IMT in Ventilatory Muscle Metaboreflex in COPD

Study Overview
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Brief Summary
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This research intends to evaluate if inspiratory muscle training (IMT) reduces inspiratory muscle metaboreflex through the decrease of calf vascular resistance and increase of calf blood flow in Chronic Obstructive Pulmonary Disease (COPD).

Detailed Description
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Patients will be selected from the Hospital de Clinicas de Porto Alegre's COPD ambulatory, by convenience. Afterwards, patients will be submitted to pulmonary function test (spirometry) and cardiopulmonary exercise tests (incremental and submaximal), maximal inspiratory pressure evaluation and induction of the inspiratory muscle metaboreflex through venous occlusion plethysmography. Disease specific health related quality of life questionnaire (Saint George Respiratory Questionnaire) and daily life dyspnea questionnaire (Baseline Dyspnea Index and Transitional Dyspnea Index) will be administered at the first and last visit of each subject. Patients will undergo inspiratory muscle training for 30 minutes per day, 7 times a week, for 8 weeks, with Inspiratory Muscle Trainer device (PowerBreath Inc.). There will be a weekly follow up at the institution's Clinical Research Center, where maximal inspiratory pressure (PImax) and inspiratory training techniques will be reevaluated. After this period, tests of pulmonary function, questionnaires exercise tolerance and induction of the inspiratory muscle metaboreflex will be reevaluated.

Official Title
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Effect of Inspiratory Muscle Training in the Ventilatory Muscle Metaboreflex in Chronic Obstructive Pulmonary Disease Patients.

Conditions
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Chronic Obstructive Pulmonary Disease

Intervention / Treatment
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* Other: Inspiratory Muscle Training
* Other: SHAM


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Selection of subjects will be made through the Hospital de Clinicas de Porto Alegre Pneumology Service's COPD ambulatory. The inclusion criteria consist of -patients with COPD with functional confirmation through spirometry as by previously defined criteria. Those selected must be classified as GOLD II-IV, with moderate to severe expiratory flow obstruction. Exclusion Criteria: Patients will be considered ineligible for this study if they develop COPD exacerbation 8 weeks prior to recruitment if systemic corticosteroids are utilized (in the last three months) if there is history of acute myocardial infarction (in the last three months) if there is presence of neuromuscular disease history of cardiovascular disease or active smoking (in the last 6 months) clinical history of peripheral vascular disease and if age is equal or superior to 85 years

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 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

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Inspiratory Muscle Training (IMT)<br>Patients from the inspiratory muscle training group will utilize a linear pressoric resistance equipment with an inspiratory charge of 30% of maximum inspiratory pressure (adjusted weekly), during 7 days of the week, session duration of 30 minutes, during 8 weeks. | Other: Inspiratory Muscle Training<br>* Patients will receive IMT for 30 min, 7 times per week, for 8 weeks using Inspiratory Muscle Trainer device (PowerBreath Inc.). During training, patients will be instructed to maintain diaphragmatic breathing, with a breathing rate at 15 to 20 breaths/min. Inspiratory load was set at 30% of maximal static inspiratory pressure, and weekly training loads were adjusted to maintain 30% of the PImax. Each week, six training sessions were performed at home and one training session was supervised at the hospital.<br>|
| Placebo Comparator: Sham IMT<br>Patients in the placebo group will be submitted to inspiratory muscle training with the same equipment as the intervention group, however without a resistance generating spring. | Other: SHAM<br>* Patients will receive SHAM training for 30 min, 7 times per week, for 8 weeks using Inspiratory Muscle Trainer device (PowerBreath Inc.) without load. Patients will be instructed to maintain diaphragmatic breathing, with a breathing rate at 15 to 20 breaths/min. Each week, six training sessions were performed at home and one training session was supervised at the hospital.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Calf blood flow |  | 8 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to exercise tolerance (tlim) | Exercise time during high intensity submaximal Cardiopulmonary exercise testing | 8 weeks | 
| Maximum Inspiratory Pressure |  | 8 weeks | 
| The St George's Respiratory Questionnaire |  | 8 weeks | 
| Baseline Dyspnea Index/Transitional Dyspnea Index |  | 8 weeks | 
| Calf vascular resistance | Calf blood flow/mean arterial pressure | 8 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Pulmonary Rehabilitation, Inspiratory Muscle Training, Inspiratory Muscle Strength, Vascular Resistance, Exercise, Chronic Obstructive Pulmonary Disease