Hydrogen cyanide concentrations in the breath of adult cystic fibrosis patients with and without Pseudomonas aeruginosa infection

Abstract

Elevated concentrations of hydrogen cyanide (HCN) have been detected in the headspace of Pseudomonas aeruginosa (PA) cultures and in the breath of children with cystic fibrosis (CF) and PA infection. The use of mouth-exhaled breath HCN as a marker of PA infection in adults is more difficult to assess as some without PA infection generate HCN in their mouths. The analysis of breath exhaled via the nose, thereby avoiding volatile compounds produced in the mouth, will demonstrate elevated concentrations of HCN in adult CF patients chronically infected with PA. Using selected ion flow mass spectrometry (SIFT-MS), the mouth and the nose-exhaled breaths of 20 adult CF patients; 10 with chronic PA infection and 10 free from PA infection, were analysed for HCN. Acetone and ethanol were also measured as controls. SIFT-MS allows direct sampling and analysis of single breath exhalations, obviating the need to collect samples into bags or onto traps, which can compromise samples. HCN was detected in the mouth-exhaled breath of patients in both groups and in the nose-exhaled breath of patients with chronic PA infection. The difference in median (IQR) nose-exhaled HCN between the groups is statistically significant (11 (0.8-18) ppbv versus 0 (0-3.2) ppbv, p = 0.03). The concentrations of acetone and ethanol in nose-exhaled and mouth-exhaled breath are in keeping with previous studies. HCN in nose-exhaled breath is a biomarker of chronic airway infection with PA in adults with CF. Its application as a non-invasive diagnostic test for early PA infection warrants further investigation.

Exhaled breath hydrogen cyanide as a marker of earlyPseudomonas aeruginosainfection in children with cystic fibrosis

“…The in vitro conditions affecting hydrogen cyanide release have been established [13, 14] and it is known that P. aeruginosa is the only organism frequently found in the CF lung that produces hydrogen cyanide [15, 16]. In vivo studies have demonstrated elevated exhaled breath hydrogen cyanide in both children and adults with CF and chronic P. aeruginosa infection, compared to controls [17, 18]. These studies demonstrated that hydrogen cyanide is a biomarker of chronic P. aeruginosa infection.…”

A widely tunable, near-infrared laser-based trace gas sensor for hydrogen cyanide (HCN) detection in exhaled breath

“…Laser spectroscopy offers advantages for trace gas detection, in particular in speed, specificity, sensitivity and real-time detection. Laser-based spectroscopic methods have been widely used for sensing, such as laserinduced breakdown spectroscopy (LIBS) [9], cavity ring in exhaled breath of CF patients [24][25][26][27]. Cystic fibrosis itself is an inherited genetic disease, which is characterized by recurrent pulmonary infections and chronic lung inflammation.…”

The in vitro identification and quantification of volatile biomarkers released by cystic fibrosis pathogens

“…[6][7][8] The second stage involves the analysis of exhaled breath samples taken from patients known to have pulmonary infection with the relevant pathogen. 9,10 This investigates if the VOCs identied in vitro can also be identied in vivo and attempts to assess the effect of host factors such as co-infection, dietary intake and diurnal variation. 11,12 If conrmed, further studies may be undertaken to investigate if the VOCs are detectable in exhaled breath early enough aer new infection to allow them to be used as a screening test.…”