Effect of pulmonary rehabilitation on quality of life in patients with COPD: the use of SF-36 summary scores as outcomes measures

PURPOSE: Pulmonary rehabilitation (PR) is an accepted therapy for patients with chronic obstructive pulmonary disease (COPD), improving both exercise capacity and quality of life (QOL). Generic measures of QOL have been criticized as being insensitive to detecting the improvement in QOL after PR in contrast to disease-specific instruments. The authors looked at the Medical Outcomes Survey Short Form 36-item questionnaire (SF-36), a generic QOL measure, to detect changes in QOL in COPD patients after completion of PR. METHODS: Patients with COPD who participated in a PR program completed the QOL questionnaire before and after completion of PR. Exercise tolerance was assessed by the 6-minute walking test. Quality of life was assessed by the SF-36; the authors calculated its eight dimensions as well as mental (MCS) and physical (PCS) component summary scores. RESULTS: The patients realized a significant improvement in exercise tolerance; 6-minute walking test distance increased from 470 +/- 104 m (mean +/- standard deviation) to 536 +/- 133 m (P = 0.0006) after PR. Quality of life also improved in nearly all dimensions and in both summary scores; PCS improved from 26.1 +/- 8.0 before PR to 30.5 +/- 9.0 after PR (P = 0.008) and MCS improved from 27.9 +/- 7.0 before PR to 34.1 +/- 5.0 after PR (P = 0.0002). CONCLUSION: The SF-36 and its summary scores are sensitive instruments to detect improvement in QOL in COPD patients after PR.     

Does body mass index influence the outcomes of a Waking-based pulmonary rehabilitation programme in COPD?

Body mass index (BMI) is an important prognostic measure in chronic obstructive pulmonary disease (COPD). However, its effects on pulmonary rehabilitation (PR) are unknown. This study aimed to evaluate the effectiveness of a walking-based PR programme across the BMI range and the impact of BMI on exercise performance and health status. A total of 601 patients with COPD completed a PR programme. The effects of BMI on exercise capacity (incremental and endurance shuttle walk tests (ISWT and ESWT)) and health status (chronic respiratory questionnaire (CRQ)) before and after PR were evaluated. 16% of patients were underweight, with 53% overweight or obese. At baseline, the obese had worse ISWT (-54 m ± 14 m; p = 0.001) despite a higher predicted forced expiratory volume in 1 s (7.4m ± 1.6%; p < 0.001). Patients in all BMI categories made clinically important improvements in ISWT distance: BMI <21, 62 m; 21-25, 59 m; 25-30, 59 m; >30, 65 m (p = < 0.001). All four domains of the CRQ increased above the level of clinical significance for all BMI categories (all p < 0.001). The majority of patients with COPD were overweight associated with a lower walking capacity. A walking-based PR programme was comparably effective across the BMI spectrum. Patients with COPD should be referred for standard PR, independent of BMI.     

Short- and long-term hospital and community exercise programmes for patients with chronic obstructive pulmonary disease

OBJECTIVE: Pulmonary rehabilitation in patients with COPD has been shown to be beneficial but the optimal setting is not known. In the present study, the efficacy of a short-term community-based exercise programme was compared with a standard hospital outpatient programme. Additionally, the usefulness of community or home programmes in maintaining improvements in the longer term was studied. METHODOLOGY: Forty-three patients with moderate to severe COPD were randomized to one of the following three groups: a 3-month hospital programme then a 9 month home programme (Hospital/Home); a 3-month hospital programme then a 9-month community programme (Hospital/Community); or a 12-month community programme (Community/Community). The initial 3-month programme was analysed by comparing the Hospital group (Hospital/Home plus Hospital/Community) with the Community group (Community/Community). Six-minute walking distance (6MWD), quality of life (Guyatt chronic respiratory disease questionnaire, CRQ) and lung function were measured at 0, 3, 6 and 12 months and results were analysed using the Wilcoxon rank sum test. RESULTS: At 3 months, there was a significant improvement from baseline in 6MWD in the Hospital group (81.3 +/- 18.3 m, P < 0.05, anova) but not the Community group (14.4 +/- 28.5 m, not significant). The difference between the groups was not significant (P = 0.058). At 3 months, there was a significant improvement in quality of life in the Hospital group (CRQ +16.3 +/- 3.1, P < 0.01, anova) and in the Community group (CRQ +10.2 +/- 4.9, P < 0.05, anova) but the difference between the groups was not significant. Following the initial 3-month programme, the dropout rate was high overall (73% by 12 months), and therefore data from the maintenance programme could not be analysed. CONCLUSIONS: A 3-month community-based exercise programme for patients with COPD did not improve 6MWD. The long-term retention rates in the programmes were poor.     

Maintaining the benefits following pulmonary rehabilitation: Achievable or not?

Pulmonary rehabilitation (PR) improves exercise capacity, health‐related quality of life (HRQoL) and dyspnoea in patients with COPD and other lung conditions. Once PR is completed, the benefits gained begin to decline unless patients continue to exercise regularly. Due to limited evidence in other lung conditions, this review aims to examine the current evidence regarding maintenance exercise programmes for patients with COPD and to determine the types of programmes that are able to maintain the benefits gained from PR to 12 months and longer. A number of factors may affect the ability to maintain exercise capacity and HRQoL in the long term including: frequency of supervised maintenance exercise; strategies used to improve adherence to maintenance exercise; facilitators and barriers to long‐term exercise training; and initial PR programme itself. The current evidence for maintenance exercise programmes that included supervised maintenance exercise was weak, and for those programmes that included unsupervised maintenance exercise (with and without support) were difficult to interpret and in many instances were no better than usual care. New research using technology has provided some promising results for the future and surveys have revealed important features that may help in the development of maintenance programmes from a participant perspective such as ongoing therapist support. How to best maintain the benefits gained from PR remains unclear. Therefore, it is likely that no one model of maintenance is ideal for all patients with COPD and that individually adapted maintenance exercise programmes need to be considered.     

Circulating haemopoietic and endothelial progenitor cells are decreased in COPD.

Circulating CD34+ cells are haemopoietic progenitors that may play a role in tissue repair. No data are available on circulating progenitors in chronic obstructive pulmonary disease (COPD). Circulating CD34+ cells were studied in 18 patients with moderate-to-severe COPD (age: mean+/-sd 68+/-8 yrs; forced expiratory volume in one second: 48+/-12% predicted) and 12 controls, at rest and after endurance exercise. Plasma concentrations of haematopoietic growth factors (FMS-like tyrosine kinase 3 (Flt3) ligand, kit ligand), markers of hypoxia (vascular endothelial growth factor (VEGF)) and stimulators of angiogenesis (VEGF, hepatocyte growth factor (HGF)) and markers of systemic inflammation (tumour necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8) were measured. Compared with the controls, the COPD patients showed a three-fold reduction in CD34+ cell counts (3.3+/-2.5 versus 10.3+/-4.2 cells.microL-1), and a 50% decrease in AC133+ cells. In the COPD patients, progenitor-derived haemopoietic and endothelial cell colonies were reduced by 30-50%. However, four COPD patients showed progenitor counts in the normal range associated with lower TNF-alpha levels. In the entire sample, CD34+ cell counts correlated with exercise capacity and severity of airflow obstruction. After endurance exercise, progenitor counts were unchanged, while plasma Flt3 ligand and VEGF only increased in the COPD patients. Plasma HGF levels were higher in the COPD patients compared with the controls and correlated inversely with the number of progenitor-derived colonies. In conclusion, circulating CD34+ cells and endothelial progenitors were decreased in chronic obstructive pulmonary disease patients and could be correlated with disease severity.     

Community based physiotherapeutic exercise in COPD self-management: a randomised controlled trial

Little is known about effects of community-based physiotherapeutic exercise programmes incorporated in COPD self-management programmes. In a randomised trial, the effect of such a programme (COPE-active) on exercise capacity and various secondary outcomes including daily activity as a marker of behaviour change was evaluated. All patients attended four 2-h self-management sessions. In addition the intervention group participated in the COPE-active programme offered by physiotherapists of private practices, consisting of a 6-month "compulsory" period (3 sessions/week) and subsequently a 5-month "optional" period (2 sessions/week). Because COPE-active was intended to change behaviour with regard to exercise, one session/week in both periods consisted of unsupervised home-based exercise training. Of 153 patients, 74 intervention and 68 control patients completed the one-year follow-up. Statistically significant between-group differences in incremental shuttle walk test-distance (35.1 m; 95% CI (8.4; 61.8)) and daily activity (1190 steps/day; 95% CI (256; 2125)) were found in favour of the intervention group. Over the 12-month period a significant difference of the chronic respiratory questionnaire (CRQ) dyspnoea-score (0.33 points; 95% CI (0.01; 0.64)) and a non-significant difference of the endurance shuttle walk test (135 m (95% CI (-29; 298)) was found. No differences were found in the other CRQ-components, anxiety and depression scores and percentage of fat free mass. This study demonstrates that a community-based reactivation programme improves exercise capacity in patients with moderately to severe COPD. Even more important, the programme improves actual daily activity after one-year which indicates behaviour change with regard to daily exercise. Registered trail number: ISRCTN81447311.     

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.     

Encouraged 6-min walking test indicates maximum sustainable exercise in COPD patients

STUDY OBJECTIVES: In patients with moderate-to-severe COPD, an encouraged 6-min walking test (6MWT) is a high-intensity submaximal exercise protocol that shows an oxygen uptake (Vo(2)) plateau after the third minute of the test. This last feature prompted the hypothesis that self-paced walking speed is set to achieve "maximal" sustainable Vo(2), namely "critical power" or "critical speed." PATIENTS AND METHODS: Eight patients with moderate-to-severe COPD (mean age, 68 +/- 7 years [+/- SD]; FEV(1), 50 +/- 13% predicted; Pao(2), 69 +/- 8 mm Hg) underwent the following tests on different days in order: (1) encouraged 6MWT; (2) standard incremental shuttle test to identify peak walking speed; (3) four different high-intensity, constant walking speed tests to exhaustion to calculate critical walking speed; and (4) timed walking test at critical walking speed (CWS) to examine sustainability of the exercise. RESULTS: 6MWT and CWS showed similar results (mean of last 3 min): Vo(2) (1,605 +/- 304 mL/min vs 1,584 +/- 319 mL/min), minute ventilation (47 +/- 12 L/min vs 48 +/- 11 L/min), respiratory exchange ratio (0.89 +/- 0.1 vs 0.90 +/- 0.1), heart rate (130 +/- 18 beats/min vs 131 +/- 16 beats/min), Borg dyspnea score (5.4 +/- 1.3 vs 5.5 +/- 2.4), and walking speed (1.49 +/- 0.1 m/s vs 1.44 +/- 0.1 m/s, respectively). CONCLUSION: This study supports that 6MWT indicates maximum sustainable exercise that might be related with its predictive value in COPD patients.     

Cost-Effectiveness of a Community-Based Exercise Programme in COPD Self-Management

Introduction: Information regarding cost-effectiveness of community-based exercise programmes in COPD is scarce. Therefore, we have investigated whether a community-based exercise programme is a cost-effective component of self-management for patients with COPD after 2 years of follow-up.

Methods: All included COPD patients participated in four self-management sessions. Additionally, patients in the COPE-active group participated in an 11-month community-based exercise programme led by physiotherapists. Patients trained 3 times/week for 6 months and two times/week during the subsequent 5 months. In both periods, one of these weekly training sessions was home-based (unsupervised). No formal physiotherapy sessions were offered to COPE-active patients in the second year. A decision analytical model with a 24-month perspective was used to evaluate cost-effectiveness. Incremental cost-effectiveness ratios (ICER) were calculated and cost-effectiveness planes were created.

Results: Data of 77 patients participating in the exercise programme and 76 patients in the control group were analysed. The ICER for an additional patient prevented from deteriorating at least 47.5 meters on the ISWT was €6257. The ICER for an additional patient with a clinically relevant improvement (≥ 500 steps/day) in physical activity was €1564, and the ICER for an additional quality-adjusted life year (QALY) was €10 950.

Conclusion: Due to a lack of maintenance of beneficial effects on our primary outcome exercise capacity after 2 years of follow-up and higher costs of the programme, the community-based exercise programme cannot be considered cost-effective compared to self-management programmes only. Nevertheless, the ICERs for the secondary outcomes physical activity and QALY are generally considered acceptable.     

Power of outcome measurements to detect clinically significant changes in pulmonary rehabilitation of patients with COPD

STUDY OBJECTIVES: Several validated instruments are used to measure outcomes, such as exercise performance, dyspnea, and health-related quality of life after pulmonary rehabilitation (PR) in patients with COPD. However, no study has simultaneously compared the responsiveness of the most frequently used outcome measurements after PR. We designed this study to investigate the capacity of several of the most frequently used outcome measurements to detect changes after PR in a population of patients with severe COPD who qualified for lung volume reduction surgery. DESIGN, PATIENTS, AND INTERVENTIONS: We evaluated 37 patients with severe COPD (FEV(1) < 40%) before and after 6 to 8 weeks of outpatient PR. The following frequently used tools were evaluated: the 6-min walk distance (6MWD); functional dyspnea with the Medical Research Council (MRC) scale; baseline and transitional dyspnea index (BDI/TDI); resting and 6MWD visual analog scale (VAS); quality of life with a generic tool (the Short Form-36 [SF-36]); and two disease-specific tools, the Chronic Respiratory Disease Questionnaire (CRQ) and the St. George's Respiratory Questionnaire (SGRQ). RESULTS: After PR, mean +/- SD 6MWD increased in 33 of 37 patients (89%), from 285 +/- 97 to 343 +/- 92 m (p = 0.009). Improvements were seen also in the MRC scale in 23 of 37 patients (62%; from 2.27 +/- 0.8 to 1.86 +/- 0.6; p = 0.01); in CRQ dyspnea in 25 of 37 patients (67%; from 3.25 +/- 0.9 to 3.90 +/- 1.4; p = 0.02); in CRQ mastery in 22 of 37 patients (60%; from 4.37 +/- 1.4 to 5.14 +/- 1.3; p = 0.01); and in BDI/TDI functional in 24 of 37 patients (64%; from 1.4 +/- 0.8 to 0.7 +/- 1.1; p = 0.002). There were smaller improvements in the SGRQ in 18 of 37 patients (48%) and in the SF-36 in 19 of 37 patients (51%), but they were not statistically significant. There were good correlations between the dyspnea components of all the tools. The 6MWD change did not correlate with the changes in the other outcomes. Clinically significant changes in the values for those outcome tools were detected in > 50% of patients for the BDI/TDI, 29% of patients for the MRC scale, in 37% of patients for the 6MWD, in 48% of patients for the VAS at peak exercise, in > 50% of patients for the CRQ, and in 40% of patients for the SGRQ. CONCLUSIONS: We conclude that the VAS peak exercise, BDI/TDI, and CRQ adequately reflect the beneficial effects of PR. The 6MWD evaluates a unique domain not related to quality of life. Due to their simplicity and sensitivity, VAS at peak exercise, 6MWD, and CRQ may be the best practical tools to evaluate responsiveness to PR.     

Effects of isolated cycle ergometer training on patients with moderate-to-severe chronic obstructive pulmonary disease

BACKGROUND: Pulmonary rehabilitation (PR) programs are beneficial to patients with chronic obstructive pulmonary disease (COPD), and lower-extremity training is considered a fundamental component of PR. Nevertheless, the isolated effects of each PR component are not well established. OBJECTIVE: We aimed to evaluate the effects of a cycle ergometry exercise protocol as the only intervention in a group of COPD patients, and to compare these results with a control group. METHODS: 25 moderate-to-severe COPD patients were evaluated regarding pulmonary function, respiratory muscle strength, exercise capacity, quality of life and body composition. Patients were allocated to one of two groups: (a) the trained group (TG; n = 13; 6 men) was submitted to a protocol of 24 exercise sessions on a cycle ergometer, with training intensity initially set at a heart rate (HR) close to 80% of maximal HR achieved in a maximal test, and load increase based on dyspnea scores, and (b) the control group (CG; n = 12; 6 men) with no intervention during the protocol period. RESULTS: TG showed within-group significant improvements in endurance cycling time, 6-min walking distance test, maximal inspiratory pressure and in the domain 'dyspnea' related to quality of life. Despite the within-group changes, no between-group significant differences were observed. CONCLUSION: In COPD patients, the results of isolated low-to-moderate intensity cycle ergometer training are not comparable to effects of multimodality and high-intensity training programs.     

Peripheral arterial disease: an underestimated aetiology of exercise intolerance in chronic obstructive pulmonary disease patients.

OBJECTIVE: To assess the prevalence of peripheral arterial disease and its implications for exercise limitation in chronic obstructive pulmonary disease (COPD) patients. METHOD: One hundred and fifty-one moderate-to-severe COPD patients (forced expiratory volume in 1 s: 37+/-6 SD% predicted) and 73 healthy age-matched control individuals (divided into 31 smokers and 42 nonsmokers) participated in this study. All COPD patients were either exsmokers or current smokers and their tobacco-smoking history was similar to that of healthy smokers. To evaluate the existence of arterial disease, lower limb perfusion pressure impairment was assessed using the ankle brachial index, whereas arterial stiffness was assessed by the pulse wave velocity (PWV). The definition of peripheral arterial disease required an ankle brachial index value of 0.90 or less, whereas the PWV increment was considered to be a direct witness of arterial stiffness increase. A 6-min walk test was performed to assess physical exercise capacity. RESULTS: Prevalence of peripheral arterial disease was higher in COPD patients than in healthy participants (81+/-3 SD; 49+/-5 SD and 9+/-2 SD%, respectively, in COPD, healthy smokers and nonsmokers). PWV mean values were significantly higher in COPD patients compared with healthy smokers and nonsmokers (10.3+/-2.1 SD m/s; 9.2+/-1.3 SD m/s and 8.7+/-2.2 SD m/s, respectively). The distance covered during the 6-min-walk test was associated positively with the degree of peripheral arterial disease (r=0.78; P=0.05) and negatively with the PWV values (r=-0.74; P=0.05). Not only tobacco-smoking history but also COPD severity was shown to influence these associations. CONCLUSION: The effect of peripheral arterial disease on exercise intolerance in COPD seems to be considerable. Therefore, COPD patients participating in a pulmonary rehabilitation programme should profit from a systematic search for arterial disease. Arterial dysfunction has to be taken into account in the multidisciplinary treatment of these patients.     

Improvements in outcomes for chronic obstructive pulmonary disease (COPD) attributable to a hospital-based respiratory rehabilitation programme

Aim: To determine whether the benefits of pulmonary rehabilitation, demonstrated in selected subjects in randomised controlled studies, can be achieved by a hospital-based respiratory rehabilitation programme conducted as part of routine clinical management. Methods: Design: A prospective longitudinal study of patients with severe chronic obstructive pulmonary disease (COPD) enrolled in a hospital based, non-medically supervised, outpatient, respiratory rehabilitation programme was undertaken. The rehabilitation programme was of pragmatic design and content, supervised by respiratory physiotherapists and comprised seven two hour sessions over one month for groups of six to eight patients. It included education on disease management, practical instruction in coping skills, as well as a progressive aerobic exercise programme for specific muscle training related to functional activities. Subjects were assessed prior to the programme but after optimisation of pharmacologic therapy, at the completion of the programme and at three months and six months post-programme. Principal outcome parameters were exercise capacity (as assessed by a six minute walk distance [MWD] test), degree of perceived breathlessness and quality of life (QOL) (assessed by the Chronic Respiratory Disease Questionnaire [CRDQ]). Results: Fifty-one subjects with severe COPD (Fev₁=0.9±0.4 1) completed the programme. There was a significant improvement in exercise capacity (a six MWD test improved from 375±126 m at baseline to 440±109 m at three months, p<0.005). There were significant improvements in QOL (in the total CRDQ score as well as in the domains of dyspnoea, fatigue and mastery). There was a reduction in the level of perceived dyspnoea (modified Borg Scale). Most improvements were maintained for three and six months following completion of the programme. Compared with the six months preceding the programme there was a reduction in hospital admissions and reduction in courses of oral steroids. Conclusions: An outpatient, hospital-based respiratory rehabilitation programme pragmatically adapted for clinical utility produces substantial and clinically significant improvements in exercise tolerance and QOL, similar in type and magnitude to those obtained in controlled clinical trials. There was an associated reduction in COPD-related morbidity. Such gains were mostly maintained for six months after completion of the programme. Thus respiratory rehabilitation must be regarded as an essential component of a comprehensive clinical programme for the management of COPD.     

Muscle strength and exercise kinetics in COPD patients with a normal fat-free mass index are comparable to control subjects

STUDY OBJECTIVE: This study was designed to investigate the extent of clinical muscle dysfunction in stable patients with COPD who were attending an out-patient pulmonary clinic compared with that of age-matched control subjects without COPD. Design and subjects: Respiratory muscle and hand grip strength, steady-state O(2) kinetics, and body composition were measured in 32 patients with COPD (19 women) [mean (+/- SD) FEV(1), 38 +/- 11% predicted] and 36 age-matched control subjects (13 women). RESULTS: Measurements of handgrip force (mean, 97 +/- 32% vs 106 +/- 26% predicted, respectively), maximal expiratory pressure (mean, 57 +/- 33% vs 61 +/- 22% predicted, respectively), steady-state O(2) kinetics (mean tau, 72 +/- 34 s vs 78 +/- 37 s, respectively) and steady-state CO(2) kinetics (mean tau, 77 +/- 38 s vs 65 +/- 32 s, respectively) at submaximal exercise were similar in patients and control subjects. All the subjects, except for one female COPD patient, had a normal fat-free mass index (FFMI), although on average the FFMI was lower in male patients (19.8 +/- 2.8) than in male control subjects (23.0 +/- 2.8; p < 0.01). CONCLUSIONS: In patients with COPD who were attending a regular outpatient pulmonary clinic, there was no evidence of reduced upper extremity and expiratory muscle strength or prolonged O(2) and CO(2) kinetics during isowork submaximal cardiopulmonary exercise compared to healthy, age-matched control subjects. Also, a normal body composition was found in nearly all COPD patients. This argues against the existence of a clinically significant systemic myopathy in most stable patients with severe COPD and normal FFMI.     

The effect of tiotropium on hyperinflation and exercise capacity in chronic obstructive pulmonary disease

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation, which results in the progressive development of dyspnea and exercise limitation. OBJECTIVE AND METHODS: To compare the effect of tiotropium with placebo on forced vital capacity (FVC) in patients with moderate-to-severe COPD and lung hyperinflation, using exercise endurance, dyspnea and health-related quality of life (HRQoL) as secondary endpoints. One hundred patients were randomized to receive either tiotropium 18 mug once daily or placebo for 12 weeks. RESULTS: Trough (predose) FVC was significantly improved with tiotropium compared to placebo on day 42 (0.27 +/- 0.08 liters) and 84 (0.20 +/- 0.08 liters; p < 0.05 for both). Trough inspiratory capacity (IC) was also significantly improved with tiotropium compared to placebo on day 42 (0.16 +/- 0.07 liters) and 84 (0.15 +/- 0.07 liters; p < 0.05 for both). Tiotropium increased the mean distance walked during the shuttle walking test by 33 +/- 12 (day 42) and 36 +/- 14 m (day 84) compared to placebo (p < 0.05 for both). On day 84, 59% of the patients in the tiotropium group and 35% of the patients in the placebo group had significant and clinically meaningful improvements in the St. George's Respiratory Questionnaire total score (p < 0.05). Numerical decreases in the focal score in the Transition Dyspnea Index in patients receiving tiotropium versus placebo suggest that tiotropium also improved dyspnea during activities of daily living. CONCLUSION: Tiotropium 18 mug once daily reduced hyperinflation with consequent improvements in walking distance and HRQoL in patients with COPD and lung hyperinflation.     

Longitudinal trends in exercise capacity and health status after pulmonary rehabilitation in patients with COPD

Pulmonary rehabilitation (PR) programmes produce initial improvements in exercise tolerance and health status in patients with chronic obstructive pulmonary disease (COPD). However, there is limited data on the longer term effects of PR. This study has examined whether the initial benefits gained in exercise tolerance and health status may be maintained after a 1-year follow-up programme. Sixty-six patients with COPD were assessed with the MRC Dyspnoea Scale and found to be moderately disabled due to dyspnoea (MRC Grades 3 and 4). These patients were then randomised to an 8 week outpatient programme of either exercise training and education (Exercise group) or to education alone (Control group). Exercise performance was assessed with the shuttle walking test and health status assessed with two disease-specific measures, the St Georges Respiratory Questionnaire and the Chronic Respiratory Disease Questionnaire. After PR, all patients were invited to attend monthly follow-up sessions for 1 year. Fifty-six patients were available for follow-up immediately after the programme and were assessed at 6 months and 1 year. This study has shown that the patients in the Exercise group maintained improvements in exercise capacity and health status up to 6 months after an 8 week programme. At 1 year there was a significant difference between the Exercise and Control groups in terms of exercise tolerance due to a considerable decline experienced by the Control group. However, neither group had maintained improvements in health status at 1 year. Further study is required to assess whether benefit may be sustained for a longer period using alternative follow-up strategies.     

Helium-hyperoxia, exercise, and respiratory mechanics in chronic obstructive pulmonary disease

RATIONALE: Hyperoxia and normoxic helium independently reduce dynamic hyperinflation and improve the exercise tolerance of patients with chronic obstructive pulmonary disease (COPD). Combining these gases could have an additive effect on dynamic hyperinflation and a greater impact on respiratory mechanics and exercise tolerance. OBJECTIVE: To investigate whether helium-hyperoxia improves the exercise tolerance and respiratory mechanics of patients with COPD. METHODS: Ten males with COPD (FEV(1) = 47 +/- 17%pred [mean +/- SD]) performed randomized constant-load cycling at 60% of maximal work rate breathing air, hyperoxia (40% O(2), 60% N(2)), normoxic helium (21% O(2), 79% He), or helium-hyperoxia (40% O(2), 60% He). MEASUREMENTS: Exercise time, inspiratory capacity (IC), work of breathing, and exertional symptoms were measured with each gas. RESULTS: Compared with air (9.4 +/- 5.2 min), exercise time was increased with hyperoxia (17.8 +/- 5.8 min) and normoxic helium (16.7 +/- 9.1 min) but the improvement with helium-hyperoxia (26.3 +/- 10.6 min) was greater than both these gases (p = 0.019 and p = 0.007, respectively). At an isotime during exercise, all three gases reduced dyspnea and both helium mixtures increased IC and tidal volume. Only helium-hyperoxia significantly reduced the resistive work of breathing (15.8 +/- 4.2 vs. 10.1 +/- 4.1 L . cm H(2)O(-1)) and the work to overcome intrinsic positive end-expiratory pressure (7.7 +/- 1.9 vs. 3.6 +/- 2.1 L . cm H(2)O(-1)). At symptom limitation, tidal volume remained augmented with both helium mixtures, but IC and the work of breathing were unchanged compared with air. CONCLUSION: Combining helium and hyperoxia delays dynamic hyperinflation and improves respiratory mechanics, which translates into added improvements in exercise tolerance for patients with COPD.     

Feasibility of high-intensity,interval-based respiratory muscle training in COPD

BACKGROUND: Specific respiratory muscle training can improve respiratory muscle function in patients with COPD, but the magnitude of improvement appears dependent on the magnitude of the training load. High training loads are difficult to achieve using conventional, constant loading techniques, but may be possible using interval-based training techniques. METHODS: To assess the feasibility of high-intensity respiratory muscle training, nine subjects with moderate-to-severe COPD (FEV(1) 34 +/- 12% predicted [mean +/- SD]) completed 8 weeks of interval-based respiratory muscle training combined with a general exercise program. This involved three 20-min sessions per week, each session comprising seven 2-min bouts of breathing against a constant inspiratory threshold load, each bout separated by 1 min of unloaded recovery. Inspiratory load was progressively incremented. Respiratory muscle strength (maximum inspiratory pressure generated against an occluded airway [PImax]) and endurance (maximum pressure generated against a progressively increasing inspiratory threshold load [Pthmax]) were measured before and immediately after the 8-week training period. RESULTS: By the third training session (week 1), subjects breathed against a threshold that required generation of pressures equivalent to 68 +/- 5% of the pretraining PImax. By week 8, this had increased to 95 +/- 12% of the pretraining PImax. On completion of training, PImax had increased by 32 +/- 27% (p < 0.05), Pthmax had increased by 56 +/- 33% (p < 0.05), and Pthmax/PImax had increased by 20 +/- 20% (p < 0.05). CONCLUSIONS: This study has demonstrated that high-intensity, interval-based respiratory muscle training is feasible in patients with moderate-to-severe COPD, resulting in significant improvements in respiratory muscle strength and endurance when performed three times a week for 8 weeks.     

Reliability, validity, and responsiveness of a 2-min walk test to assess exercise capacity of COPD patients

PURPOSES: To investigate the reliability, validity, and responsiveness of a 2-min walk test (2MWT) in Chinese COPD patients with moderate-to-severe disease. METHODS: This study consisted of two parts. Forty-seven stable COPD patients with moderate-to-severe disease participated in the first part of study for the investigation of reliability and validity. The demographic and anthropomorphic data collected included age, gender, body weight, height, and body mass index. Each subject performed a pulmonary function test, a cardiopulmonary exercise test, three trials of a 2MWT, and two trials of 6-min-walk test (6MWT) in random order within a 5-day period. Fifteen of these subjects participated in the second part of study for the evaluation of the responsiveness of the 2MWT following pulmonary rehabilitation. The 2MWT and 6MWT were conducted before and after the program for comparison. RESULTS: Forty-five subjects (mean [+/- SD] age, 71.8 +/- 8.3 years; mean FEV1, 0.88 +/- 0.27 L) completed the first part of study, and 9 subjects (mean age, 74 +/- 8.7 years; mean FEV1, 0.94 +/- 0.28 L) completed the second part of study. The intraclass correlation coefficient of the repeated 2MWTs was high (R = 0.9994; p < 0.05), mean differences across trials ranged from 0.3 to 0.8 m (95% confidence interval, -3.1 to 4.6 m) demonstrated its high test-retest reliability. Significant correlations were found between the 2MWT and the 6MWT, the maximum oxygen uptake (V(O2)max) in milliliters per minute, and the V(O2)max in milliliters per kilogram per minute (r = 0.937, 0.454, and 0.555 respectively; p < 0.0125). Following rehabilitation, there were significant improvements in the mean 2MWT and 6MWT walking distance of 17.2 +/- 13.8 m and 60.6 +/- 35.5 m, respectively, with moderate effect sizes (0.61 and 0.53, respectively) and large standardized mean responses (1.25 and 1.70, respectively). High correlation was found between changes in the 2MWT and the 6MWT (r = 0.70; p < 0.05). CONCLUSION: The 2MWT was shown to be a reliable and valid test for the assessment of exercise capacity and responsive following rehabilitation in patients with moderate-to-severe COPD. It is practical, simple, and well-tolerated by patients with severe COPD symptoms.     

Does thoracic bioimpedance accurately determine cardiac output in COPD patients during maximal or intermittent exercise?

STUDY OBJECTIVES: The monitoring of cardiac output (CO) during exercise rehabilitation in patients with COPD, often including strenuous exercise, is advisable. Invasive methods (thermodilution, Fick method) are accurate, but for clinical routine use noninvasive CO estimation is required. We have shown that impedance cardiography (Physio Flow; Manatec Biomedical; Macheren, France) is reliable in COPD patients at rest and during a recumbent, light-intensity exercise. The aim of our study was to evaluate the validity of this noninvasive device in COPD patients during a maximal incremental exercise test (IET) and also during a strenuous intermittent work exercise test (IWET). DESIGN: Prospective comparative study of the impedance cardiograph vs the direct Fick method applied to oxygen. PATIENTS: Eight patients with moderate-to-severe COPD (59 +/- 6 years old; FEV(1), 38 +/- 15% predicted; residual volume, 194 +/- 64% predicted) [mean +/- SD].Measurements and main results: Forty-nine simultaneous measurements of CO by means of the direct Fick method (COfick) and CO measured by the impedance cardiograph (COpf) were obtained during the IET, and 108 measurements were made during the IWET. The correlation coefficients between the two measurements were r = 0.85 and r = 0.71 for the IET and the IWET, respectively. COpf was higher than COfick. The difference between the two methods was 3.2 +/- 2.9 L/min during the IET and 2.5 +/- 2.1 L/min during the IWET. Expressed as a percentage of the mean of the two measurements, this corresponded to 31 +/- 21% and 25 +/- 20%, respectively. CONCLUSIONS: The relatively high number of values differing by > 20% precludes the use of impedance cardiography in clinical routine in such a difficult setting (hyperinflated patients and intense exercise).