Six-minute walk test and respiratory muscle strength in patients with uncontrolled severe asthma: a pilot study

Abstract

OBJECTIVE: To evaluate respiratory muscle strength and six-minute walk test (6MWT) variables in patients with uncontrolled severe asthma (UCSA). METHODS: This was a cross-sectional study involving UCSA patients followed at a university hospital. The patients underwent 6MWT, spirometry, and measurements of respiratory muscle strength, as well as completing the Asthma Control Test (ACT). The Mann-Whitney test was used in order to analyze 6MWT variables, whereas the Kruskal-Wallis test was used to determine whether there was an association between the use of oral corticosteroids and respiratory muscle strength. RESULTS: We included 25 patients. Mean FEV1 was 58.8 ± 21.8% of predicted, and mean ACT score was 14.0 ± 3.9 points. No significant difference was found between the median six-minute walk distance recorded for the UCSA patients and that predicted for healthy Brazilians (512 m and 534 m, respectively; p = 0.14). During the 6MWT, there was no significant drop in SpO2. Mean MIP and MEP were normal (72.9 ± 15.2% and 67.6 ± 22.2%, respectively). Comparing the patients treated with at least four courses of oral corticosteroids per year and those treated with three or fewer, we found no significant differences in MIP (p = 0.15) or MEP (p = 0.45). CONCLUSIONS: Our findings suggest that UCSA patients are similar to normal subjects in terms of 6MWT variables and respiratory muscle strength. The use of oral corticosteroids has no apparent impact on respiratory muscle strength.

12-Week Inspiratory Muscle Training Improves Respiratory Muscle Strength in Adult Patients with Stable Asthma: A Randomized Controlled Trial

“…Contrary to our results, Rondinel et al [ 27 ] showed that IMT did not improve functional capacity assessed by the 6MWD, possibly because the subjects had good prior exercise tolerance and no aerobic intervention. In addition, no significant differences in blood oxygen saturation or heart rate were found between the two groups in our study, which is consistent with the results of Pereira et al, who found no significant drop in blood oxygen saturation [ 50 ]. Although our data indicated no significant differences in the 6MWD between the two groups, the IMT group increased by 37 m, which tended to surpass the 25-m increase obtained in the BTE group, and also exceed the MCID for 6MWD.…”

“…Functional capacity was similar between the BTE and IMT groups over the course of the study. In the 6MWT, walking distance, blood oxygen saturation, and heart rate can provide indicators of functional capacity, pulmonary gas exchange, and cardiovascular stress, respectively [ 50 ]. Our results suggested that both BTE and IMT induced similar increases in the 6MWD, which is consistent with the results of Majewski et al [ 26 ], in which the subjects with bronchial asthma received an 8-week stretching exercise followed by abdominal breathing training.…”

Respiratory muscles dysfunction and respiratory diseases

“…Однако при тяжелом течении заболевания гиперинфляция легких резко возрастает, что снижает эффективность работы РМ [29]. Кроме того, в этих случаях легочная гиперинфляция уже не способна компенсировать нарушение проходимости бронхов, приводя лишь к существенному возрастанию энергетических затрат на инспирацию воздуха, что способствует развитию утомления РМ [30]. Возрастающий остаточный объем легких и функциональная остаточная емкость приводят к уплощению диафрагмы и ограничению амплитуды ее движений.…”

Resistência muscular inspiratória em adultos com asma: uma revisão sistemática

“…Já quanto ao protocolo de carga máxima, os valores ≥600 segundos podem ser considerados preservados 16,21 . Nossos achados confirmam a hipótese de que a avaliação da resistência pode ser mais relevante do que a força em pacientes com doença pulmonar crônica 11,12 , tendo em vista os achados conflitantes de força muscular ventilatória 22,23 , enquanto a endurance parece ser reduzida em adultos asmáticos, baseado em nosso estudo. Além disso, esses resultados destacam a necessidade de avaliar a endurance muscular ao longo do acompanhamento clínico desses pacientes, considerando que essa musculatura tornase mais utilizada durante os períodos de crise aguda da doença 13 .…”