Comparison of cell profiles in separately evaluated fractions of bronchoalveolar lavage (BAL) fluid in children

Abstract

Background - Bronchoalveolar lavage (BAL) has been widely accepted as a routine procedure in the differential diagnosis of respiratory diseases in adults. However, there is only limited information about the value of BAL in children and there is no standardisation of the procedures. Methods - The difference in cellular profiles of sequential BAL fractions from children was analysed to assess the effect of evaluating bronchial and alveolar fractions separately. Twenty five children (mean age 13.4 years) were examined by fibreoptic bronchoscopy under general anaesthesia, combined with local application of lignocaine. The investigation was part of the clinical evaluation of an infective pulmonary problem. Bronchoalveolar lavage was performed from the right middle lobe using four 20 ml aliquots of normal saline and the four fractions of recovered fluid were evaluated separately. Results - The total cell count was lowest in the first aspirate (1.8 x 106) and increased gradually from fraction 1 to fraction 4. Similarly, the viability of the cells was lowest in fraction 1 and gradually improved from fraction 1 to fraction 4. In the differential count the number of neutrophils decreased from fraction 1 (8.3%) to fraction 4, with fractions 2 (5.4%), 3 (3.4%), and 4 (2.4%) being significantly different from fraction 1. There were no differences in the numbers of eosinophils, lymphocytes, or macrophages between individual fractions. Conclusions - These results show that the cell profile of the first 'bronchial' fraction is different from subsequent samples. It should be evaluated separately while the second and third aliquots may be pooled.