Efeitos agudos do alongamento de músculos respiratórios em asmáticos: estudo cross-over, randomizado e duplo-cego

Abstract

Introduction: Asthma is an inflammatory disease which attacks may reverse spontaneously or with pharmacological treatment. Prolonged exposure to its effects may impair action of the respiratory muscles. Thus, while the stretching these muscles is seen as a potential technique benefit in the treatment and control of chronic lung disease, few studies evaluated asthmatics. Objectives: Assess the acute effects of a stretching protocol of respiratory muscles on lung volumes, respiratory rate, minute volume, shortening velocity index of respiratory muscles and exercise tolerance in asthmatics with controlled disease. Materials and methods: crossover, randomized, double-blind study in which the sample was composed of asthmatic allocated into two groups: stretching group (GA) and placebo group (PG). The GA received a stretching protocol, while the GP, placebo maneuver. The variables were analyzed during the exercise using plethysmography optoelectronics. Statistical analysis: the mean of lung volumes, respiratory rate, minute volume and velocity of shortening index of the respiratory muscles between groups were compared by two-way ANOVA with Bonferroni post hoc. The exercise tolerance time and perceived exertion were compared between groups by paired t test. Was considered significant statistical value p <0.05. Preliminary results: We assessed 11 asthmatic with a mean age of 35.5 ± 7.8 years, BMI 24.4 ± 2.4 kg / m2, FVC and FEV1 equal to 95.8 ± 10.3 and 85.3 ± 11, 5% of the predicted value, respectively. There were no differences in lung volumes between groups (stretching versus placebo) during exercise, occurring differences in intra-group analysis of its stages (p <0.01). The respiration rate, and minute volume were similar in both groups (p = 0.68 and 0.52). The shortening velocity index of the inspiratory muscles pulmonary rib cage was lower in the stretching group, particularly in moments of pedaling load (GP = 0.571 ± 0.222, 0.533 ± 0.204 GA = L / s) and recovery (GP = 0.591 ± 0.222, GA = 0.531 ± 0.244 L / s), however there was no statistically significant difference (p = 0.27). The time of exercise tolerance was similar between groups (GP = 245 ± 109 seconds versus 218 ± GA = 55.5 sec, p = 0.31). The change in Borg score for perception of fatigue was lower in GA (6.86 ± 0.55 versus 7.59 ± 0.73, p = 0.02). Conclusion: The stretching of respiratory muscles, considering its acute effects, does not modify the pulmonary volumes, respiratory rate, minute volume and the shortening velocity index of respiratory muscles of asthma patients with controlled disease. The results suggest that the technique did not influence exercise tolerance with constant load, although it was observed a lower sense of fatigue in individuals who underwent technique.