Effects of Chronic and Acute Pulmonary Hyperinflation on Phrenic Nerve Conduction in Patients with COPD

The Importance of the Diaphragm in Neuromotor Function in the Patient with Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a constant and chronic narrowing of the respiratory airways, with numerous associated symptoms, not always related to the pathological adaptation of the lungs. Statistical projections show that COPD could become the third leading cause of death globally by 2030, with a significant increase in deaths by 2060. Skeletal muscle dysfunction, including the diaphragm, is one of the causes linked to the increase in mortality and hospitalization. Little emphasis is given by the scientific literature to the importance of the diaphragm towards functional neuromotor pathological expressions. The article reviews the adaptation of the skeletal muscles, with greater attention to the adaptations of the diaphragm, thereby highlighting the non-physiological variations that the main respiratory muscle undergoes and the neuromotor impairment found in COPD. The text could be an important reflection from a clinical and rehabilitation point of view, to direct greater attention to the function and adaptation of the diaphragm muscle.

Walking distance in incremental shuttle walking test as a predictor of physical activity in patients diagnosed with low-risk chronic obstructive pulmonary disease

OBJECTIVES

Research on the determinants of physical activity in mildly symptomatic patients with chronic obstructive pulmonary disease is lacking. This study examined the predictors of physical activity in patients with low-risk chronic obstructive pulmonary disease.

METHODS

A total of 41 male patients with chronic obstructive pulmonary disease belonging to Group A of the Global Initiative for Chronic Obstructive Lung Disease were included. Regarding the objective index, the physical activity (number of steps/day and the amount of Ex (metabolic equivalent × hours)/day) of the participants was measured with a tri-axis accelerometer. In addition, regarding the evaluation index, respiratory function and dynamic lung hyperinflation were measured by a spirometer, skeletal muscle mass was measured using bioelectrical impedance analysis, skeletal muscle strength (grip and lower limb muscle strength) was measured using a dynamometer, exercise capacity was measured by the incremental shuttle walking test, and health-related quality of life was measured.

RESULTS

Significant correlations were found between the number of steps per day and age (ρ = -0.501, p < 0.01), forced vital capacity predictive values (ρ = 0.381, p < 0.05), dynamic lung hyperinflation (ρ = 0.454, p < 0.01), grip strength (ρ = 0.318, p < 0.05), and walking distance in incremental shuttle walking test (ρ = 0.779, p < 0.01), but not skeletal muscle mass, lower limb muscle strength, or health-related quality of life. A multiple-regression analysis with the number of steps per day as the dependent variable extracted only walking distance in incremental shuttle walking test, yielding a moderate single-regression equation (steps/day = -934.909 + 11.052 × walking distance in incremental shuttle walking test, adjusted R2 = 0.548, p < 0.001).

CONCLUSION

It was suggested that the amount of physical activity of patients with low-risk chronic obstructive pulmonary disease could be predicted by walking distance in incremental shuttle walking test.

Health status can predict diaphragmatic muscle thickness in COPD: pilot study

Abstract Introduction: Among the systemic implications of chronic obstructive pulmonary disease (COPD) there are changes in the diaphragm and impact on health status. However, there are few studies on the possible relationship between these variables, and whether health status could predict diaphragmatic muscle thickness (DMT). Objective: To investigate whether there is a relationship between DMT and the prognostic mortality index Body Mass-Index, Airway Obstruction, Dyspnea and Exercise Capacity (BODE), dyspnea and health status, and to investigate whether health status can predict DMT in patients with COPD entering a pulmonary rehabilitation program. Methods: This is a pilot study with a cross-sectional design. Diaphragmatic muscle thickness was evaluated using ultrasound; health status through the COPD Assessment Test (CAT); the sensation of dyspnea by the modified Medical Research Council scale; and mortality, using the BODE index. Results: The sample consisted of 13 patients (68.69 ± 9.3 years) classified as having moderate to severe COPD. There was a strong and inverse correlation between diaphragmatic muscle thickness and health status (r = -0.735; p = 0.004). Simple regression analysis demonstrated that health status influenced diaphragmatic muscle thickness (β = -0.002; IC 95% - 0.004 to -0.001; p = 0.004), explaining 49% of the variance. However, no correlations were observed between diaphragmatic muscle thickness with dyspnea (r = 0.005; p = 0.985) or with the BODE mortality index (r = -0.219; p = 0.472). Conclusion: This pilot study demonstrated a strong inverse correlation between health status and DMT. In addition, health status was able to predict DMT in patients with COPD.