Longitudinal monitoring of lung injury in children after acute chlorine exposure in a swimming pool.

RATIONALE: Acute exposure to chlorine gas results in respiratory impairment, but few data are available on the pathobiology of the underlying lung damage. OBJECTIVES: To assess lung function and potential lung damage pathways in the acute phase and longitudinally over a 15-mo follow-up after acute chlorine exposure. METHODS: Ten previously healthy children were accidentally exposed to chlorine gas at a swimming pool because of an erroneous servicing procedure. The fraction of nitric oxide in exhaled air (Fe(NO)), exhaled breath condensate compounds, and serum Clara cell-specific protein CC16 were repeatedly measured. MAIN RESULTS: In the acute phase, all patients had respiratory distress (one child required mechanical ventilation) and reduced lung function (median and interquartile range: FVC, 51 [43-60]\% predicted; FEV(1), 51 [46-60]\% predicted). This was accompanied by low Fe(NO) (4.7 [3.9-7.9] ppb), high exhaled breath condensate leukotriene B(4) (LTB(4)) levels (24.4 [22.5-24.9] pg/ml), and increased serum CC16 levels (mean +/- SEM, 23.4 +/- 2.5 microg/L). Lung function returned to normal in 15 d (FVC, 97\% predicted [82-108], and FEV(1), 92\% predicted [77-102]). Fe(NO) reached normal values after 2 mo (12.6 [11.4-15] ppb), whereas LTB(4) levels were still increased (12 [9.3-17.1] pg/ml). CONCLUSION: Children acutely exposed to chlorine in a swimming pool presented a substantial lung function impairment associated with biochemical exhaled breath alterations, represented mainly by an increase in LTB(4) and a reduction in Fe(NO). Although lung function and Fe(NO) improved within a few weeks, the increased levels of exhaled LTB(4) persisted for several months.