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; FEV1, 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 (LTB4) levels (24.4 [22.5-24.9] mu g/ml), and increased serum CC16 levels (mean +/- SEM, 23.4 +/- 2.5 mu g/L). Lung function returned to normal in 15 d (FVC, 97% predicted [82-108], and FEV1, 92% predicted [77-102]). Fe-NO reached normal values after 2 mo (12.6 [114-15] ppb), whereas LTB4 levels were still increased (12 [9.3-17.1] rho g/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 LTB4 and a reduction in Fe-NO. Although lung function and Fe-NO improved within a few weeks, the increased levels of exhaled L(T)B4 persisted for several months.