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Small Airway Involvement in Patients With Chronic Hypersensitivity Pneumonitis

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02523833
Recruitment Status : Completed
First Posted : August 14, 2015
Last Update Posted : May 2, 2018
Information provided by (Responsible Party):
Olívia Meira Dias, University of Sao Paulo General Hospital

Brief Summary:

Hypersensitivity pneumonitis (HP) is a syndrome with variable clinical presentation in which lung inflammation is caused by inhalation of specific organic antigens or low molecular weight particles in previously sensitized individuals. Systemic symptoms may or may not be present. Chronic HP represents the final stage of the disease, caused by prolonged exposure to a particular antigen, leading to pulmonary fibrosis. In chronic HP, pulmonary function tests (PFTs) commonly present a restrictive ventilatory pattern, with decreased diffusion of carbon monoxide (DLCO). Some patients can also have obstructive disorders with expiratory flow limitation, due to obstruction of the small airways typically caused by bronchiolar involvement in this pathology. However, PFTs are relatively insensitive for detecting small airway involvement when there is concomitant interstitial fibrosis. First, conventional PFTs may be normal in patients with small airway involvement, since they contribute to less than 30% of the total airway resistance. In addition, damage to the small airways in HP is generally occurring parallel to areas of focal fibrosis - even when small airways are involved, these regions can be completely ignored, since they are excluded from ventilation. In summary, traditional PFTs are not sufficiently sensitive to detect diffuse small airway involvement in these diseases. In these cases, other functional tests, such as forced oscillation technique (FOT) and high resolution computer tomography (HRCT) scans of the chest with expired studies, could be used for this purpose.

This will be a cross-sectional study, which will include the following evaluations in 28 patients with HP recruited from our clinic:

- Clinical variables: (A) demographic and anthropometric data; (B) Clinical data: Onset of symptoms and time of diagnosis

C) Dyspnea score:

D) Smoking: * Current or former smoker * Smoking history (number of cigarettes smoked per day and for how long);

  • Spirometry with forced and slow maneuvers before and after bronchodilator (salbutamol);
  • Plethysmography to measure lung volumes;
  • Diffusion capacity of carbon monoxide (DLCO);
  • High-resolution chest CT with expiratory scans;
  • Six-minute walk test;
  • Cardio-respiratory test using a maximal incremental treadmill.
  • Forced oscillation technique (FOT).

Condition or disease Intervention/treatment Phase
Hypersensitivity Pneumonitis Airway Disease Small Drug: Salbutamol Not Applicable

  Show Detailed Description

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 27 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Other
Official Title: Evaluation of Small Airway Involvement in Patients With Chronic Hypersensitivity Pneumonitis and Its Impact on Exercise Limitation
Actual Study Start Date : September 1, 2015
Actual Primary Completion Date : June 1, 2017
Actual Study Completion Date : November 20, 2017

Arm Intervention/treatment
Chronic HP patients
Chronic hypersensitivity pneumonitis patients - use of salbutamol
Drug: Salbutamol
Salbutamol after spirometry, plethysmography and forced oscillation technique.
Other Name: Aerolin

Primary Outcome Measures :
  1. Pletismography - forced expiratory volume in 1 second / forced vital capacity (FEV1/FVC) < 0.7, residual volume (VR) and VR/total lung capacity (TLC) values and changes with salbutamol [ Time Frame: One day visit ]
    Percentage of VEF1/FVC < 0.7, residual volume (VR) >120% predicted and VR/total lung capacity (TLC)>.45 values and changes with salbutamol

Secondary Outcome Measures :
  1. Air trapping in expiratory chest CT scans [ Time Frame: One day visit ]
    Expiratory / inspiratory mean lung attenuation ratio as a measure of air trapping

  2. Reactance and impedance of small airways through forced oscillation technique [ Time Frame: One day visit ]
    Reactance and impedance of small airways

Other Outcome Measures:
  1. Maximal cardiopulmonary exercise testing [ Time Frame: One day visit ]
    Decrease of inspiratory capacity > 10% during maximal cardiopulmonary exercise testing

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 75 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Diagnosis of chronic hypersensitivity pneumonitis confirmed by:

    • patients with known exposure to antigen, tomographic criteria and absence of other diagnoses;
    • confirmation with histology obtained by transthoracic biopsy, surgical biopsy or bronchoalveolar lavage with lymphocytosis above 30%;
  • Age between 18 to 75 years;
  • Clinically stable (no exacerbations or hospitalizations related to the underlying disease) for at least 6 weeks;
  • Compliance with signing an informed consent for participation in the project.

Exclusion Criteria:

  • Patients with FEV1 and / or DLCO <30% predicted;
  • Patients using supplemental oxygen;
  • Previous diagnosis of asthma or COPD;
  • Pregnant women;
  • Musculoskeletal disorders that limit exercise;
  • Another medical condition that might interfere with the execution of tests;
  • Current or past smoking history with tobacco intake greater than 30 pack-years;
  • Severe heart disease functional class New York Heart Association (NYHA) III-IV) and / or decompensated hear failure.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02523833

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Olívia Meira Dias
São Paulo, Brazil, 05409002
Sponsors and Collaborators
University of Sao Paulo General Hospital
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Principal Investigator: Carlos Roberto R de Carvalho, MD, PhD Heart Institute (InCor)

Publications of Results:
Other Publications:
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Responsible Party: Olívia Meira Dias, Medical doctor, University of Sao Paulo General Hospital Identifier: NCT02523833     History of Changes
Other Study ID Numbers: SDC 3966/13/091
First Posted: August 14, 2015    Key Record Dates
Last Update Posted: May 2, 2018
Last Verified: May 2018
Additional relevant MeSH terms:
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Alveolitis, Extrinsic Allergic
Immune System Diseases
Lung Diseases
Respiratory Tract Diseases
Respiratory Tract Infections
Lung Diseases, Interstitial
Respiratory Hypersensitivity
Hypersensitivity, Immediate
Bronchodilator Agents
Autonomic Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Anti-Asthmatic Agents
Respiratory System Agents
Tocolytic Agents
Reproductive Control Agents
Adrenergic beta-2 Receptor Agonists
Adrenergic beta-Agonists
Adrenergic Agonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action