W./min of oxygen (O2) delivery was required for a dog in cardiopulmonary bypass (CPB) with artificial blood i. e, perfluorochemical (PFC) emulsion. Although O2 required by tissue can be supplied by artificial blood, the real blood is still necessary after CPB, because artificial blood disappears rapidly from blood vessels and has no coagulability. Seventy-five % of autologous blood which may provide 10g/dl of hemoglobin (Hb) concentration after CPB will be enough to maintain hemodynamics and coagulability in good condition. The purpose of this paper is to establish a method to remove 75% of blood and to study whether 8ml/kg/min of oxygen can be still delivered by PFC during CPB at the perfusion rate of 120ml/kg/min after 75% of blood was removed at the beginning of CPB.
Six adult mongrel dogs weighing 9 to 12kg were anesthetized and canulated into the aorta, SVC, and IVC. Hartmann's solution was infused rapidly (120ml/kg/min) into the aorta, and venous blood was simultaneously washed out from SVC and IVC. It was studied how much volume of venous blood should be washed out to remove various amounts of autologous blood. After preserving 75% of blood in this way, dogs were placed on CPB with 35w/v% PFC emulsion primed in bubble oxygenator. Hb and PFC concentration, pH, and PO2 of the perfusate were measured. Arterial O2 content was calculated.
Result: Seventy-five % of blood was obtained by washing out venous blood approximately 2/13 of body weight of a dog. Hb concentration of the perfusate decreased to 10% of pre-CPB value in average. Concentration of PFC were more than 25w/v% in all cases. As the arterial O2 content could be kept over 6.7 vol.%, more than 8ml/kg/min of oxygen could be delivered at the perfusion rate of 120ml/kg/min.
