Effect of dynamic hyperinflation on exertional dyspnea, exercise performance and quality of life in COPD

There is increasing evidence that dynamic hyperinflation (DH) have negative effects on exercise performance and quality of life in chronic obstructive pulmonary disease (COPD) patients. The aim of this study was to investigate effect of dynamic hyperinflation on exertional dyspnea, exercise performance and quality of life in patients with COPD. 72 clinically stable patients with moderate to severe COPD and 30 healthy age-matched control subjects were included in this study. Pulmonary function tests including lung volumes and maximal respiratory muscle forces, arterial blood gas analyses, evaluation of exertional dyspnea with the Borg scale, and The Saint George Respiratory Questionnaire (SGRQ, Turkish version) were performed at rest and after a 6-min walk test. We measured the change in inspiratory capacity (AlphaIC) after exercise to reflect DH. 80% of patients with COPD significantly decreased IC after exercise (DH). AlphaIC were -0.27 +/- 0.26 L in COPD and 0.8 +/- 0.17 L in controls (p= 0.001). A stepwise multiple regression analysis showed that to be a patient with COPD, Basal Dyspnea Index (BDI) and AlphaIC were the best predictors of 6 MWD (r(2)= 0.53, p< 0.001). FEV1 added an additinal 9% to the variance in 6 MWD. Exertional dyspnea (AlphaBorg) correlated with AlphaIC (r= -0.44, p= 0.0001) and BDI (r= 0.34, p= 0.02). AlphaIC significantly correlated with symptom (r= -0.36, p= 0.008), activity (r= -0.31, p= 0.03) and total scores (r= -0.30, p= 0.04) of SGRQ. Dynamic hyperinflation can often occur during exersice in patients with COPD. Extent of dynamic hyperinflation could able to explain exercise capacity limitation, exercise dyspnea, and poor quality of life in patients with COPD.     

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.     

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.     

Tiotropium and simplified detection of dynamic hyperinflation

STUDY OBJECTIVE: To detect dynamic hyperinflation (DH) by evaluating reduction in inspiratory capacity (IC) during metronome-paced hyperventilation (MPH) in patients with moderate-to-severe COPD, studied before and after treatment with tiotropium. METHODS: IC and FEV(1) were measured before and immediately after MPH at two times resting the respiratory rate for 20 s in 60 COPD patients (28 men; mean age, 66 +/- 10 years [+/- SD]) before and after 30 days of treatment with tiotropium bromide, 18 mug. Patients were encouraged to maintain a constant tidal volume during MPH. RESULTS: At baseline, mean FEV(1) was 1.5 +/- 0.1 L (+/- SE) [57 +/- 1.6% of predicted], mean FVC was 2.6 +/- 0.1L (77 +/- 1.8% of predicted), and mean FEV(1)/FVC was 56 +/- 1%. After 180 mug of aerosolized albuterol sulfate, mean FEV(1) was 1.7 +/- 0.1 L (63 +/- 1.5% of predicted) [p < 0.001] and mean FEV(1)/FVC was 58 +/- 1%. Compared to baseline, after 30 days and 1.5 h after tiotropium there was an increase in IC of 0.18 +/- 0.04L (p < 0.0001); FEV(1) of 0.13 +/- 0.03 L (5.6 +/- 0.8% of predicted; p = 0.0002); FVC of 0.22 +/- 0.05 L (6.5 +/- 1.3% of predicted; p < 0.001); and decrease in end-expiratory lung volume (EELV)/total lung capacity (TLC) of - 3.1 +/- 0.6% (p = 0.0001); a decrease in end-inspiratory lung volume (EILV)/TLC of - 2.9 +/- 1.3% (p = 0.03); and no change in TLC (- 0.06 +/- 0.05 L). Results following MPH-induced DH at baseline and after 30 days of tiotropium were similar, with decreases in IC (- 0.35 +/- 0.03 L; p < 0.001); FEV(1) (- 0.05 +/- 0.04 L; p = 0.2); and FVC (- 0.22 +/- 0.03 L; p < 0.0001); no change in TLC; and increases in EELV/TLC (11.8 +/- 1.0% of predicted; p < 0.0001) and EILV/TLC (4.0 +/- 1.3% of predicted, p < 0.003). CONCLUSION: In patients with moderate-to-severe COPD, tiotropium did not reduce MPH-induced DH and reduction in IC, compared to baseline. However, because tiotropium induced bronchodilation and increased baseline IC, lower operational lung volumes may blunt the effect of MPH-induced DH. The noninvasive simplicity of MPH-induced DH provides a clinically useful screening surrogate to monitor changes in IC following treatment with tiotropium.     

Flow limitation and dynamic hyperinflation during exercise in COPD patients after single lung transplantation

STUDY OBJECTIVE: Using the negative expiratory pressure (NEP) method, we have previously shown that patients receiving single lung transplantation (SLT) for COPD do not exhibit expiratory flow limitation and have little dyspnea at rest. In the present study, we assessed whether SLT patients exhibit flow limitation, overall hyperinflation, and dyspnea during exercise. METHODS: Expiratory flow limitation assessed by the NEP method and inspiratory capacity maneuvers used to determine end-expiratory lung volume (EELV) and end-inspiratory lung volume (EILV) were performed at rest and during symptom-limited incremental cycle exercise in eight SLT patients. RESULTS: At the time of the study, the mean (+/- SD) FEV(1), FVC, functional residual capacity, and total lung capacity (TLC) amounted to 55 +/- 14%, 67 +/- 12%, 137 +/- 16%, and 110 +/- 11% of predicted, respectively. At rest, all patients did not experience expiratory flow limitation and were without dyspnea. At peak exercise, the maximal mechanical power output and maximal oxygen consumption amounted to 72 +/- 20% and 65 +/- 8% of predicted, respectively, with a maximal dyspnea Borg score of 6 +/- 3. All but one patient exhibited flow limitation and dynamic hyperinflation; the EELV and EILV amounted to 74 +/- 5% and 95 +/- 9% TLC, respectively. The patient who did not exhibit flow limitation during exercise had the lowest dyspnea score. CONCLUSION: Most SLT patients for COPD exhibit expiratory flow limitation and dynamic hyperinflation during exercise, whereas maximal dyspnea is variable.     

吸入性噻托溴铵对慢性阻塞性肺疾病患者深吸气量和运动耐量的影响

目的 探讨每天一次吸入噻托溴铵对于慢性阻塞性肺疾病(COPD)深吸气量(IC)和运动耐量的影响以及常用的肺功能指标与运动耐量的相关性.方法 吸入噻托溴铵18 μg/d,在第0天、第28天和第56天分别测定肺功能、6分钟步行试验(6MWT)和呼吸困难评分.结果 噻托溴铵吸人后第28天和第56天肺功能指标第1秒用力呼气容积...     

Exercise in severe COPD: Is walking different from stair-climbing?

BACKGROUND: It remains unclear whether the 6-min walking test can predict performance during stair-climbing in severe COPD patients. The present study aimed to assess different pathophysiological changes between walking and stair-climbing in these patients. METHODS: Sixteen COPD patients (mean FEV1 33+/-13% predicted) underwent a 6-min walking test and performed stair-climbing (44 steps) in a randomized, cross-over design. Blood gases, blood lactate, lung function parameters, maximal inspiratory mouth, sniff nasal and twitch mouth pressures, blood pressure, heart rate, and Borg Dyspnea Scale (BDS) were measured before and after exercise. RESULTS: The median drop of PaO2 during walking (2.6 mmHg) and stair-climbing (2.4 mmHg) was comparable (p=0.93). However, stair-climbing caused more dyspnea (median BDS 6.5 vs. 5.5, p=0.01), a higher median blood lactate (1.1 vs. 0.3 mmol/l p<0.001), a more pronounced drop in mean pH (-0.05+/-0.02 vs. -0.03+/-0.03, p=0.02) and a higher increase in mean systolic blood pressure (27+/-11 vs. 13+/-16 mmHg; p=0.009). Stair-climbing, but not walking, caused prolonged lung hyperinflation (mean TLC difference 4.4+/-4.7% predicted, p=0.003). There was no relationship between the 6-min walking distance (314+/-104 m) and the time needed for stair-climbing (55+/-33 s), nor were there any differences in inspiratory muscle strength and heart rate. CONCLUSION: Although the drop of PaO2 was comparable, stair-climbing resulted in more prolonged hyperinflation of the lungs, higher blood lactate production and more dyspnea than walking. The walking distance was not related to the time needed to manage stair-climbing. Therefore, pathophysiological changes during the 6-min walking test do not anticipate those during stair-climbing in patients with severe COPD.     

Diaphragm activation during exercise in chronic obstructive pulmonary disease

Although it has been postulated that central inhibition of respiratory drive may prevent development of diaphragm fatigue in patients with chronic obstructive pulmonary disease (COPD) during exercise, this premise has not been validated. We evaluated diaphragm electrical activation (EAdi) relative to maximum in 10 patients with moderately severe COPD at rest and during incremental exhaustive bicycle exercise. Flow was measured with a pneumotachograph and volume by integration of flow. EAdi and transdiaphragmatic pressures (Pdi) were measured using an esophageal catheter. End-expiratory lung volume (EELV) was assessed by inspiratory capacity (IC) maneuvers, and maximal voluntary EAdi was obtained during these maneuvers. Minute ventilation (V E) was 12.2 +/- 1.9 L/min (mean +/- SD) at rest, and increased progressively (p < 0.001) to 31.0 +/- 7.8 L/min at end-exercise. EELV increased during exercise (p < 0.001) causing end-inspiratory lung volume to attain 97 +/- 3% of TLC at end-exercise. Pdi at rest was 9.4 +/- 3.2 cm H(2)O and increased during the first two thirds of exercise (p < 0.001) to plateau at about 13 cm H(2)O. EAdi was 24 +/- 6% of voluntary maximal at rest and increased progressively during exercise (p < 0.001) to reach 81 +/- 7% at end-exercise. In conclusion, dynamic hyperinflation during exhaustive exercise in patients with COPD reduces diaphragm pressure-generating capacity, promoting high levels of diaphragm activation.     

Effects of imposed pursed-lips breathing on respiratory mechanics and dyspnea at rest and during exercise in COPD

STUDY OBJECTIVES: To investigate the effect of volitional pursed-lips breathing (PLB) on breathing pattern, respiratory mechanics, operational lung volumes, and dyspnea in patients with COPD. SUBJECTS: Eight COPD patients (6 male and 2 female) with a mean (+/-SD) age of 58 +/- 11 years and a mean FEV1 of 1.34 +/- 0.44 L (50 +/- 21% predicted). METHODS: Wearing a tight-fitting transparent facemask, patients breathed for 8 min each, with and without PLB at rest and during constant-work-rate bicycle exercise (60% of maximum). RESULTS: PLB promoted a slower and deeper breathing pattern both at rest and during exercise. Whereas patients had no dyspnea with or without PLB at rest, during exercise dyspnea was variably affected by PLB across patients. Changes in the individual dyspnea scores with PLB during exercise were significantly correlated with changes in the end-expiratory lung volume (EELV) values estimated from inspiratory capacity maneuvers (as a percentage of total lung capacity; r2 = 0.82, p = 0.002) and with changes in the mean inspiratory ratio of pleural pressure to the maximal static inspiratory pressure-generating capacity (PcapI) [r2 = 0.84; p = 0.001], measured using an esophageal balloon, where PcapI was determined over the range of inspiratory lung volumes and adjusted for flow. CONCLUSION: PLB can have a variable effect on dyspnea when performed volitionally during exercise by patients with COPD. The effect of PLB on dyspnea is related to the combined change that it promotes in the tidal volume and EELV and their impact on the available capacity of the respiratory muscles to meet the demands placed on them in terms of pressure generation.     

Spirometric correlates of improvement in exercise performance after anticholinergic therapy in chronic obstructive pulmonary disease.

We wished to determine which resting spirometric parameters best reflect improvements in exercise tolerance and exertional dyspnea in response to acute high-dose anticholinergic therapy in advanced COPD. We studied 29 patients with stable COPD (FEV(1) = 40 +/- 2% predicted [%pred]; mean +/- SEM) and moderate to severe chronic dyspnea. In a double-blind placebo-controlled cross-over study, patients performed spirometry and symptom-limited constant-load cycle exercise before and 1 h after receiving 500 micrograms of nebulized ipratropium bromide (IB) or saline placebo. There were no significant changes in spirometry, exercise endurance, or exertional dyspnea after receiving placebo. In response to IB (n = 58): FEV(1), FVC, and inspiratory capacity (IC) increased by 7 +/- 1%pred, 10 +/- 1%pred, and 14 +/- 2%pred, respectively (p < 0.001), with no change in the FEV(1)/FVC ratio. After receiving IB, exercise endurance time (Tlim) increased by 32 +/- 9% (p < 0.001) and slopes of Borg dyspnea ratings over time decreased by 11 +/- 6% (p < 0.05). Percent change (%Delta) in Tlim correlated best with DeltaIC%pred (p = 0.020) and change in inspiratory reserve volume (DeltaTLC%pred) (p = 0.014), but not with DeltaFVC%pred, DeltaPEFR%pred, or DeltaFEV(1)%pred. Change in Borg dyspnea ratings at isotime near end exercise also correlated with DeltaIC%pred (p = 0.04), but not with any other resting parameter. Changes in spirometric measurements are generally poor predictors of clinical improvement in response to bronchodilators in COPD. Of the available parameters, increased IC, which is an index of reduced resting lung hyperinflation, best reflected the improvements in exercise endurance and dyspnea after IB. IC should be used in conjunction with FEV(1) when evaluating therapeutic responses in COPD.     

Are patients with COPD more active after pulmonary rehabilitation?

BACKGROUND: Despite a variety of benefits brought by pulmonary rehabilitation to patients with COPD, it is unclear whether these patients are more active during daily life after the program. METHODS: Physical activities in daily life (activity monitoring), pulmonary function (spirometry), exercise capacity (incremental cycle-ergometer testing and 6-min walk distance testing), muscle force (quadriceps and handgrip force, and inspiratory and expiratory maximal pressures), quality of life (chronic respiratory disease questionnaire), and functional status (pulmonary functional status and dyspnea questionnaire-modified version) were assessed at baseline, after 3 months of a multidisciplinary rehabilitation program, and at the end of a 6-month multidisciplinary rehabilitation program in 29 patients (mean [+/- SD] age, 67 +/- 8 years; FEV(1), 46 +/- 16% predicted). RESULTS: Exercise capacity, muscle force, quality of life, and functional status improved significantly after 3 months of pulmonary rehabilitation (all p < 0.05), with further improvements in muscle force, functional status, and quality of life at 6 months. Movement intensity during walking improved significantly after 3 months (p = 0.046) with further improvements after 6 months (p = 0.0002). Walking time in daily life did not improve significantly at 3 months (mean improvement, 7 +/- 35%; p = 0.21), but only after 6 months (mean improvement, 20 +/- 36%; p = 0.008). No significant changes occurred in other activities or in the pattern of the time spent walking in daily life. Changes in dyspnea after the program were significantly related to changes in walking time in daily life (r = 0.43; p = 0.02). CONCLUSION: If one aims at changing physical activity habits in the daily life of COPD patients, the contribution of long-lasting programs might be important.     

Comparison of oxygen consumption in performing daily activities between patients with chronic obstructive pulmonary disease and a healthy population

OBJECTIVE: The purposes of this study were to compare the daily activity oxygen consumption (VO(2)) and peak oxygen consumption (VO(2peak)) for chronic obstructive pulmonary disease (COPD) patients and healthy individuals; to compare dyspnea levels found in COPD patients and healthy individuals when they performed daily activities and exercise tests; and to establish standard VO(2) values for daily activities for COPD patients. DESIGN: This was an exploratory and correlative study. SETTING: The study took place at the Research Center of Sports Medicine at Taipei Medical University, in Taipei, Taiwan. SUBJECTS: The study included 27 COPD patients and 18 healthy subjects whose ages, weights, and heights were matched. Outcome Measures: VO(2peak) and the VO(2) for performing daily activities including sitting, standing, walking, walking with a 2-kg load, and walking upstairs for 2 stories. INTERVENTION: All data were collected by means of questionnaires and treadmill exercise tests. VO(2) was measured using an AEROSPORT KB1-C metabolic measurement system. RESULTS: There was no significant difference in VO(2) found between the 2 groups when they were performing daily activities, but the VO(2peak) was significantly lower in the COPD group (13.90 +/- 2.93 mL kg(-1) min(-1)) compared with the healthy control group (16.15 +/- 1.86 mL kg(-1) min(-1)) (P =.01). The dyspnea level of the COPD group when they were performing daily activities and exercise tests was more severe than that of the healthy control group. The mean VO(2) values for daily activities in COPD patients were as follows: sitting 3.41 (+/-0.82), standing 3.67 (+/-0.90), walking 10.06 (+/-2.19), walking with a 2-kg load 10.28, and walking upstairs 8.16 (+/-1.36) mL kg(-1) min(-1). CONCLUSION: The results of this study reveal that there were no differences in VO(2) values for performing daily activities between COPD patients and healthy individuals. However, an increase in dyspnea level occurred during daily activities, and it was found to be more severe for COPD patients than for healthy individuals. A key factor was probably that COPD patients had an obviously lower VO(2peak) and higher relative exercise intensity for daily activities than did healthy individuals.     

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.     

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.     

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.     

The effect of pulmonary rehabilitation in patients with post-tuberculosis lung disorder

STUDY OBJECTIVES: Although the benefit of pulmonary rehabilitation (PR) has been demonstrated for patients with COPD, the benefit for patients with non-COPD lung disorders is still unclear. In the present study, we compared the effect of PR on patients with post-tuberculosis (TBC) lung disorders and patients with COPD. DESIGN: We performed a prospective nonrandomized open trial over a 9-week period. PATIENTS AND METHODS: Thirty-two patients with post-TBC lung disorders (thoracoplasty, 25 patients; mean [+/- SD] age, 71 +/- 5 years; FEV(1), 0.84 +/- 0.29 L) and 32 age-matched and FEV(1)-matched COPD patients were enrolled in the study. First, we compared the exercise tolerance between groups using a 6-min walking test. Next, we trained the patients using a 9-week outpatient PR program. We assessed improvement using clinical dyspnea ratings, a daily activity score, and the results of a 6-min walking test. RESULTS: When age and FEV(1) were matched, the distance covered during the 6-min walking test did not differ between the groups. After rehabilitation, significant improvement was observed in both the post-TBC group and the COPD group in terms of Medical Research Council dyspnea grade, transition dyspnea index, activity score, and 6-min walking distance (42 m [p < 0.01] vs 47 m [p < 0.01], respectively). The magnitudes of the improvement in these parameters were comparable between the groups. CONCLUSIONS: PR is as beneficial in post-TBC lung disorder patients as in COPD patients if the severity of the disability is similar.     

Predictors of dynamic hyperinflation during the 6-minute walk test in stable chronic obstructive pulmonary disease patients

Background

Dynamic hyperinflation (DH) is a major contributor to exercise limitation in chronic obstructive pulmonary disease (COPD). Therefore, we aimed to elucidate the physiological factors responsible for DH development during the 6-minute walk test (6MWT) in COPD patients and compare ventilatory response to the 6MWT in hyperinflators and non-hyperinflators.

Methods

A total of 105 consecutive subjects with stable COPD underwent a 6MWT, and the Borg dyspnea scale, oxygen saturation (S_pO₂), breathing pattern, and inspiratory capacity (IC) were recorded before and immediately after walking. The change in IC was measured, and subjects were divided into hyperinflators (ΔIC >0.0 L) and non-hyperinflators (ΔIC ≤0.0 L). Spirometry, the Modified Medical Research Council (MMRC) dyspnea scale and St George’s Respiratory Questionnaire (SGRQ) were also assessed.

Results

DH was present in 66.67% of subjects. ΔIC/IC was significantly and negatively correlated with the small airway function. On multiple stepwise regression analysis forced expiratory flow after exhaling 50% of the forced vital capacity (FEF_50%) was the only predictor of ΔIC/IC. Non-hyperinflators had a higher post-walking V_T (t=2.419, P=0.017) and post-walking V_E (t=2.599, P=0.011) than the hyperinflators did. Age and resting IC were independent predictors of the 6-minute walk distance (6MWD) in hyperinflators.

Conclusions

DH was considerably common in subjects with COPD. Small airway function may partly contribute to the DH severity during walking. The ventilator response to the 6MWT differed between hyperinflators and non-hyperinflators. Resting hyperinflation is an important predictor of functional exercise capacity in hyperinflators.     

Effects of formoterol on exercise tolerance in severely disabled patients with COPD

OBJECTIVE: We wished to evaluate the effects of inhaled formoterol, a long-acting beta(2)-adrenergic agonist, on exercise tolerance and dynamic hyperinflation (DH) in severely disabled chronic obstructive pulmonary disease (COPD) patients. DESIGN: In a two-period, crossover study, 21 patients with advanced COPD (FEV(1)=38.8+/-11.7% predicted, 16 patients GOLD stages III-IV) were randomly allocated to receive inhaled formoterol fumarate 12 microg twice daily for 14 days followed by placebo for 14 days, or vice versa. Patients performed constant work-rate cardiopulmonary exercise tests to the limit of tolerance (Tlim) on a cycle ergometer: inspiratory capacity (IC) was obtained at rest and each minute during exercise. Baseline and transitional dyspnoea indices (BDI and TDI) were also recorded. RESULTS: Eighteen patients completed both treatment periods. Formoterol treatment was associated with an estimated increase of 130 s in Tlim compared with placebo (P=0.052): this corresponded to a 37.8% improvement over placebo (P=0.012). Enhanced exercise tolerance after bronchodilator was associated with diminished DH marked by higher inspiratory reserve and tidal volumes at isotime and exercise cessation (P<0.05). There was no significant difference between formoterol and placebo on exercise dyspnoea ratings; however, all domains of the TDI improved (P相似文献   

Functional predictors of exertional dyspnea, 6-min walking distance and HRCT fibrosis score in idiopathic pulmonary fibrosis

BACKGROUND: Exertional dyspnea and exercise incapacity are the most prominent and disabling symptoms and the main contributors to health-related quality of life in patients with idiopathic pulmonary fibrosis (IPF). OBJECTIVES: There are no comprehensive studies on pulmonary function tests (PFTs), dyspnea, exercise capacity and radiographic scores in IPF. We therefore sought to investigate the functional variables that can predict dyspnea, exercise capacity and disease extent in IPF. METHODS: Thirty-four patients with IPF according to the ATS/ERS criteria underwent PFTs, Medical Research Council (MRC) dyspnea scoring, 6-min walking distance (6-MWD) and radiographic evaluation of fibrosis (HRCT score). RESULTS: The 6-MWD (% pred.) was more impaired than PFTs. Residual volume (RV) showed the best correlation with the extent of fibrosis (r = -0.67, p = 0.0001) and, together with the alveolar-arterial gradient for O(2) [DeltaP(A - a)O(2)], was an independent predictor of disease extent (R(2) = 0.44). PFTs showed significant though weak correlations with MRC score and 6-MWD. According to the regression analysis, DL(CO) and the HRCT fibrosis score were independent predictors of dyspnea, though they explained only 28% of the overall variance. FEV(1) and DeltaP(A - a)O(2) were independent predictors of 6-MWD (R(2) = 0.31). CONCLUSIONS: PFTs and lung volumes in particular are closely related to the HRCT score, a measure of the extent of IPF. The correlation of dyspnea score and 6-MWD to PFTs is limited, due to the complexity of mechanisms leading to exercise limitation in IPF. Therefore dyspnea and exercise performance are largely independent indices and should be followed together with PFTs and HRCT score in order to better assess the status and progress of IPF patients.