Steven A. Schonfeld

Changes in pulmonary diffusing capacity and closing volume after running a marathon

The purpose of this study was to evaluate changes in lung function after running a marathon. Pulmonary function tests were administered to 8 men before, immediately after, and the day following competition (mean run time = 3 hr 30 min). Subjects completed maximum expiratory flow volume maneuvers breathing air and 80% He/20% O2. Lung volumes were determined by N2 washout and single breath He dilution. Closing volumes (CV) were determined using a single breath O2 test. Pulmonary diffusing capacity (DLCO), pulmonary capillary blood volume (Vc), and membrane diffusing capacity (DM) were measured with the single breath technique. There were no changes in lung volumes or flow rates, except for an increase in FEV1, after the marathon. The He/O2 delta Vmax50, delta Vmax25, and isoflow values were similar pre- compared to post-race. There were significant decreases, however, in DLCO, DM and increases in CV post-race. Vc remained similar to pre-race values. These results suggest that small airways obstruction does not occur after a marathon. The significant increase in alveolar-capillary membrane resistance, however, may reflect the occurrence of subclinical edema. Such a change would decrease lung elastic recoil and could explain the increase in CV.

Rapid Diagnosis of Legionnaires' Disease by Bronchoalveolar Lavage

Legionella pneumophila has, in recent years, emerged as a common pulmonary pathogen in the normal and immuno-compromised patient (ICP). Making a specific etiologic diagnosis of pneumonia in the latter group is a common clinical dilemma often complicated by poor specimen availability and risks of invasive procedures. Improved staining and isolation techniques for L pneumophila would suggest that early diagnosis could be possible if adequate specimens were available. This report summarizes our experience with bronchoalveolar lavage (BAL) with which we have diagnosed L pneumophila in eight immunocompromised patients, well in advance of more traditional methods. On the basis of this experience, we would advocate early BAL in the ICP as a rapid, safe, moderately sensitive and specific diagnostic test to aid in the identification of L pneumophila.