Abstract
BACKGROUND: Bronchoalveolar lavage (BAL) is a valuable diagnostic tool, with an optimal recovery rate of ≥ 30% for effective diagnosis. The primary cause of BAL recovery failure is bronchial collapse due to negative pressure, which is potentially influenced by bronchial wall weakness. This study aimed to measure suction pressure levels during bronchial collapse to explore their relationship with BAL recovery rates. METHODS: We included 103 patients who underwent BAL procedures at Fukujuji Hospital from May 2024 to July 2025. Suction pressure levels during bronchial obstruction were evaluated and compared between patients with a BAL recovery rate < 30% (the failure group) and those with a BAL recovery rate ≥ 30% (the success group). RESULTS: Of the 103 patients, 13 were categorized into the failure group, and 90 into the success group. The median age of patients in the failure group was 74 years (range 47-86), with 7 males (53.8%), which was not significantly different from that of patients in the success group (median age 72 years [range 18-90], P = .290; male n = 56 [62.2%], P = .560). Patients in the failure group had significantly lower suction pressure levels during bronchial obstruction than those in the success group did (median 8 hPa [95% confidence interval: 3-13] vs 10 hPa [4-22], P < .001). The area under the receiver operating characteristic curve for suction pressure levels during bronchial obstruction for predicting BAL recovery failure was 0.807 (95% confidence interval: 0.687-0.927). A cutoff value of <9.5 hPa was identified as a predictable suction pressure level causing bronchial obstruction, with a sensitivity of 67.8% and a specificity of 92.3%. CONCLUSION: Suction pressure levels during bronchial obstruction were predictive of BAL recovery rate failure, suggesting that a weak bronchial wall may be more prone to collapse under suction pressure.