Arm exercise capacity and dyspnea ratings in subjects with chronic obstructive pulmonary disease

PURPOSE: This study aimed to compare the metabolic, ventilatory, and dyspnea responses to unsupported arm exercise, supported arm exercise and leg exercise between subjects with chronic obstructive pulmonary disease (COPD) and healthy age-matched controls. METHODS: For this study, 21 subjects with COPD (mean age, 62 +/- 2 years; predicted forced expiratory volume in 1 second [FEV(1)], 37 +/- 3%) and 7 healthy age-matched control subjects (% pred FEV(1) = 109 +/- 5%) were included in the analyses of three incremental exercise tests to peak work capacity: unsupported arm exercise, supported arm exercise (arm ergometry), and leg exercise (cycle ergometry). Work level, oxygen consumption (VO(2)), minute ventilation (V(E)), dyspnea, and rate of perceived exertion were measured each minute. RESULTS: Peak work level and peak VO(2) were significantly reduced in the subjects with COPD for all exercise tests (P <.01 for all), as compared with the control subjects. Within the COPD group, the VO(2) and V(E) at peak exercise were significantly lower for unsupported arm exercise than for both the leg and supported arm exercises (both P <.001). The ratio of V(E) to maximal voluntary ventilation was high for leg exercise (96%), supported arm exercise (91%), and unsupported arm exercise (77%) among the subjects with COPD. At a given percentage of VO(2) peak, dyspnea scores were similar for all the exercise tests. CONCLUSIONS: Ventilatory constraints limit exercise performance in COPD. The lowest amount of work, in terms of VO(2,), was during unsupported arm exercise. Because the subjects with COPD had scores showing similar levels of dyspnea at the same percentage of VO(2) peak, it is suggested that patients be encouraged to reach equivalent dyspnea levels when performing unsupported and supported arm exercise training and leg training.     

Hyperinflation, dyspnea, and exercise intolerance in chronic obstructive pulmonary disease

Expiratory flow limitation is the pathophysiologic hallmark of chronic obstructive pulmonary disease (COPD), but dyspnea (breathlessness) is its most prominent and distressing symptom. Acute dynamic lung hyperinflation, which refers to the temporary increase in operating lung volumes above their resting value, is a key mechanistic consequence of expiratory flow limitation, and has serious mechanical and sensory repercussions. It is associated with excessive loading and functional weakness of inspiratory muscles, and with restriction of normal VT expansion during exercise. There is a strong correlation between the intensity of dyspnea at a standardized point during exercise, the end-expiratory lung volume, and the increased ratio of inspiratory effort to volume displacement (i.e., esophageal pressure relative to maximum: Vt as a % of predicted VC). This increased effort-displacement ratio in COPD crudely reflects the neuromechanical dissociation of the respiratory system that arises as a result of hyperinflation. The corollary of this is that any intervention that reduces end-expiratory lung volume will improve effort-displacement ratios and alleviate dyspnea. In flow-limited patients, bronchodilators act by improving dynamic airway function, thus enhancing lung emptying and reducing lung hyperinflation. Long-acting bronchodilators have recently been shown to reduce hyperinflation during both rest and exercise in moderate to severe COPD. This lung deflation allows greater Vt expansion for a given inspiratory effort during exercise with consequent improvement in dyspnea and exercise endurance.     

Effects of endurance training on skeletal muscle bioenergetics in chronic obstructive pulmonary disease.

Physiologic adaptations after an 8-wk endurance training program were examined in 13 patients with chronic obstructive pulmonary disease (COPD) (age, 64 +/- 4 [SD] yr; FEV1, 43 +/- 9% pred; PaO2, 72 +/- 8 mm Hg; and PaCO2, 36 +/- 2 mm Hg) and in eight healthy sedentary control subjects (61 +/- 4 yr). Both pre- and post-training studies included: (1) whole-body oxygen consumption (V O2) and one-leg O2 uptake (V O2leg) during exercise; and (2) intracellular pH (pHi) and inorganic phosphate to phosphocreatine ratio ([Pi]/[PCr]) during exercise; and half-time of [PCr] recovery. After training, the two groups increased peak V O2 (p < 0.05 each) and showed a similar fall in submaximal femoral venous lactate levels (p < 0.05 each). However, control subjects increased peak V E (p < 0.01) and raised peak O2 delivery (p = 0.05), not shown in patients with COPD. Both groups increased post-training O2 extraction ratio (p < 0.05). The most consistent finding, however, was in patients with COPD, who had a substantial improvement in cellular bioenergetics: (1) half-time of [PCr] recovery fell from 50 +/- 8 to 34 +/- 7 s (p = 0.02); and (2) at a given submaximal work rate, [Pi]/[PCr] ratio decreased and pHi increased (p < 0.05 each). We conclude that beneficial effects of training in patients with COPD essentially occurred at muscle level during submaximal exercise.     

Maximum inspiratory muscle endurance capacity during resistive loading in chronic obstructive pulmonary disease

In 10 patients with stable severe chronic obstructive pulmonary disease (COPD) we evaluated the relationship between the degree of airway obstruction and hyperinflation, and the maximum inspiratory muscle endurance capacity during added inspiratory resistive loading. We measured the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) and airway resistance (Raw) as indices of airway obstruction, and the ratio of functional residual capacity to total lung capacity (FRC/TLC) as an index of hyperinflation. The mean resting transdiaphragmatic pressure to its maximum (Pdi/Pdimax), the tension time index of the diaphragm, and the maximum transdiaphragmatic pressure (Pdimax) were also determined. Following 15 min of resting breathing, the patients breathed through added inspiratory resistances which were progressively increased every 3 min until exhaustion. Maximum endurance capacity (ECmax) was defined as the product of the esophageal pressure - time integral and frequency at the maximum load sustainable for 3 min. ECmax correlated significantly with Raw (r = -0.67, p less than 0.04). The addition of FRC/TLC to the analysis resulted in a significant increase in the correlation coefficient (r = 0.86, p less than 0.01). ECmax did not correlate with FEV1/FVC. Both resting Pdi/Pdimax and Pdimax independently influenced ECmax. In addition, Pdimax correlated significantly with FRC/TLC, and resting Pdi/Pdimax with Raw. We conclude that in stable patients with severe COPD, both airway obstruction and hyperinflation affect maximum inspiratory muscle endurance capacity during inspiratory resistive loading.     

Health status, dyspnea, lung function and exercise capacity in patients with chronic obstructive pulmonary disease.

SETTING: A secondary hospital outside Oslo. OBJECTIVE: To assess relationships between health status and measures of dyspnea, lung function and exercise capacity in patients with chronic obstructive pulmonary disease (COPD), to identify dimensions where lung-specific instruments associate and discriminate better than general measures. DESIGN: We assessed health status in 59 out-patients with COPD, using the following instruments: Short Form 36 (SF-36)-a general health status measure, Respiratory Quality of Life Questionnaire (RQLQ)-a lung-specific measure, the Karnofsky performance scale, and a rating scale. All patients rated their dyspnea and had spirometry and exercise capacity measured. RESULTS: Mean (SD) patient age was 57.3 (9.7) years, FEV1 47% (15%) of predicted, 6 minute walk distance 503 m (122 m). Dyspnea was the strongest predictor for health status. Both SF-36 and RQLQ had dimensions associating well with dyspnea and exercise capacity. The associations with FEV1 ranged from none to moderate. CONCLUSION: All RQLQ scales had a moderate to substantial association with indices of dyspnea and exercise capacity, while the SF-36 associated well only in dimensions related to physical health. The general measure has a broader scope and complements the lung-specific measure. These findings support the construct validity of both the SF-36 and the RQLQ, and justify using a general measure to supplement a lung-specific measure.     

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.     

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.     

Serial changes in exercise capacity,quality of life and cardiopulmonary responses after pulmonary rehabilitation in patients with chronic obstructive pulmonary disease

Background and Objectives

Patients with chronic obstructive pulmonary disease (COPD) often have poor health-related quality of life (HRQL), exercise capacity and cardiopulmonary function. Pulmonary rehabilitation (PR) is beneficial to improve exercise capacity and HRQL. However, series changes of these parameters remain unclear.

Pulmonary rehabilitation improves heart rate variability at peak exercise,exercise capacity and health-related quality of life in chronic obstructive pulmonary disease

Objective

Patients with chronic obstructive pulmonary disease (COPD) appear to have impaired cardiac autonomic modulation with depressed heart rate variability (HRV). Pulmonary rehabilitation (PR) is recommended as an integral part of the management. However, the effect of PR on HRV at peak exercise remains unclear.

Methods

Sixty-four patients with COPD participated in a 12-week, 2 sessions-per-week, hospital-based PR program. Baseline and post-PR status were evaluated by spirometry, HRV, health-related quality of life (HRQL, St. George's Respiratory Questionnaire, SGRQ), cardiopulmonary exercise test, respiratory muscle strength, and dyspnea Borg's scale.

Results

After PR, there were significant improvements in the time and frequency domains of HRV with increased standard deviation of the normal R–R intervals, difference between adjacent normal R–R intervals within a given time minus one, high-frequency and decreased low-frequency, as well as concurrent improvements in HRQL, exercise capacity, dyspnea score, and respiratory muscle strength (all p < 0.05).

Conclusions

PR results in significant improvements in autonomic function, with concurrent improvements in HRQL and exercise capacity.     

Effect of alprazolam on exercise and dyspnea in patients with chronic obstructive pulmonary disease

To evaluate the efficacy of a mild anxiolytic, alprazolam, in relieving dyspnea, we conducted a randomized, placebo-controlled double-blind study on patients with chronic obstructive lung disease. Twenty-four patients had alprazolam (0.5 mg bid) or placebo administered for one week, followed by placebo for one week, then either placebo or alprazolam for the third week. Assessment tests were performed at the outset, end of the first and second weeks, and finally end of the third week. The parameters measured were: pulmonary function, exercise testing on a bicycle ergometer, and the distance covered in a 12 minute walk. Subjective sensations of dyspnea at rest and during guarded exercise, as well as subjective feelings of calmness or anxiety were also recorded. There was no difference in mechanical lung function, but the PO2 tended to decrease and PCO2 to increase after alprazolam administration. The maximum exercise level attained and the distance covered in the 12 minute walk was unchanged. The subjective perception of dyspnea was the same before and after alprazolam, at rest and during exercise. We conclude that alprazolam is not effective in relieving exercise dyspnea in patients with obstructive lung disease.     

Targeted inspiratory muscle training improves respiratory muscle function and reduces dyspnea in patients with chronic obstructive pulmonary disease

STUDY OBJECTIVE: To examine the effects of targeted inspiratory muscle training on respiratory muscle function, clinical ratings of dyspnea, and perception of resistive loads in symptomatic patients with chronic obstructive pulmonary disease. DESIGN: Randomized, placebo-controlled trial with an 8-week treatment period. SETTING: Outpatient pulmonary clinic and pulmonary function laboratory. PARTICIPANTS: We studied 19 patients with moderate to severe chronic obstructive pulmonary disease, assigning 10 patients to an experimental group and 9 to a control group. INTERVENTIONS: Patients in both groups trained for 15 minutes twice each day using a device that provided breath-to-breath visual feedback of training intensity. Patients in the experimental group trained at six increasing levels of inspiratory resistance, whereas the patients in the control group trained at a constant, nominal level of resistance. MEASUREMENTS AND RESULTS: Although there was no statistically discernible difference in the effects of targeted muscle training on the mean difference in maximal inspiratory pressures between the two groups (9.83 cm H2O; 95% CI, -7.37 to 27.03), patients in the experimental group did show a significant increase in inspiratory muscle strength (15.03 cm H2O; P = 0.01). Experimental subjects also had decreased dyspnea after 8 weeks of training compared with control subjects (P = 0.003). Improvements in physiologic values and in dyspnea ratings were correlated. The perception of added resistive loads was not affected by inspiratory muscle training. CONCLUSIONS: Targeted inspiratory muscle training may enhance respiratory muscle function and reduce dyspnea in symptomatic patients with moderate to severe chronic obstructive pulmonary disease.     

The acute effects of noninvasive ventilatory support during exercise on exercise endurance and dyspnea in patients with chronic obstructive pulmonary disease: a systematic review

PURPOSE: The objective of this study was to review studies systematically, in which the acute effects of noninvasive ventilatory support (NIVS) during exercise were evaluated in patients with chronic obstructive pulmonary disease (COPD). In addition, a quantitative analysis was performed on the effects of NIVS on exertional dyspnea and exercise endurance. METHODS: Literature was searched in electronic databases, and by scanning lists of references of studies and abstract books of annual congresses of the American Thoracic Society and European Respiratory Society. Preliminary data of a study by our own group into the effects of NIVS on exercise endurance in patients with COPD were added. The systematic review was carried out on the basis of a validated methodological screening list. For the quantitative analysis, Glass delta of individual studies were pooled to aggregate a summary effect size. RESULTS: Fifteen studies were identified. Seven of these studies met the inclusion criteria, including a total of 65 patients with COPD. The methodological quality of the included studies varied from 31% to 54% of the maximum score of 13 points. Statistically significant summary effect sizes were found in the analysis of exertional dyspnea (P <.05) as well as in the analysis of exercise endurance (P <.001), indicating improvements in these outcomes in favor of NIVS. CONCLUSIONS: The present systematic review suggests that NIVS during exercise may acutely reduce exertional dyspnea and improve exercise endurance, in patients with COPD.     

Inspiratory muscle training in patients with COPD: effect on dyspnea, exercise performance, and quality of life

OBJECTIVE: The aim of the study was to assess the effect of target-flow inspiratory muscle training (IMT) on respiratory muscle function, exercise performance, dyspnea, and health-related quality of life (HRQL) in patients with COPD. PATIENTS AND METHODS: Twenty patients with severe COPD were randomly assigned to a training group (group T) or to a control group (group C) following a double-blind procedure. Patients in group T (n = 10) trained with 60 to 70% maximal sustained inspiratory pressure (SIPmax) as a training load, and those in group C (n = 10) received no training. Group T trained at home for 30 min daily, 6 days a week for 6 months. MEASUREMENTS: The measurements performed included spirometry, SIPmax, inspiratory muscle strength, and exercise capacity, which included maximal oxygen uptake (VO(2)), and minute ventilation (VE). Exercise performance was evaluated by the distance walked in the shuttle walking test (SWT). Changes in dyspnea and HRQL also were measured. RESULTS: Results showed significant increases in SIPmax, maximal inspiratory pressure, and SWT only in group T (p < 0.003, p < 0.003, and p < 0.001, respectively), with significant differences after 6 months between the two groups (p < 0.003, p < 0.003, and p < 0.05, respectively). The levels of VO(2) and VE did not change in either group. The values for transitional dyspnea index and HRQL improved in group T at 6 months in comparison with group C (p < 0.003 and p < 0.003, respectively). CONCLUSIONS: We conclude that targeted IMT relieves dyspnea, increases the capacity to walk, and improves HRQL in COPD patients.     

Respiratory muscle function and drive in chronic obstructive pulmonary disease

Respiratory, and particularly inspiratory, muscle function is altered in COPD. Many of these alterations are secondary to a mechanical disadvantage related to hyperinflation. Other factors, including corticosteroid therapy and nutritional depletion, are also deleterious to muscle function. In addition, the load imposed on the respiratory muscles is increased in COPD. Combined with the altered respiratory muscle function, this increase induces important changes in respiratory muscle drive and recruitment. Moreover, the imbalance between respiratory muscle function and load is an important determinant of dyspnea and hypercapnia. Because much of the lung and airway derangements are irreversible in COPD, the respiratory muscles appear to be an attractive target for therapeutic interventions.     

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.