Benefícios da técnica de air stacking em sujeitos com esclerose lateral amiotrófica

Abstract

INTRODUCTION: Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterized by progressive weakness of peripheral and respiratory muscles. The respiratory muscle impairment generates weakness, reducing lung expansion and reducing the capacity to produce cough, favoring increase in morbidity and mortality associated with acute respiratory infections. The Air Stacking technique (AS) improves lung inflation that could lead to the expansion, optimization of lung recoil pressure, increased peak cough flow (PCF) and elimination of secretion. OBJECTIVES: The objectives were divided in two studies: Study 1) Conduct a previous protocol for analysis and description of changes in PCF, distribution of volumes in the chest wall (CW) and its compartments (pulmonary rib cage – RCp, abdominal rib cage – RCa and abdomen - Ab), breathing pattern and shortening velocity index of respiratory muscles before and after AS technique in healthy subjects adopting the posture of 45° inclined position; Study 2) To evaluate and compare the acute effects of AS on PCF and CW volumes in subjects with ALS versus matched healthy by Optoelectronic Plethysmography (OEP) using the posture of 45° inclined position. METHODOLOGY: For Study 1 were evaluated healthy individuals allocated into one group. For Study 2, subjects with ALS were allocated to the experimental group (GE) and matched healthy subjects as age, gender and body mass index were allocated to the control group (GC). In both studies, subjects were evaluated for lung function, respiratory muscle strength, PCF, CW volumes, breathing pattern and shortening velocity index of respiratory muscles and distribution in their magazines before (PreAS), during (AS) and after AS (PostAS). RESULTS: In study 1 were evaluated 20 healthy subjects and observed significant increases (mean ± standard deviation) in PFT (1.76 ± 0.08 L/s, p < 0.05), in AS and PostAS moments compared to PreAS; Inspiratory capacity (IC) (~600 ± 0.15 ml), being higher among MIC and IC moments; CW volumes and end inspiratory volume (ΔEIV) (p < 0.0001), being higher among RCp and RCa compartments; Minute volume (VE) (p < 0.0001) and shortening velocity index of inspiratory muscles (p < 0.0001), expiratory (p <0.0001) and diaphragm (p < 0.0005). In Study 2 were evaluated 18 subjects (9 with ALS). In intragroup analysis were observed significant increases (p < 0.0005) in PCF (4.4 ± 2.2L vs 7 ± 4.1L/s; ± 7.6 vs 11.6 ± 4.5L 3.1L/s) and IC (± 1.7 vs 2.2 ± 0.6L 0.4L; 3.1 ± 0.6 L vs 3.6 ± 0.9L) between AS and PreAS moments of GE and GC groups, respectively. Intergroup analysis showed that this increase in the PCF and the IC was significantly higher in GE (59%, 29.4%, respectively) (p < 0.0001). The contribution in volume of PT compartments for CI occurred differently in both groups. While performing the technique, it was observed that the AB compartment obtained a greater contribution (0.69 ± 0.2 vs 0.92 ± 0.4 L) for the increase in IC in GE group (p <0.005); unlike the GC, where the largest contribution (1.8 ± 0.5 vs 2.2 ± 0.5 L) was observed in the CT compartment (p = 0.004). Regarding the vital capacity, only GE increases were obtained after performing the technique (1.8 ± 0.5 vs 2.2 ± 0.7, p < 0.05). CONCLUSION: The present study shows that AS is safe and effective in increasing PCF and CW volumes. In healthy subjects the technique probably works in a way to increase lung compliance, unlike subjects with ALS who may act in alveolar recruitment ventilating the most distal pulmonary areas, prior hypoventilated.