Inspiratory Muscle Training and Neuromuscular Electrical Stimulation in Chronic Obstructive Pulmonary Disease

Inspiratory Muscle Training and Neuromuscular Electrical Stimulation in Chronic Obstructive Pulmonary Disease

Effects of Inspiratory Muscle Training and Neuromuscular Electrical Stimulation in Patients With Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a significant current public health problem, characterized by the presence of limited airflow. However, COPD has important manifestations beyond the lungs, the so-called systemic effects. These included dysfunction of peripheral and respiratory muscles. The growing amount of evidence has shown that patients with COPD also present important deficits in postural balance and consequently, increased risk of falling. As an essential part of the management of COPD, pulmonary rehabilitation (PR) alleviates dyspnea and fatigue, improves exercise tolerance and health-related quality of life, and reduces hospital admissions and mortality for COPD patients. Exercise is the key component of PR, which is composed of exercise assessment and training therapy. Currently, two modalities of therapy have been suggested as complementary to pulmonary rehabilitation: inspiratory muscular training (IMT) and neuromuscular electrical stimulation (NMES). Based on the premise that peripheral and respiratory muscle dysfunction can negatively impact postural control of patients with COPD, and given the importance of balance as a modifiable risk factor for falls, it is important to investigate whether the use of these therapeutic modalities (IMT and/or NMES) is capable of improving the short-term effects of pulmonary rehabilitation and also promoting improved balance.

IMT + NMES + Pulmonary Rehabilitation IMT will be performed using a device with linear load pressure (POWERbreathe Medic Plus ®, SP, BR). NMES will be applied using an calibrated electrical stimulator (Neurodyn High Volt, IBRAMED, São Paulo/São Paulo, Brazil). Pulmonary Rehabilitation: The physical training part of pulmonary rehabilitation will consist of aerobic and resistance exercise.

IMT will be performed using a device with linear load pressure (POWERbreathe Medic Plus ®, SP, BR). Pulmonary Rehabilitation: The physical training part of pulmonary rehabilitation will consist of aerobic and resistance exercise.

NMES will be applied using an calibrated electrical stimulator (Neurodyn High Volt, IBRAMED, São Paulo/São Paulo, Brazil). Pulmonary Rehabilitation: The physical training part of pulmonary rehabilitation will consist of aerobic and resistance exercise.

Pulmonary Rehabilitation: The physical training part of pulmonary rehabilitation will consist of aerobic and resistance exercise.

IMT will be performed using the POWERbreathe® Medic Plus inspiratory training device for five sets of 10 repetitions each, with a one-minute interval between each set. The initial load set will be 30% of maximal inspiratory pressure (MIP), during the first two weeks to allow for an adjustment period. The IMT wil be performed two times per week for 8 weeks. NMES will be applied using an calibrated electrical stimulator (Neurodyn High Volt, IBRAMED, São Paulo/São Paulo, Brazil). The following parameters will be used: 50 Hz frequency, pulse duration of 400 µs, work cycle of 5 seconds ON and 15 seconds OFF (first month) adjusted for 10 seconds ON and 30 seconds OFF (second month) and maximum intensity tolerated during 2 times per week for 8 weeks. Pulmonary Rehabilitation The pulmonary rehabilitation will consist of aerobic and resistance exercise during 8 weeks.

IMT will be performed using the POWERbreathe® Medic Plus (POWERbreathe Medic Plus ®, SP, BR) inspiratory training device for five sets of 10 repetitions each, with a one-minute interval between each set. The initial load set will be 30% of maximal inspiratory pressure (MIP), during the first two weeks to allow for an adjustment period. After that, load increases occurred as follows: 35% of MIP in week 3, 40% of MIP in week 4, 45% of MIP in week 5, 50% of MIP at week 6, 55% of MIP in week 7, and 60% of MIP in weeks 8. Pulmonary Rehabilitation The pulmonary rehabilitation will consist of aerobic and resistance exercise during 8 weeks.

NMES will be applied using an calibrated electrical stimulator (Neurodyn High Volt, IBRAMED, São Paulo/São Paulo, Brazil). The following parameters will be used: 50 Hz frequency, pulse duration of 400 µs, work cycle of 5 seconds ON and 15 seconds OFF (first month) adjusted for 10 seconds ON and 30 seconds OFF (second month) and maximum intensity tolerated during 2 times per week for 8 weeks. Pulmonary Rehabilitation The pulmonary rehabilitation will consist of aerobic and resistance exercise during 8 weeks.

Pulmonary Rehabilitation The pulmonary rehabilitation will consist of aerobic and resistance exercise during 8 weeks.

Static postural balance will be assessed on a portable force platform (AccuSway Plus, AMTI®, MA, USA) using the center of pressure displacement amplitude in the anteroposterior direction (COP) (cm).

Static postural balance will be assessed on a portable force platform (AccuSway Plus, AMTI®, MA, USA) using the area of ellipse (AE) (cm2).

Static postural balance will be assessed on a portable force platform (AccuSway Plus, AMTI®, MA, USA) using the velocity of displacement of center of pressure (COPvel) (cm/s).

Static postural balance will be assessed on a portable force platform (AccuSway Plus, AMTI®, MA, USA) using the center of area of pressure and area of ellipse (AE) (cm2).

Static and dynamic postural balance will assessed using the Berg Balance Scale (score points). Scores range from 0 to 56, with higher scores indicating better balance.

Static and dynamic postural balance will assessed using the Balance Evaluation Systems Test (score points). The total score of the test (108 points) will be calculated with a percentage score (0-100%) and higher scores indicate better balance performance.

Dynamic postural balance will assessed using the Timed Up and Go (seconds). A faster time indicate a better functional performance and a score of ≥12 seconds used as a cut-point.

Balance confidence questionnaire will measured through the Activities Specific Balance Confidence Scale (total score points). The questionnaire contains 16 items scored on a range from 0% to 100% (0 indicating no confidence and 100 indicating full confidence).

Balance confidence questionnaire will measured through Falls Efficacy Scale-International (total score points). The total score ranges from 16 to 64 points. Higher values indicate less fall-related self-efficacy (and more concern about falling).

Handgrip strength and quadriceps muscle strength will be assessed by dynamometry, respectively, Kgf and Newtons.

Respiratory muscle strength (cmH2O) and inspiratory muscle endurance (cmH2O) will measured through digital pressure manometry and incremental and constant test, respectively

Health-related quality of life will measured by Saint George's Respiratory Questionnaire. Overall scores range from 0 (no effect on quality of life) to a maximum score of 100 (maximum perceived distress).

The oxidant profile will be assessed by Thiobarbituric Acid Reactive Substances -TBARS (nmol de MDA/mL).

Peripheral muscle resistance of the lower limbs will assessed through 30-second Sit-to-Stand tests (repetitions)

Inclusion Criteria: Clinical diagnosis of COPD, in stages II, III and IV, according to criteria of the Global Initiative for COPD (GOLD); Clinically stable, i.e., absence of infections or exacerbations in the last 3 months; Medical team allows patient to exercise Availability of attending the rehabilitation program. Exclusion Criteria: Unstable primary pathologies (cardiovascular, renal, metabolic, psychiatric); Hemodynamic instability; Nutritional supplementation on the 4 weeks preceding the study; Severe hearing or visual impairment recorded on patient chart or self-referred; Obesity (BMI > 30 kg/m2); Neurological or musculoskeletal condition that severely limits mobility and postural control, thus making it impossible to carry out the assessments; Electronic devices, such as heart pacemakers and implantable cardioverter defibrillator; Skin injuries and infection where electrodes would be placed; Prior participation in pulmonary rehabilitation programs 3 months previous to the study; Vertigo; Active smoker and/or alcoholic; Neurological impairment or cerebellar lesions; Deficit in cognitive function; Severe vitamin D deficiency; Physically active.