Analysis of predicted factors for bronchoalveolar lavage recovery failure: An observational study

BACKGROUND: The bronchoalveolar lavage (BAL) recovery rate should generally be more than 30% for effective diagnosis. However, there have been no reports investigating a target bronchus for BAL, and the cause of BAL recovery failure is uncertain. Therefore, this study detected predictive factors for BAL recovery failure through investigations on a target bronchus for BAL by using a 3D image analysis system. Therefore, this study detected predictive factors for BAL recovery failure. MATERIALS AND METHODS: We retrospectively collected data from 338 adult patients who underwent BAL procedures at Fukujuji Hospital from June 2018-March 2022. Factors correlated with the BAL recovery rate were detected. Furthermore, the patients were divided into the failure group (recovery rate <30%; 36 patients) and the success group (recovery rate ≥30%; 302 patients), and data were compared between the two groups by analysing the target bronchus by using a 3D image analysis system. RESULTS: The patients in the failure group were older (median 74.5 years old [IQR 68.0–79.0] vs. median 70.0 years old [IQR 59.0–76.0], p = 0.016), more likely to be male (n = 27 [75.0%] vs. n = 172 [57.0%], p = 0.048), more likely to have COPD (n = 7 [19.4%] vs. n = 14 [4.6%], p = 0.003), and more likely to perform a target site of BAL other than the middle/lingual lobe (n = 11 [30.5%] vs. n = 35 [11.6%], p = 0.004) than those in the success group. The area of the bronchial wall was positively related to the recovery rate (r = 0.141, p = 0.009), and the area of the bronchial wall in the failure group was lower than that in the success group (median 10.5 mm(2) [interquartile range (IQR) 8.1–14.6] vs. median 14.5 mm(2) [11.4–19.0], p<0.001). CONCLUSION: The study shows that a thin bronchial wall, COPD, and a target site of BAL other than the middle/lingual lobe were identified as the predicted factors for BAL recovery failure. The weakness of the bronchial wall might cause bronchial collapse during the BAL procedure.