Desensitization to dyspnea in COPD with specificity for exercise training mode

Patients with chronic obstructive pulmonary disease (COPD) exhibit improved exercise capacity after physical training due to reconditioning and improved ventilatory efficiency. Other possible effects are improved ventilatory muscle function and desensitization to dyspnea. We compared general physical training (GPT), consisting of walking and stair climbing exercises, with inspiratory muscle training (IMT), consisting of targeted breathing through inspiratory resistances, in two groups with severe COPD. Seven subjects; age 60 (8) years, forced expiratory volume in one second (FEV1) 0.84 (0.35) L, arterial oxygen tension (PaO2) 11.1 (0.8) kPa, arterial carbon dioxide tension (PaCO2) 4.9 (0.3) kPa, had GPT and nine subjects; age 60 (9) years, FEV1 0.83 (0.31) L, PaO2 10.4 (0.8) kPa, PaCO2 4.4 (0.5) kPa had IMT. Each group trained daily for 30 minutes for eight weeks and 70% of the sessions were supervised. Six minute walking distance increased in both groups: 32 m (6.9% P < 0.05) with GPT and 23 m (4.8%; P < 0.05) with IMT but significant improvements in symptom-limited incremental cycle exercise performance were not detected. Breathlessness by visual analog scale was reduced following 6-minute walks after GPT (P < 0.05) but not after IMT. Following maximal incremental tests, breathlessness scores were unchanged for both groups. COPD patients performing regular physical exercise report reductions in breathlessness which are specific to the exercise training mode

Methods of rehabilitation in chronic obstructive pulmonary disease

Selected aspects of pulmonary rehabilitation (PR) were examined in subjects with chronic obstructive pulmonary disease (COPD) seeking objective evidence of improvements in exercise tolerance, respiratory muscle function, symptoms and survival prospects. Each group of subjects had moderately severe airflow obstruction and every effort was made to select subjects without reversibility of airflow obstruction so as to dissociate any physiological changes accompanying bronchodilatation from those genuinely due to improvement in other modalities. Two supervised methods of physical training were compared over eight weeks. General physical training, consisting of timed walking and stair climbing, increased the six-minute walking distance by 7% in seven subjects. Respiratory muscle training consisting of targeted inspiratory resistance breathing, increased walking distance by 5% in nine subjects. A significant reduction in breathlessness was observed which appeared to be specific for walking assessment after general physical training. Acute and chronic administration of aminophyl1ine, giving mean plasma theophylline levels within the accepted therapeutic range, improved airflow obstruction despite the selection of subjects. Acute administration increased walking distance by 6% and produced evidence of increased respiratory drive. Chronic administration increased maximum exercise ventilation by 11% and maximum oxygen uptake by 10%. None of these studies produced evidence of change in respiratory muscle strength. Long-term oxygen therapy (LTOT) improved survival prospects in 72 subjects with hypoxic cor pulmonale. Pulmonary haemodynamics were stable in 45 subjects after 12 months of LTOT. The benefit was apparent soon after commencement of LTOT and the survival curves were similar for males and females. Survival was closely related to the degree of airflow obstruction but not to arterial blood gas tensions or pulmonary haemodynamics. Death rate accelerated after about ten years indicating that the benefit was temporary. In general, the changes which v/ere observed with different aspects of PR were modest reflecting wide individual variations in response. Future endeavours need to identify specific clinical or pathophysiological features which are associated with potential improvements. This approach will lead to the rational selection of subjects for particular forms of treatment and the appropriate use of resources

A controlled study of community-based exercise training in patients with moderate COPD.

BackgroundThe effectiveness of clinic-based pulmonary rehabilitation in advanced COPD is well established, but few data exist for less severe patients treated in alternative settings. The purpose of this study was to investigate whether a novel, community-based exercise program (CBE) was feasible and effective for patients with moderate COPD.MethodsNineteen patients with moderate COPD (mean FEV1 62%) and self-reported exercise impairment were randomized to 12-weeks of progressive endurance and strength training at a local health club under the guidance of a certified personal trainer, or to continuation of unsupervised habitual physical activity. Outcomes assessed at baseline and 12 weeks included session compliance, intensity adherence, treadmill endurance time, muscle strength, dyspnea, and health status.ResultsCompliance was 94% and adherence was 83%. Comparisons between CBE and control groups yielded the following mean (SEM) differences in favor of CBE: endurance time 134 (74) seconds versus -59 (49) seconds (P=0.041) and TDI 5.1 (0.8) versus -0.2 (0.5) (P&lt;0.001). The CBE group increased muscle strength (weight lifted) by 11.8 kilograms per subject per week of training (P&lt;0.001). SGRQ was not significantly changed.ConclusionsWe demonstrated the feasibility and effectiveness of a novel community-based exercise program involving health clubs and personal trainers for patients with moderate COPD.Trial registrationClinicalTrials.gov Identifier NCT01985529

Improvement in self-reported exercise participation with the combination of tiotropium and rehabilitative exercise training in COPD patients

Steven Kesten1, Richard Casaburi2, David Kukafka3, Christopher B Cooper41Boehringer Ingelheim GmbH, Ingelheim, Germany; 2Harbor-UCLA Medical Center, Torrance, CA, USA; 3Northern Colorado Pulmonary Consultants PC, Fort Collins, CO, USA; 4UCLA School of Medicine, Los Angeles, CA, USABackground: Improvements in ventilatory mechanics with tiotropium increases exercise tolerance during pulmonary rehabilitation. We wondered whether tiotropium also increased physical activities outside of pulmonary rehabilitation.Methods: COPD patients participating in 8 weeks of pulmonary rehabilitation were studied in a randomized, double-blind, placebo-controlled trial of tiotropium 18 &amp;micro;g daily (tiotropium = 47, placebo = 44). Study drug was administered for 5 weeks prior to, 8 weeks during, and 12 weeks following pulmonary rehabilitation. Patients completed a questionnaire documenting participation in pre-defined activities outside of pulmonary rehabilitation during the 2 weeks prior to each visit. Patients who submitted an activity questionnaire at week 4 and on at least one subsequent visit were included in the analysis. For each patient, the number of sessions was multiplied with the duration of each activity and then summed to give overall activity duration.Results: Patients (n = 46) had mean age of 67 years, mean baseline FEV1 of 0.84 L (33% predicted). Mean (SE) increase in duration of activities (minutes during 2 weeks prior to each visit) from week 4 (prior to PR) to week 13 (end of PR) was 145 (84) minutes with tiotropium and 66 (96) minutes with placebo. The increase from week 4 to week 25 (end of follow-up) was 262 (96) and 60 (93) minutes for the respective groups. Increases in activity duration from week 4 to weeks 17, 21, and 25 were statistically significant with tiotropium. No statistical differences over time were observed within the placebo-treated group and differences between groups were not significant.Conclusions: Tiotropium appears to amplify the effectiveness of pulmonary rehabilitation as seen by increases in patient self-reported participation in physical activities.Keywords: activity, chronic obstructive pulmonary disease, exercise, pulmonary rehabilitation, tiotropiu

Development and implementation of treadmill exercise testing protocols in COPD

Christopher B Cooper1, Marlon Abrazado1, Daniel Legg2, Steven Kesten21David Geffen School of Medicine, University of California, Los Angeles, CA, USA; 2Boehringer Ingelheim Pharmaceuticals Inc., Ingelheim, GermanyBackground: Because treadmill exercise testing is more representative of daily activity than cycle testing, we developed treadmill protocols to be used in various clinical settings as part of a two-year, multicenter, chronic obstructive pulmonary disease (COPD) trial evaluating the effect of tiotropium on exercise.Methods: We enrolled 519 COPD patients aged 64.6 &amp;plusmn; 8.3 years with a postbronchodilator forced expiratory volume in one second (FEV1) of 1.25 &amp;plusmn; 0.42 L, 44.3% &amp;plusmn; 11.9% predicted. The patients performed symptom-limited treadmill tests where work rate (W) was increased linearly using speed and grade adjustments every minute. On two subsequent visits, they performed constant W tests to exhaustion at 90% of maximum W from the incremental test.Results: Mean incremental test duration was 522 &amp;plusmn; 172 seconds (range 20&amp;ndash;890), maximum work rate 66 &amp;plusmn; 34 watts. For the first and second constant W tests, both at 61 &amp;plusmn; 33 watts, mean endurance times were 317 &amp;plusmn; 61 seconds and 341 &amp;plusmn; 184 seconds, respectively. The mean of two tests had an intraclass correlation coefficient of 0.85 (P &amp;lt; 0.001). During the second constant W test, 88.2% of subjects stopped exercise because of breathing discomfort; 87.1% for Global Initiative for Chronic Obstructive Lung Disease (GOLD) Stage II, 88.5% for GOLD Stage III, and 90.2% for GOLD Stage IV.Conclusion: The symptom-limited incremental and constant work treadmill protocol was well tolerated and appeared to be representative of the physiologic limitations of COPD.Keywords: chronic obstructive pulmonary disease, exercise testing, endurance, tiotropiu

Venous Admixture in COPD: Pathophysiology and Therapeutic Approaches

Chronic obstructive and interstitial lung diseases impair pulmonary gas exchange leading to wasted ventilation (alveolar dead space) and wasted perfusion (venous admixture). These two fundamental types of abnormality represent opposite ends of the spectrum of ventilation-perfusion mismatch with V˙/Q˙ ratios of infinity and zero. Treatment approaches that improve airway function, reduce air trapping and hyperinflation have received much attention and might be successful at ameliorating the problems associated with high V˙/Q˙. However, in patients with low V˙/Q˙ abnormality in whom venous admixture leads to hypoxemia, there are few therapeutic options. Indeed, some patients are refractory to treatment with supplemental oxygen particularly during exercise. Theoretically these patients could benefit from an intervention that increased mixed venous oxygen content thereby ameliorating the deleterious effects of venous admixture. In this perspective article we discuss the mechanisms whereby venous admixture contributes to hypoxemia and reduced oxygen delivery to tissues. We explore methods which could potentially increase mixed venous oxygen content thus ameliorating the deleterious effects of venous admixture. One such intervention that warrants further investigation is the therapeutic creation of an arterio-venous fistula. Such an approach would be novel, simple and minimally invasive. There is reason to believe that complications would be minor leading to a favorable risk-benefit analysis. This approach to treatment could have significant impact for patients with COPD but should also benefit any patient with chronic hypoxemia that impairs exercise performance

Automated analysis of intraoperative phase in laparoscopic cholecystectomy: A comparison of one attending surgeon and their residents

OBJECTIVE: This study compares the intraoperative phase times in laparoscopic cholecystectomy performed by an attending surgeon and supervised residents over 10-years to assess operative times as a marker of performance and any impact of case severity on times. DESIGN: Laparoscopic cholecystectomy videos were uploaded to Touch Surgery™ Enterprise, a combined software and hardware solution for securely recording, storing, and analysing surgical videos, which provide analytics of intraoperative phase times. Case severity and visualisation of the critical view of safety (CVS) were manually assessed using modified 10-point intraoperative gallbladder scoring system (mG10) and CVS scores, respectively. Attending and residents' times were compared unmatched and matched by mG10. SETTING: Secondary analysis of anonymized laparoscopic cholecystectomy video, recorded as standard of care. PARTICIPANTS: Adult patients who underwent elective laparoscopic cholecystectomy a single UK hospital. Cases were performed by one attending and their residents. RESULTS: 159 (attending=96, resident=63) laparoscopic cholecystectomy videos and intraoperative phase times were reviewed on Touch Surgery™ Enterprise and analyzed. Attending cases were more challenging (p=0.037). Residents achieved higher CVS scores (p=0.034) and showed longer dissection of hepatocystic triangle (HCT) times (p=0.012) in more challenging cases. Residents' total operative time (p=0.001) and dissection of HCT (p=0.002) times exceeded the attending's in low-severity matched cases (mG10=1). Residents' total operative times (p<0.001), port insertion/gallbladder exposure (p=0.032), and dissection of HCT (p<0.001) exceeded the attending's in matched cases (mG10=2). Residents' total operative (p<0.001), dissection of HCT (p<0.001), and gallbladder dissection (p=0.010) times exceeded the attendings in unmatched cases. CONCLUSIONS: Residents' total operative and dissection of HCT times significantly exceeded the attending's unmatched cases and low-severity matched cases which could suggest training need, however, also reflects an expected assessment of competence, and validates time as a marker of performance

Tiotropium reduces risk of exacerbations irrespective of previous use of inhaled anticholinergics in placebo-controlled clinical trials

Data have highlighted the potential bias introduced by withdrawal of inhaled corticosteroids at randomization in chronic obstructive pulmonary disease trials examining inhaled corticosteroids. Analyses were conducted to determine whether this was true of inhaled anticholinergic withdrawal in tiotropium trials.status: publishe