Cystic fibrosis (CF) patients characteristically have severe chronic airway inflammation associated with bacterial infection. A noninvasive marker of airway inflammation could be a useful guide to treatment of CF lung disease. The aim of this study was to assess whether measurement of hydrogen peroxide (H2O2) and nitric oxide (NO) in exhaled air can serve to monitor the effect of treatment with antibiotics in CF‐children with acute infective pulmonary exacerbations. Sixteen CF‐patients (mean age 12.3 yrs) with exacerbation of their lung infection were treated with intravenous antibiotics in an uncontrolled study. During treatment, H2O2 in exhaled air condensate was measured twice a week. In addition, serial NO measurements were performed in nine patients. During antibiotic treatment the median H2O2 concentration in exhaled air condensate decreased significantly from 0.28 µM (range 0.07–1.20 µM) to 0.16 µM (range 0.05–0.24 µM, p=0.002) and the mean forced expiratory volume in one second significantly increased from 55% predicted to 75% pred (p=0.001). In individual subjects, changes of H2O2 and FEV1 between pairs of serial measurements correlated weakly (p=0.08). Data on exhaled NO were inconclusive; exhaled NO did not change systematically during treatment. It is concluded that cystic fibrosis patients with an acute pulmonary exacerbation have abnormally high concentrations of hydrogen peroxide, but not of nitric oxide, in exhaled air, which decrease during intravenous antibiotic treatment. Further controlled studies should establish if exhaled hydrogen peroxide, may serve as a noninvasive parameter of airway inflammation to guide antibiotic treatment in cystic fibrosis lung disease.

Personally measured weekly exposure to NO 2 and respiratory health among preschool children. K. Mukala, J. Pekkanen, P. Tiittanen, S. Alm, R.O. Salonen, J. Tuomisto. #ERS Journal Ltd 1999. ABSTRACT: Nitrogen dioxide is known as a deep lung irritant. The aim of this study was to find out whether the relatively low ambient air NO 2 concentrations in the northern city of Helsinki had an impact on the respiratory health of children.The association between personal exposure to ambient air NO 2 and respiratory health was investigated in a 13-week follow-up study among 163 preschool children aged 3±6 yrs. Personal weekly average exposure to NO 2 was measured by passive diffusion samplers attached to the outer garments. Symptoms were recorded daily in a diary by the parents. Among 53 children, peak expiratory flow (PEF) was measured at home in the mornings and evenings. The association between NO 2 exposure and respiratory symptoms was examined with Poisson regression.The median personal NO 2 exposure was 21). An increased risk of cough was associated with increasing NO 2 exposure (risk ratio=1.52; 95% confidence interval 1.00±2.31). There was no such association between personal weekly NO 2 exposure and nasal symptoms, but a nonsignificant negative association was found between the exposure and the weekly average deviation in PEF.In conclusion, even low ambient air NO 2 concentrations can increase the risk of respiratory symptoms among preschool children. Eur Respir J 1999; 13: 1411±1417.

Measurement of nitric oxide in exhaled air is a noninvasive method to assess airway inflammation in asthma. This study was undertaken to establish the reference range of exhaled NO in healthy school-aged children and to determine the influence of ambient NO, noseclip and breath-holding on exhaled NO, using an off-line balloon sampling method.All children attending a primary school (age range 8-13 yrs) underwent NO measurements on two occasions with high and low ambient NO. Each time, the children performed four expiratory manoeuvres into NO-impermeable balloons, with and without 10 s of breath-holding and with and without wearing a noseclip. Exhalation flow and pressure were not controlled. NO was measured within 4 h after collection, by means of chemiluminescence. All children completed a questionnaire on respiratory and allergic disorders, and performed flow/volume spirometry.With low ambient NO, the mean exhaled NO value of 72 healthy children with negative questionnaires and normal lung function was 5.1¡0.2 parts per billion (ppb) versus a mean of 6.8¡0.3 ppb in the remaining 49 children with positive questionnaires for asthma and allergy, and/or recent symptoms of cold (p~0.001). Exhaled and ambient NO were significantly related, especially with ambient NO w10 ppb (r~0.86, p~0.0001 versus r~0.34, p~0.004 for ambient values v10 ppb). The use of a noseclip, with low ambient NO and without breath-holding, caused a small decrease in exhaled NO values (p~0.001). The effect of breath-holding on exhaled NO depended on ambient NO. With ambient NO w10 ppb, exhaled NO decreased, whereas with ambient NO v10 ppb, exhaled NO increased after 10 s breath-hold.It is concluded that off-line sampling in balloons is a simple and, hence, attractive method for exhaled nitric oxide measurements in children which differentiates between groups with and without self-reported asthma, allergy and colds, when ambient nitric oxide is v10 parts per billion. Wearing a noseclip and breath-holding affected measured values and should, therefore be standardized or, preferably, avoided. Eur Respir J 2001; 17: 898-903.

The concentration of nitric oxide in exhaled air, a marker of airway inflammation, depends critically on the flow of exhalation. Therefore, the aim of this study was to determine the effect of varying the flow on end-expiratory NO concentration and NO output in children with asthma or cystic fibrosis (CF) and in healthy children.Nineteen children with stable asthma, 10 with CF, and 20 healthy children exhaled from TLC while controlling expiratory flow by means of a biofeedback signal at approximately 2, 5, 10 and 20% of their vital capacity per second. NO was measured in exhaled air with a chemiluminescence analyser. Comparisons between the three groups were made by analysing the NO concentration at the endexpiratory plateau and by calculating NO output at different flows.Exhaled NO decreased with increasing flow in all children. Children with asthma had significantly higher NO concentrations than healthy children, but only at the lowest flows. Asthmatics using inhaled steroids (n=13) tended to have lower median exhaled NO than those without steroids. The slope of linearized (log-log transformed) NO/flow plots was significantly steeper in asthmatics than in healthy controls. CF patients had a significantly lower NO concentration and output over the entire flow range studied, compared to asthmatic and control subjects, with a similar NO/flow slope as control subjects.In conclusion, the nitric oxide concentration in exhaled air is highly flow-dependent, and the nitric oxide-flow relationship differs between asthmatics versus cystic fibrosis patients and control subjects. Assessment of the nitric oxide/flow relationship may help in separating asthmatics from normal children.