Methods of Determining Asthma Severity in Children
Condition: Asthma
MeSH terms: Asthma
Study type: Observational

Summary: 
      Current methods of measuring asthma severity can be problematic when used with children. A
      measurement called exhaled breath condensates (EBC) may be a more useful way to determine
      asthma severity in childhood. The purpose of this study is to determine if EBC measurements
      are useful for determining asthma severity in asthmatic children as compared to currently
      used laboratory measures.

      Study hypotheses: 1) A broad panel of EBC measures will distinguish asthmatic children not on
      inhaled corticosteroids (ICS) from both asthmatic children routinely taking ICS and
      nonasthmatic controls. 2) Standardized equipment and methodologies for EBC collection,
      processing, storage, shipping, and pH and mediator measurements can be developed that will
      eliminate significant contamination from oropharyngeal saliva and allow for shipping and
      processing at a central site.
    

Detailed description: 
      The current national guidelines for assessing asthma severity have several limitations for
      use in asthmatic children. One major limitation is that spirometric measures of airflow
      limitation, including forced expiratory volume in one second (FEV1), generally cannot be
      reliably obtained in children less than 7 years of age. Furthermore, most children with
      asthma have essentially normal measures of airflow by spirometry or peak flow, so such
      measurements are generally not useful in diagnosis and treatment. Previous studies indicate
      that lung-specific biomarkers of inflammation, such as bronchial hyperresponsiveness
      measures, might simplify, improve, and optimize the guidelines. Collection of EBC samples may
      also be useful; EBC samples can be obtained by noninvasive means and are easier to obtain
      than conventional samples. However, contamination by saliva is an issue in collecting EBC
      samples, and standardization of sample collection is needed. This study will compare the
      utility of two different sample collecting equipment, the EcoScreen and the R-Tube. This
      study will also evaluate the usefulness of EBC samples in distinguishing between asthmatic
      children taking ICS, asthmatic children not taking ICS, and nonasthmatic children.

      There are 2 parts to this study. In Part A, two EBC samples will be collected from each
      participant. Some participants will be have one EBC sample taken by the EcoScreen and the
      other taken by the R-Tube; other participants will have both samples taken by the R-Tube. In
      Part B, asthmatics taking ICS, asthmatics not taking ICS, and nonasthmatics will give 2 EBC
      samples each via the R-Tube.

      Participants will be asked to complete a questionnaire on their asthma symptoms and allergies
      and will have a brief physical exam. Allergy skin prick testing, urine collection,
      measurement of exhaled nitric oxide, and conventional incentive spirometry (used to obtain
      several measures of lung function) will also occur. Participants will also be asked to donate
      a blood sample.
    

Intervention name(s): R-Tube or EcoScreen
Intervention type(s): Device
Intervention description(s): Device for collection of exhaled breath condensates (EBC) collection (i.e. condensing and collecting breath vapor from a cold, solid surface)
Observational model: Case-Control
Time perspective: Prospective