Positive Airway Pressure for the Treatment of Asthma
Condition: Asthma; Sleep Apnea
MeSH terms: Asthma; Sleep Apnea Syndromes
Study type: Interventional

Summary: 
      Asthma is an extremely common disorder, which is becoming more prevalent. The purpose of this
      study is to examine how nocturnal lung volumes contribute to asthma severity, which may
      explain part of the link between asthma and obesity. The investigators seek to test the
      hypothesis that raising lung volumes during the night will improve asthma symptoms. The
      investigators work may lead to new targets for therapy.
    

Detailed description: 
      Asthma is a chronic respiratory disease characterized by airway inflammation and airway
      hyperresponsiveness, which causes airflow obstruction. It is extremely prevalent, affecting
      an estimated 22 million Americans, and costly with loss of productivity and direct healthcare
      costs in the billions of dollars. The incidence and prevalence of asthma are increasing, both
      in the US and around the world. This increase comes despite greater understanding of the
      inflammatory and allergic basis for asthma, and despite better antiinflammatory medications.
      One explanation for the increasing prevalence of asthma is the concomitant increase in
      obesity, with the majority of Americans now overweight or obese. Numerous studies have
      convincingly linked asthma and obesity, and demonstrated increased obstruction with weight
      gain and decreased obstruction with weight loss. However, the mechanisms that underlie this
      linkage are not known.

      We believe that low lung volumes contribute to the pathogenesis and severity of asthma.
      End-expiratory lung volume is decreased in obesity, and likely falls further during sleep,
      particularly in overweight and obese patients. Both upper and lower airway resistance
      increase with decreasing lung volumes, as airways become smaller. However, prior work has
      shown that lower airway resistance increases out of proportion to the decrease in lung volume
      that occurs during sleep in asthma patients. This difference between controls and people with
      asthma has not been further explored, yet may provide insight into asthma pathogenesis and
      provide potential targets for therapy.

      Therefore, we propose a series of experiments to define the impact of lung volumes during
      sleep on airway resistance. One of these experiments will be to to test the hypothesis that
      lung stretch can be used therapeutically by tonically and dynamically increasing lung volumes
      during sleep using bi-level positive airway pressure. This research can help delineate asthma
      pathogenesis and may help improve therapeutic options in this exceedingly common disease.
    

Intervention name(s): Bilevel PAP (4 weeks); Usual Care (4 weeks); Washout Period (4 weeks)
Intervention type(s): Device; Other; Other
Intervention description(s): Subjects will use bilevel PAP each night for 4 weeks. The pressure levels will be adjusted by the investigators to increase lung volumes during the night.; Subjects will continue with their usual asthma care. Investigators will make no changes to their medications or other habits.; Subjects will continue with their usual asthma care in between the Usual Care and Bilevel PAP periods. Investigators will make no changes to their medications or other habits.
Other intervention name(s): Bilevel positive airway pressure
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Asthma; Nocturnal Asthma; Lung volumes; Deep inspiration; Obstructive sleep apnea