Hyperinflation and its management in COPD

Single-Breath Simultaneous Measurement of DLNO and DLCO as Predictor of the Emphysema Component in COPD - A Retrospective Observational Study

Background

Chronic Obstructive Pulmonary Disease (COPD) is a respiratory condition characterized by heterogeneous abnormalities of the airways and lung parenchyma that cause different clinical presentations. The assessment of the prevailing pathogenetic components underlying COPD is not usually pursued in daily practice, also due to technological limitations and cost.

Aim

To assess non-invasively the lung emphysema component of COPD by the simultaneous measurement of DLNO and DLCO via a single-breath (sDLNO and sDLCO).

Methods

COPD patients aged ≥40 years of both genders were recruited consecutively and labelled by computed tomography as "with significant" emphysema (>10% of CT lung volume) or "with negligible" emphysema otherwise. Current lung function tests such as sDLNO, sDLCO and Vc (the lung capillary blood volume) were measured. All possible subsets of independent spirometric and diffusive parameters were tested as predictors of emphysema, and their predicted power compared to each parameter alone by ROC analysis and area under the curve (AUC).

Results

Thirty-one patients with "significant emphysema" were compared to thirty-one with "negligible emphysema". FEV1 and FEV1/FVC seemed to be the best spirometric predictors (AUC 0.80 and 0.81, respectively), while sDLCO and Vc had the highest predicted power among diffusive parameters (AUC 0.92 and 0.94, respectively). sDLCO and Vc values were the parameters most correlated to the extent of CT emphysema. Six subsets of independent predictors were identified and included at least one spirometric and one diffusive parameter. According to goodness-to-fit scores (AIC, BIC, log-likelihood and pseudo R2), RV coupled with sDLCO or Vc proved the best predictors of emphysema.

Conclusion

When investigating the parenchymal destructive component due to emphysema occurring in COPD, sDLNO, sDLCO and Vc do enhance the predictive power of current spirometric measures substantially. sDLNO, sDLCO and Vc contribute to phenotype of the main pathogenetic components of COPD easily and with high sensitivity. Organizational problems, radiation exposure, time and costs could be reduced, while personalized and precision medicine could be noticeably implemented.

Effect of a Conical-PEP Mask on Exercise in Subjects With COPD

BACKGROUND

Dynamic hyperinflation (DH) is a major pathophysiology of COPD that is directly related to dyspnea and exercise intolerance. Positive expiratory pressure (PEP) might reduce DH and dyspnea during exercise, but at present, there is insufficient evidence to conclude whether it is beneficial for DH, dyspnea, and exercise capacity in COPD.

METHODS

A randomized crossover trial with concealed allocation was conducted in 37 moderate to very severe subjects with COPD (34 males, age 66.6 ± 7.4 y, FEV1% of predicted 56.3 ± 13.7). The experimental condition was conical-PEP breathing with a PEP of around 5 cm H2O during a spot marching exercise at a constant speed, inducing 71 ± 9% age-predicted maximum heart rate to symptom limit or 25 min. The control condition was usual breathing. Exercise endurance time and end-exercise symptoms were recorded. Inspiratory capacity (IC) was measured pre-exercise and immediately post exercise. Cardiopulmonary function and breathlessness were monitored throughout the test and after 10 min of recovery.

RESULTS

There were no complications or adverse effects during exercise with a conical-PEP mask. Conical-PEP showed longer exercise times than control (median 11.0 [interquartile range 7.7-17.0] min vs 8 [6.0-11.5] min, respectively, P < .001). Most stopped exercising because of breathlessness and leg fatigue. At the end of exercise, IC and breathlessness showed non-significant differences between the conditions, but breathlessness was significantly lower in conical-PEP (median 4 [1.5-5.0] than control 5 [3-6] on Borg scale at isotime for control [8 min]).

CONCLUSIONS

Breathing with a 5 cm H2O conical-PEP mask improved exercise time (median 27.1% [0.6-52.9]) in subjects with COPD. The improvement in exercise with the conical-PEP mask was associated with slower development of breathlessness, possibly due to delays in DH development.

Functional Predictors Discriminating Asthma-COPD Overlap (ACO) from Chronic Obstructive Pulmonary Disease (COPD)

Background

A significant proportion of patients with obstructive lung disease have clinical and functional features of both asthma and chronic obstructive pulmonary disease (COPD), referred to as the asthma-COPD overlap (ACO). The distinction of these phenotypes, however, is not yet well-established due to the lack of defining clinical and/or functional criteria. The aim of our investigations was to assess the discriminating power of various lung function parameters on the assessment of ACO.

Methods

From databases of 4 pulmonary centers, a total of 540 patients (231 males, 309 females), including 372 patients with asthma, 77 patients with ACO and 91 patients with COPD, were retrospectively collected, and gradients among combinations of explanatory variables of spirometric (FEV1, FEV1/FVC, FEF25-75), plethysmographic (sReff, sGeff, the aerodynamic work of breathing at rest; sWOB), static lung volumes, including trapped gases and measurements of the carbon monoxide transfer (DLCO, KCO) were explored using multiple factor analysis (MFA). The discriminating power of lung function parameters with respect to ACO was assessed using linear discriminant analysis (LDA).

Results

LDA revealed that parameters of airway dynamics (sWOB, sReff, sGeff) combined with parameters of static lung volumes such as functional residual capacity (FRCpleth) and trapped gas at FRC (VTG FRC) are valuable and potentially important tools discriminating between asthma, ACO and COPD. Moreover, sWOB significantly contributes to the diagnosis of obstructive airway diseases, independent from the state of pulmonary hyperinflation, whilst the diffusion capacity for carbon monoxide (DLCO) significantly differentiates between the 3 diagnostic classes.

Conclusion

The complexity of COPD with its components of interaction and their heterogeneity, especially in discrimination from ACO, may well be differentiated if patients are explored by a whole set of target parameters evaluating, interactionally, flow limitation, airway dynamics, pulmonary hyperinflation, small airways dysfunction and gas exchange disturbances assessing specific functional deficits.

Control of the expiratory flow in a lung model and in healthy volunteers with an adjustable flow regulator: a combined bench and randomized crossover study

Background

Pursed-lips breathing (PLB) is a technique to attenuate small airway collapse by regulating the expiratory flow. During mandatory ventilation, flow-controlled expiration (FLEX), which mimics the expiratory flow course of PLB utilizing a digital system for measurement and control, was shown to exert lung protective effects. However, PLB requires a patient’s participation and coordinated muscular effort and FLEX requires a complex technical setup. Here, we present an adjustable flow regulator to mimic PLB and FLEX, respectively, without the need of a patient’s participation, or a complex technical device.

Methods

Our study consisted of two parts: First, in a lung model which was ventilated with standard settings (tidal volume 500 ml, respiratory rate 12 min⁻¹, positive end-expiratory pressure (PEEP) 5 cmH₂O), the possible reduction of the maximal expiratory flow by utilizing the flow regulator was assessed. Second, with spontaneously breathing healthy volunteers, the short-term effects of medium and strong expiratory flow reduction on airway pressure, the change of end-expiratory lung volume (EELV), and breathing discomfort was investigated.

Results

In the lung model experiments, expiratory flow could be reduced from − 899 ± 9 ml·s⁻¹ down to − 328 ± 25 ml·s⁻¹. Thereby, inspiratory variables and PEEP were unaffected. In the volunteers, the maximal expiratory flow of − 574 ± 131 ml·s⁻¹ under baseline conditions was reduced to − 395 ± 71 ml·s⁻¹ for medium flow regulation and to − 266 ± 58 ml·s⁻¹ for strong flow regulation, respectively (p < 0.001). Accordingly, mean airway pressure increased from 0.6 ± 0.1 cmH₂O to 2.9 ± 0.4 cmH₂O with medium flow regulation and to 5.4 ± 2.4 cmH₂O with strong flow regulation, respectively (p < 0.001). The EELV increased from baseline by 31 ± 458 ml for medium flow regulation and 320 ± 681 ml for strong flow regulation (p = 0.033). The participants rated breathing with the flow regulator as moderately uncomfortable, but none rated breathing with the flow regulator as intolerable.

Conclusions

The flow regulator represents an adjustable device for application of a self-regulated expiratory resistive load, representing an alternative for PLB and FLEX. Future applications in spontaneously breathing patients and patients with mandatory ventilation alike may reveal potential benefits.

Trial registration: DRKS00015296, registered on 20th August, 2018; URL: https://www.drks.de/drks_web/setLocale_EN.do.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01886-7.

Bi-Level Positive Airway Pressure for Non-invasive Respiratory Support of Foals

Respiratory insufficiency and pulmonary health are important considerations in equine neonatal care. As the majority of foals are bred for athletic pursuits, strategies for respiratory support of compromised foals are of particular importance. The administration of supplementary oxygen is readily implemented in equine practice settings, but does not address respiratory insufficiency due to inadequate ventilation and is no longer considered optimal care for hypoxia in critical care settings. Non-invasive ventilatory strategies including continuous or bi-level positive airway pressure are effective in human and veterinary studies, and may offer improved respiratory support in equine clinical practice. The current study was conducted to investigate the use of a commercial bi-level positive airway pressure (BiPAP) ventilator, designed for home care of people with obstructive respiratory conditions, for respiratory support of healthy foals with pharmacologically induced respiratory insufficiency. A two sequence (administration of supplementary oxygen with, or without, BiPAP), two phase, cross-over experimental design was used in a prospective study with six foals. Gas exchange and mechanics of breathing (increased tidal volume, decreased respiratory rate and increased peak inspiratory flow) were improved during BiPAP relative to administration of supplementary oxygen alone or prior studies using continuous positive airway pressure, but modest hypercapnia was observed. Clinical observations, pulse oximetry and monitoring of expired carbon dioxide was of limited benefit in identification of foals responding inappropriately to BiPAP, and improved methods to assess and monitor respiratory function are required in foals.

The effect of long-acting dual bronchodilator therapy on exercise tolerance, dynamic hyperinflation, and dead space during constant work rate exercise in COPD

We investigated whether dual bronchodilator therapy (glycopyrrolate/formoterol fumarate; GFF; Bevespi Aerosphere) would increase exercise tolerance during a high-intensity constant work rate exercise test (CWRET) and the relative contributions of dead space ventilation (V_D/V_T) and dynamic hyperinflation (change in inspiratory capacity) to exercise limitation in chronic obstructive pulmonary disease (COPD). In all, 48 patients with COPD (62.9 ± 7.6 yrs; 33 male; GOLD spirometry stage 1/2/3/4, n = 2/35/11/0) performed a randomized, double blind, placebo (PL) controlled, two-period crossover, single-center trial. Gas exchange and inspiratory capacity (IC) were assessed during cycle ergometry at 80% incremental exercise peak work rate. Transcutaneous [Formula: see text] (Tc[Formula: see text]) measurement was used for V_D/V_T estimation. Baseline postalbuterol forced expiratory volume in 1 s (FEV₁) was 1.86 ± 0.58 L (63.6% ± 13.9 predicted). GFF increased FEV₁ by 0.18 ± 0.21 L relative to placebo (PL; P < 0.001). CWRET endurance time was greater after GFF vs. PL (383 ± 184 s vs. 328 ± 115 s; difference 55 ± 125 s; P = 0.013; confidence interval: 20-90 s), a 17% increase. IC on GFF was above placebo IC at all time points and fell less with GFF vs. PL (P ≤ 0.0001). Isotime tidal volume (1.54 ± 0.50 vs. 1.47 ± 0.45 L; P = 0.022) and ventilation (52.9 ± 19.9 vs. 51.0 ± 18.9 L/min; P = 0.011) were greater, and respiratory rate was unchanged (34.9 ± 9.2 vs. 35.1 ± 8.0 br/min, P = 0.865). Isotime V_D/V_T did not differ between groups (GFF 0.28 ± 0.08 vs. PL 0.27 ± 0.09; P = 0.926). GFF increased exercise tolerance in patients with COPD, and the increase was accompanied by attenuated dynamic hyperinflation without altering V_D/V_T.NEW & NOTEWORTHY This study was a randomized clinical trial (NCT03081156) that collected detailed physiology data to investigate the effect of dual bronchodilator therapy on exercise tolerance in COPD, and additionally to determine the relative contributions of changes in dead space ventilation (V_D/V_T) and dynamic hyperinflation to alterations in exercise limitation. We utilized a unique noninvasive method to assess V_D/V_T (transcutaneous carbon dioxide, Tc[Formula: see text]) and found that dual bronchodilators yielded a moderate improvement in exercise tolerance. Importantly, attenuation of dynamic hyperinflation rather than change in dead space ventilation was the most important contributor to exercise tolerance improvement.

Prevalence and clinical features of most frequent phenotypes in the Italian COPD population: the CLIMA Study

Background

Chronic obstructive pulmonary disease (COPD) is a complex, progressive respiratory condition characterized by heterogeneous clinical presentations (phenotypes). The aim of this study was to assess the prevalence of the main COPD phenotypes and match of each phenotype to the most fitting clinical and lung function profile.

Methods

the CLIMA (Clinical Phenotypes in Actual Clinical Practice) study was an observational, cross-sectional investigation involving twenty-four sites evenly distributed throughout Italy. Patients were tentatively grouped based on their history and claimed prevailing symptoms at recruitment: chronic cough (CB, suggesting chronic bronchitis); dyspnoea (possible emphysema components, E); recurrent wheezing (presuming asthma components, A). Variables collected were: anagraphics; smoking habit; history of asthma; claim of >1 exacerbations in the previous year; blood eosinophil count; total blood IgE and alpha¹ anti-trypsin (α¹-AT) levels; complete lung function, and the chest X-ray report. mMRC, CAT, BCS, EQ5d-5L were also used. The association between variables and phenotypes were checked by Chi-square test and multinomial logistic regression.

Results

The CB phenotype was prevalent (48.3%), followed by the E and the A phenotypes (38.8% and 12.8%, respectively). When dyspnoea was the prevailing symptom, the probability of belonging to the COPD-E phenotype was 3.40 times higher. Recurrent wheezing was mostly related to the COPD-A phenotype. Lung function proved more preserved in the COPD-CB phenotype. Smoke; n. exacerbations/year; VR, and BODE index were positively correlated with the COPD-E phenotype, while SpO₂, FEV₁/FVC, FEV₁/VC, and FEV₁ reversibility were negatively correlated. Lower DLco values were highly probative for the COPD-E phenotype (p<0.001). Conversely, smoke, wheezing, plasma eosinophils, FEV₁ reversibility, and DLco were positively correlated with the COPD-A phenotype. The probability of belonging to the COPD-A phenotype raised by 2.71 times for any increase of one unit in % plasma eosinophils (p<0.001). Also multiparametrical scores contributed to discriminate the three phenotypes.

Conclusion

The recognition of the main phenotypes of COPD can be effectively pursued by means of a few clinical and instrumental parameters, easy to obtain also in current daily practice. The phenotypical approach is crucial in the management of COPD as it allows to individualize the therapeutic strategy and to obtain more effective clinical outcomes.

Effect of the expiratory positive airway pressure on dynamic hyperinflation and exercise capacity in patients with COPD: a meta-analysis

Expiratory positive airway pressure (EPAP) is widely applicable, either as a strategy for pulmonary reexpansion, elimination of pulmonary secretion or to reduce hyperinflation. However, there is no consensus in the literature about the real benefits of EPAP in reducing dynamic hyperinflation (DH) and increasing exercise tolerance in subjects with chronic obstructive pulmonary disease (COPD). To systematically review the effects of EPAP application during the submaximal stress test on DH and exercise capacity in patients with COPD. This meta-analysis was performed from a systematic search in the PubMed, EMBASE, PeDRO, and Cochrane databases, as well as a manual search. Studies that evaluated the effect of positive expiratory pressure on DH, exercise capacity, sensation of dyspnea, respiratory rate, peripheral oxygen saturation, sense of effort in lower limbs, and heart rate were included. GRADE was used to determine the quality of evidence for each outcome. Of the 2,227 localized studies, seven studies were included. The results show that EPAP did not change DH and reduced exercise tolerance in the constant load test. EPAP caused a reduction in respiratory rate after exercise (− 2.33 bpm; 95% CI: − 4.56 to − 0.10) (very low evidence) when using a pressure level of 5 cmH₂O. The other outcomes analyzed were not significantly altered by the use of EPAP. Our study demonstrates that the use of EPAP does not prevent the onset of DH and may reduce lower limb exercise capacity in patients with COPD. However, larger and higher-quality studies are needed to clarify the potential benefit of EPAP in this population.

Metronome-Paced Incremental Hyperventilation May Predict Exercise Tolerance and Dyspnea as a Surrogate for Dynamic Lung Hyperinflation During Exercise

Background

Dynamic lung hyperinflation (DLH) has been evaluated based on decreased inspiratory capacity (IC) during exercise load. However, this is not routinely done in clinical practice. We have developed a convenient method of metronome-paced incremental hyperventilation (MPIH) and reported its usefulness. In the present study, we compared these two methods for evaluating DLH and examined whether our MPIH method can be used to predict DLH during exercise.

Methods

DLH was measured by MPIH and constant load exercise (CLE) in 35 patients with stable COPD. DLH was defined as the most decreased IC (IC_lowest) and the most decreases in IC from IC at rest (-IC_lowest), and we compared between these two methods.

Results

The IC_lowest in CLE and the -IC_lowest in MPIH were significantly lower in emphysema-dominant COPD than in emphysema-nondominant COPD. Both IC_lowest and -IC_lowest showed significant correlations between the two methods (r = 0.67, p < 0.01 and r = 0.44, p < 0.01, respectively). The endurance time of CLE was significantly correlated with IC_lowest following MPIH (r = 0.62, p < 0.01) but not with that obtained by the CLE method. Furthermore, the IC_lowest of MPIH was more significantly correlated with endurance time in emphysema-dominant COPD. Weak but significant correlations between the -IC_lowest obtained by each method and maximum modified Borg scale were observed (MPIH: r = 0.38, p = 0.02; CLE: r = 0.37, p = 0.03).

Conclusion

The MPIH method may be a convenient method to predict exercise tolerance and dyspnea as a clinically useful synergic screening surrogate for DLH during exercise.

Efficacy of tiotropium and olodaterol combination therapy on dynamic lung hyperinflation evaluated by hyperventilation in COPD: an open-label, comparative before and after treatment study

Background: Dynamic lung hyperinflation (DLH) following metronome-paced incremental hyperventilation (MPIH) was reported to be useful for assessment of pathophysiological impairment in patients with chronic obstructive pulmonary disease (COPD), and the effects of tiotropium and olodaterol on DLH following MPIH have not been reported.

Methods: Treatment consisted of administration of tiotropium/olodaterol 5/5 μg inhalation solution (2.5/2.5 μg per actuation) using a soft-mist inhaler once a day. We compared outcomes before and after 8 weeks of treatment. The primary outcome was defined as a decrease in inspiratory capacity (IC) from rest by MPIH, which is an index of DLH. The secondary outcomes were COPD assessment test (CAT), forced expiratory volume in 1 s (FEV₁), and 6-min walking distance (6MWD). In addition, we investigated whether there were correlations between changes with treatment in DLH and FEV₁, 6MWD, and dyspnea.

Results: Thirty-three of the 38 registered patients completed this study. Most of these 33 patients had mild to moderate COPD. Decreasing IC by MPIH was significantly reduced by treatment for 8 weeks, with a mean change of about −0.11 to −0.13 mL (P <0.05). In addition, CAT score, FEV₁, and 6MWD improved with treatment (P <0.05). There were no significant correlations between changes in DLH, FEV₁, 6MWD, or dyspnea with treatment.

Conclusions: The results of this study showed that the combination of tiotropium and olodaterol is effective for improvement of DLH following hyperventilation.

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European Respiratory Society International Congress 2018: Allied Respiratory Professionals' report of highlighted sessions

This article provides an overview of outstanding sessions that were supported by Assembly 9 during the recent European Respiratory Society International Congress in Paris, France. Session content was mainly targeted at allied health professionals such as respiratory physiologists, respiratory physiotherapists and respiratory nurses. Recent developments and novel findings related to pulmonary function testing, respiratory muscle function assessments and treatment, and multidimensional and multidisciplinary approaches to the assessment and management of dyspnoea were the focus of these sessions and are summarised here.

Relationship between exercise endurance and static hyperinflation in a post hoc analysis of two clinical trials in patients with COPD

Background

Lung hyperinflation and exercise intolerance are hallmarks of chronic obstructive pulmonary disease (COPD). However, their relationship remains uncertain. A combined analysis of two placebo-controlled, randomized studies examined the effects of the long-acting muscarinic antagonist umeclidinium (UMEC) and long-acting β₂-agonist vilanterol (VI) separately and in combination on static hyperinflation, exercise endurance time (EET), and their relationship in patients with COPD.

Methods

Patients with moderate-to-severe stable COPD and resting functional residual capacity >120% predicted were randomized to UMEC/VI 62.5/25 μg, UMEC 62.5 μg, VI 25 μg, or placebo for 12 weeks. Inspiratory capacity (IC), residual volume (RV), total lung capacity (TLC), and EET in an endurance shuttle-walk test were measured. In this post hoc analysis, IC/TLC, RV/TLC, and IC were used as hyperinflation markers.

Results

After 12 weeks, UMEC/VI and UMEC and VI showed significant improvements in hyperinflation versus placebo when measured by absolute change from baseline in IC/TLC (trough and 3 hours postdose [P≤0.011]). UMEC/VI showed significant improvements versus UMEC and VI in absolute changes in IC/TLC (trough and 3 hours postdose [P≤0.001]). Statistical significance for comparisons with placebo and between treatments for absolute changes in IC and percentage changes in RV/TLC followed similar patterns to those for absolute changes in IC/TLC. UMEC/VI showed significant improvements in EET versus placebo at day 2 and week 12, measured as change from baseline in seconds (P≤0.002) and as a percentage from baseline (P≤0.005). There was a lack of evidence to suggest a correlation between improvements in static hyperinflation and EET at any time point.

Conclusion

Although the dual bronchodilator UMEC/VI demonstrated greater improvements in static hyperinflation markers than UMEC or VI and significant improvements in exercise endurance, no direct relationship was observed between static hyperinflation and exercise endurance.

Assessment of dyspnea and dynamic hyperinflation in male patients with chronic obstructive pulmonary disease during a six minute walk test and an incremental treadmill cardiorespiratory exercise test

The six minute walk test (6MWT) is a standardized test that provides information on exercise capacity in patients with COPD. It is considered a submaximal test in opposition to incremental cardiopulmonary exercise tests (CPET) that provide valuable information on all the systems involved in exercise.

OBJECTIVES

1. To compare the perceptive, physiological responses and degree of dynamic hyperinflation during two exercise tests: the 6MWT and the incremental CPET on a treadmill. 2. To evaluate how dyspnea is related to dynamic hyperinflation (DH) and other functional parameters in both tests.

METHODS

29 stable COPD male patients, age 68±5.8 years, mean post-bronchodilator FEV1 57±11%, were recruited. To evaluate dynamic hyperinflation, inspiratory capacity (IC) was measured at rest and upon completing each one of the tests. At the same time, perceived dyspnea and leg discomfort were rated on specific modified Borg scales.

RESULTS

The mean walk distance in 6MWT was 494±88m. The Borg scale rating for shortness of breath upon completing the test was 4.7±2, whilst 2.9±2 for leg discomfort. IC changed from 2.53±0.63l before to 2.34±0.60l after completion of the test. In the treadmill CPET, maximal oxygen consumption (V˙O₂max) was 21.8±5mL/kg/min with 6.6±2 dyspnea and 4.3±2 leg discomfort on Borg scales. IC changed from 2.17±0.53l to 1.20±0.43l.

CONCLUSIONS

Dynamic hyperinflation occurs in male COPD patients during submaximal exercise such as the 6MWT. This phenomenon is more pronounced after incremental CPET on a treadmill. Despite being dyspnea the dominant limiting symptom for both tests, we observed different physiological responses.

Noninvasive positive pressure ventilation enhances the effects of aerobic training on cardiopulmonary function

Purpose

The purpose of this study was to determine the effect of aerobic training under noninvasive positive pressure ventilation (NPPV) on maximal oxygen uptake (V˙O2max).

Methods

Ten healthy young male volunteers participated in the study. Before the training, stroke volume (SV) and cardiac output (CO) were measured in all subjects under 0, 4, 8, and 12 cmH₂O NPPV at rest. Then, the subjects exercised on a cycle ergometer at 60% of pre-training V˙O2max for 30 min daily for 5 consecutive days with/without NPPV. The 5-day exercise protocol was repeated after a three-week washout period without/with NPPV. The primary endpoint was changes in V˙O2max. The secondary endpoints were changes in SV, CO, maximum heart rate (HR_max), maximum respiratory rate (RR_max), maximum expiratory minute volume (VE_max) and the percent change in plasma volume (PV).

Results

NPPV at 12 cmH₂O significantly reduced SV and CO at rest. V˙O2max significantly increased after 5 days training with and without NPPV, but the magnitude of increase in V˙O2max after training under 12 cmH₂O NPPV was significantly higher than after training without NPPV. VE_max significantly increased after training under NPPV, but not after training without NPPV. HR_max and RR_max did not change during training irrespective of NPPV. The percent change in PV was similar between training with and without NPPV. The 5-day training program with NPPV resulted in greater improvement in V˙O2max than without NPPV.

Conclusions

Aerobic training under NPPV has add-on effects on V˙O2max and exercise-related health benefits in healthy young men.

Dynamics of airway response in lung microsections: a tool for studying airway-extra cellular matrix interactions

The biological configuration of extracellular matrix (ECM) plays a key role in how mechanical interactions of the airway with its parenchymal attachments affect the dynamics of airway responses in different pulmonary disorders including asthma, emphysema and chronic bronchitis. It is now recognized that mechanical interactions between airway tissue and ECM play a key regulatory role on airway physiology and kinetics that can lead to the reorganization and remodeling of airway connective tissue. A connective tissue is composed of airway smooth muscle cells (ASM) and the ECM, which includes variety of glycoproteins and therefore the extent of interactions between ECM and ASM affects airway dynamics during exacerbations of major pulmonary disorders. Measurement of the velocity and magnitude of airway closure or opening provide important insights into the functions of the airway contractile apparatus and the interactions with its surrounding connective tissues. This review highlights suitability of lung microsection technique in studying measurements of airway dynamics (narrowing/opening) and associated structural distortions in airway compartments.

Diagnosis, assessment, and phenotyping of COPD: beyond FEV₁

COPD is now widely recognized as a complex heterogeneous syndrome, having both pulmonary and extrapulmonary features. In clinical practice, the diagnosis of COPD is based on the presence of chronic airflow limitation, as assessed by post-bronchodilator spirometry. The severity of the airflow limitation, as measured by percent predicted FEV1, provides important information to the physician to enable optimization of management. However, in order to accurately assess the complexity of COPD, there need to be other measures made beyond FEV1. At present, there is a lack of reliable and simple blood biomarkers to confirm and further assess the diagnosis of COPD. However, it is possible to identify patients who display different phenotypic characteristics of COPD that relate to clinically relevant outcomes. Currently, validated phenotypes of COPD include alpha-1 antitrypsin deficiency, and "frequent exacerbators". Recently, a definition and assessment of a new phenotype comprising patients with overlapping features of asthma and COPD has been suggested and is known as "asthma COPD overlap syndrome". Several other phenotypes have been proposed, but require validation against clinical outcomes. Defining phenotypes requires the assessment of multiple factors indicating disease severity, its impact, and its activity. Recognition and validation of COPD phenotypes has an important role to play in the selection of evidence-based targeted therapy in the future management of COPD, but regardless of the diagnostic terms, patients with COPD should be assessed and treated according to their individual treatable characteristics.

The Impact of Homogeneous Versus Heterogeneous Emphysema on Dynamic Hyperinflation in Patients With Severe COPD Assessed for Lung Volume Reduction

Dynamic hyperinflation (DH) is a pathophysiologic hallmark of Chronic Obstructive Pulmonary Disease (COPD). The aim of this study was to investigate the impact of emphysema distribution on DH during a maximal cardiopulmonary exercise test (CPET) in patients with severe COPD.

This was a retrospective analysis of prospectively collected data among severe COPD patients who underwent thoracic high-resolution computed tomography, full lung function measurements and maximal CPET with inspiratory manouvers as assessment for a lung volume reduction procedure. ΔIC was calculated by subtracting the end-exercise inspiratory capacity (eIC) from resting IC (rIC) and expressed as a percentage of rIC (ΔIC %). Emphysema quantification was conducted at 3 predefined levels using the syngo PULMO-CT (Siemens AG); a difference >25% between best and worse slice was defined as heterogeneous emphysema.

Fifty patients with heterogeneous (62.7% male; 60.9 ± 7.5 years old; FEV₁% = 32.4 ± 11.4) and 14 with homogeneous emphysema (61.5% male; 62.5 ± 5.9 years old; FEV₁% = 28.1 ± 10.3) fulfilled the enrolment criteria. The groups were matched for all baseline variables. ΔIC% was significantly higher in homogeneous emphysema (39.8% ± 9.8% vs.31.2% ± 13%, p = 0.031), while no other CPET parameter differed between the groups. Upper lobe predominance of emphysema correlated positively with peak oxygen pulse, peak oxygen uptake and peak respiratory rate, and negatively with ΔIC%. Homogeneous emphysema is associated with more DH during maximum exercise in COPD patients.

Can COPD patients who hyperinflate during daily life activities be identified by laboratory tests?

BACKGROUND

Identification of patients with chronic obstructive pulmonary disease (COPD) who develop dynamic hyperinflation (DH) during activities in daily life (ADL) is important, because of the association between DH and dyspnea and exercise limitation.

OBJECTIVE

We aimed to answer the question whether measurements of DH during metronome-paced tachypnea (MPT) or cardiopulmonary exercise testing (CPET) can be used to identify patients who develop DH during ADL.

METHODS

DH was measured by tracking changes in inspiratory capacity during CPET, MPT and ADL. Bland-Altman plots were used to evaluate agreement in DH between methods. With a receiver operating characteristic (ROC) analysis, the overall accuracy of MPT and CPET to identify patients who hyperinflate during ADL was assessed.

RESULTS

There are broad limits of agreement in DH between methods. ROC curve analyses showed good overall accuracy of both CPET and MPT to identify patients who hyperinflate during ADL. For CPET, area under the curve (AUC) = 0.956 (95% CI 0.903-1.009). For MPT, AUC = 0.840 (95% CI 0.699-0.981). Sensitivity and specificity to identify patients who hyperinflate during ADL with CPET were 96 and 83%, respectively, and with MPT, they were 89 and 77%, respectively.

CONCLUSION

Both CPET and MPT can serve as screening tools to identify patients who are susceptible to developing DH during ADL. In practice, MPT is the most simple and inexpensive surrogate. However, the sensitivity of MPT is not optimal. When DH does not occur during CPET, it is unlikely to occur during ADL.

No room to breathe: the importance of lung hyperinflation in COPD

Patients with chronic obstructive pulmonary disease (COPD) are progressively limited in their ability to undertake normal everyday activities by a combination of exertional dyspnoea and peripheral muscle weakness. COPD is characterised by expiratory flow limitation, resulting in air trapping and lung hyperinflation. Hyperinflation increases acutely under conditions such as exercise or exacerbations, with an accompanying sharp increase in the intensity of dyspnoea to distressing and intolerable levels. Air trapping, causing increased lung hyperinflation, can be present even in milder COPD during everyday activities. The resulting activity-related dyspnoea leads to a vicious spiral of activity avoidance, physical deconditioning, and reduced quality of life, and has implications for the early development of comorbidities such as cardiovascular disease. Various strategies exist to reduce hyperinflation, notably long-acting bronchodilator treatment (via reduction in flow limitation and improved lung emptying) and an exercise programme (via decreased respiratory rate, reducing ventilatory demand), or their combination. Optimal bronchodilation can reduce exertional dyspnoea and increase a patient's ability to exercise, and improves the chance of successful outcome of a pulmonary rehabilitation programme. There should be a lower threshold for initiating treatments appropriate to the stage of the disease, such as long-acting bronchodilators and an exercise programme for patients with mild-to-moderate disease who experience persistent dyspnoea.

[Cost-effectiveness of lung volume reduction coil treatment in emphysema. STIC REVOLENS]

BACKGROUND

Medical therapeutic options for the treatment of emphysema remain limited. Lung volume reduction surgery is infrequently used because of its high morbi-mortality. Endobronchial lung volume reduction coil (LVRC(®), PneumRx, Mountain View, CA) treatment has been recently developed and has been shown to be feasible and associated with an acceptable safety profile, while resulting in improvements in dyspnea, exercise capacity and lung function. The objective of this study is to analyze the cost effectiveness of LVRC treatment in severe emphysema.

METHODS

This prospective, multicenter study, randomized with a 1:1 ratio (LVRC vs conventional treatment) will include 100 patients who will be followed up for 1year. The primary outcome measure is the 6-month improvement of the 6-minute walk test: the percentage of patients showing an improvement of at least 54m will be compared between groups. A cost-effectiveness study will estimate the cost of LVRC treatment, the global cost of this therapeutic option and will compare the cost between patients treated by LVRC and by medical treatment alone.

EXPECTED RESULTS

This study should allow validating the clinical efficacy of LVRC in severe emphysema. The cost-effectiveness study will assess the medical-economic impact of the LVRC therapeutic option.

Extrinsic Threshold PEEP Reduces Post-exercise Dyspnea in COPD Patients: A Placebo-controlled, Double-blind Cross-over Study

PURPOSE

Most patients with chronic obstructive pulmonary disease (COPD) complain of dyspnea during and following exercise, and the development of intrinsic positive end-expiratory pressure (PEEP) is thought to contribute to lung hyperinflation and dyspnea. Many people with COPD use pursed lip breathing (PLB) in an attempt to produce extrinsic PEEP to reduce lung hyperinflation and dyspnea during and following exertion. We hypothesized that the use of a threshold, extrinsic PEEP device would reduce post-exercise dyspnea in people with COPD.

METHODS

A double blind, crossover study was conducted on post-exercise dyspnea in 8 patients with COPD whose exercise tolerance was limited by dyspnea. Subjects performed two identical 6-minute treadmill bouts that led to a Borg dyspnea rating of at least 5/10. Dyspnea, heart rate, and oxygen-hemoglobin saturation (SpO(2)) were recorded at rest, every 2 minutes during exercise and at 2, 5, and 10 minutes post-exercise. Immediately following the exercise bouts, the subjects used either a threshold PEEP device for 6 breaths at 10 cm H(2)O or a Sham device.

RESULTS

Heart rate and SpO(2) were not different between treatments any time point before, during, or after exercise. Dyspnea ratings were not different between devices at rest or during exercise, but were lower in the post-exercise period following use of PEEP (p < 0.05). When asked which device, if any, the subjects would prefer to use to relieve post-exercise dyspnea, 7 of 8 chose the PEEP device and one had no preference.

CONCLUSIONS

We found that the use of a PEEP device can help reduce postexercise dyspnea in patients with COPD.