[A single absolute critical threshold of oxygen transport and anemia in patients with isovolemic hypovolemia]

The oxygen parameters in patients in dynamics of early period after surgical stoppage of gastro-intestinal bleeding and urgent intravascular volume replacement have been investigated. The concentration of erythrocyte hemoglobin was the main reason of the change of oxygen transport (DO2) from the lung to exchange vessels. The fluctuations of DO2 was accompanied by unidirectional change of the integrated value of oxygen consumption (VO2), even in cases of normal level of the blood lactic acid. The lactate concentration changed independent of DO2. That is the reason why the absolute critical threshold of oxygen transport could not be revealed. In addition, we have considered the change of oxygen parameters depending on the concentration of hemoglobin. The decrease of hemoglobin concentration to 6 g/dl was accompanied by the stepped reduction of DO2, but under its decrease below 6 g/dl no further reduction of DO2 could happen because of hyperdynamic hemodynamic reaction. All this in combination with the possible intensification of anaerobic metabolism from the data of lactate level at the higher hemoglobin concentrations, allowed us to think, that the critical threshold of anemia of 6 g/dl is not absolute for all cases.