We investigated the risk of aspiration using the lipid-laden macrophage index(LLMI) from aryngeal lavages in infants with bronchiolitis.

Laryngeal lavages from 22 infants with acute bronchiolitis caused by respiratory syncytial virus(RSV) were evaluated during the acute stage. Repeat studies were performed at 3 to 4 weeks after the initial study(remission stage). Lavage cell counts and differentials were determined. The amount of lipid per single macrophage was evaluated and the LLMI was determined by evaluating 100 cells. Comparisons between acute stage and remission stage were made. Twenty-four hour pH monitoring(pHm) was performed in 12 patients.

The total cell number was significantly higher in the acute stage compared with the remission stage( P <0.05). The LLMIs in the acute stage were significantly higher than those in the remission stage( P <0.05). The neutrophils percentage of laryngeal lavage correlated with the LLMI(r=0.69, P <0.001). Four children had positive pHm recordings(pH-positive infants) and eight had negative pHm recordings(pH-negative infants). The pH-positive infants had higher LLMI and higher neutrophils percentage than those of the pH-negative infants( P <0.05).

These findings suggest that there is a transient increased risk of aspiration during bronchiolitis. The LLMI from laryngeal lavage may be a useful marker for pulmonary aspiration in infants with bronchiolitis.