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High levels of lipid-laden macrophages (LLM) in bronchial washings have been associated with food aspiration. We studied the time course of appearance and clearance of LLM in rabbits undergoing either a single milk instillation, five weekly milk instillations or saline (control) instillations into the airways. Cells were obtained by bronchoalveolar lavage of intubated rabbits at uniform time intervals following the single or the last of five milk/saline instillations. LLM semi-quantitative indexes were derived using oil-red-O staining. Significantly elevated indexes were found in both milk groups 6 hr after milk instillation. In the single saline and milk instillation groups the indexes were not different beginning on the 4th day, and indexes from 8 of 9 rabbits had returned to baseline by the 6th day. However, indexes remained significantly elevated up to 17 days in the group receiving weekly milk instillations. Indexes from all rabbits in the repeat milk instillation group remained elevated for 12 days or longer. This group also developed increased numbers of binucleated macrophages. Quantitation of LLM in this model appears to be a sensitive indicator of recurrent lipid aspiration, these cells remaining in the airways for several days after the last aspiration event.

Twenty-four hospitalized patients with cystic fibrosis were enrolled into a 2-d, double-blind, placebo-controlled, randomized crossover trial comparing albuterol inhalation aerosol with a saline placebo. Aerosols were administered with the first three of four chest physiotherapy sessions given 4 h apart. Spirometry was measured before and 45 min after 7:00 A.M. and 3:00 P.M. therapy and before therapy at 7:00 P.M. and 7:00 A.M. the next morning. The mean percent change in FVC, FEV1, and FEF25-75% at 7:00 A.M. was 10.7, 14.8, and 19.6% with albuterol versus 2.4, 1.0, and -0.8% with placebo (p = 0.0012, < 0.0001, and = 0.003, respectively). A greater than 8% change in FEV1 separated changes with albuterol versus placebo with 96% specificity and occurred in 75% of all patients with albuterol; 71% at 7:00 A.M. versus 24% at 3:00 P.M. The reduction in response at 3:00 P.M. (p < 0.01) was presumably due to prolonged effects of morning therapy ( > 4 h). Individual changes in spirometry were significantly more positive and homogeneous with albuterol versus placebo at both 7:00 A.M. and 3:00 P.M. The mean percent change for the FVC, FEV1, and FEF25-75 across the day (7:00 A.M. pretherapy to 7:00 P.M. pretherapy) was 8.1, 10.1, and 9.7% with albuterol versus 3.9, 3.5 and 2.6% with placebo (p = 0.029, 0.036, and 0.232, respectively). The more positive and homogeneous changes in spirometry with albuterol, along with greater changes in these measures across the day when compared with placebo, suggest that albuterol improves pulmonary function in a majority of hospitalized patients with cystic fibrosis.