Background: Cyanide (CN) has been shown to be chronically present in the airways of cystic fibrosis (CF) patients, as a byproduct Pseudomonas’ metabolism. We sought to determine the concentrations of CN in the sputum of CF patients, who were admitted to the hospital with acute clinical exacerbations using 2 different approaches.
Methods: Sputum was collected within 1 day (median) of admission and immediately analyzed for the presence of total and free CN.
Results: We found 1) toxic levels of CN in the sputum of our patients, ranging from 27 to 401 µM, 2) the majority of the cyanide was in the form of free, thus diffusible, CN and 3) no cyanide in the blood.
Conclusions: While the chronic presence of CN in patients colonized with pseudomonas is not a new concept, the present data support the view that very high levels of free cyanide are present in the airways of CF patients during an acute clinical exacerbation, i.e. levels compatible with concentrations of CN able to virtually stop the mitochondrial activity. It becomes therefore urgent to investigate whether, in CF patients, cyanide is a significant factor affecting the short and long-term outcome and whether a specific treatment of CN intoxication of the airways is warranted during an exacerbation.