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A3669 - Total Cyanide in the Sputum of Cystic Fibrosis Patients During an Acute Exacerbation
Author Block: D. Guck1, N. Tubbs2, D. Kim3, P. Haouzi4; 1Internal Medicine, Penn State Hershey Medical Center, Hershey, PA, United States, 2Pulmonary Medicine, Penn State Hershey Medical Center, Hershey, PA, United States, 3Pulmonary / Critical Care Medicine, Penn State Hershey Medical Center, Hershey, PA, United States, 4Penn State Hershey Med Ctr, Hershey, PA, United States.
RATIONALE: Pseudomonas aeruginosa is the most important respiratory pathogen colonizing the airways of adult cystic fibrosis (CF) patients. This bacteria is a substantial contributor to the development of lung structural damage and thus to the morbidity and mortality in the CF population. One aspect of the “toxicity” of P. aeruginosa has long been overlooked: its ability to produce cyanide (CN). CN has been previously found to be present in the high micromolar range in the sputum of chronically infected CF patients, well above CN toxicity levels (10 micromolar). Our objective was to determine the concentration of CN in sputum ([CN]sp) of CF patients presenting an acute exacerbation requiring hospital admission.
METHODS: Sputum was obtained from eleven CF patients admitted to the hospital for an acute exacerbation. Sputum was collected at bedside on admission and immediately brought to the laboratory for analysis. The sputum was sequentially mixed with perchloric acid, sodium hypochlorite, and barbituric acid-pyridine solution to determine the total pool of CN present following the approach proposed by Lundquist and Sorbo (1989) in the blood. The solution was scanned between 400-700nm and the peak of absorbance at 580 nm was measured ~10 minutes later. Using a standardized curve, [CN]sp was determined. The CF-ABLE score was also determined for each patient.
RESULTS: Pseudomonas aeruginosa was isolated in ten out of the eleven patients. Cyanide was present in the sputum of all patients in concentrations ranging from 28 to 401 micromolar but without any correlation with FEV1, the number of admissions or CF-ABLE scores.
CONCLUSION: This study showed that cyanide is present at very high concentration in cystic fibrosis patients presenting an acute exacerbation. Whether change in [CN]sp could be used as a potential marker of an acute exacerbation in a given patient and whether CN plays an important contribution in triggering CF exacerbation remain to be determined. Finally, the pool of free cyanide must be evaluated as all the proteins and iron present in the sputum could be trapping free cyanide and limit its diffusion/toxicity to the airway epithelium, reducing the actual risk related to the presence of such very high pool of the total CN that we have found in the airways.