1986 Volume 8 Issue 2 Pages 218-228
BAL is a widely used technique in the diagnosis and evaluation of various pulmonary diseases, but the procedure has not been uniform among institutes, particularly in terms of the volume of instilled fluid and lavage times. This study was performed in order to investigate optimal lavage procedures using computed tomography (CT) and fractional alterations of cellular and biochemical components. We carried out BAL under observation with CT 20 times in 15 subjects (7 times in 3 healthy volunteers and 13 times in 12 patients with pulmonary diseases) to detect the lavage area. Numbers of cells and surfactant apoprotein content were also measured in each lavage fraction of BALF obtained by 6 sequential 50 ml lavages. When sequentially increasing volume of 10, 20, 30, 40, 50, 60, 70 and 80 ml of normal saline were instilled in healthy volunteers, the distribution area gradually extended and reached the subpleural lung region at volumes over 40 ml. Instillation volumes over 60 ml frequently provoked cough and caused spillover of the fluid. In repeated lavage with 50 ml, the density of the fluid distributed in the lung increased sequentially on CT, however the area already was extensive after the first instillation. Numbers of cells and surfactant apoprotein were greatest in fraction 2 and thereafter decreased gradually. The surfactant apoprotein content in fraction 5 and 6 decreased to less than 10% of the total. It is considered that lavage over 4 times has little significance concerning in the alveolar lining layer. Therefore procedure of 4 sequential 50 ml lavages is recommended. However in cases such as chronic bronchitis or pneumoconiosis, the lavage area did not reach subpleural lung region, and extended only to the proximal peribronchial region. These cases demonstrated a lower recovery rate of BALF. Unrecovered fluid was almost completely absorbed within 3 hours after BAL in healthy volunteers, however it still remained 7 hours after BAL in patients with diffuse panbronchiolitis, farmer's lung, sarcoidosis and interstitial pneumonia associated with rheumatoid arthritis. Concentration of cells was significantly (p<0.05) lower in BALF obtained by 5 sequential 20 ml lavages in comparison with that by 4 sequential 50 ml lavages, however differential cell counts and lymphocytes subpopulations showed no significance (p>0.1) between them. This suggests that 4 sequential 50 ml lavages are superior to 5 sequential 20 ml lavages not only in lavage area but also in effectiveness of lavage.
