Treinamento muscular inspiratório em pacientes com doenças pulmonares intersticiais

Abstract

Introduction: The effects of inspiratory muscle training (IMT) in patients with chronic lung diseases are already well established: improvement in inspiratory muscle function, functional capacity and quality of life, in addition reduce dyspnea, which is the main symptom of patients with interstitial lung disease (ILD). However, the effects of IMR in these patients have not yet been specifically investigated. In addition, the perception of these patients about this physical therapy intervention is also unknown. Objective: To evaluate the effect of IMT on: dyspnea, inspiratory muscle endurance, inspiratory muscle strength, functional capacity, and quality of life; in addition to discuss the perception of these patients about inspiratory muscle training. Methods: Quasi-experimental study with measurements pre- and post-intervention and qualitative study with post-intervention semi-structured interview. Patients with diagnosis of ILD, aged between 40-80 years, dyspnea scale (Medical Research Council scale - MRC) ≥ 2, not participating in pulmonary rehabilitation and not using supplemental oxygen at rest were eligible. Patients unable to understand or perform the assessment procedures or training program were excluded. Participants performed 8 weeks home based IMT, daily, twice a day, with 2 sets of 30 breaths. The initial load was 50% of the maximum inspiratory pressure (MIP) and weekly the load was readjusted 50% of the new MIP, keeping Borg between 4 and 6. During the COVID-19 pandemic, readjustments were made remotely with the average change in load from previous data. Data distribution was evaluated using the Shapiro Wilk test. In variables with normal distribution, paired T test was used to compare pre and post training, if non-normal, Wilcoxon test was used. In the qualitative study, the data saturation method was used. Results: 14 participants (8 women) with mean age of 64±7 years and forced vital capacity of 67 ±15% of predicted were studied. There was a statistical difference in all variables: decrease in dyspnea (3 vs 2, p=0.001) and improvement in inspiratory muscle endurance time (257.8 ± 74.5 vs 833.1 ± 192.0 seconds, p=0.001). There was an increase in MIP (76.5 ± 30.8 vs 132.7 ± 24.7cmH2O, p = 0.001), in functional capacity (410.4 ± 78 vs 431.1 ± 64.3 m, p=0.031) and quality of life (54.9 ± 11.8 vs 69.0 ± 16.5 points, p = 0.001). In the qualitative study, three themes were elaborated: 1) dyspnea and other symptoms in daily life: e.g. “I felt tired, especially during the shower and cleaning the house.”; 2) less symptoms and better performance: e.g. “I wash clothes, clean my house, change clothes, I do everything without symptoms.”; 3) IMT: time dedicated to my health: e.g. “I saw my daily evolution with each exercise.”. Conclusion: IMT had a positive impact on dyspnea, inspiratory muscle function, functional capacity, and quality of life in patients with ILD. Participants noticed improvements in symptoms and performance related to daily activities.