IMT in Ventilatory Muscle Metaboreflex in COPD

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

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).

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.

Pulmonary Rehabilitation, Inspiratory Muscle Training, Inspiratory Muscle Strength, Vascular Resistance, Exercise, Chronic Obstructive Pulmonary Disease

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.

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.

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.

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.

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

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