Abstract

Since bronchoalveolar lavage (BAL) fluid can give a dynamic impression of what is present or developing in situ on the air exchange surface, we worked with BAL fluid to solve the etiopathogenesis of pulmonary complications due to cardiopulmonary bypass (CPB). Forty BAL fluid samples were obtained in 10 patients, undergoing coronary artery bypass grafting (CABG) surgery. Samples were obtained at the following time periods: 1. preoperatively; 2. at the end of the first hour after anesthetic induction; 3. at the conclusion of 30 min. of crossclamp on CPB; 4. 20 h after CPB. Neither calcium nor potassium ions were detectable in any sample. Mean pH of preoperative bronchoalveolar lavage fluid was 6.361 (SD±3,55.10-2) and the other mean pH values were 6.375 (SD±0.44), 6.567 (SD±0.165), 6.470 (SD±9,29.10-2), respectively. There was not any significant change between the first two steps (p=0.241). Likewise, the change between the third and fourth samples was not statistically significant (p=0.074). However, the change between the second and third studies was statistically significant (p=0.005). And also, the change between preoperative and final studies was statistically significant (p=0.007). The mean recoveries of lavage fluids was about 64% in the first samplings, 75% in the second, 73.4% in the third, and 56% in the fourth. This study reveals that CPB alters one of the main favorable conditions of ecosystem in bronchoalveolar space, namely the pH. Besides, excessive mucous secretion in an involved lung due to CPB which limits making BAL is the reason for atelectasis. As reported in the previous studies, since bronchoalveolar pH changes affect substances like surfactant, this study will set the baseline for further studies.