The side-effects of cardiopulmonary bypass on the lungs: changes in bronchoalveolar lavage fluids

Although technical refinements have improved the safety of cardiac operatio ns, postoperative dysfunction of lung and other organs occurs frequently af ter cardiopulmonary bypass (CPB). The aim of the present study was to searc h the aetiopathogenesis of pulmonary complications due to CBP. Ten patients with stable coronary artery disease, undergoing coronary artery bypass gra fting (CABG) surgery, were included in the study. Forty bronchoalveolar lav age (BAL) fluid samplings were performed in the 10 patients. Samples were o btained at the following time periods: (1) preoperatively; (2) at the end o f the first hour after anaesthetic induction; (3) at the conclusion of 30 m in of crossclamp on CPB; and (4) at the conclusion of 20 h after the end of CPB, postoperatively. Cell contents of bronchoalveolar lavage fluid, alveo lar macrophage viability, eosinophil cationic protein (ECP) levels and myel operoxidase (MPO) concentrations were analysed in each bronchoalveolar lava ge fluids. While the percentage of preoperative macrophages was 85.90% and the percent age of preoperative neutrophils was 2.40%. they were 77.00% and 11.30% in t he postoperative samples, respectively. Mean alveolar macrophage viability was 96.20% preoperatively and 90.40% in the postoperative period. Preoperat ive eosinophil cationic protein mean concentration was < 2 <mu>g/l and mean response value (RV) was 28.80. Preoperative mean myeloperoxidase concentra tion was 7.66 ng/ml. Postoperative eosinophil cationic protein mean respons e value was 63.40 and mean myeloperoxidase concentration was 59.25 ng/ml. T here were significant differences between third and final samples with rega rd to both neutrophil percentages (p = 0.028) and MPO levels (p = 0.005). W hile the preoperative mean PaO2 value was 89.39 mmHg and mean SaO(2) value was 97.12%, they were calculated in the postoperative arterial blood specim ens of patients, without inhaling O-2, as 65.31 mmHg and 93.84%. These chan ges between blood gas analyses reflect the impairment of the lungs (p = 0.0 09 and p = 0.007. respectively). Neither alveolar macrophage viability nor ECP levels changed significantly between consecutive periods. However, when the results of the first and fourth samples were compared, we saw the cumu lative effects of CPB, in that alveolar macrophages lost their viability an d ECP mean RVs rose. These changes were statistically significant (p = 0.02 7 and p = 0.013. respectively). However, postoperative ECP levels were not like those found in a patient with asthma. Also, changes between alveolar m acrophage percentages (p = 0.028). between neutrophil percentages (p = 0.03 6) and between MPO concentrations (p = 0.005) were statistically significan t. Again, changes in neutrophil percentages between first and final samples correlated with changes in MPO levels between same periods (r = 0.657, p = 0.039).