Pursed-lips Breathing and Dynamic Hyperinflation

Study Overview
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Brief Summary
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Background: Dynamic hyperinflation (DH) is an important factor leading to dyspnea and consequent limitations in functional capacity of chronic obstructive pulmonary disease (COPD) patients. It has not been completely elucidated whether pursed-lips breathing (PLB) is able to minimize DH and its effects on exercise tolerance in these patients. The aim of this study was to evaluate the acute effect of PLB on DH and functional capacity in patients with COPD. Design: Randomized cross-over study. Setting: The study will be conducted in an outpatient pulmonary rehabilitation program in Florianópolis, Brazil. Subjects: Twenty-five patients with COPD (16 men, mean age 64 (7) years, FEV1=41.7 (14.7)% predicted, BMI=27.6 (5.13)kg/m2). Interventions: Patients will randomly perform two six-minute walk tests with and without PLB (6MWTPLB and 6MWTNon-PLB) and two Glittre-ADL tests with and without PLB (TGlittrePLB and TGlittreNon-PLB). Main measures: At baseline and immediately after the tests, the inspiratory capacity (IC) will be assessed by the slow vital capacity (SVC) maneuver.

Detailed Description
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Pulmonary function testing Lung function will be tested using an Easy One spirometer (NDD Medical Technologies Inc., Zurich, Switzerland), and calibration checked before each evaluation. Spirometry will be performed in accordance with ATS/ERS standards (Miller et al, 2005). The predicted values will be calculated from the equations proposed by Pereira et al. (2007). Inspiratory capacity (IC) measurement IC will be measured with the patient in the sitting position, using an Easy One portable spirometer (NDD Medical Technologies Inc., Zurich, Switzerland), before and immediately after the tests, by the slow vital capacity maneuver starting from a stable end-expiratory volume, in accordance with ATS/ERS standards (Miller et al,2005). A minimum of three maneuvers (maximum of eight) will be performed and, in order to be considered reproducible, two curves could not vary by more than 5% or 150mL. The higher value of two reproducible curves will be used for analysis. DH is considered when the IC decreased 10% and/or 150mL or more compared to the basal value (O'Donnell et al, 2001). Six-minute walk test The 6MWT will be performed according to the guidelines of the American Thoracic Society (2002). Pulse oxygen saturation (SpO2; Oxi-Go, Oximeter Plus, Roslyn Heights, New York, USA) and dyspnea (Borg CR10 scale) will be measured at the beginning and at the end of the test. Predicted values for walking distance will be calculated according to Iwama et al. (2009). Glittre-ADL test The TGlittre consists of completing a circuit as follows: from a sitting position, the subject stands up and walks along a flat 10-m long course, in the middle of which there is a two-step ladder (each step 17 cm high x 27 cm deep) to be climbed; after completing the 10 m, the subject faces a shelf containing three 1-kg objects positioned on the top shelf (shoulder height) and moves them one by one to the bottom shelf (waist height) and then to the floor; the objects are then returned to the bottom shelf and finally to the top shelf again; the subject walks back, climbing up and down the steps, until reaching the starting point (chair), sits down and immediately begins the next lap. The subjects carry a weighted backpack (2.5 kg for women, 5.0 kg for men) and are instructed to complete five laps on this circuit as quickly as possible. SpO2 and dyspnea index (Borg CR10 scale) will be measured at the beginning of the test, at the end of each lap, and at the end of the test (Skumlien et al, 2006).

Official Title
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Pursed-lips Breathing Reduces Reduces Dynamic Hyperinflation Induced by Activities of Daily Living Test in Patients With COPD

Conditions
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Chronic Obstructive Pulmonary Disease

Intervention / Treatment
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* Other: Pursed-lips breathing
* Other: No pursed-lips breathing


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: COPD GOLD stages 2, 3, and 4 of severity of airflow limitation history of smoking ≥ 20 pack-years clinical stability in the four weeks prior to the study protocol Exclusion Criteria: long-term oxygen therapy current smoking any pulmonary disease other than COPD comorbidities that would compromise their ability to perform any of the evaluations in the study

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Pursed-lips breathing<br>All patients performed both tests (six-minute walk test and Glittre ADL test) with pursed-lips breathing. | Other: Pursed-lips breathing<br>* Expiration with pursed-lips during functional capacity tests.<br>|
| Placebo Comparator: No pursed-lips breathing<br>All patients performed both tests (six-minute walk test and Glittre ADL test) without pursed-lips breathing. | Other: No pursed-lips breathing<br>* To avoid pursed-lips breathing, subjects use a a mouthpiece (2cm diameter X 2cm length) such as the one used in pulmonary functional tests.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dynamic hyperinflation | Effect of pursed-lips breathing on inspiratory capacity during the six-minute walk test and Glittre-ADL test. | At the beginning and immediately after de six-minute walk test and Glittre ADL test. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Six-minute walk test performance | Effect of pursed-lips breathing on the distance walked (meters) during the six-minute walk test. | Both tests (with and without pursed-lips breathing) will be held at least two days to one week apart. | 
| Glittre-ADL test performance | Effect of pursed-lips breathing on the time spent (minutes) performing the Glittre-ADL tes. | Both tests (with and without pursed-lips breathing) will be held at least two days to one week apart. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Inspiratory capacity, Positive-pressure respiration, Exercise, Activities of daily living, COPD.