Efeitos agudos da técnica de breath-stacking sobre os volumes pulmonares e pico de fluxo de tosse em pacientes com Esclerose Lateral Amiotrófica (ELA)

Abstract

Background: Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease that attacks the upper and lower motor neurons. The main muscle components that will alter the respiratory system are the inspiratory, expiratory and bulbar muscles, which lead to chronic respiratory failure. The breath-stacking maneuver (BS) allows an increase in lung volumes and it’s considered easy to use, shows good applicability and can be used in these patients. However, BS benefits are still controversial regarding changes amplitude in lung volume and cough flow generation. Aim: The aims of this study were to compare the acute respiratory effects in lung volume, breathing pattern and cough flow generation of BS maneuver in supine position and 45o inclination position in healthy subjects (Article 1) as well as to evaluated the effects of BS maneuver at 45o inclination position in ALS subjetcs and healthy subjects (Article 2). Methods: Article 1 - 14 healthy subjects (7M), nonsmoking with preserved lung function, aged 23.79±2.48 years, BMI 23.31±1.84 kg/m2, FVC 4.26±0.60L, FEV1/FVC 0.83± 0.01 L were recruited to the study. The effects of BS maneuver were compared in two positions. Subjects were asked to cough spontaneously before and after BS maneuver. Article 2 - 22 subjects (both genders) were recruited to the study; 7 outpatients with ALS (51.57 ± 13.35 years, BMI 24.63 ± 1.94 kg/m2, FVC 2.57 ± 0.85L, FEV1/FVC 0.83 ± 0.07L) and 15 healthy subjects (49.00 ± 14.78 years, BMI 23.48 ± 1.77 kg/m2, FVC 4.22 ± 0.61L, FEV1/FVC 0.83 ± 0.01L). The BS maneuver was performed with trunk inclination of 45° and cough flow was calculated before and after BS maneuver. Lung volumes and breathing pattern were assessed by opto–electronic plethysmography (OEP), (BTS Bioengineering, Italy) throughout the protocol in both studies. Results: Article 1 - The BS maneuver showed increase in cough flow (5.21 vs 6.09 L/s, p < 0.005) only at 45º position. There was a significant increase in lung volume of chest (lung + abdominal) immediately after the maneuver in both positions (supine: 0.182L vs 0.220L and 45º: 0.211L vs 0.279L (p < 0.05). Article 2 – There was lung volume increment in the chest wall (CW) in both groups during BS maneuver (0.35 ± 0.10 to 1.79 ± 1.11L in subjects with ALS and from 0.42 ± 0.19 to 2.87 ± 0.64 L; Δ1.44 L vs Δ2.44 L), p < 0.0001. The maneuver induced an increase in cough flow in both groups: ALS subjects (2.21 ± 0.71 vs 3.39 ±0.73 L/s) and healthy subjects (5.19 ± 1.28 vs. 6.30 ± 1.07 L/s), p < 0.001. Conclusion: The results suggest that the application of BS causes an increase in lung volume and cough flow, at 45° inclination of the trunk, in ALS and healthy subjects.