Relationship between body composition, peripheral muscle strength and functional exercise capacity in patients with severe chronic obstructive pulmonary disease

The influence of body composition and peripheral muscle strength on 6-minute walk distance was assessed by performing dual energy X-ray absorptiometry scanning, spirometry and dynamometry testing in 13 men and 13 women with severe chronic obstructive pulmonary disease. Multivariate modelling showed that 76% of the variance in 6-minute walk distance could be explained by an equation incorporating lung function, quadriceps strength and lean leg mass. These findings indicate an important role for lower limb strength measures in pulmonary rehabilitation training programmes.     

Factors associated with improvement in breathing capacity during exercise in patients with chronic obstructive pulmonary disease

OBJECTIVES: The aim of this study was to explore the relationship between resting pulmonary function indices and the ratio of minute ventilation at peak exercise to the maximal voluntary ventilation (VEmax/MVV) and to determine whether an improvement in breathing capacity during exercise (i.e. VEmax/MVV > 1) is associated with greater exercise capacity in patients with COPD. METHODOLOGY: The results of pulmonary function tests and incremental, symptom-limited cardiopulmonary exercise testing in 84 patients with predominantly moderate to severe COPD were reviewed. Multiple linear regression analysis was applied to determine the relationship of VEmax/MVV with selected independent variables at rest. Multiple logistic regression was used to determine significant predictors of VEmax/MVV 1. RESULTS: FEV1/FVC and inspiratory capacity (IC) were the only variables among resting pulmonary function indices that were significant independent determinants of VEmax/MVV and the stepwise analysis generated the following equation: VEmax/MVV = (-1.05E-02 x FEV1/FVC) + (0.15 x IC) + 1.28; r= 0.701, P < 0.001. Using multiple logistic regression with VEmax/MVV 1 as a dependent categorical variable, FEV1/FVC was the only significant predictor among resting pulmonary indices of a VEmax/MVV ratio of > 1 (Odds ratio 0.93, 95%CI 0.89, 0.97). There was a significant association between VEmax/MVV and peak oxygen uptake (VO2max) after adjusting for FEV1 (r = 0.66, P < 0.001). If the categorical variable of VEmax/MVV ( 1) was used instead of a continuous variable, a significant association with VO2max remained after adjusting for FEV1 (r = 0.60, P < 0.001). CONCLUSIONS: Among resting pulmonary function indices, the FEV1/FVC ratio is the best determinant of an improvement in breathing capacity during exercise in COPD patients. After adjusting for FEV1, an improvement in breathing capacity during exercise is associated with significantly higher exercise capacity.     

Systemic inflammation after inspiratory loading in chronic obstructive pulmonary disease

Objective

Patients with chronic obstructive pulmonary disease (COPD) present systemic inflammation. Strenuous resistive breathing induces systemic inflammation in healthy subjects. We hypothesized that the increased respiratory load that characterizes COPD can contribute to systemic inflammation in these patients.

Patients and methods

To test this hypothesis, we compared leukocyte numbers and levels of circulating cytokines (tumor necrosis factor alpha [TNFα], interleukin-1β [IL-1β], IL-6, IL-8, and IL-10), before and 1 hour after maximal incremental inspiratory loading in 13 patients with stable COPD (forced expiratory volume in one second [FEV₁] 29 ± 2.5% ref) and in 8 healthy sedentary subjects (FEV₁ 98 ± 5% ref).

Results

We found that: (1) at baseline, patients with COPD showed higher leukocyte counts and IL-8 levels than controls (p < 0.01); and, (2) one hour after maximal inspiratory loading these values were unchanged, except for IL-10, which increased in controls (p < 0.05) but not in patients with COPD.

Conclusions

This study confirms the presence of systemic inflammation in COPD, shows that maximal inspiratory loading does not increase the levels of pro-inflammatory cytokines (IL-1β, IL-8) in COPD patients or controls, but suggests that the former may be unable to mount an appropriate systemic anti-inflammatory response to exercise.     

稳定期COPD患者深吸气量与运动耐力的关系

目的 探讨深吸气量 (IC)及相关肺功能指标与稳定期中重度 COPD患者运动耐力的相关性.方法 对62例处于稳定期的中重度 COPD 患者进行常规肺功能检测及斜坡式功率递增症状限制性心肺运动试验,测定相关肺通气功能参数、气体交换参数.结果 COPD患者的 IC%pred与运动耐力 [峰值摄氧量占预计值的百分比 (peak ·V O2%pred)]有显著的相关性 (r =0.74,P <0.001),IC%pred对 peak ·V O2%pred 有显著预测意义.结论 IC%pred对稳定期 COPD患者运动耐力的预测较其他肺功能指标更有优势.     

Home respiratory muscle training in patients with chronic obstructive pulmonary disease

OBJECTIVE AND BACKGROUND: The benefits of inspiratory muscle strength training in decreasing symptoms, disability or handicap of patients affected by COPD are not well established. The objective of this study was to assess the efficacy of the constant use of a new flow-volumetric inspiratory exerciser, named Respivol, in improving respiratory functional parameters in COPD patients. METHODS: Twenty consecutive ambulatory patients affected by COPD were enrolled. Each patient was assessed, before and after 3 and 6 months inspiratory exercise with Respivol, for the following clinical parameters: maximal inspiratory pressure, maximal expiratory pressure, dyspnoea grade, quality of life by a self-administered St George questionnaire and a 6-min walking test. After a brief progressive ambulatory training programme, inspiratory exercise with Respivol was performed at home for 6 months. All patients used Respivol together with medical treatment. RESULTS: Maximal inspiratory pressure and maximal expiratory pressure values were significantly increased after 3 and 6 months of exercise. Dyspnoea grade was significantly reduced and the 6-min walking test showed an increase in effort tolerance, after 6 months of home training. Quality of life assessment showed an improvement, associated with a decrease of respiratory disease symptoms. CONCLUSIONS: Inspiratory muscle strength training with Respivol seems to be efficient in reducing symptoms and improving quality of life in adults with COPD.     

Effects of high-intensity exercise training in a pulmonary rehabilitation programme for patients with chronic obstructive pulmonary disease

BACKGROUND AND OBJECTIVES: The benefits of pulmonary rehabilitation for patients with COPD depend on the intensity of training. Traditional pulmonary rehabilitation programmes (PRPs) do not consistently achieve high-intensity training and have variable training effects. This study examined the effects of high-intensity exercise training on cardiac and pulmonary function in COPD patients. METHODS: Patients with COPD participated in a 6-week, cardiopulmonary exercise test-based PRP. Spirometry, 6-min walking distance and cardiopulmonary exercise test were used to evaluate cardiopulmonary function, respiratory muscle strength and endurance at rest, during exercise and before and after the programme. Patients were encouraged to complete high-intensity exercise with a targeted training intensity of at least 75% maximum oxygen uptake (VO(2)). RESULTS: Thirty-four COPD patients were enrolled into the study; 16 completed the high-intensity training, 18 did not. At the end of the 12-session PRP, submaximal exercise capacity (6-min walking distance, 461.8 +/- 77.2-502.7 +/- 66.9 m, P < 0.001) improved in both the patients who completed high-intensity training and those who did not. Only the patients who completed high-intensity training had significant improvements in FVC (2.47 +/- 0.70-2.70 +/- 0.62 L, P = 0.024) at rest, maximal exercise capacity (peak VO(2), 1001.6 +/- 286.4-1116.1 +/- 320.4 mL/min, P = 0.020) and work efficiency (7.3 +/- 1.4-8.4 +/- 1.8 mL/min/watt, P = 0.026). There was no statistically significant difference between the two groups in the change in the physiological parameters before and after exercise. CONCLUSIONS: Exercise training in a PRP improved submaximal exercise capacity. Only patients who completed high-intensity exercise training showed improvements in maximal exercise capacity, FVC and work efficiency.     

性别差异对中重度慢性阻塞性肺疾病患者运动耐力的影响

目的 比较中重度慢性阻塞性肺疾病(COPD)患者运动耐力的性别差异.方法 本研究对151例中、重度COPD患者的肺功能(PFT)和功率递增心肺运动试验(CPET)结果进行了分析.将患者分为Ⅱ级COPD组和Ⅲ级COPD组.并选择43例年龄、性别、身高、体质量相匹配的正常人作为对照组.本研究测定第1秒用力呼气容积(FEV1)、用力肺活量(FVC)、峰值运动功率(Peak Load)、峰值摄氧量(Peak (V)O2)、峰值心率(Peak HR)、峰值氧脉搏(Peak(V)O2/HR)、最大分钟通气量(M(V)E)、气促指数(M(V)E/MVV)等指标.本研究分别在不同COPD分级和性别之间分析比较了上述指标的差异.结果 Ⅱ级COPD组和Ⅲ级COPD组的女性患者的Peak (V)O2实/预％和Peak (V)O2/HR实/预％较同组男性更高(P值均＜0.05).Ⅲ级COPD男性患者的运动耐力较Ⅱ级有明显降低(P＜0.0001),然而,Ⅲ级、Ⅱ级COPD女性患者之间运动耐力差异无统计学意义(P=0.246).结论 在中、重度COPD患者中,男性运动耐力下降较女性更为严重,吸烟可能是造成这一差异的重要因素.     

Exercise training increases respiratory muscle strength and exercise capacity in patients with chronic obstructive pulmonary disease and respiratory muscle weakness

BackgroundHow respiratory muscle strength influences the effectiveness of pulmonary rehabilitation (PR) in patients with chronic obstructive pulmonary disease (COPD) is unclear.ObjectiveTo investigate the benefits of PR in subjects with COPD according to respiratory muscle strength.MethodsNinety-seven subjects with COPD were evaluated using maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), pulmonary function tests, the cardiopulmonary exercise test (CPET), and the St. George's Respiratory Questionnaire (SGRQ). Subjects were divided into four groups: 1 (normal MIP and MEP); 2 (low MIP); 3 (low MEP); and 4 (low MIP and MEP). Subjects underwent PR for 3 months; MIP, MEP, SGRQ, and CPET were evaluated post-PR.ResultsSubjects with both poor MIP and MEP had the highest dyspnea score, lowest exercise capacity, and poorest health-related quality of life (HRQoL). PR improved exercise capacity and HRQoL in all groups, with more improvement in MIP, MEP, tidal volume (on exercise), and dyspnea (at rest) in subjects with both low MIP and MEP.ConclusionsPatients with respiratory muscle weakness had worse dyspnea, lower exercise capacity, and poorer HRQoL at baseline. Exercise training improved respiratory muscle strength with concurrent improvement of exercise capacity, HRQoL, and dyspnea score. Subjects with both poor baseline MIP and MEP showed greater benefits of PR.     

Cardiac response to exercise in mild-to-moderate chronic obstructive pulmonary disease

Objective Chronic obstructive pulmonary disease （COPD） increases the risk of cardiovascular problem.The symptom of dyspnea on exertion may be associated with pulmonary dysfunction or heart failure, or both. The study objective was to determine whether cardiac dysfunction adds to the mechanism of dyspnea caused mainly by impaired lung function in patients with mild-tomoderate COPD. Methods Patients with COPD and healthy controls performed incremental and constant work rate exercise testing. Venous blood samples were collected in 19 COPD patients and 10 controls before and during constant work exercise for analysis of Nterminal-pro-BNP （NT-pro-BNP）. Results Peak oxygen uptake and constant work exercise time （CWET） were significantly lower in COPD group than in control group （15.81±3.65 vs 19.19±6.16 ml/min kg, P=0.035 and 7.78±6.53 min vs 14.77±7.33 rain, P=0.015, respectively）. Anaerobic threshold, oxygen pulse and heart rate reserve were not statistically significant between COPD group and control group. The NT-pro-BNP levels both at rest and during constant work exercise were higher in COPD group compared to control group, but without statistical significance. The correlations between CWET and NT-proBNP at rest or during exercise in patients with COPD were not statistically significant. Conclusions Heart failure does not contribute to exercise intolerance in mild-to-moderate COPD.（J Geriatr Cardioi 2009; 6：147-150）.     

Clinical impact of forced vital capacity on exercise performance in patients with chronic obstructive pulmonary disease

BackgroundForced vital capacity (FVC) has been suggested to be a good biomarker for decreased exercise performance in patients with chronic obstructive pulmonary disease (COPD). However, as FVC is highly correlated with forced expiratory volume in 1 second (FEV₁), the relationship between FVC and exercise capacity should be assessed within the category of FEV1, i.e., COPD severity. However, this was not considered in previous studies. Thus, limited data are available on the association between reduced FVC and exercise capacity measured by 6-min walk distance (6MWD) based on COPD severity.MethodsWe performed a cross-sectional study using data from the Korean COPD Subgroup Study (KOCOSS) cohort. We evaluated 1,386 patients with moderate (n=895) and severe-to-very severe (n=491) COPD. Reduced FVC was defined as FVC <80% predicted and short 6MWD as <350 m. Multivariable logistic regression was used to evaluate the association between reduced FVC and short 6MWD.ResultsThere were no significant differences in respiratory symptoms and quality of life between the patients with reduced FVC and those with preserved FVC. However, patients with reduced FVC had shorter 6MWD (30.5 cm in moderate and 34.5 cm in severe-to-very severe COPD) and higher BODE index scores than those with preserved FVC. The cubic spline model revealed 6MWD peaked around 93% predicted of FVC in moderate COPD, whereas FVC showed a positive association with 6MWD in severe-to-very severe COPD. Multivariable analyses showed that reduced FVC was significantly associated with short 6MWD in both moderate [adjusted odds ratio (aOR) =1.44, 95% confidence interval (CI): 1.03–2.02] and severe-to-very severe (adjusted OR =1.55, 95% CI: 1.01–2.40) COPD.ConclusionsReduced FVC was significantly associated with shorter 6MWD in moderate-to-very severe COPD patients, suggesting that reduced FVC might be reflective of 6MWD-measured exercise capacity in moderate-to-very severe COPD.     

Pulmonary rehabilitation improves exercise capacity and quality of life in underweight patients with chronic obstructive pulmonary disease

Background and objective: An estimated 20–40% of COPD patients are underweight. We sought to confirm the physiological and psychosocial benefits of pulmonary rehabilitation programmes (PRP) in underweight compared with non‐underweight patients with COPD. Methods: Twenty‐two underweight COPD patients with BMI <20 kg/m², and 22 non‐underweight COPD patients, who were matched for FEV₁ and age, were studied. All patients had moderate‐to‐very severe COPD. All patients participated in 12‐week, hospital‐based outpatient PRP consisting of two sessions per week. Baseline and post‐PRP status were evaluated by spirometry, cardiopulmonary exercise testing, ventilatory muscle strength and the St. George's Respiratory Questionnaire (SGRQ). Results: At baseline, the age distribution and airflow obstruction were similar in underweight and non‐underweight patients with COPD. Baseline exercise capacity, inspiratory muscle strength and SGRQ total and symptoms scores were significantly lower in the underweight patients (all P < 0.05). After the PRP, there was significant weight gain in the underweight COPD patients (mean increase 0.8 kg, P = 0.01). There were also significant improvements in peak oxygen uptake, peak workload and the SGRQ total, symptoms, activity and impact scores in both underweight and non‐underweight patients with COPD (all P < 0.05). Conclusions: Underweight patients with COPD have impaired exercise capacity and health‐related quality of life (HRQL). Exercise training with supplemental oxygen may result in significant weight gains and improvements in exercise capacity and HRQL. Exercise training is indicated for underweight patients with COPD.     

Respiratory muscle weakness and normal ventilatory drive in dilative cardiomyopathy

BACKGROUND: In dilative cardiomyopathy several factors influence dyspnoea.Patients with chronic heart failure may demonstrate impairmentof breathing pattern, ventilatory drive and respiratory musclestrength, as well as reduction of ventilatory efficiency. Thepurpose of this study was to evaluate whether dilative cardiomyopathyis accompanied by changes in breathing pattern, respiratorymuscle weakness and ventilatory neural drive. METHODS: We investigated 47 patients (36 men, mean age=47·8±11·2years) with chronic heart failure due to dilative cardiomyopathy,and 30 healthy subjects (10 men, mean age=35·4±11·7years) served as controls. Patients and controls underwent evaluationof left ventricular ejection fraction by 2D echocardiography,spirometry, body plethysmography, mouth occlusion pressure andrespiratory muscle strength, as well as by submaximal treadmillexercise testing with gas exchange measurements. The patients'results were compared to controls and predicted standard normalvalues, and evaluated for differences according to the degreeof severity of functional impairment. RESULTS: Patients with dilative cardiomyopathy demonstrated a slightreduction in lung volumes (15% of the patients with obstructiveand 15% with restrictive lung function pattern) and diffusioncapacity (20·4±6·8 vs 15·4±6·7ml. min^–1 . kPa^–1; P<0·01). In neuraldrive, as assessed by mouth occlusion pressure, there was nosignificant difference between patients and controls. Therewas a slight but significant reduction in respiratory musclestrength, as assessed by measuring maximal inspiratory pressurein patients with dilative cardiomyopathy (6·7±2·4kPavs 8·6±3·5kPa; P<0·01). The observedchanges were more pronounced in the severe chronic heart failurepatients (with a reduction in ventilatory efficiency) whereasno relationship among indices of cardiac or respiratory functionwas found. CONCLUSION: Patients with chronic heart failure due to dilative cardiomyopathydevelop respiratory muscle weakness without changes in neuralventilatory drive, and slight changes in breathing pattern relatedto the severity of the disease.     

慢性阻塞性肺疾病的呼吸肌功能

慢性阻塞性肺疾病患者常存在呼吸肌收缩力和(或)耐力下降,引起呼吸困难,限制患者活动能力,使患者的运动量减少,日常生活质量降低;如果病情得不到控制,可以导致高碳酸性呼吸衰竭,严重者造成患者死亡.呼吸肌功能评价在慢性阻塞性肺疾病患者临床病情评估和预后判断方面很有应用价值.最大吸气压和最大呼气压测定是临床最常用的、可信的、非创伤性的评价呼吸肌功能的指标.研究结果显示最大吸气压较一秒量敏感.呼吸肌本身的病理改变和肺过度充气导致膈肌的收缩初长度缩短等原因可以引起呼吸肌功能障碍.可以应用抗胆碱药物、β2-受体激动剂、运动训练、营养支持及同化激素、心理支持、患者教育等治疗慢性阻塞性肺疾病呼吸肌功能障碍.蛋白酶抑制剂、过氧化物酶体增殖物激活受体、硫酸镁有希望成为治疗慢性阻塞性肺疾病呼吸肌功能障碍的方法.     

肺活量与用力肺活量差值预测慢性阻塞性肺疾病患者运动能力的研究

目的:探讨慢性阻塞性疾病(chronic obstructive pulmonary disease,COPD)患者慢肺活量(vital capacity,VC)与用力肺活量(forced vital capacity,FVC)的差值(VC-FVC)与运动能力的关系。方法:共97例COPD患者完成了常规肺功能和心肺运动试验,根据VC-FVC的结果分为两组:1组VCFVC 77例,另1组VC≤FVC 20例,比较这两组的运动反应。结果:VCFVC组的第1秒用力肺活量(FEV1)和最大摄氧量(peak VO2)均显著低于VC≤FVC组,VC-FVC与peak VO2有显著的负相关(r=-0.404,P0.001),FEV1占预计值百分比(FEV1%)与peak VO2有显著的正相关(r=0.418,P0.001),以peak VO2作为因变量进行多元逐步回归分析显示,VC-FVC、FEV1%和年龄与peak VO2相关,可解释peak VO235.9%的变化。结论:VC和FVC测定简单,其差值不仅可以反应COPD患者气体受限的程度,还可预测其运动能力。     

Air trapping: The major factor limiting diaphragm mobility in chronic obstructive pulmonary disease patients

Background and objective:   Patients with COPD can have impaired diaphragm mechanics. A new method of assessing the mobility of the diaphragm, using ultrasound, has recently been validated. This study evaluated the relationship between pulmonary function and diaphragm mobility, as well as that between respiratory muscle strength and diaphragm mobility, in COPD patients.
Methods:   COPD patients with pulmonary hyperinflation ( n  = 54) and healthy subjects ( n  = 20) were studied. Patients were tested for pulmonary function, maximal respiratory pressures and diaphragm mobility using ultrasound to measure the craniocaudal displacement of the left branch of the portal vein.
Results:   COPD patients had less diaphragm mobility than did healthy individuals (36.5 ± 10.9 mm vs 46.3 ± 9.5 mm, P  = 0.001). In COPD patients, diaphragm mobility correlated strongly with pulmonary function parameters that quantify air trapping (RV: r  = −0.60, P  < 0.001; RV/TLC: r  = −0.76, P  < 0.001), moderately with airway obstruction (FEV₁: r  = 0.55, P  < 0.001; airway resistance: r  = −0.32, P  = 0.02) and weakly with pulmonary hyperinflation (TLC: r  = −0.28, P  = 0.04). No relationship was observed between diaphragm mobility and respiratory muscle strength (maximal inspiratory pressure: r  = −0.11, P  = 0.43; maximal expiratory pressure: r  = 0.03, P  = 0.80).
Conclusion:   The results of this study suggest that the reduction in diaphragm mobility in COPD patients is mainly due to air trapping and is not influenced by respiratory muscle strength or pulmonary hyperinflation.     

营养支持与呼吸操提高COPD患者生存质量的探讨

目的观察营养支持与呼吸操对慢性阻塞性肺疾病(COPD)患者缓解期呼吸肌和生存质量的影响。方法将40例COPD缓解期患者随机分为两组,对照组和观察组,给予营养支持同时行呼吸操训练,3个月后分别进行肺功能及生存质量评估。结果观察组较对照组在肺功能及活动耐力、心理状态、社会适应能力等方面均明显改善(P<0.01)。结论营养支持与呼吸操训练能提高老年COPD患者呼吸功能和生存质量