Comparison of tracheal aspirate and bronchoalveolar lavage specimens from premature infants

Lung fluid obtained by tracheal aspiration (TA) or bronchoalveolar lavage (BAL) has been used to study bronchopulmonary dysplasia (BPD). These two sample collection methods have seldom been compared. Paired BAL and TA specimens were collected 1, 3, 7 and 28 days after birth in 40 infants <34 weeks' gestation during a randomized, controlled trial of dexamethasone for BPD prophylaxis. Interleukin 8 (IL-8) and cell counts were measured. Compared to subjects without BPD, those who developed BPD or died by 28 days had elevated IL-8 in epithelial lining fluid on day 1 in both BAL specimens (20 ng/ml vs. 2 ng/ml) and TA specimens (101 ng/ml vs. 18 ng/ml). IL-8 levels (r = 0.55) and neutrophil proportions (r = 0.51) were moderately correlated between BAL and TA samples. TA specimens may be suitable substitutes for BAL samples in some studies of newborn lung fluid.