RES/TUE/01 MEASURING BIOMARKERS IN THE BREATH OF CHILDREN: DIRECT OR INDIRECT MEASURES OF HYDROGEN CYANIDE

¹B Enderby, ¹W Lenney, ²D Smith. ¹University Hospital North Staffordshire, Stoke on Trent; Staffordshire, UK; ²Institute of Science and Technology in Medicine; Keele University, Stoke on Trent; Staffordshire, UK

Aim: An in-vitro study using the selected ion flow tube mass spectrometry (SIFT–MS) technique has revealed elevated levels of the gas hydrogen cyanide (HCN) above plated pure growth samples of Pseudomonas aeruginosa.^{1 2} It was subsequently shown that these findings are reproducible in-vivo in children with cystic fibrosis. This study aimed to demonstrate that HCN can be measured in the breath of children with asthma and cystic fibrosis using SIFT–MS, both on and off-line.

Method: Children with either asthma (n  =  13) or cystic fibrosis (n  =  15) were recruited from the paediatric outpatient clinic. Each child gave three slow inhalations and exhalations directly into the SIFT–MS instrument via a heated viral filter (on-line) while wearing a nose-clip. Following this, a sample of their breath was also collected in a plastic container (off-line), incubated at 37°C and analyzed using the SIFT–MS instrument. Dry air was also analyzed using the off-line technique, to assess if HCN was produced by the bag itself.

Results: HCN concentrations measured in children with cystic fibrosis were once again shown to be significantly higher compared with those with asthma (p<0.001; Mann–Whitney U test). An excellent correlation was also seen between bag and on-line breath HCN levels (r²  =  0.82, see fig 1). Control bags were found to contain no HCN.

Conclusion: It was shown that HCN can also be measured accurately off-line using SIFT–MS. Breath samples can be quickly and easily obtained in the clinical setting, even from very young children and in those who are acutely unwell and are therefore unable to breathe directly into the instrument.

RES/TUE/02 FILAGGRIN NULL MUTATIONS MAY PREDICT INCREASED RISK OF ASTHMA EXACERBATIONS IN CHILDREN AND YOUNG ADULTS

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