Is it possible to predict, whether BAL salvage is going to be diagnostic?

Bronchoalveolar lavage (BAL) is used in the diagnosis of interstitial lung diseases. BAL is diagnostic when ≥ 60% of the instilled volume is recovered. There are no reliable markers useful to predict whether BAL volume is going to be diagnostic. Our goal was to search for pulmonary function markers which could anticipate whether the recovered volume of instilled fluid would be ≥ 60% of administered volume. BAL volumes and quality were analyzed in the context of disease, medical condition and lung function test results of the subjects hospitalized at the Pulmonology Ward from January 2015 to October 2016. The patients' average age was 61 (29-89). Among 80 procedures, diagnostic BAL (≥ 60%) has been obtained in 58 cases. The analysis of the group of patients with an interstitial lung disease confirmed that there is a correlation between decreasing BAL recovered volume and an increase of RV[%pred] (r = -0.34) and RV/TLC[%pred] (r = -0.41); p < 0.05. There was no significant correlation with DLCO. RV/TLC[%pred] was the parameter with the highest predictive value for an anticipated correct BAL recovery. The curve analysis of the receiver operating characteristic (ROC) showed a diagnostic accuracy (AUC 0.73, 95% CI 0.61-0.86). Pulmonary hyperinflation may have a predictive role in anticipating a proper recovery of the BAL fluid volume.