A comparison of the effects of salbutamol and ipratropium bromide on exercise endurance in patients with COPD

Clinical characteristics and natural course of chronic obstructive pulmonary disease and/or asthma in Japanese patients: a summary report of two Hokkaido-based cohort studies

Chronic obstructive pulmonary disease (COPD) and asthma are the most common chronic airway diseases and are characterized by chronic airway inflammation and airflow limitation. Japanese patients with COPD or asthma have characteristics different from those of Westerners. Therefore, understanding the characteristics and clinical course of Japanese patients with COPD and those with asthma, particularly severe asthma, is critical for their management and appropriate treatment. The Hokkaido COPD cohort and Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) are high-quality cohort studies of COPD and asthma in the Japanese population and provide valuable data. This report summarizes the clinical findings from the two cohort studies and provides data for more appropriate management of Japanese patients with COPD and/or asthma. Overall, 279 patients with COPD were followed up for up to 10 years in the Hokkaido COPD cohort study, and 127 with severe asthma were followed up for up to 6 years in the Hi-CARAT study. Seventy-nine patients with mild-to-moderate asthma provided baseline data for the Hi-CARAT study. In each disease, several distinct factors, including systemic status and non-pulmonary factors, were associated with important clinical outcomes, such as lung function decline, exacerbations, impaired quality of life, and mortality. Therefore, multifaceted evaluation based on the characteristics of the Japanese population is necessary for the management of COPD and asthma.

Dynamic exercise changes in venous pressure and liver stiffness in Fontan patients: effects of Treprostinil

BACKGROUND

Systemic venous hypertension and low cardiac output are believed to be important mediators of liver injury after the Fontan procedure. Pulmonary vasodilators have the potential to improve such haemodynamics. The aim of this study was to assess the acute effects of exercise on liver stiffness and venous pressures and to assess the impact of inhaled Treprostinil on this response.

METHODS

In this prospective, double-blind, placebo-controlled, crossover trial, 14 patients with a Fontan circulation were randomised to inhalation of placebo and Treprostinil. Incremental and constant work rate exercise tests were performed to assess the effect of Treprostinil on exercise tolerance. Venous pressures were measured throughout and liver stiffness at rest and immediately after peak exercise.

RESULTS

Mean age was 27.8 ± 7.9 years and 66% were females. Exercise acutely increased liver stiffness by 30% (mean shear wave speed: 2.38 ± 0.71 versus 2.89 ± 0.51 ms, p = 0.02). Peripheral venous pressures increased acutely during both incremental (12.1 ± 2.4 versus 22.6 ± 8.0 mmHg, p < 0.001) and constant work rate exercise (12.5 ± 2.5 versus 23.4 ± 5.2 mmHg, p < 0.001). Overall, Treprostinil failed to attenuate exercise-induced increases in liver stiffness. Compared with placebo, Treprostinil did not significantly impact venous pressure responses, VO2peak, nor exercise endurance times.

CONCLUSIONS

Peripheral venous pressure increased acutely during exercise by an average of 88% above baseline and was not altered by administration of inhaled Treprostinil. Liver stiffness measured immediately post-exercise increased acutely by an average of 30%, with no attenuation following Treprostinil inhalation.

Use of exercise testing in the evaluation of interventional efficacy: an official ERS statement

This document reviews 1) the measurement properties of commonly used exercise tests in patients with chronic respiratory diseases and 2) published studies on their utilty and/or evaluation obtained from MEDLINE and Cochrane Library searches between 1990 and March 2015.

Exercise tests are reliable and consistently responsive to rehabilitative and pharmacological interventions. Thresholds for clinically important changes in performance are available for several tests. In pulmonary arterial hypertension, the 6-min walk test (6MWT), peak oxygen uptake and ventilation/carbon dioxide output indices appear to be the variables most responsive to vasodilators. While bronchodilators do not always show clinically relevant effects in chronic obstructive pulmonary disease, high-intensity constant work-rate (endurance) tests (CWRET) are considerably more responsive than incremental exercise tests and 6MWTs. High-intensity CWRETs need to be standardised to reduce interindividual variability. Additional physiological information and responsiveness can be obtained from isotime measurements, particularly of inspiratory capacity and dyspnoea. Less evidence is available for the endurance shuttle walk test. Although the incremental shuttle walk test and 6MWT are reliable and less expensive than cardiopulmonary exercise testing, two repetitions are needed at baseline. All exercise tests are safe when recommended precautions are followed, with evidence suggesting that no test is safer than others.

Responsiveness of Various Exercise-Testing Protocols to Therapeutic Interventions in COPD

Exercise intolerance is a key element in the pathophysiology and course of Chronic Obstructive Pulmonary Disease (COPD). As such, evaluating exercise tolerance has become an important part of the management of COPD. A wide variety of exercise-testing protocols is currently available, each protocol having its own strengths and weaknesses relative to their discriminative, methodological, and evaluative characteristics. This paper aims to review the responsiveness of several exercise-testing protocols used to evaluate the efficacy of pharmacological and nonpharmacological interventions to improve exercise tolerance in COPD. This will be done taking into account the minimally important difference, an important concept in the interpretation of the findings about responsiveness of exercise testing protocols. Among the currently available exercise-testing protocols (incremental, constant work rate, or self-paced), constant work rate exercise tests (cycle endurance test and endurance shuttle walking test) emerge as the most responsive ones for detecting and quantifying changes in exercise capacity after an intervention in COPD.

Inhaled fentanyl citrate improves exercise endurance during high-intensity constant work rate cycle exercise in chronic obstructive pulmonary disease

CONTEXT

Activity limitation and dyspnea are the dominant symptoms of chronic obstructive pulmonary disease (COPD). Traditionally, efforts to alleviate these symptoms have focused on improving ventilatory mechanics, reducing ventilatory demand, or both of these in combination. Nevertheless, many patients with COPD remain incapacitated by dyspnea and exercise intolerance despite optimal therapy.

OBJECTIVES

To determine the effect of single-dose inhalation of nebulized fentanyl citrate (a μ-opioid agonist drug) on exercise tolerance and dyspnea in COPD.

METHODS

In a randomized, double-blind, placebo-controlled, crossover study, 12 stable patients with COPD (mean ± standard error of the mean post-β(2)-agonist forced expiratory volume in one second [FEV(1)] and FEV(1) to forced vital capacity ratio of 69% ± 4% predicted and 49% ± 3%, respectively) received either nebulized fentanyl citrate (50 mcg) or placebo on two separate days. After each treatment, patients performed pulmonary function tests and a symptom-limited constant work rate cycle exercise test at 75% of their maximum incremental work rate.

RESULTS

There were no significant postdose differences in spirometric parameters or plethysmographic lung volumes. Neither the intensity nor the unpleasantness of perceived dyspnea was, on average, significantly different at isotime (5.0 ± 0.6 minutes) or at peak exercise after treatment with fentanyl citrate vs. placebo. Compared with placebo, fentanyl citrate was associated with 1) increased exercise endurance time by 1.30 ± 0.43 minutes or 25% ± 8% (P=0.01); 2) small but consistent increases in dynamic inspiratory capacity by ∼0.10 L at isotime and at peak exercise (both P≤0.03); and 3) no concomitant change in ventilatory demand, breathing pattern, pulmonary gas exchange, and/or cardiometabolic function during exercise. The mean rate of increase in dyspnea intensity (1.2 ± 0.3 vs. 2.9 ± 0.8 Borg units/minute, P=0.03) and unpleasantness ratings (0.5 ± 0.2 vs. 2.9 ± 1.3 Borg units/minute, P=0.06) between isotime and peak exercise was less after treatment with fentanyl citrate vs. placebo.

CONCLUSION

Single-dose inhalation of fentanyl citrate was associated with significant and potentially clinically important improvements in exercise tolerance in COPD. These improvements were accompanied by a delay in the onset of intolerable dyspnea during exercise near the limits of tolerance.

Functional imaging using computer methods to compare the effect of salbutamol and ipratropium bromide in patient-specific airway models of COPD

BACKGROUND

Salbutamol and ipratropium bromide improve lung function in patients with chronic obstructive pulmonary disease (COPD). However, their bronchodilating effect has not yet been compared in the central and distal airways. Functional imaging using computational fluid dynamics offers the possibility of making such a comparison. The objective of this study was to assess the effects of salbutamol and ipratropium bromide on the geometry and computational fluid dynamics-based resistance of the central and distal airways.

METHODS

Five patients with Global Initiative for Chronic Obstructive Lung Disease Stage III COPD were randomized to a single dose of salbutamol or ipratropium bromide in a crossover manner with a 1-week interval between treatments. Patients underwent lung function testing and a multislice computed tomography scan of the thorax that was used for functional imaging. Two hours after dosing, the patients again underwent lung function tests and repeat computed tomography.

RESULTS

Lung function parameters, including forced expiratory volume in 1 second, vital capacity, overall airway resistance, and specific airway resistance, changed significantly after administration of each product. On functional imaging, the bronchodilating effect was greater in the distal airways, with a corresponding drop in airway resistance, compared with the central airways. Salbutamol and ipratropium bromide were equally effective at first glance when looking at lung function tests, but when viewed in more detail with functional imaging, hyporesponsiveness could be shown for salbutamol in one patient. Salbutamol was more effective in the other patients.

CONCLUSION

This pilot study gives an innovative insight into the modes of action of salbutamol and ipratropium bromide in patients with COPD, using the new techniques of functional imaging and computational fluid dynamics.

Respiratory and skeletal muscle strength in chronic obstructive pulmonary disease: impact on exercise capacity and lower extremity function

PURPOSE

We sought to quantify the impact of respiratory muscle and lower extremity strength on exercise capacity and lower extremity function (LEF) in patients with chronic obstructive pulmonary disease (COPD).

METHODS

In 828 persons with COPD, we assessed the impact of reduced respiratory (maximum inspiratory pressure, MIP) and lower extremity muscle strength (quadriceps strength, QS) on exercise capacity (6-minute walk test, 6MWT), and LEF (short physical performance battery). Multiple regression analyses taking into account key covariates, including lung function and smoking, tested the associations between muscle strength and exercise and functional capacity.

RESULTS

For each 0.5 SD decrement in QS, men walked 18.3 m less during 6MWT (95% confidence interval [CI], -24.1 to -12.4); women 25.1 m less (95% CI, -31.1 to -12.4). For each 0.5 SD decrement in MIP, men walked 9.4 m less during 6MWT (95% CI, -15.2 to -3.6); women 8.7 m less (95% CI, -14.1 to -3.4). For each 0.5 SD decrease in QS, men had a 1.32 higher odds (95% CI, 1.11-1.15) of poor LEF; women had a 1.87 higher odds (95% CI, 1.54-2.27). Lower MIP (per 0.5 SD) was associated with increased odds of poor LEF in women (odds ratio = 1.18; 95% CI, 1.00-1.39), but not in men (odds ratio = 1.10; 95% CI, 0.93-1.31).

CONCLUSIONS

In COPD, reduced respiratory and lower extremity muscle strength are associated with decreased exercise and functional capacity. Muscle weakness is likely an important component of impairment and disability in patients with COPD.

Acute administration of bronchodilators on exercise tolerance in treated COPD patients

Exercise intolerance is a major feature in patients with Chronic Obstructive Pulmonary Disease (COPD). Bronchodilators increase endurance time (ET) and reduce dynamic hyperinflation (DH). We evaluated whether a single-dose of salbutamol/ipratropium + flunisolide (BD+ICS), added on top of the regular treatment, may improve ET in COPD patients. In a single-blind randomized crossover pilot trial, nebulised BD+ICS or placebo (PL) was administered 30 min before a constant load cardiopulmonary test, in 22 moderate-to-severe COPD patients (FEV₁: 53.9% pred). ET was the primary outcome measured. BD+ICS did not improve ET or VO₂ peak with respect to PL. BD+ICS increased pre-test FEV₁ and pre-test Inspiratory Capacity but did not modify DH. In a retrospective analysis, patients were divided in Improvers (N=11) and Non-Improvers (N=11) according to the difference in ET between BD+ICS and PL (> 25 s). Improvers had a worst BODE index, a higher static hyperinflation and poorer Vd/Vt ratio at peak of exercise with respect to Non-Improvers. Improvers only had a significant increase from BD+ICS on pre-test FEV₁ and IC. In conclusion, although a single-dose BD+ICS did not improve ET in COPD patients under regular treatment, a subgroup of more severe patients may have some benefit from that.

[Position of anticholinergic drugs in the treatment of childhood asthma]

Anticholinergic drugs block muscarinic effect of acetylcholine on the receptors of postjunctional membranes and so inhibit the answer of the postganglionic parasympathetic nerve. The loss of M2 muscarinic receptors function occurs in asthmatics and it contributes to bronchial hyperresponsiveness and it is not a chronic feature of asthma, instead it characterizes asthma exacerbation. The loss of M2 muscarinic receptor function in children and adults happens during antigen bronchoprovocation or during exposition of asthmatics to ozone. After inhalation, ipratropium bromide (IB) can be found in a small quantity in circulation and it links less readily to muscarinic receptors on airway smooth muscles as related to its absorption after intravenous application. In the stepwise approach of asthma inhaled anticholinergics is recommended if the symptoms of the disease cannot be adequately controlled by a regular inhalation of antiinflammatory drugs with beta2-agonist and oral steroids. The improvement of the airway inspiratory capacity is more elevated than the improvement of FEV1 after inhalation of IB. IB has similar effect as salbutamol and it is recommended to control a stable chronic obstructive disease. During our numerous investigations and up-to-date experience in the usage of 5-7 microg/kg/body mass of IB repeated every 4-6 hours in combination with salbutamol, we did not notice adverse effects of the drug in infants. IB is recommended for hospital treatment of children.

Impact of bronchodilator therapy on exercise tolerance in COPD

Exercise tolerance is an important parameter in patients with COPD and a primary goal of treatment is to reduce dyspnea to facilitate physical activities and improve health-related quality of life. This review examines the link between expiratory flow limitation and dyspnea to explain the rationale for the use of bronchodilators and review the characteristics of different types of exercise tests, with specific focus on which tests are likely to show a response to bronchodilators. An earlier literature search of studies published up to 1999 assessed the effects of bronchodilatort therapy on dypsnea and exercise tolerance among patients with COPD. This current review examines the clinical evidence published since 1999. Thirty-one randomized studies of exercise tolerance associated with short- and long-acting beta(2)-agonists and anticholinergics were identified. Evidence for the efficacy of bronchodilators in enhancing exercise capacity is often contradictory and possibly depends on the exercise test and study methodology. However, further studies should confirm the benefit of long-acting bronchodilators in improving spontaneous everyday physical activities.

Advantages of endurance treadmill walking compared with cycling to assess bronchodilator therapy

BACKGROUND

Walking is a familiar daily activity that is generally limited by breathlessness, whereas cycling is an uncommon physical effort typically limited by leg discomfort. The hypothesis was that patients with COPD would exhibit greater improvements in exercise endurance and relief of breathlessness with bronchodilator therapy during treadmill walking compared with cycling.

METHODS

In this randomized, 2 x 2, double-blind, placebo-controlled, crossover trial, 20 patients with COPD (age, 64 +/- 7 years; FEV(1), 56 +/- 14% predicted) performed constant-load endurance exercise on the treadmill and cycle ergometer at 85% of capacity after inhaling normal saline (NS) or arformoterol (ARF) (15 microg).

RESULTS

Increases in endurance times and consistency of responses were greater with treadmill walking (Delta: 157 +/- 286 s; P = .024; 80% improved) than with cycle exercise (Delta: 110 +/- 219 s; P = .038; 65% improved) with ARF compared with NS. However, these changes were not significantly different. The slope of breathlessness-time (mean Delta = -29%; P = .007) and the magnitude of oxygen desaturation were significantly lower with ARF compared with NS during treadmill, but not cycle, exercise. Inspiratory capacity values were similar between modes of exercise when comparing the same study medication.

CONCLUSIONS

Improved endurance times support both constant-load treadmill and cycle exercise to assess the efficacy of bronchodilator therapy in patients with COPD. Unique differences in physiologic and perceptual responses with bronchodilation demonstrate advantages of treadmill walking as an exercise stimulus.

TRIAL REGISTRATION

clinicaltrials.gov; Identifier: NCT00754546.

Responsiveness of patient-reported breathlessness during exercise in persistent asthma

BACKGROUND

The purpose of the study was to examine the responsiveness of a computerized system whereby the patient reports spontaneously any change in the intensity of breathlessness during exercise. The hypotheses were that hypercapnia would increase and hyperoxia would decrease the slope of power production-breathlessness ratings compared with a control condition during cycle ergometry.

METHODS

Thirty adult subjects (15 women and 15 men) with persistent asthma (mean [+/- SD] FEV(1)/FVC ratio, 57 +/- 10%) completed an initial familiarization visit and three study visits. All subjects inhaled two puffs of albuterol (180 microg) in order to standardize lung function prior to exercise. At visits 2 to 4, subjects breathed one of the three gas mixtures administered in a random order while performing a ramp exercise test. The experimental conditions were as follows: hypercapnia (5% carbon dioxide); hyperoxia (40% oxygen); and control (room air).

RESULTS

Lung function was the same before and after exercise with the three experimental conditions. With hypercapnia, peak ventilation was increased, peak oxygen consumption, and power production were reduced, the slope of power-breathlessness was increased, and 25 patients (83%) reported breathlessness as the limiting symptom. With hyperoxia, peak ventilation was decreased, peak power production and the slope of power-breathlessness were unchanged, and 16 patients (53%) reported leg discomfort as the limiting symptom.

CONCLUSIONS

Breathing 5% carbon dioxide altered physiologic responses and the slope of power production-breathlessness during exercise. The responses to hyperoxia were inconsistent. The continuous method for patient-reported breathlessness was responsive to hypercapnia, but not to hyperoxia, during incremental exercise.

The effect of bronchodilators and oxygen alone and in combination on self-paced exercise performance in stable COPD

Both oxygen therapy and bronchodilators reduce exertional breathlessness and improve exercise tolerance in patients with stable chronic obstructive pulmonary disease (COPD). However their relative effectiveness and the value of their combined use on exercise performance has not been assessed. The effects of 5 mg of salbutamol plus 500 microg ipratropium bromide nebulisation followed by a 6-min walking test while breathing O(2) were studied in a randomised, single-blind, placebo controlled, crossover trial in 28 patients with severe or very severe COPD, breathless on exertion and with oxygen saturation < or = 89% at rest or on exercise. Bronchodilator reversibility was minimal. The 6-min walking distance increased from 356 (128)m to 377 (117)m after the bronchodilator (P<0.05), to 406 (109)m after supplementary oxygen but without bronchodilators (P 0.011 versus bronchodilators/air and 0.001 versus placebo/air), and to 430 (109)m after the combination of oxygen and the bronchodilators (P<0.0001 versus placebo/air and bronchodilators/air; P=0.014 versus placebo/oxygen). End-exercise dyspnea only fell significantly when oxygen and bronchodilator were combined. In severe or very severe COPD patients with relatively fixed airway obstruction bronchodilators enhance exercise performance obtained with oxygen. Clinically relevant improvement is possible when therapies with a different mechanism of action are combined.

The effect of tiotropium bromide on health-related quality of life in chronic obstructive pulmonary disease

Tiotropium bromide is a once-daily anticholinergic recommended for maintenance treatment of chronic obstructive pulmonary disease. The 24-h bronchodilation in patients with chronic obstructive pulmonary disease achieved with tiotropium treatment is currently unique. However, there is an increasing demand for proven efficacy in parameters of more direct interest to patients, in addition to physiological parameters. This article reviews the data currently available on the efficacy of tiotropium to improve the health-related quality of life of patients with chronic obstructive pulmonary disease.

Dyspnoea with activities of daily living versus peak dyspnoea during exercise in male patients with COPD

Dyspnoea measurements in chronic obstructive pulmonary disease (COPD) can be broadly divided into two categories: those that assess breathlessness during exercise, and those that assess breathlessness during daily activities. We investigated the relationships between dyspnoea at the end of exercise and during daily activities with clinical measurements and mortality in COPD patients. We examined 143 male outpatients with moderate to very severe COPD. The peak Borg score at the end of progressive cycle ergometry was used for the assessment of peak dyspnoea rating during exercise, and the Baseline Dyspnea Index (BDI) score was used for dyspnoea with activities of daily living. Relationships between these dyspnoea ratings with other clinical measurements of pulmonary function, exercise indices, health status and psychological status were then investigated. In addition, their relationship with the 5-year mortality of COPD patients was also analyzed to examine their predictive ability. Although the BDI score was significantly correlated with airflow limitation, diffusing capacity, exercise indices, health status and psychological status, the Borg score at the end of exercise had non-existent or only weak correlations with them. The BDI score was strongly significantly correlated with mortality, whereas the Borg score was not. Dyspnoea during daily activities was more significantly correlated with objective and subjective measurements of COPD than dyspnoea at the end of exercise. In addition, the former was more predictive of mortality. Dyspnoea with activities of daily living is considered to be a better measurement for evaluating the disease severity of COPD than peak dyspnoea during exercise.

Exercise Capacity Deterioration in Patients With COPD

BACKGROUND

Although exercise capacity is an important outcome measure in patients with COPD, its longitudinal course has not been analyzed in comparison to the change in pulmonary function.

PURPOSES

To examine how exercise capacity would deteriorate over time in patients with COPD, and what factors would contribute to it.

METHODS

A total of 137 male outpatients with moderate-to-very-severe COPD were examined. The average age was 69.0 +/- 6.6 years (+/- SD), and the mean postbronchodilator FEV(1) was 45.9 +/- 15.4% predicted. Progressive cycle ergometry and pulmonary function testing were performed at entry, and every 6 months thereafter over 5 years. Due to the presence of missing data, a mixed-effect model analysis was then used to estimate the longitudinal changes in various clinical parameters.

RESULTS

Peak oxygen uptake (Vo(2)), peak minute ventilation (Ve), and peak tidal volume (Vt) during exercise declined significantly over time (p < 0.0001), which was no less rapid than the deterioration in FEV(1). The mean decline rates for peak Vo(2) were 32 +/- 60 mL/min/yr and 0.5 +/- 1.0 mL/min/kg/yr. Multiple regression analysis revealed that the changes in peak Ve, peak Vt, and peak respiratory rates were significant predictors for the change in peak Vo(2).

CONCLUSION

We demonstrated clear evidence of measurable and progressive deterioration in exercise capacity in COPD patients, which was no less rapid than the decline in airflow limitation. Dynamic ventilatory constraints during exercise also deteriorated over time, which most significantly contributed to this exercise capacity deterioration. In addition to pulmonary function, the longitudinal follow-up of exercise capacity is important not to miss the overall deterioration in COPD.

Inhaled beta-agonists improve lung function but not maximal exercise capacity in cystic fibrosis

BACKGROUND

To investigate the effects of inhaled beta-agonists on sub-maximal and maximal exercise capacity, breathing pattern, dyspnoea, leg-discomfort and spirometry in patients with cystic fibrosis (CF).

OBJECTIVES

Eight patients performed two maximal incremental cycle-ergometry tests on separate days with inhaled placebo or salbutamol (600 microg) administered before each test in a randomized, double-blind, placebo-controlled crossover trial. Primary outcomes were exercise duration (Exdur) in seconds (s) and maximal oxygen uptake (VO2max) in litres/minute (L/min). Forced expiratory volume in 1 s (FEV1) was measured immediately pre-inhaler, post-inhaler and post-exercise. Dyspnoea and leg-discomfort were assessed post-exercise.

RESULTS

Within-day FEV1 comparisons demonstrated that the placebo test day FEV1 improved significantly post-exercise (0.11 L, p<0.05) and the salbutamol test day FEV1 improved significantly post-inhaler (0.22 L, p<0.001) and post-exercise (0.07 L, p<0.01). Between-day FEV1 comparisons demonstrated significant improvements in post-inhaler (0.17 L, p<0.05) and post-exercise (0.13 L, p<0.05) FEV1 following salbutamol. Sub-maximal and maximal exercise showed no significant difference as shown by Exdur (547+/-154 s vs. 529+/-127 s) and VO2max (1.9+/-0.5 L/min vs. 1.9+/-0.6 L/min). No significant change in breathing pattern, dyspnoea or leg-discomfort was detected. The study had a power of 92% to detect a 10% improvement in Exdur.

CONCLUSIONS

In adults with CF, salbutamol improves post-exercise FEV1 and is safe when administered immediately before exercise but does not improve exercise capacity, exercise-induced dyspnoea or leg-discomfort.

New Treatment for Chronic Obstructive Pulmonary Disease: Tiotropium Bromide

Objective:

To review chronic obstructive pulmonary disease (COPD) and evaluate the role of tiotropium bromide in its treatment.

Data Sources:

MEDLINE was searched for articles published between 1990 and June 2004 that contained the terms tiotropium and chronic obstructive pulmonary disease.

Study Selection/Data Extraction:

Selected studies documented clinical outcomes related to the use of tiotropium bromide and included a complete description of methods and results. These studies were examined to determine the extent of the effect of tiotropium on clinical outcomes involved in COPD.

Data Synthesis:

Tiotropium bromide has a long duration of action and thus can be dosed just once daily. It was found to improve lung function, reduce symptoms, improve health status, and decrease exacerbations compared with both placebo and other bronchodilator medications.

Conclusions:

Tiotropium appears to be a valuable addition to the current therapies available for COPD.

Responsiveness of Continuous Ratings of Dyspnea during Exercise in Patients with COPD

PURPOSE

To examine the responsiveness of a new computerized method for patients to provide continuous ratings of dyspnea during exercise in patients with chronic obstructive pulmonary disease (COPD).

METHODS

In this randomized, double-blind study the effects of an inhaled bronchodilator (BD), albuterol/ipratropium bromide solution, were compared with normal saline (NS) in 30 patients with COPD (age, 66+/-9 yr; forced expiratory volume in 1 s, 48+/-14% pred). At visit 1, patients were familiarized with the cycle ergometer and computer, monitor, and mouse system to provide continuous ratings of dyspnea during exercise. At subsequent visits 2-3 d apart, patients performed pulmonary function tests followed by incremental ramp (15 W.min-1) and, 1 h later, constant work (at 55% of maximal work capacity) exercise tests.

RESULTS

During incremental exercise the slopes of VO2:dyspnea and VE:dyspnea regressions were significantly lower, and patients exercised longer (Delta=0.4 min; P=0.003) with BD therapy compared with NS. During constant work exercise there was a significant reduction in dyspnea at the same exercise duration (5.0+/-2.8 vs 6.2+/-2.8 units on the 0-10 category-ratio scale; P=0.02) and patients exercised longer (Delta=0.9 min; P=0.04) with BD therapy. Changes in lung function at rest did not correlate significantly with changes in dyspnea ratings during exercise.

CONCLUSIONS

Continuous ratings of dyspnea were responsive to inhaled bronchodilator therapy during both incremental and constant work exercise tests in patients with symptomatic COPD.

Effect of bronchoscopic lung volume reduction on dynamic hyperinflation and exercise in emphysema

Endobronchial valve placement improves pulmonary function in some patients with chronic obstructive pulmonary disease, but its effects on exercise physiology have not been investigated. In 19 patients with a mean (SD) FEV(1) of 28.4 (11.9)% predicted, studied before and 4 weeks after unilateral valve insertion, functional residual capacity decreased from 7.1 (1.5) to 6.6 (1.7) L (p = 0.03) and diffusing capacity rose from 3.3 (1.1) to 3.7 (1.2) mmol . minute(-1) . kPa(-1) (p = 0.03). Cycle endurance time at 80% of peak workload increased from 227 (129) to 315 (195) seconds (p = 0.03). This was associated with a reduction in end-expiratory lung volume at peak exercise from 7.6 (1.6) to 7.2 (1.7) L (p = 0.03). Using stepwise logistic regression analysis, a model containing changes in transfer factor and resting inspiratory capacity explained 81% of the variation in change in exercise time (p < 0.0001). The same variables were retained if the five patients with radiologic atelectasis were excluded from analysis. In a subgroup of patients in whom invasive measurements were performed, improvement in exercise capacity was associated with a reduction in lung compliance (r(2) = 0.43; p = 0.03) and isotime esophageal pressure-time product (r(2) = 0.47; p = 0.03). Endobronchial valve placement can improve lung volumes and gas transfer in patients with chronic obstructive pulmonary disease and prolong exercise time by reducing dynamic hyperinflation.

The airway cholinergic system: physiology and pharmacology

The present review summarizes the current knowledge of the cholinergic systems in the airways with special emphasis on the role of acetylcholine both as neurotransmitter in ganglia and postganglionic parasympathetic nerves and as non-neuronal paracrine mediator. The different cholinoceptors, various nicotinic and muscarinic receptors, as well as their signalling mechanisms are presented. The complex ganglionic and prejunctional mechanisms controlling the release of acetylcholine are explained, and it is discussed whether changes in transmitter release could be involved in airway dysfunctions. The effects of acetylcholine on different target cells, smooth muscles, nerves, surface epithelial and secretory cells as well as mast cells are described in detail, including the receptor subtypes involved in signal transmission.

Exercise responses during endurance testing at different intensities in patients with COPD

Endurance time on submaximal exercise tests is a sensitive measure in detecting changes after medical intervention and is used as an outcome in clinical trials, although there has been little discussion regarding the appropriate intensity. Therefore, we investigated whether there were differences in exercise responses between endurance tests at high versus moderate intensity, and analyzed which test was more appropriate. Thirty-seven patients with chronic obstructive pulmonary disease participated in the study. They performed cycle endurance tests at high and moderate submaximal workloads representing 80% and 60% of the maximum work rate reached on progressive cycle ergometry, respectively. Each type of exercise test was performed after inhaling salbutamol 400 microg, ipratropium bromide 80 microg or an identical placebo. Endurance time on the 80% endurance test was much shorter than on the 60% endurance test. The coefficients of variation for the endurance time were lower on the 80% test. Statistically significant improvements in the endurance time after bronchodilators in comparison to placebo were found only on the 80% test. When using the endurance time as an outcome, the high intensity endurance test is preferable to the moderate intensity endurance test, as the high intensity test demonstrated shorter exercise time, less variability and higher sensitivity.