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

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.

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.

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 mm2 [interquartile range (IQR) 8.1-14.6] vs. median 14.5 mm2 [11.4-19.0], p<0.001).

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.