title: Exhaled breath hydrogen cyanide as a marker of earlyPseudomonas aeruginosainfection in children with cystic fibrosis.
abstract: Hydrogen cyanide is readily detected in the headspace abovePseudomonas aeruginosacultures and in the breath of cystic fibrosis (CF) patients with chronic (P. aeruginosa) infection. We investigated if exhaled breath HCN is an early marker ofP. aeruginosainfection. 233 children with CF who were free fromP. aeruginosainfection were followed for 2 years. Their median (interquartile range) age was 8.0 (5.0-12.2) years. At each study visit, an exhaled breath sample was collected for hydrogen cyanide analysis. In total, 2055 breath samples were analysed. At the end of the study, the hydrogen cyanide concentrations were compared to the results of routine microbiology surveillance.P. aeruginosawas isolated from 71 children during the study with an incidence (95% CI) of 0.19 (0.15-0.23) cases per patient-year. Using a random-effects logistic model, the estimated odds ratio (95% CI) was 3.1 (2.6-3.6), which showed that for a 1- ppbv increase in exhaled breath hydrogen cyanide, we expected a 212% increase in the odds ofP. aeruginosainfection. The sensitivity and specificity were estimated at 33% and 99%, respectively. Exhaled breath hydrogen cyanide is a specific biomarker of newP. aeruginosainfection in children with CF. Its low sensitivity means that at present, hydrogen cyanide cannot be used as a screening test for this infection.
authors.affiliation: Academic Department of Child Health, University Hospital of North Staffordshire, Stoke on Trent, UK; Institute of Science and Technology in Medicine, Keele University, Keele, UK.
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Gilchrist
authors.affiliation: School of Computing and Mathematics, Keele University, Keele, UK.
authors.forename: John
authors.initials: J
authors.lastname: Belcher
authors.affiliation: Manchester Adult Cystic Fibrosis Centre, University Hospital of South Manchester, Manchester, UK.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Jones
authors.affiliation: Institute of Science and Technology in Medicine, Keele University, Keele, UK.
authors.forename: David
authors.initials: D
authors.lastname: Smith
authors.affiliation: Division of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, UK.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Smyth
authors.affiliation: Institute of Child Health, Alder Hey Children's Hospital, Liverpool, UK.
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Southern
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Patrik
authors.initials: P
authors.lastname: Španěl
authors.affiliation: Manchester Adult Cystic Fibrosis Centre, University Hospital of South Manchester, Manchester, UK.
authors.forename: A Kevin
authors.initials: AK
authors.lastname: Webb
authors.affiliation: Academic Department of Child Health, University Hospital of North Staffordshire, Stoke on Trent, UK; Institute of Science and Technology in Medicine, Keele University, Keele, UK.
authors.forename: Warren
authors.initials: W
authors.lastname: Lenney