Assessment of the tissue respiration intensity after cardiopulmonary bypass by studying erythrocytes morphology

Introduction.It was previously unknown that the form of erythrocytes depends on their interaction with oxygen. The form of red blood cells is reversible and changes both after passing through the lungs (oxygenator), and after gas exchanges in the tissues.Purpose of the study. In order to study the effect of cardiopulmonary bypass (CPB) on the erythrocyte morphology, the intensity of gas exchanges in the body tissues of the patient was determined using morphometric analysis of the form of erythrocytes.Material and methods.To achieve this goal, we developed a method for the morphometric analysis of erythrocytes «in vitro». Blood test was performed before surgery, on the 10th and every 30thminute of CPB, 12 hours after surgery.Results.Using this fact, we studied tissue respiration intensity. We found that normal arterial blood contains 85 % [80–95 %] red blood cells covered with small «villi» (0.3–0.4 μm), whereas venous blood consists mostly of «large-villous» erythrocytes (length of the «villi» 0.4–1.0 μm, 70 % [6–80 %]). During pairwise comparison we found the significant difference in the proportion of «large-villous» red blood cells in arterial blood before (15 % [5–20 %]) and after (35 % [20–50 %]) CPB. Partial pressure of oxygen and carbon dioxide changes throughout CPB and it shows changes in oxygen carrying capacity of blood. Decrease in the oxygen capacity of the blood reflects the intensity of tissue respiration on the one hand, and the degree of mechanical damage to red blood cells on the other.Conclusion.Heart surgery in infrared conditions lead to pronounced shifts in the ratio of discocytes and pathological forms of red blood cells in the blood. Inhibition of the red blood oxygen consumption during CPB indicates changes in the metabolic reactions, erythrocytes morphology and functionality. These data give us more complete understanding of the pathophysiological changes throughout CPB. The proposed method of erythrocytes morphometric analysis can be used as an express blood test in heart surgery with CPB, enabling better understanding of red blood state.