Effects of tiotropium on lung hyperinflation, dyspnoea and exercise tolerance in COPD.

The aim of this study was to test the hypothesis that use of tiotropium, a new long-acting anticholinergic bronchodilator, would be associated with sustained reduction in lung hyperinflation and, thereby, would improve exertional dyspnoea and exercise performance in patients with chronic obstructive pulmonary disease. A randomised, double-blind, placebo-controlled, parallel-group study was conducted in 187 patients (forced expiratory volume in one second 44 +/- 13% pred): 96 patients received 18 microg tiotropium and 91 patients received placebo once daily for 42 days. Spirometry, plethysmographic lung volumes, cycle exercise endurance and exertional dyspnoea intensity at 75% of each patient's maximal work capacity were compared. On day 42, the use of tiotropium was associated with the following effects at pre-dose and post-dose measurements as compared to placebo: vital capacity and inspiratory capacity (IC) increased, with inverse decreases in residual volume and functional residual capacity. Tiotropium increased post-dose exercise endurance time by 105 +/- 40 s (21%) as compared to placebo on day 42. At a standardised time near end-exercise (isotime), IC, tidal volume and minute ventilation all increased, whilst dyspnoea decreased by 0.9 +/- 0.3 Borg scale units. In conclusion, the use of tiotropium was associated with sustained reductions of lung hyperinflation at rest and during exercise. Resultant increases in inspiratory capacity permitted greater expansion of tidal volume and contributed to improvements in both exertional dyspnoea and exercise endurance.     

Does dynamic hyperinflation contribute to dyspnoea during exercise in patients with COPD?

Dynamic hyperinflation (DH) during exercise occurs in most but not all patients with advanced chronic obstructive pulmonary disease (COPD). It is not known whether the presence or absence of DH has implications for dyspnoea and exercise tolerance. Therefore, we compared detailed ventilatory and sensory responses to exercise in hyperinflators and nonhyperinflators with moderate-to-severe COPD. Nonhyperinflators (n=65) were retrospectively identified from a sample of 427 patients and case-matched to a group of hyperinflators (n=65) based on sex, age, body mass index and % predicted forced expiratory volume in 1 s. Resting pulmonary function and constant work rate cycle exercise responses were compared. Hyperinflators decreased inspiratory capacity (IC) from rest to peak exercise by 0.46±0.24 L whereas the nonhyperinflators increased IC by 0.10±0.15 L (p<0.0001). There were no significant group differences in endurance time (9.11±5.98 versus 8.87±5.24 min) or dyspnoea intensity for any given time or ventilation. An inflection in tidal volume versus ventilation occurred in the majority of nonhyperinflators (n=61) and hyperinflators (n=62) at a similar time and ventilation. Mechanical constraints on tidal volume expansion and the attendant rise in dyspnoea intensity were similar in both groups. Dyspnoea intensity during exercise was associated with progressive mechanical constraints on tidal volume expansion regardless of the presence of DH.     

Dynamic hyperinflation and exercise intolerance in chronic obstructive pulmonary disease.

The role of dynamic hyperinflation (DH) in exercise limitation in chronic obstructive pulmonary disease (COPD) remains to be defined. We examined DH during exercise in 105 patients with COPD (FEV(1) = 37 +/- 13% predicted; mean +/- SD) and studied the relationships between resting lung volumes, DH during exercise, and peak oxygen consumption (VO(2)). Patients completed pulmonary function tests and incremental cycle exercise tests. We measured the change in inspiratory capacity (Delta IC) during exercise to reflect changes in DH. During exercise, 80% of patients showed significant DH above resting values. IC decreased 0.37 +/- 0.39 L or 14 +/- 15% predicted during exercise (p < 0.0005), but with large variation in range. Delta IC correlated best with resting IC, both expressed %predicted (r = -0.50, p < 0.0005). Peak VO(2) (%predicted maximum) correlated best with the peak tidal volume attained (VT standardized as % of predicted vital capacity) (r = 0.68, p < 0.0005), which, in turn, correlated strongly with IC at peak exercise (r = 0.79, p < 0.0005) or at rest (r = 0.75, p < 0.0005). The extent of DH during exercise in COPD correlated best with resting IC. DH curtailed the VT response to exercise. This inability to expand VT in response to increasing metabolic demand contributed importantly to exercise intolerance in COPD.     

Effectiveness of salmeterol versus ipratropium bromide on exertional dyspnoea in COPD.

The hypothesis of the study was that salmeterol and ipratropium would have similar dyspnoea ratings during steady-state cycle ergometry at 1 h, but that salmeterol would reduce dyspnoea at 6 h after administration in patients with chronic obstructive pulmonary disease (COPD). The study design was a randomized, double-blind trial in 16 patients (aged 63 +/- 11 yrs) with symptomatic COPD. Two days after familiarization with testing procedures, patients were randomly assigned to receive either two puffs (42 microg) of salmeterol and two puffs of placebo inhaler, or two puffs (36 microg) of ipratropium from each of two inhalers (total, 72 microg). Two days later, patients received the alternative medication. During exercise at 60% of peak oxygen consumption patients rated dyspnoea and performed inspiratory capacity manoeuvres each minute. Forced expiratory volume in one second was 1.13+/-0.48 L (37+/-13% predicted). Dyspnoea ratings were similar for salmeterol and ipratropium at 1 and 6 h. Inspiratory capacity was similar for salmeterol and ipratropium at 1 h, but significantly higher for salmeterol at 6 h (delta = 120 mL; p = 0.03). It is concluded that with the doses used, salmeterol and ipratropium provided similar dyspnoea ratings during exercise at 1 and 6 h after administration.     

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.     

Physiological responses to high intensity, constant-load arm exercise in COPD

The aim of the study was to compare the metabolic, ventilatory and dyspnoea responses of a single bout of high intensity, constant-load arm exercise to peak arm exercise in people with chronic obstructive pulmonary disease (COPD). Thirty people with COPD (mean age+/-SD=65+/-8 years; FEV1% predicted=56+/-12%) were included. All subjects performed an incremental arm exercise test to peak work capacity on an arm ergometer and, on a separate day, a constant-load arm exercise test at 80% of the peak work rate achieved on the incremental test. Throughout both exercise tests, oxygen consumption (VO2), minute ventilation (VE), dyspnoea and rate of perceived exertion (RPE) were measured each minute. Peak work rate on the incremental test was 33.0+/-10.1 W with a mean duration of 6.6+/-2.0 min. The mean duration of the constant-load test of 7.1+/-2.9 min was not significantly different to the incremental test (p=0.3). At end exercise, VE, dyspnoea and RPE for the constant-load test was significantly higher compared to the incremental test (VE: 41.3+/-14.4 L/min and 38.3+/-11.8 L/min; dyspnoea: 5.6+/-2.7 and 4.6+/-2.1; RPE: 7.1+/-2.3 and 6.0+/-2.0; all p<0.05). Constant-load arm exercise at 80% peak work rate elicits higher ventilatory, dyspnoea and RPE responses at end exercise compared to incremental arm exercise in people with COPD. This finding suggests that an intensity of 80% peak work rate may be too high as an initial training intensity for supported arm exercise in people with COPD.     

Dynamic hyperinflation and tolerance to interval exercise in patients with advanced COPD.

Dynamic hyperinflation (DH) contributes importantly to the limitation of constant-load exercise (CLE) in patients with chronic obstructive pulmonary disease (COPD). However, its role in the limitation of interval exercise (IE) remains to be explored. The change (Delta) in inspiratory capacity (IC) was measured to reflect changes in DH in 27 COPD patients (forced expiratory volume in one second mean+/-SEM % predicted: 40+/-3) at the end of a symptom-limited CLE test at 80% of peak work capacity (WRmax) and an IE test at 100% WRmax (30 s of work, alternated with 30 s of unloaded pedalling). At the limit of tolerance in both IE and CLE, patients exhibited similar DH (DeltaIC: 0.39+/-0.05 L and 0.45+/-0.05 L, respectively). However, exercise endurance time (t end) for IE (32.7+/-3.0 min) was significantly greater than for CLE (10.3+/-1.6 min). The IE t end correlated with resting IC, expressed as % pred normal. At 30 and 90% of total IE t end, DeltaIC (0.43+/-0.06 and 0.39+/-0.05 L, respectively) and minute ventilation (31.1+/-1.6 and 32.7+/-2.2 L.min(-1), respectively) were not significantly different. Resting hyperinflation helps to explain the limitation of interval exercise. Implementation of interval exercise for rehabilitation should provide important clinical benefits because it prolongs exercise endurance time and allows sustaining higher stable ventilation.     

Training with inspiratory pressure support in patients with severe COPD.

This study evaluates the effects of training with noninvasive ventilatory support in patients with chronic obstructive pulmonary disease in a randomised, controlled, observer-blinded trial. Twenty-nine patients with chronic obstructive pulmonary disease and with a ventilatory limited exercise capacity (forced expiratory volume in one second < 60% predicted, breathing reserve at maximal exercise < 20% of maximally voluntary ventilation, resting arterial oxygen tension > or = 8 kPa (60 mmHg), end-exercise arterial oxygen saturation measured by pulse oximetry > or = 85%) completed an 8-week supervised outpatient cycle exercise programme. Fourteen patients were randomised to training with inspiratory pressure support of 10 cmH2O and 15 patients to training with control (sham) inspiratory pressure support of 5 cmH2O. Outcome measures were the incremental shuttle walking test and a constant-load cycle endurance test at 75% of peak work rate including the measurement of physiological responses, and health status measured using the St. George's Respiratory Questionnaire. Statistically significant between-group differences were found in favour of the inspiratory pressure support of 10 cmH2O group for improvement in shuttle walking distance (16+/-17 versus 3+/-13%), cycle endurance (164+/-124 versus 88+/-128%), and the reduction in minute ventilation during exercise (-11+/-10 versus -2+/-9%). It was concluded that exercise training with inspiratory pressure support of 10 cmH2O resulted in statistically significantly larger improvements in exercise performance than training with inspiratory pressure support of 5 cmH2O in patients with chronic obstructive pulmonary disease suffering from a ventilatory limited exercise capacity. Inspiratory pressure support of 10 cmH2O may be considered as adjunct during high-intensity exercise training.     

Noninvasive ventilation during walking in patients with severe COPD: a randomised cross-over trial.

It was hypothesised that noninvasive positive-pressure ventilation (NPPV) applied during walking prevents exercise-induced hypoxaemia and improves exercise performance in severe chronic obstructive pulmonary disease (COPD) patients already receiving long-term NPPV. A total of 20 COPD patients (mean+/-sd age 65.1+/-8.7 yrs, forced expiratory volume in one second 27+/-8% predicted and total lung capacity 116+/-27% pred) reporting dyspnoea, even during mild exertion, underwent two 6-min walking tests with a rollator and supplemental oxygen (2.1+/-0.9 L.min(-1)) in a randomised cross-over design: with and without pressure-limited NPPV as used at home (inspiratory:expiratory pressure 2.9+/-0.44:0.4+/-0.1 kPa (29+/-4:4+/-1 mbar), respiratory frequency 20+/-2 breaths.min(-1)). The arterial oxygen tension significantly increased by 1.39+/-1.43 kPa (95% confidence interval (CI) 0.71-2.07 kPa) after walking with NPPV, but significantly decreased by 1.43+/-1.06 kPa (95% CI -1.92 - -0.94 kPa) without NPPV. Dyspnoea, as assessed by the Borg dyspnoea scale, significantly decreased from 6 (interquartile range (IQR) 4.5-10) to 4 (1.5-4.5) and walking distance significantly increased from 209 (IQR 178-279) to 252 (203-314) m when walking was NPPV-aided. In chronic hypercapnic chronic obstructive pulmonary disease, high-intensity noninvasive positive-pressure ventilation can also be administered during walking with unchanged ventilator settings compared with settings used at rest, thus resulting in improved oxygenation, decreased dyspnoea and increased walking distance. Therefore, noninvasive positive-pressure ventilation during walking could prevent hypoxia-induced complications and could, in future, play a role in palliative care.     

Ventilatory constraints during exercise in patients with chronic heart failure

We examined the degree of ventilatory constraint in patients with a history of chronic heart failure (CHF; n = 11; mean +/- SE age, 62 +/- 4 years; cardiac index [CI], 2.0 +/- 0.1; and ejection fraction [EF], 24 +/- 2%) and in control subjects (CTLS; n = 8; age, 61 +/- 5 years; CI, 2.6 +/- 0.3) by plotting the tidal flow-volume responses to graded exercise in relationship to the maximal flow-volume envelope (MFVL). Inspiratory capacity (IC) maneuvers were performed to follow changes in end-expiratory lung volume (EELV) during exercise, and the degree of expiratory flow limitation was assessed as the percent of the tidal volume (VT) that met or exceeded the expiratory boundary of the MFVL. CHF patients had significantly (p < 0.05) reduced baseline pulmonary function (FVC, 76 +/- 4%; FEV(1), 78 +/- 4% predicted) relative to CTLS (FVC, 99 +/- 4%; FEV(1), 102 +/- 4% predicted). At peak exercise, oxygen consumption (VO(2)) and minute ventilation (V(E)) were lower in CHF patients than in CTLS (VO(2), 17 +/- 2 vs 32 +/- 2 mL/kg/min; VE, 56 +/- 4 vs 82 +/- 6 L/min, respectively), whereas VE/carbon dioxide output was higher (42 +/- 4 vs 29 +/- 5). In CTLS, EELV initially decreased with light exercise, but increased as VE and expiratory flow limitation increased. In contrast, the EELV in patients with CHF remained near residual volume (RV) throughout exercise, despite increasing flow limitation. At peak exercise, IC averaged 91 +/- 3% and 79 +/- 4% (p < 0.05) of the FVC in CHF patients and CTLS, respectively, and flow limitation was present over > 45% of the VT in CHF patients vs < 25% in CTLS (despite the higher VE in CTLS). The least fit and most symptomatic CHF patients demonstrated the lowest EELV, the greatest degree of flow limitation, and a limited response to increased inspired carbon dioxide during exercise, all consistent with VE constraint. We conclude that patients with CHF commonly breathe near RV during exertion and experience expiratory flow limitation. This results in VE constraint and may contribute to exertional intolerance.     

Physiological effects of roflumilast at rest and during exercise in COPD

The purpose of this study was to investigate the effects of 500 μg roflumilast, taken once daily for 12 weeks, on airway physiology during rest and exercise in patients with moderate-to-severe chronic obstructive pulmonary disease. This randomised, double-blind, placebo-controlled, parallel-group study was conducted in 250 patients with a post-bronchodilator forced expiratory volume in 1 s (FEV(1)) of 30-80% predicted and a functional residual capacity of ≥ 120% pred. Pre- and post-bronchodilator spirometry and body plethysmography, and pre-bronchodilator constant work rate cycle exercise at 75% of peak work rate were evaluated. Exercise measurements included ventilation, breathing pattern, inspiratory capacity (IC) and arterial oxygen saturation measured by pulse oximetry (S(p,O(2))). Compared with placebo, 12 weeks of treatment with roflumilast was associated with: small but progressive increases in pre- and post-bronchodilator FEV(1) and FEV(1)/forced vital capacity; small decreases in specific airway resistance; and no significant changes in resting vital capacity, IC or measurements of lung hyperinflation. There was no treatment effect on exercise endurance time. At a standardised exercise time after roflumilast, compared with placebo, IC increased by 0.12 L (p = 0.008) and S(p,O(2)) increased by 0.7% (p = 0.020); peak ventilation increased by 1.9 L · min(-1) (p = 0.014). Roflumilast treatment was associated with progressive improvement of airway function but not lung hyperinflation. Newly described non-bronchodilator effects of roflumilast included small but consistent improvements in air trapping and S(p,O(2)) during exercise.     

Effects of hyperoxia on ventilatory limitation during exercise in advanced chronic obstructive pulmonary disease

We studied interrelationships between exercise endurance, ventilatory demand, operational lung volumes, and dyspnea during acute hyperoxia in ventilatory-limited patients with advanced chronic obstructive pulmonary disease (COPD). Eleven patients with COPD (FEV(1.0) = 31 +/- 3% predicted, mean +/- SEM) and chronic respiratory failure (Pa(O(2)) 52 +/- 2 mm Hg, Pa(CO(2 ))48 +/- 2 mm Hg) breathed room air (RA) or 60% O(2) during two cycle exercise tests at 50% of their maximal exercise capacity, in randomized order. Endurance time (T(lim)), dyspnea intensity (Borg Scale), ventilation (V E), breathing pattern, dynamic inspiratory capacity (IC(dyn)), and gas exchange were compared. Pa(O(2)) at end-exercise was 46 +/- 3 and 245 +/- 10 mm Hg during RA and O(2), respectively. During O(2), T(lim) increased 4.7 +/- 1.4 min (p < 0.001); slopes of Borg, V E, V CO(2), and lactate over time fell (p < 0.05); slopes of Borg-V E, V E-V CO(2), V E-lactate were unchanged. At a standardized time near end-exercise, O(2) reduced dyspnea 2.0 +/- 0.5 Borg units, V CO(2) 0.06 +/- 0.03 L/min, V E 2.8 +/- 1.0 L/min, and breathing frequency 4.4 +/- 1.1 breaths/min (p < 0.05 each). IC(dyn) and inspiratory reserve volume (IRV) increased throughout exercise with O(2) (p < 0.05). Increased IC(dyn) was explained by the combination of increased resting IRV and decreased exercise breathing frequency (r(2) = 0.83, p < 0.0005). In conclusion, improved exercise endurance during hyperoxia was explained, in part, by a combination of reduced ventilatory demand, improved operational lung volumes, and dyspnea alleviation.     

Constant-load cycle endurance performance: test-retest reliability and validity in patients with COPD

The purpose of this study was to evaluate the rest-retest reliability and validity of a constant-load endurance exercise test on a cycle ergometer with a workload of 75% of maximal work capacity (W(max)) in patients with moderate to severe chronic obstructive pulmonary disease (COPD). In 60 patients with COPD (FEV(1) 40 +/- 15% pred), exercise endurance time was measured with a constant-load endurance exercise tests at 75% of W(max), on two different occasions. In a subgroup of 20 patients, test-retest reliability of the measurement of end-exercise ventilatory and metabolic responses was assessed. Validity of the cycle endurance test was assessed comparing endurance time and total work performed during the cycle endurance test to peak oxygen uptake (VO(2peak)) and the 12-minute walking distance (12MWD).Test and retest assessments of cycle endurance time did not differ statistically significantly (P =.40). Highly significant intraclass correlation coefficients (ICC > or = 0.85; P <.001) were found between test and retest of assessment of endurance time as well as of end-exercise ventilatory and metabolic responses. In addition, statistically significant correlation coefficients were found between VO(2peak) and endurance time (r = 0.50; P =.001) and total work performed (r = 0.72; P <.001) during the constant-load cycle test. Significant correlation coefficients of the same magnitude were found between 12MWD and endurance time (r = 0.58; P =.001) and total work performed (r = 0.72; P <.001) during the constant-load cycle test. It is concluded that constant-load exercise testing on a cycle ergometer with a workload of 75% of maximal work capacity is a reliable and valid method to assess exercise endurance in patients with COPD.     

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.     

Lack of additional effect of adjunct of assisted ventilation to pulmonary rehabilitation in mild COPD patients

Different modalities of assisted ventilation improve breathlessness and exercise tolerance in patients with chronic obstructive pulmonary disease (COPD).The aim of this study was to evaluate the effects of the addition of assisted ventilation during exercise training on the outcome of a structured pulmonary rehabilitation programme (PRP) in COPD patients. Thirty-three male patients with stable COPD (mean (SD) forced expiratory volume in 1 s (FEV1) 44 (16) % pred), without chronic ventilatory failure, undergoing a 6-week multidisciplinary outpatient PRP including exercise training, were randomised to training during either mask proportional assist ventilation (PAV: 18 patients) or spontaneous breathing (SB: 15 patients). Assessment included exercise tolerance, dyspnoea, leg fatigue, and health-related quality of life (HRQL). Five out of 18 patients (28%) in the PAV group dropped out due to lack of compliance with the equipment. Both groups showed significant post-PRP improvements in exercise tolerance (peak work rate difference: 20 (95% Cl 2.4-37.6) and 14 (3.8% CI to 24.2) W in PAV and SB group, respectively), dyspnoea and leg fatigue, but not in HRQL, without any significant difference between groups. It is concluded that with the modality and in the patients assessed in this study assisted ventilation during training sessions included in a multidisciplinary PRP was not well tolerated by all patients and gave no additional physiological benefit in comparison with exercise training alone.     

Inspiratory fraction and exercise impairment in COPD patients GOLD stages II-III.

The inspiratory-to-total lung capacity ratio or "inspiratory fraction" (inspiratory capacity(IC)/total lung capacity (TLC)) may be functionally more representative than traditional indices of resting airflow limitation and lung hyperinflation in patients with chronic obstructive pulmonary disease (COPD). In the present retrospective study, a comparison was made of the individual performance of post-bronchodilator IC, IC/TLC and forced expiratory volume in one second (FEV(1)) in predicting a severely reduced peak oxygen uptake (V'(O(2)); <60% predicted) in 44 COPD patients Global Initiative for Chronic Obstructive Lung Disease stages II-III (post-bronchodilator FEV(1) ranging from 31-79% pred). Patients with lower IC/TLC values (相似文献   

Long-term reduction of hyperinflation in stable COPD by non-invasive nocturnal home ventilation

OBJECTIVE: The role of non-invasive positive pressure ventilation (NPPV) in stable COPD with chronic ventilatory failure remains controversial. The impact of long-term home nocturnal NPPV treatment on deflation has not yet been evaluated in detail. METHODS: Retrospective explorative study of 46 patients with stable COPD undergoing NPPV treatment. Effects of NPPV on body plethysmographic parameters, blood gas tensions and inspiratory muscle function after 6.2 (+/-1.7) and 12.7 (+/-2.1) months of treatment. Further, evaluation of 1-year survival, compliance and ventilation parameters. RESULTS: One-year survival was 89.1%. The effectiveness of ventilation was proven by a significant reduction in nocturnal and daytime PaCO2. We observed a decrease in the ratio of residual volume (RV) to total lung capacity (TLC) on the average of 5.2+/-9.8% (or 15.2+/-29.7% pred.; P<0.01) at six and 3.9+/-9.0% (or 12.9+/-18.6% pred.; P<0.001) at 12 months. As a consequence, we found significant improvements in inspiratory capacity (IC), vital capacity (VC) and forced expiratory volume in one second (FEV1). For patients with the most severe hyperinflation (RV/TLC>75%), we found a significant positive correlation between inspiratory positive airway pressure (IPAP) and reductions in PaCO2 (r=0.56; P<0.05) and RV/TLC (r=0.50; P<0.05). CONCLUSIONS: In severe hypercapnic stable COPD long-term nocturnal NPPV can reduce hyperinflation with sustained improved daytime blood gas parameters.     

Effect of fluticasone propionate/salmeterol on lung hyperinflation and exercise endurance in COPD

STUDY OBJECTIVE: To examine the effect of fluticasone propionate, 250 microg/salmeterol, 50 microg combination (FSC 250/50) twice daily on lung hyperinflation and associated measures of exercise performance in patients with COPD. DESIGN: This was a randomized, double-blind, parallel-group study. PATIENTS: Eligible patients were > or = 40 years old with a diagnosis of COPD, prealbuterol FEV(1) < 70% of predicted, FEV1/FVC ratio > or = 0.70, and functional residual capacity (FRC) > or = 120% of predicted normal. INTERVENTIONS: Patients were randomized to FSC 250/50; salmeterol, 50 microg; or placebo twice daily for 8 weeks. Predose and postdose spirometry, plethysmography, and constant-load cycle cardiopulmonary exercise test evaluations were compared. The primary comparison was FSC 250/50 with placebo. The salmeterol group was included for exploratory comparisons with FSC 250/50. RESULTS: A total of 185 patients (mean baseline FEV1 of 41% predicted) were enrolled. At rest, FSC 250/50 significantly reduced postdose FRC and increased inspiratory capacity (IC) compared with placebo (differences of - 0.35 +/- 0.12 L and 0.33 +/- 0.06 L [mean +/- SE], respectively, at week 8; p > or = 0.003) and increased exercise endurance time (difference, 132 +/- 45 s; p = 0.004). At a standardized time during exercise (isotime), FSC 250/50 increased postdose IC by 0.20 +/- 0.05 L over placebo with associated improvements in tidal volume and minute ventilation (p < 0.05 vs placebo at week 8). Improvement in exercise time was significantly correlated with the increase in IC (r = 0.45, p < 0.001) but not FEV1 (r = 0.23, p = 0.08). Predose comparisons of FSC 250/50 with salmeterol and placebo favored FSC 250/50. CONCLUSION: We conclude that FSC 250/50 decreases lung hyperinflation at rest and during exercise with an associated increase in exercise endurance time when compared with placebo.     

Respiratory muscle endurance training in chronic obstructive pulmonary disease: impact on exercise capacity, dyspnea, and quality of life

Inspiratory muscle training may have beneficial effects in certain patients with chronic obstructive pulmonary disease (COPD). Because of the lack of a home training device, normocapnic hyperpnea has rarely been used as a training mode for patients with COPD, and is generally considered unsuitable to large-scale application. To study the effects of hyperpnea training, we randomized 30 patients with COPD and ventilatory limitation to respiratory muscle training (RMT; n = 15) with a new portable device or to breathing exercises with an incentive spirometer (controls; n = 15). Both groups trained twice daily for 15 min for 5 d per week for 8 wk. Training-induced changes were significantly greater in the RMT than in the control group for the following variables: respiratory muscle endurance measured through sustained ventilation (+825 +/- 170 s [mean +/- SEM] versus -27 +/- 61 s, p < 0.001), inspiratory muscle endurance measured through incremental inspiratory threshold loading (+58 +/- 10 g versus +21.7 +/- 9.5 g, p = 0.016), maximal expiratory pressure (+20 +/- 7 cm H(2)O versus -6 +/- 6 cm H(2)O, p = 0.009), 6-min walking distance (+58 +/- 11 m versus +11 +/- 11 m, p = 0.002), V O(2peak) (+2.5 +/- 0.6 ml/kg/min versus -0.3 +/- 0.9 ml/kg/min, p = 0.015), and the SF-12 physical component score (+9.9 +/- 2.7 versus +1.8 +/- 2.4, p = 0.03). Changes in dyspnea, maximal inspiratory pressure, treadmill endurance, and the SF-12 mental component score did not differ significantly between the RMT and control groups. In conclusion, home-based respiratory muscle endurance training with the new device used in this study is feasible and has beneficial effects in subjects with COPD and ventilatory limitation.