Dynamic hyperinflation and dyspnea during the 6-minute walk test in stable chronic obstructive pulmonary disease patients.

The purpose of this study was to investigate the relationship between dynamic hyperinflation and dyspnea and to clarify the characteristics of dyspnea during the 6-minute walk test (6MWT) in chronic obstructive pulmonary disease patients. Twenty-three subjects with stable moderate chronic obstructive pulmonary disease (age 73.8±5.8 years, all male) took part in this study. During the 6MWT, ventilatory and gas exchange parameters were measured using a portable respiratory gas analysis system. Dyspnea and oxygen saturation were recorded at the end of every 2 minute period during the test. There was a significant decrease in inspiratory capacity during the 6MWT. This suggested that dynamic hyperinflation had occurred. Dyspnea showed a significant linear increase, and there was a significant negative correlation with inspiratory capacity. It was suggested that one of the reasons that dyspnea developed during the 6MWT was the dynamic hyperinflation. Even though the tidal volume increased little after 2 minutes, dyspnea increased linearly to the end of the 6MWT. These results suggest that the mechanisms generating dyspnea during the 6MWT were the sense of respiratory effort at an early stage and then the mismatch between central motor command output and respiratory system movement.

Effects of nutritional supplementation combined with low-intensity exercise in malnourished patients with COPD.

STUDY OBJECTIVES: The first aim of this study was to investigate the effects of nutritional supplementation combined with low-intensity exercise on body components, exercise tolerance, and health-related quality of life (HRQOL) in malnourished patients with COPD. The second aim of this study was to examine the degree of systemic inflammation and the actual changes in levels of systemic CRP, TNFα, IL-6 and IL-8 actual changes after a combination of nutritional supplementation and low-intensity exercise in these patients. DESIGN: A prospective randomized trial. PATIENTS: Thirty-two moderate to severe, clinically stable malnourished COPD patients. METHODS: Patients were randomly divided into a nutritional supplementation with low-intensity exercise group and a control group. Lung function, maximum inspiratory and expiratory muscle force, the Chronic Respiratory Disease Questionnaire (CRQ), the 6-min walking distance (6MWD), and the Borg scale were measured at baseline and were re-assessed at 3 months after intervention. The degree of systemic inflammation and the changes in levels of systemic CRP, TNFα, IL-6 and IL-8 were assessed before and after a combination nutritional supplementation with low-intensity exercise. RESULTS: Body weight and FFM increased significantly after 12 weeks of nutritional supplementation therapy in patients with COPD. The dietary intake energy increased and the REE:REEpred ratio decreased significantly in the nutrition with low-intensity exercise group. PI(max), Quadriceps muscle force and the 6-min walking distance (6MWD) increased significantly from baseline through week 12. Health status, as assessed by CRQ, improved in the domains of dyspnea and total sores significantly in the nutrition with low-intensity exercise group after intervention. In this group, hsCRP, IL-6, IL-8, and TNFα, decreased significantly after intervention compared with the control group. CONCLUSIONS: The combination of nutritional supplementation with low-intensity exercise training was successful in increasing weight and energy intake as well as exercise capacity and health-related QOL in our patients. Moreover, REE and major inflammatory cytokines decreased significantly after nutritional supplementation with low-intensity exercise training. The present study results suggest a potential role for the combination of nutritional supplementation and low-intensity exercise in the management of malnourished patients with COPD.

Effective home-based pulmonary rehabilitation in patients with restrictive lung diseases.

Patients with chronic obstructive pulmonary disease (COPD) are commonly referred for pulmonary rehabilitation (PR), but the use of PR is not common for patients with restrictive lung disease, neuromuscular diseases, and those who have sustained a severe respiratory illness or undergone thoracic surgery. We investigated the effects of PR in patients with restrictive lung diseases in comparison with COPD patients using a home-based setting. Twenty-six restrictive lung diseases patients and 40 COPD patients who had a Medical Research Council (MRC) dyspnea score >or= 2, a clinically stable condition, and who had completed a 6-month PR program, were enrolled in the present study. The definition of restrictive lung disease was a forced vital capacity (FVC) of 70%. Our PR consisted of breathing retraining, exercise training, respiratory muscle stretching calisthenics, level walking, inspiratory and expiratory muscle exercises, and a monthly education program. Patients were strongly instructed to practice this program daily at home, and were supervised by a respiratory therapist every 2 weeks in our hospital. Patients with restrictive lung diseases showed the significant increases in inspiratory and expiratory muscle forces, the 6-minute walking distance, the Chronic Respiratory Disease Questionnaire and the Short-Form 36, and decreased MRC scores after 6 months. In conclusion, our home-based PR improves respiratory muscle forces, exercise tolerance, health-related quality of life, and the perception of dyspnea in patients with restrictive lung disease to the same extent as in COPD patients.