Hanneke van Helvoort

Inspiratory muscle training protocol for patients with chronic obstructive pulmonary disease (IMTCO study): a multicentre randomised controlled trial

Introduction Inspiratory muscle training (IMT) has been applied during pulmonary rehabilitation in patients with chronic obstructive pulmonary disease (COPD). However, it remains unclear if the addition of IMT to a general exercise training programme leads to additional clinically relevant improvements in patients with COPD. In this study, we will investigate whether the addition of IMT to a general exercise training programme improves 6 min walking distance, health-related quality of life, daily physical activity and inspiratory muscle function in patients with COPD with inspiratory muscle weakness. Methods and analysis Patients with COPD (n=170) with inspiratory muscle weakness (Pi,max <60 cm H2O or <50%pred) will be recruited to a multicentre randomised placebo controlled trial of IMT and allocated into one of the two groups. Patients in both groups will follow a 3 month general exercise training programme, in combination with home-based IMT. IMT will be performed with a recently developed device (POWERbreathe KH1). This device applies an inspiratory load that is provided by an electronically controlled valve (variable flow resistive load). The intervention group (n=85) will undertake an IMT programme at a high intensity (≥50% of their Pi,max), whereas the placebo group (n=85) will undertake IMT at a low training intensity (≤10% of Pi,max). Total daily IMT time for both groups will be 21 min (6 cycles of 30 breaths). Improvement in the 6 min walking distance will be the primary outcome. Inspiratory muscle function, health-related quality of life and daily physical activity will be assessed as secondary outcomes. Ethics and dissemination Ethics approval has been obtained from relevant centre committees and the study has been registered in a publicly accessible clinical trial database. The results will be easily interpretable and should immediately be communicated to healthcare providers, patients and the general public. Results This can be incorporated into evidence-based treatment recommendations for clinical practice. ClinicalTrials.gov NCT01397396.

Heart failure and COPD: partners in crime?

Chronic obstructive pulmonary disease (COPD) and heart failure (HF) are both common diseases with major impact and seem to coexist more frequently than expected from their separate population prevalences. However, estimates of combined prevalence must be interpreted carefully because of imperfections and difficulties in assessment of both diseases. This review aims to highlight HF prevalence in patients with COPD and vice versa, with a critical analysis of studies performed. First, definition, diagnosis, and prevalence of COPD and of HF will be discussed. Subsequently, an overview of important studies concerning combined prevalence with their limitations will be presented. Finally, pathogenic mechanisms and diagnostic considerations in clinical practice will be discussed.

Dynamic hyperinflation after metronome-paced hyperventilation in COPD– A 2 year follow-up

UNLABELLED In contrast to the decline in FEV(1), the behavior of dynamic hyperinflation (DH) over time is unknown in patients with COPD. Metronome-paced hyperventilation (MPH) is a simple applicable surrogate for exercise to detect DH. OBJECTIVE To evaluate changes in MPH-induced DH during two years follow-up in mild-to-severe COPD patients. Additionally, influence of smoking status on DH and the relation between DH and other lung function parameters were assessed. METHODS Patients were recruited from a randomized controlled trial conducted in general practice. Measurements of lung function and DH were performed at baseline and after 12 and 24 months. DH was assessed by MPH with breathing frequency set at twice the baseline rate. Change in inspiratory capacity after MPH was used to reflect change in end-expiratory lung volume and therefore DH, presuming constant total lung capacity. RESULTS During follow-up, 68 patients completed all measurements. DH increased by 0.23±0.06L (p≤0.001). No significant changes in FEV(1) %pred were seen. Smokers had lower FEV(1) and a more rapid decline than non-smokers. DH in smokers increased more over time compared to non-smokers. The amount of DH correlated positively with resting inspiratory capacity. CONCLUSION After two years, a significant increase in MPH-induced DH in COPD patients was demonstrated, which was not accompanied by a decline in FEV(1). It might be that DH is a sensitive measure to track consequences of changes in airflow obstruction.

Diagnostic accuracy of metronome-paced tachypnea to detect dynamic hyperinflation

This prospective study was carried out to investigate if metronome‐paced tachypnea (MPT) can serve as an accurate diagnostic tool to identify patients with chronic obstructive pulmonary disease (COPD) who are susceptible to develop dynamic hyperinflation during exercise. Commonly, this is assessed by measuring change in inspiratory capacity (IC) during cardiopulmonary exercise testing (CPET), which, however, is complex and laborious.

Validity of Oxycon Mobile in measuring inspiratory capacity in healthy subjects.

Introduction:  Inspiratory capacity (IC) assessments have been performed mainly in laboratory settings, because of fixed measurement devices. Oxycon Mobile® (OM) is the mobile and wireless version of Oxycon Pro® (OP), a commonly used fixed measurement device. The purpose of this study was to examine IC agreement between OM and OP at rest and during steady‐state exercise. Also, the within‐ and between‐days variability of IC’s were determined.

Exercises Commonly Used in Rehabilitation of Patients With Chronic Obstructive Pulmonary Disease: Cardiopulmonary Responses and Effect Over Time

OBJECTIVES To compare conventional exercise-based assessment of pulmonary rehabilitation (PR) with improvement in training exercises employed during a PR program, and to describe the cardiopulmonary response of different training exercises during PR of patients with chronic obstructive pulmonary disease (COPD). DESIGN Observational study. SETTING Inpatient PR. PARTICIPANTS Patients with moderate to very severe COPD (N=18). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Cardiopulmonary responses to interval cycling, arm exercise, and a test of functional activities of daily living (ADLs) were evaluated during the PR training program using a mobile telemetric breath-by-breath system. The effects of PR were evaluated by comparing pre-PR and post-PR training activities, incremental and constant work-rate cycling, and a 6-minute walk test. RESULTS Interval cycling and the ADLs test were moderate-intensity to heavy-intensity exercises (70%-80% of maximal oxygen consumption), while the arm exercise was a low-intensity activity (40% of maximal oxygen consumption). After 12 weeks of PR, cycle load, arm weights, and walking distances during training activities had increased alongside increased muscle mass. At iso-intensities, no cardiopulmonary changes in the training exercises were observed. Exercise duration of constant work-rate cycling and 6-minute walk distance increased by 160% and 14%, respectively, after PR, with concurrent right-shifts of anaerobic threshold and a decrease in heart rate. CONCLUSIONS Supervised increases in weight, load, and walking distance during training activities were useful clinical outcomes for patients, demonstrating the beneficial effects of progressive training on physical performance. However, for physiologic evaluation of PR, conventional tests, such as maximal incremental cycling, endurance cycling, and a 6-minute walk test, had greater validity. Physiologic evaluation of the training exercises showed that the training program complied with the training recommendations for PR.

Similar Dynamic Hyperinflation during Arm and Leg Exercise at Similar Ventilation in Chronic Obstructive Pulmonary Disease

PURPOSE Patients with chronic obstructive pulmonary disease (COPD) report more dyspnea during arm than during leg exercise. One of the major causes of dyspnea is dynamic hyperinflation (DH), which is caused by airflow limitation as well as increase in ventilation. The aims of our study were to compare DH at equal ventilation (isoventilation) during arm and legwork and to investigate the effects of breathing pattern on DH. METHODS Thirteen clinically stable patients with mild to very severe COPD (forced expiratory volume in 1 s = 59% ± 21%) participated in this study. Arm and leg constant work rate (CWR) ergometry were performed in random order with ventilation equal to that at 50% of peak armload. The corresponding leg load of that level of ventilation was determined from the incremental leg test. Respiratory physiology was measured breath-by-breath. Change in inspiratory capacity, measured at rest and at 2-min intervals, was used to reflect DH. RESULTS At steady-state isoventilation (37 ± 2 and 36 ± 2 L · min for arm and leg CWR tests, respectively, P > 0.05), armload was 29 ± 5 W and leg load was 52 ± 6 W (P < 0.001). The level of DH, 0.32 ± 0.09 and 0.27 ± 0.08 L during arm and leg exercises, respectively, was not significantly different. However, breathing frequency was greater during arm than during leg exercise (24 ± 1 vs 21 ± 1 breaths per minute, P < 0.01), and the opposite was true for tidal volume (1.56 ± 0.15 vs 1.69 ± 0.14 L, P < 0.01). CONCLUSIONS At similar ventilation, we found a similar degree of DH during arm and leg CWR tests in patients with mild to very severe COPD. Although differences in breathing pattern were observed between arm and leg exercises, these did not affect the level of DH.

COPD Anno 2011: emphasis on bronch(iol)odilation.

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of disability and death worldwide. Although COPD is considered to be a preventable and treatable disease, there are concerns that COPD remains substantially underdiagnosed and undertreated. Even in mild disease, patients suffer from significant impairments in health status, which places a considerable burden on patients as well as society. Symptomatic patients are likely to progress to more advanced disease. To avoid breathlessness, they adapt and gradually reduce their activities, which, inevitably, leads to further deconditioning. As a consequence, a progressive deterioration in physical activity with increasing severity of COPD can be observed. Because physical activity is closely related to exacerbation rate, hospitalization, and mortality in patients with COPD, it is important to recognize the role of pharmaceutical interventions in enabling patients to stay physically active. Bronch(iol)odilation not only has important direct effects (symptom relief), but also exerts indirect effects on exercise capacity, exacerbation rate, health status, and mortality. In patients with COPD, the latter effects may be even more important than the direct effects. In this review the current view on causes and consequences of activity limitation in COPD is summarized. From this perspective, the rationale behind bronch(iol)odilator therapy as the cornerstone of treatment for patients with COPD will be discussed.

Doing Science: Writing conference abstracts

In this edition of Doing Science, we will address abstract writing, with a focus on conference abstracts. By providing an opportunity for discussing your work with your peers in specialised meetings, writing and submitting an abstract is often the very first step when you want to show the world the results of your work; be it your research, a clinical case or a review of the literature [1]. However, it can be be a daunting task to condense hours and hours of hard work into abstract format. But fear not! This edition of Doing Science will give you several approaches to writing abstracts, using your own data as well as that of others. Before we begin, a key message: always remember that writing an abstract follows typically the same path as writing a paper [2]. Begin by planning it, before actually writing it, proofreading it, sharing it with colleagues and finally doing the final revision and editing before you submit. In most cases, the keys to success are an important research question and interesting material to analyse in the hope of answering it. That being said, good abstract writing skills will increase your acceptance rate even for data of moderate importance, or seemingly complicated research ideas. So let’s begin... As every researcher knows, the function of a scientific abstract is to provide an overview of your work. But keep in mind that the abstract is what the referees will use to decide whether your work is accepted or rejected for presentation on the meeting. Also, have you remembered that the abstract is the only part of a paper that is published in conference proceedings [3]? Many researchers will even acknowledge that when they scroll through a conference programme, they look only at the titles …

Heart failure and chronic obstructive pulmonary disease: lung function test interpretation

However, all patients should be treated with a beta-blocker regarding their history of heart failure. Thus, CAD should not influence beta-blocker treatment. As we discussed in the manuscript, aetiology of heart failure was not documented in the study. There might have been a gender-related difference in the incidence of diastolic heart failure that may have had an influence on our results, but nevertheless, we evaluated ‘real-life’ treatment of patients by GPs or specialists. The population of the study, as well as the design (cross sectional), was too small for evaluation of clinical outcomes. Several publications have demonstrated a similar clinical outcome for female and male patients with chronic heart failure. This could imply that female patients might have a better outcome than male patients when treated similarly. We agree that this suggestion cannot be concluded from our study, but might attract attention for future trials.