Exhaled breath temperature measurement and asthma control in children prescribed inhaled corticosteroids: A cross sectional study.

BACKGROUND: Exhaled breath temperature (EBT) reflects airways (both eosinophilic and neutrophilic) inflammation in asthma and thus may aid the management of children with asthma that are treated with anti-inflammatory drugs. A new EBT monitor has become available that is cheap and easy to use and may be a suitable monitoring device for airways inflammation. Little is known about how EBT relates to asthma treatment decisions, disease control, lung function, or other non-invasive measures of airways inflammation, such as exhaled nitric oxide (ENO). OBJECTIVE: To determine the relationships between EBT and asthma treatment decision, current control, pulmonary function, and ENO. METHODS: Cross-sectional prospective study on 159 children aged 5-16 years attending a pediatric respiratory clinic. EBT was compared with the clinician's decision regarding treatment (decrease, no change, increase), asthma control assessment (controlled, partial, uncontrolled), level of current treatment (according to British Thoracic Society guideline, BTS step), ENO, and spirometry. RESULTS: EBT measurement was feasible in the majority of children (25 of 159 could not perform the test) and correlated weakly with age (R = 0.33, P = <0.01). EBT did not differ significantly between the three clinician decision groups (P = 0.42), the three asthma control assessment groups (P = 0.9), or the current asthma treatment BTS step (P = 0.57). CONCLUSIONS & CLINICAL IMPLICATIONS: EBT measurement was not related to measures of asthma control determined at the clinic. The routine intermittent monitoring of EBT in children prescribed inhaled corticosteroids who attend asthma clinics cannot be recommended for adjusting anti-inflammatory asthma therapy.

Protease concentration in amniotic fluid at term and early childhood respiratory symptoms.

OBJECTIVE: Asthma is a common chronic disease associated with altered proteolytic activity. The present study tested the hypothesis that altered protease concentration in amniotic fluid (AF), an index of airway fluid at birth, precedes early cough and wheeze. METHODS: AF was collected and analysed for the following: matrix metalloproteinases (MMP) -2, -8 and -9, tissue inhibitor of metalloproteinases (TIMP) -1 and 2, plasminogen activator inhibitor (PAI)-1. Infant were followed up at ages 1, 2 and 3 years. RESULTS: Samples of AF were obtained in 92 infants. There were inconsistent and relatively small differences in some analytes between those individuals with and without symptoms at ages one and two years. PAI-1 concentrations were reduced in association with cough at age 1 year (p = 0.035). Reduced MMP-8:TIMP-2 ratio was associated with wheeze at age 2 years (p = 0.038). There were no associations between AF analytes and symptoms at 3 years of age. CONCLUSION: There is heterogeneity in concentrations of proteases and their inhibitors in airways at birth but in this exploratory study, there was no consistent evidence that protease concentration at birth was important to later respiratory symptoms.

Comparative repeatability of two handheld fractional exhaled nitric oxide monitors.

BACKGROUND: The use of portable fractional exhaled nitric oxide (FENO) devices is increasingly common in the diagnosis and management of allergic airways inflammation. METHODS: We tested two handheld FENO devices, to determine (a) if there was adequate intradevice repeatability to allow the use of single breath testing, and (b) if the devices could be used interchangeably. In a mixed pediatric population, including normal, asthmatic, and children with peanut allergies, 858 paired values were collected from the NIOX-MINO® and/or the NObreath® devices. RESULTS: The NIOX-MINO® showed excellent repeatability (mean difference of 0.1 with 95% limits of agreement between -7.93 to 7.72 ppb), while the NObreath® showed good repeatability (mean difference of -1.61 with 95% limits of agreement between -14.1 and 10.8 ppb). Intradevice repeatability was good but not adequate and the NIOX-MINO® systematically produced higher results than the NObreath® [mean difference of 7.8 ppb with 95% limits of agreement from -11.55 to 27.52 ppb (-33% to 290%)]. CONCLUSIONS: Our results support the manufacturer's advice that single breath testing is appropriate for the NIOX-MINO®. NObreath® results indicate that the mean of more than one breath should be utilized. The devices cannot be used interchangeably.