Dynamic hyperinflation during daily activities: does COPD global initiative for chronic obstructive lung disease stage matter?

[Inspiratory muscle training during pulmonary rehabilitation]

INTRODUCTION

Inspiratory muscle training (IMT) is part of the management of patients with pulmonary diseases during rehabilitation. Since the last recommendations of the Société de pneumologie de langue française, several studies have focused on the role of inspiratory muscle training during pulmonary rehabilitation.

BACKGROUND

IMT, in comparison to standard care or sham-IMT, improves the strength and endurance of the inspiratory muscles, decreases dyspnoea during the activities of daily living, improves walking distance and quality of life. However, the different studies did not show an additional effect of IMT during a pulmonary rehabilitation program compared to a rehabilitation program without IMT, with regard to improvement of exercise capacity and quality of life.

OUTLOOK

One study showed an improvement in dyspnoea of effort, but these results are yet to be confirmed. Finally, it seems appropriate to associate IMT with an exercise-training program before chest or abdominal surgery, even if further studies are necessary.

CONCLUSION

During a pulmonary rehabilitation program, IMT does not provide additional benefits. However, when patients cannot perform a global exercise training, IMT has shown benefit. IMT provides additional benefits in pre-operative programs.

Slow chest compression acutely reduces dynamic hyperinflation in people with chronic obstructive pulmonary disease: a randomized cross-over trial

Background: Strategies to minimize dynamic hyperinflation (DH) and dyspnea, such as slow chest compression (SCC), are relevant in people with chronic obstructive pulmonary disease (COPD).Objectives: To analyze the acute effects of SCC after exercise on DH and dyspnea in people with COPD and to identify responders to the technique.Methods: This is a cross-over study with 40 patients. Two six-minute step tests (6MSTs) were performed followed by a one-minute application of SCC (6MST_SCC) or rest (6MST_CONTROL), at random. End-expiratory lung volume (EELV) and dyspnea were assessed. A difference ≥76 ml in ΔEELV between SCC and control characterized the responders.Results: The performance in 6MST_SCC and 6MST_CONTROL were similar. There was a greater reduction in EELV after 6MST_SCC compared to 6MST_CONTROL (124 ± 193 ml vs. 174 ± 183 ml; p = .049), while there was no difference in change in dyspnea between the SCC and control groups. Twenty-one participants were SCC responders and had higher functional residual capacity [FRC: 5.36 ± 1.09 vs. 4.58 ± 0.94; p = .02; cutoff point: 4.56; sensitivity = 76%; specificity = 53%; AUC = 0.71 (95%CI: 0.54 to 0.87); p = .02].Conclusion: SCC applied immediately after exercise reduced DH, but did not reduce dyspnea in people with COPD. The technique is beneficial only for some patients and FRC can help to identify them.

Day and Night Control of COPD and Role of Pharmacotherapy: A Review

The topic of 24-hour management of COPD is related to day-to-night symptoms management, specific follow-up and patients' adherence to therapy. COPD symptoms strongly vary during day and night, being worse in the night and early morning. This variability is not always adequately considered in the trials. Night-time symptoms are predictive of higher mortality and more frequent exacerbations; therefore, they should be a target of therapy. During night-time, in COPD patients the supine position is responsible for a different thoracic physiology; moreover, during some sleep phases the vagal stimulation determines increased bronchial secretions, increased blood flow in the bronchial circulation (enhancing inflammation) and increased airway resistance (broncho-motor tone). Moreover, in COPD patients the circadian rhythm may be impaired. The role of pharmacotherapy in this regard is still poorly investigated. Symptoms can be grossly differentiated according to the different phenotypes of the disease: wheezing recalls asthma, while dyspnea is strongly related to emphysema (dynamic hyperinflation) or obstructive bronchiolitis (secretions). Those symptoms may be different targets of therapy. In this regard, GOLD recommendations for the first time introduced the concept of phenotype distinction suggesting the use of inhaled corticosteroids (ICS) particularly when an asthmatic pattern or eosiophilic inflammations are present, and hypothesized different approaches to target symptoms (ie, dyspnea) or exacerbations. Pharmacotherapy should be evaluated and possibly directed on the basis of circadian variations, for instance, supporting the use of twice-daily rapid-action bronchodilators and evening dose of ICS. Recommendations on day and night symptoms monitoring strategies and choice of the specific drug according to patient's profile are still not systematically investigated or established. This review is the summary of an advisory board on the topic "24-hour control of COPD and role of pharmacotherapy", held by five pulmonologists, experts in respiratory pathophysiology, pharmacology and sleep medicine.

Effectiveness of Energy Conservation Techniques in Patients with COPD

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) might suffer from severe dyspnea, which importantly impacts on the performance of activities of daily living (ADL). Patient training of energy conservation techniques (ECTs) might be useful to improve the tolerance and execution of these ADL, but objective studies evaluating the effect of teaching ECTs on the metabolic equivalent of task (MET) in patients with COPD are sparse.

OBJECTIVES

The aim of this study was to test the hypothesis that practicing ECTs after a 2-week ECT teaching period would reduce the energy expenditure (MET) in performing an activity in patients with severe COPD.

METHODS

Energy expenditure was assessed with a gas exchange system (OxyconTM Mobile) during one out of five standardized ADL before and after a 2-week intervention period in which ECTs were taught. These ECTs comprised a good breathing technique, an ergonomic way of performing the activity, and the use of assistive devices.

RESULTS

Thirty-two patients with COPD (mean FEV1: 39 ± 14%; female: n = 18; age: 68 ± 7 years) were included. A significantly lower MET (2.3 ± 0.6 to 2.1 ± 0.5; p < 0.05) and less desaturation (89.7 ± 5.2 vs. 91.1 ± 5.5% HbO2; p < 0.05) were seen while performing the same activity after the intervention. However, there was no significant difference in the time spent on the task performed (6.0 ± 3.9 vs. 6.7 ± 4.0 min; p > 0.05).

CONCLUSIONS

A 2-week educative program on ECTs successfully reduces the energy spent for performing ADL relevant to the patient without any significant increase in the time spent on the activity.

Impact of pulmonary rehabilitation on activities of daily living in patients with chronic obstructive pulmonary disease

A high proportion of patients with chronic obstructive pulmonary disease (COPD) experience problems during the performance of activities of daily living (ADLs). We aimed to determine the effects of a comprehensive 8-wk pulmonary rehabilitation program on the physiologic response to and performance of ADLs in patients with COPD. Before and after pulmonary rehabilitation, 31 patients with COPD [71% men; mean age: 64.2 (SD 8.4) years; mean forced expiratory volume in the first second: 54.6 (SD 19.9) % predicted] performed physical function tests, the Canadian Occupational Performance Measure (COPM), and an ADL test consisting of the following: putting on socks, shoes, and vest; stair climbing; washing up four dishes, cups, and saucers; doing groceries and putting away groceries in a cupboard; folding eight towels; and vacuum cleaning for 4 min. Metabolic load, ventilation, and dynamic hyperinflation were assessed using an Oxycon mobile device. In addition, symptoms of dyspnea and fatigue and time to complete ADLs were recorded. After rehabilitation, patients with COPD used a significantly lower proportion of their peak aerobic capacity and ventilation to perform ADLs, accompanied by lower Borg scores for dyspnea and fatigue. Furthermore, patients needed significantly less time to complete ADLs. Dynamic hyperinflation occurred during the performance of ADLs, which did not change following pulmonary rehabilitation. Changes in physical function, including six-min walk distance, constant work rate test, quadriceps muscle strength, and COPM were significantly correlated with change in average total oxygen uptake during the performance of the ADL test. A comprehensive pulmonary rehabilitation program can improve the physiologic response to and actual performance of ADLs in patients with COPD. NEW & NOTEWORTHY A high proportion of patients with chronic obstructive pulmonary disease (COPD) experience problems during the performance of activities of daily living (ADLs). This study clearly demonstrated that a comprehensive pulmonary rehabilitation program can improve the performance of ADLs in patients with COPD, indicated by a significantly shorter time to perform ADLs and a lower metabolic load and dyspnea sensation.

Inhaled therapies in patients with moderate COPD in clinical practice: current thinking

COPD is a complex, heterogeneous condition. Even in the early clinical stages, COPD carries a significant burden, with breathlessness frequently leading to a reduction in exercise capacity and changes that correlate with long-term patient outcomes and mortality. Implementation of an effective management strategy is required to reduce symptoms, preserve lung function, quality of life, and exercise capacity, and prevent exacerbations. However, current clinical practice frequently differs from published guidelines on the management of COPD. This review focuses on the current scientific evidence and expert opinion on the management of moderate COPD: the symptoms arising from moderate airflow obstruction and the burden these symptoms impose, how physical activity can improve disease outcomes, the benefits of dual bronchodilation in COPD, and the limited evidence for the benefits of inhaled corticosteroids in this disease. We emphasize the importance of maximizing bronchodilation in COPD with inhaled dual-bronchodilator treatment, enhancing patient-related outcomes, and enabling the withdrawal of inhaled corticosteroids in COPD in well-defined patient groups.

Effect of Yoga Breathing (Pranayama) on Exercise Tolerance in Patients with Chronic Obstructive Pulmonary Disease: A Randomized, Controlled Trial

OBJECTIVE

Pulmonary rehabilitation improves exercise tolerance in patients with chronic obstructive pulmonary disease (COPD). However, many patients do not have access to pulmonary rehabilitation programs. We hypothesized that an alternative to pulmonary rehabilitation to improve exercise tolerance is the practice of pranayama, or yoga breathing, which could be done independently at home. We also sought to determine whether yoga nonprofessionals could adequately teach pranayama to patients.

DESIGN

Proof-of-concept, randomized, double-blind, controlled pilot trial.

SETTINGS/LOCATION

Two academic pulmonary practices.

SUBJECTS

Forty-three patients with symptomatic, moderate-to-severe COPD.

INTERVENTIONS

Twelve weeks of pranayama plus education versus education alone. Two yoga professionals trained the research coordinators to conduct all pranayama teaching and monitored the quality of the teaching and the practice of pranayama by study participants.

OUTCOME MEASURES

The primary outcome was a change in the 6-min walk distance (6MWD). Secondary outcomes included changes in lung function, markers of oxidative stress and systemic inflammation, and measures of dyspnea and quality of life.

RESULTS

The 6MWD increased in the pranayama group (least square mean [95% confidence interval] = 28 m [-5 to 61]) and decreased in the control group (-15 m [-47 to 16]), with a nearly significant treatment effect (p = 0.06) in favor of pranayama. Pranayama also resulted in small improvements in inspiratory capacity and air trapping. Both groups had significant improvements in various measures of symptoms, but no overall differences in respiratory system impedance or markers of oxidative stress or systemic inflammation.

CONCLUSION

This pilot study successfully demonstrated that pranayama was associated with improved exercise tolerance in patients with COPD. Lay personnel were able to adequately teach patients to practice pranayama. These results suggest that pranayama may have significant clinical benefits for symptomatic patients with COPD, a concept that needs to be confirmed in future, larger clinical trials.

The Mozart study: a relation between dynamic hyperinflation and physical activity in patients with chronic obstructive pulmonary disease?

BACKGROUND

Many patients with chronic obstructive pulmonary disease (COPD) experience dyspnoea during exercise, resulting in a reduction of physical activity (PA). Dynamic hyperinflation (DH) is seen as a major cause of dyspnoea in COPD.

OBJECTIVE

The objective of the current study was to investigate the relationship between DH, in terms of the amount of DH and the development and recovery rate of DH in patients with COPD, and PA.

METHODS

Thirty-five patients with stable COPD were included from an outpatient clinic (14 GOLD II and 21 GOLD III, median age 65). PA was assessed using an accelerometer. Subjects underwent metronome-paced tachypnoea (MPT) to induce DH. To quantify the amount of DH during MPT, a decrease in inspiratory capacity (IC) or a change in IC as percentage of total lung capacity was used.

RESULTS

No significant correlations were found between the parameters describing DH and PA. Secondary correlation analyses showed a negative correlation between static hyperinflation (SH) and PA (r = -0·39; P = 0·02). The pattern of breathing during MPT and the test itself showed high interpatient variability.

CONCLUSIONS

The absence of a significant correlation between DH and PA is contrary to previous studies. SH did show a correlation with PA. The variety in results and the technical difficulties in execution of the measurements ask for a new, more reliable, method to detect DH and investigate its relation with PA in patients with COPD.

Ventilatory demand and dynamic hyperinflation induced during ADL-based tests in Chronic Obstructive Pulmonary Disease patients

Background

Airflow limitation frequently leads to the interruption of activities of daily living (ADL) in patients with Chronic Obstructive Pulmonary Disease (COPD). These patients commonly show absence of ventilatory reserve, reduced inspiratory reserve volume, and dynamic hyperinflation (DH).

Objective

To investigate ventilatory response and DH induced by three ADL-based protocols in COPD patients and compare them to healthy subjects.

Method

Cross-sectional study. COPD group: 23 patients (65±6 years, FEV1 37.2±15.4%pred); control group: 14 healthy subjects (64±4 years) matched for age, sex, and body mass index. Both groups performed all three tests: Glittre-ADL test; an activity test that involved moving objects on a shelf (TSHELF); and a modified shelf protocol isolating activity with upper limbs (TSHELF-M). Ventilatory response and inspiratory capacity were evaluated.

Results

Baseline ventilatory variables were similar between groups (p>0.05). The ventilatory demand increased and the inspiratory capacity decreased significantly at the end of the tests in the COPD group. Ventilatory demand and DH were higher (p<0.05) in the TSHELF than in the TSHELF-M in the COPD group (p<0.05). There were no differences in DH between the three tests in the control group (p>0.05) and ventilatory demand increased at the end of the tests (p<0.05) but to a lower extent than the COPD group.

Conclusion

The TSHELF induces similar ventilatory responses to the Glittre-ADL test in COPD patients with higher ventilatory demand and DH. In contrast, the ventilatory response was attenuated in the TSHELF-M, suggesting that squatting and bending down during the Glittre-ADL test could trigger significant ventilatory overload.

Longitudinal changes in handgrip strength, hyperinflation, and 6-minute walk distance in patients with COPD and a control group

BACKGROUND

In COPD, a decreased inspiratory capacity to total lung capacity ratio (IC/TLC) is associated with dynamic hyperinflation and poor exercise capacity. The association with upper-extremity force measured by handgrip strength (HGS) and 6-min walk distance (6MWD) has not been previously described. We hypothesized that IC/TLC affects muscle strength in the upper and lower extremities, affecting HGS and 6MWD.

METHODS

We prospectively measured lung function, HGS, and 6MWD in 27 patients with COPD and 12 healthy nonsmokers twice, 1 year apart. The patients were classified according to level of hyperinflation: IC/TLC > 25% or IC/TLC ≤ 25%.

RESULTS

Patients with COPD had reduced lung function, static hyperinflation, and reduced HGS and 6MWD compared with the control subjects on both evaluations (P < .01). There was a statistically significant deterioration in HGS, IC/TLC, and 6MWD after 1-year follow-up in the COPD compared with the control group (P < .001). More hyperinflation (IC/TLC < 0.25) was associated with lower HGS and 6MWD (P < .001). Changes in IC/TLC correlated with changes in HGS (r = 0.429, P < .05). Multivariate analysis determined that IC/TLC is an independent factor associated with HSG and 6MWD.

CONCLUSIONS

HGS and 6MWD are reduced in patients with COPD, particularly in those with hyperinflation and evidence of longitudinal deterioration not seen in control subjects. This finding suggests that resting hyperinflation may exert a detrimental effect on cardiac function and plays a role in reduced exercise performance in patients with COPD.

Effects of dynamic hyperinflation on exercise capacity and quality of life in stable COPD patients

BACKGROUND AND AIMS

Dynamic hyperinflation (DH) is an important pathophysiological characteristic of chronic obstructive pulmonary disease (COPD). There is increasing evidence that DH has negative effects on exercise performance and quality of life. The objective of this study was to explore effects of DH on exercise capacity and quality of life in stable COPD patients.

METHODS

Fifty-eight COPD patients and 20 matched healthy individuals underwent pulmonary function test, 6-min walk test and symptom-limited cardiopulmonary exercise test (CPET). End-expiratory lung volume/total lung capacity ratio (EELVmax/TLC) at peak exercise of CPET was evaluated, and EELVmax/TLC ≥ 75% was defined as 'severe dynamic hyperinflation (SDH)'.

RESULTS

Of the 58 patients studied, 29 (50.0%) presented with SDH (SDH+ group, EELVmax/TLC 79.60 ± 3.60%), having worse maximal exercise capacity reflected by lower peakload, maximal oxygen uptake (VO2 max), maximal carbon dioxide output (VCO2 max) and maximal minute ventilation (VEmax) than did those without SDH (SDH- group, EELVmax/TLC 67.44 ± 6.53%). The EELVmax/TLC ratio at peak exercise had no association with variables of pulmonary function and 6-min walk distance (6MWD), but correlated inversely with peakload, VO2 max, VCO2 max and VEmax (r = -0.300~-0.351, P < 0.05). Although no significant differences were observed, patients with EELVmax/TLC ≥ 75% tended to have higher COPD assessment test score (15.07 ± 6.55 vs 13.28 ± 6.59, P = 0.303).

CONCLUSIONS

DH develops variably during exercise and has a greater impact on maximal exercise capacity than 6MWD, even in those with the same extent of pulmonary function impairment at rest.

A review of the effectiveness of psychological interventions used for anxiety and depression in chronic obstructive pulmonary disease

BACKGROUND

Anxiety and depression are recognised co-morbidities associated with COPD and have been related to poor health outcomes. Therapies to relieve anxiety and depression are currently not detailed in clinical guidelines.

METHODS

A systematic review of psychological interventions for anxiety and depression in adults with COPD was conducted. Meta-analysis utilising the random effects model was undertaken for 4 studies that employed the same psychological intervention type, Cognitive Behavioural Therapy (CBT).

RESULTS

Seven studies met the inclusion criteria. Four studies used CBT. Included studies utilised psychotherapy, uncertainty management and minimal psychological therapy. 70% of participants were male. Many studies had poor methodological quality. The meta-analysis showed a small decrease in symptoms for both anxiety (SMD -0.49, 95% CI -1.04, 0.06, P=0.08, n=193) and depression (SMD -0.37, 95% CI -0.86, 0.11, P=0.13, n=193). No change occurred when sensitivity analyses were conducted.

CONCLUSION

Anxiety and depression in COPD patients are known to impact on health outcomes. Effective psychological interventions such as CBT may assist people with COPD in reducing psychological burden. There remains a need for well-designed studies to provide substantive evidence for the use of psychological interventions in this patient population.

The effects of dynamic hyperinflation on CT emphysema measurements in patients with COPD

OBJECTIVES

Dynamic hyperinflation (DH) significantly affects dyspnea and intolerance to exercise in patients with chronic obstructive pulmonary disease (COPD). Quantitative computed tomography (QCT) of the chest is the modality of choice for quantification of the extent of anatomical lung damage in patients with COPD. The purpose of this article is to assess the effects of DH on QCT measurements.

METHODS

The study sample comprised patients with Global initiative for Chronic Obstructive Lung Disease (GOLD) stages III and IV COPD referred for chest CT. We examined differences in total lung volume (TLV), emphysema volume (EV), and emphysema index (EI) determined by QCT before and after DH induction by metronome-paced tachypnea (MPT). Initial (resting) and post-MPT CT examinations were performed with the same parameters.

RESULTS

Images from 66 CT scans (33 patients) were evaluated. EV and EI, but not TLV, increased significantly (p<0.0001) after DH induction.

CONCLUSION

QCT showed significant increases in EV and EI after MPT-induced DH in patients with GOLD stages III and IV COPD. For longitudinal assessment of patients with COPD using QCT, we recommend the application of a pre-examination rest period, as DH could mimic disease progression. QCT studies of the effects of DH-preventive therapy before exercise could expand our knowledge of effective measures to delay DH-related progression of COPD.

ACCORD COPD II: a randomized clinical trial to evaluate the 12-week efficacy and safety of twice-daily aclidinium bromide in chronic obstructive pulmonary disease patients

BACKGROUND AND OBJECTIVES

Aclidinium bromide is a long-acting muscarinic antagonist approved for the long-term maintenance treatment of bronchospasm associated with chronic obstructive pulmonary disease (COPD). This 12-week phase III study evaluated efficacy and tolerability of aclidinium 200 or 400 μg in patients with moderate-to-severe COPD.

METHODS

In this double-blind study, 544 patients with COPD were randomized to placebo or twice-daily aclidinium 200 or 400 μg administered by Genuair(®)/Pressair(®). Lung function, health status [measured by the St. George's Respiratory Questionnaire (SGRQ)], dyspnea [measured using the Transition Dyspnea Index (TDI)], and safety were assessed throughout the study.

RESULTS

Mean changes from baseline in morning trough forced expiratory volume in 1 s (FEV(1)) at week 12 (primary endpoint) were significantly higher for aclidinium than for placebo (200 μg, 51 mL; 400 μg, 72 mL; both p < 0.05). Aclidinium also significantly improved other lung function outcomes. At week 12, improvements from baseline were observed with aclidinium in SGRQ total score (200 μg, -6.0; 400 μg, -5.4) and TDI focal score (200 μg, 1.0; 400 μg, 1.3). Furthermore, clinically important improvements in SGRQ total and TDI focal scores were achieved by 45 and 51 % of patients, respectively, who received aclidinium 400 μg, with a significant difference versus placebo for TDI (p < 0.05). Anticholinergic-related adverse events (e.g., dry mouth) were infrequent, occurring <2 % for any event in any treatment group. Both aclidinium doses were well tolerated.

CONCLUSION

This study demonstrates efficacy and safety of aclidinium in COPD patients. Unexpected baseline imbalances between treatment groups may have impacted the aclidinium treatment benefit in this study.

Oxygen and ventilatory output during several activities of daily living performed by COPD patients stratified according to disease severity

OBJECTIVES

To measure the oxygen and ventilatory output across all COPD stages performing 18 common ADL and identify the activities that present the highest metabolic and ventilatory output as well as to compare the energy expenditure within each disease severity.

MATERIALS AND METHODS

Metabolic (VO2 and VCO2), ventilatory (f and VE), cardiovascular (HR) and dyspnea (Borg score) variables were assessed in one hundred COPD patients during the completion of eighteen ADL grouped into four activities domains: rest, personal care, labor activities and efforts.

RESULTS

The activities with the highest proportional metabolic and ventilatory output (VO2/VO2max and VE/MVV) were walking with 2.5 Kg in each hand and walking with 5.0 Kg in one hand. Very severe patients presented the highest metabolic, ventilatory output and dyspnea than mild patients (p<0.05).

CONCLUSIONS

COPD patients present an increased proportion of energy expenditure while performing activities of daily living. The activities that developed the highest metabolic and ventilatory output are the ones associated to upper and lower limbs movements combined. Very severe patients present the highest proportional estimated metabolic and ventilatory output and dyspnea. Activities of daily living are mainly limited by COPD's reduced ventilatory reserve.

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.

Dynamic hyperinflation correlates with exertional oxygen desaturation in patients with chronic obstructive pulmonary disease

BACKGROUND

Dynamic hyperinflation (DH) causes exercise limitation and exertional dyspnea in patients with chronic obstructive pulmonary disease (COPD). Exertional desaturation (ED) also occurs commonly in COPD but neither routine physiologic parameters nor imaging predict ED accurately. In this study we evaluated the relationship between DH and ED during 6-min walk testing (6MWT).

METHODS

We measured ED and DH in patients with stable COPD. SpO2 was measured by continuous pulse oximetry during 6MWT. ED was defined as a decline in SpO2 (ΔSpO2) ≥4 %. DH was determined by measuring inspiratory capacity (IC) before and after the 6MWT using a handheld spirometer. DH was defined as ΔIC >0.0 L. We correlated DH and ED with clinical and pulmonary physiologic variables by regression analysis, χ (2), and receiver operator curve (ROC) analysis.

RESULTS

Thirty males [age = 65 ± 9.4 years, FEV1 % predicted = 48 ± 14 %, and DLCO % predicted = 50 ± 21 % (mean ± SD)] were studied. ΔSpO2 correlated with ΔIC (r = 0.49, p = 0.005) and age (r = 0.39, p = 0.03) by univariate analysis; however, only ΔIC correlated on multivariate regression analysis (p = 0.01). ΔSpO2 did not correlate with FEV1, FVC, FEF25-75, RV, DLCO % predicted, BMI, smoking, BORG score, or distance covered in 6MWT. DH strongly correlated with ED (p = 0.001). On ROC analysis, DH had an area under the curve of 0.92 for the presence of ED (sensitivity = 90 %; specificity = 77 %, p < 0.001).

CONCLUSION

Routine pulmonary function test results and clinical variables did not correlate with ED in patients with stable COPD. Dynamic hyperinflation strongly correlates with exertional desaturation and could be a reason for this desaturation.

Effects of body mass index on task-related oxygen uptake and dyspnea during activities of daily life in COPD

BACKGROUND

Patients with COPD use a higher proportion of their peak aerobic capacity during the performance of domestic activities of daily life (ADLs) compared to healthy peers, accompanied by a higher degree of task-related symptoms. To date, the influence of body mass index (BMI) on the task-related metabolic demands remains unknown in patients with COPD. Therefore, the aim of our study was to determine the effects of BMI on metabolic load during the performance of 5 consecutive domestic ADLs in patients with COPD.

METHODOLOGY

Ninety-four COPD patients and 20 healhty peers performed 5 consecutive, self-paced domestic ADLs putting on socks, shoes and vest; folding 8 towels; putting away groceries; washing up 4 dishes, cups and saucers; and sweeping the floor for 4 min. Task-related oxygen uptake and ventilation were assessed using a mobile oxycon, while Borg scores were used to assess task-related dyspnea and fatigue.

PRINCIPAL FINDINGS

1. Relative task-related oxygen uptake after the performance of domestic ADLs was increased in patients with COPD compared to healthy elderly, whereas absolute oxygen uptake is similar between groups; 2. Relative oxygen uptake and oxygen uptake per kilogram fat-free mass were comparable between BMI groups; and 3. Borg symptom scores for dyspnea en fatigue were comparable between BMI groups.

CONCLUSION

Patients with COPD in different BMI groups perform self-paced domestic ADLs at the same relative metabolic load, accompanied by comparable Borg symptom scores for dyspnea and fatigue.

Clinical phenotypes of COPD: identification, definition and implications for guidelines

The term phenotype in the field of COPD is defined as "a single or combination of disease attributes that describe differences between individuals with COPD as they relate to clinically meaningful outcomes". Among all phenotypes described, there are three that are associated with prognosis and especially are associated with a different response to currently available therapies. There phenotypes are: the exacerbator, the overlap COPD-asthma and the emphysema-hyperinflation. The exacerbator is characterised by the presence of, at least, two exacerbations the previous year, and on top of long-acting bronchodilators, may require the use of antiinflammatory drugs. The overlap phenotype presents symptoms of increased variability of airflow and incompletely reversible airflow obstruction. Due to the underlying inflammatory profile, it uses to have a good therapeutic response to inhaled corticosteroids in addition to bronchodilators. Lastly, the emphysema phenotype presents a poor therapeutic response to the existing antiinflammatory drugs and long-acting bronchodilators together with rehabilitation are the treatments of choice. Identifying the peculiarities of the different phenotypes of COPD will allow us to implement a more personalised treatment, in which the characteristics of the patients, together with their severity will be key to choose the best treatment option.

Six-minute walk distance predictors, including CT scan measures, in the COPDGene cohort

BACKGROUND

Exercise tolerance in COPD is only moderately well predicted by airflow obstruction assessed by FEV(1). We determined whether other phenotypic characteristics, including CT scan measures, are independent predictors of 6-min walk distance (6MWD) in the COPDGene cohort.

METHODS

COPDGene recruits non-Hispanic Caucasian and African American current and ex-smokers. Phenotyping measures include postbronchodilator FEV(1) % predicted and inspiratory and expiratory CT lung scans. We defined % emphysema as the percentage of lung voxels < -950 Hounsfield units on the inspiratory scan and % gas trapping as the percentage of lung voxels < -856 Hounsfield units on the expiratory scan.

RESULTS

Data of the first 2,500 participants of the COPDGene cohort were analyzed. Participant age was 61 ± 9 years; 51% were men; 76% were non-Hispanic Caucasians, and 24% were African Americans. Fifty-six percent had spirometrically defined COPD, with 9.3%, 23.4%, 15.0%, and 8.3% in GOLD (Global Initiative for Chronic Obstructive Lung Disease) stages I to IV, respectively. Higher % emphysema and % gas trapping predicted lower 6MWD (P < .001). However, in a given spirometric group, after adjustment for age, sex, race, and BMI, neither % emphysema nor % gas trapping, or their interactions with FEV(1) % predicted, remained a significant 6MWD predictor. In a given spirometric group, only 16% to 27% of the variance in 6MWD could be explained by age, male sex, Caucasian race, and lower BMI as significant predictors of higher 6MWD.

CONCLUSIONS

In this large cohort of smokers in a given spirometric stage, phenotypic characteristics were only modestly predictive of 6MWD. CT scan measures of emphysema and gas trapping were not predictive of 6MWD after adjustment for other phenotypic characteristics.

Cardiac injury in patients with COPD presenting with dyspnea: a pilot study

PURPOSE

The aim of this pilot study was to test the hypothesis that myocardial ischemia complicates the management of some patients with chest-pain-free chronic obstructive pulmonary disease (COPD) exacerbations.

METHODS

In this prospective, observational, cohort study, patients admitted to a 350-bed community teaching hospital, with dyspnea and a primary diagnosis of COPD exacerbation, were followed for enzymatic and electrocardiographic evidence of myocardial ischemia for the first 24 hours of hospital admission.

RESULTS

A total of 114 patients were studied. Overall, four patients had definite myocardial infarctions, one had definite myocardial ischemia and 14 had possible myocardial ischemia. In multiple logistic regression models, age, number of coronary risk factors, and amount of administered albuterol were not associated with myocardial injury.

CONCLUSION

While unrecognized myocardial injury is relatively rare in patients with an exacerbation of COPD, it occurs frequently enough to warrant some caution since beta-agonists are the mainstays of therapy.