[The concentration of calcium and its fractions during heart surgery using extracorporeal circulation].

Changes in the concentration of calcium and its fractions have been studied in 115 patients subject to standard bypass techniques. It has been found that calcium homeostasis disturbances do really develop and are caused by the use of solutions that are not balanced with blood in their calcium content. The main source of calcium in hemodiluents was gelatinol. A decrease in gelatinol volume to 450-600 ml prevented the onset of marked hypercalcemia. As ionized calcium (Ca2+) concentration is determined not only by the total Ca level, but also by the shifts in the degree of pH- and pCO2-dependent ionization and binding and in ligand and protein content, Ca2+ determination is considered an optimal method of calcium homeostasis control during cardiopulmonary bypass.