[Quantitative gradations in the functional state of the oxygen transport system in heart surgery patients].

The paper deals with the objectivisation of quantitative criteria for defining the functional classes of the oxygen transport system. For this, the spiroergometric findings of patients with valvular and congenital heart diseases before and after their surgical correction were processed by using currently available mathematical methods of cluster analysis. Five classes of the functional status were identified. These included 0, I, II, III, and IV. The criteria proposed can be useful in cardiac surgical care.