The Importance of Pulmonary Artery Circulation during Cardiopulmonary Bypass

Abstract

This study sought to determine changes in transpulmonary difference in blood cells and alveolar-arterial oxygen (A-aO 2 ) gradient when pulmonary artery circulation was obstructed in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). Eighteen patients were divided into group A (control group; X-clamp placed on aorta, n = 9) and group B (pulmonary ischaemia group; X-clamp placed on aorta and pulmonary artery, n = 9). Haematological parameters were compared before CPB and up to 90 min after declamping. A-aO 2 gradient differences were compared before and 2 h and 6 h after declamping. A transpulmonary increase in leucocyte levels normalized after 60 min in group A but remained higher in group B. A transpulmonary increase in neutrophils normalized after 60 min in group A and 90 min in group B. Increased lymphocyte levels normalized after 30 min in group A and 90 min in group B. A-aO 2 gradient was determined as: group A (294.8 ± 74.3) and group B (321.2 ± 73.3) before Xclamping; group A (132.7 ± 22.7) and group B (236.6 ± 41.5) 2 h after declamping; and group A (72.2 ± 22.7) and group B (189.4 ± 88.9) 6 h after declamping. When pulmonary artery circulation was obstructed during the X-clamping period, leucocyte, neutrophil and lymphocyte sequestration within both lungs increased, and an increased A-aO 2 gradient was observed because of tissue damage. To prevent post-operative complications, precautions to maintain normal pulmonary artery circulation are recommended.

Pulmonary Congestion Due to Right and Left Heart Output Mismatching: A Case Report and Literature Review

“…The pulmonary circulation during hypothermic CPB may not be the same as normal circulation during conscious state, so that it is worth while to pay attention to it and calculate specific parameters (Hashimoto et al, 2000;Ege et al, 2003;Buggeskov, 2018). According to the above literature and our experience, resuming of normal heart filling and normal right and left heart work are important to re-open the pulmonary microcirculation, restore pulmonary blood flow, drive pulmonary venous air, and reduce pulmonary congestion (Figure 1D).…”