Daily activities are sufficient to induce dynamic pulmonary hyperinflation and dyspnea in chronic obstructive pulmonary disease patients

Lung Hyperinflation as Treatable Trait in Chronic Obstructive Pulmonary Disease: A Narrative Review

Lung hyperinflation (LH) is a common clinical feature in patients with chronic obstructive pulmonary disease (COPD). It results from a combination of reduced elastic lung recoil as a consequence of irreversible destruction of lung parenchyma and expiratory airflow limitation. LH is an important determinant of morbidity and mortality in COPD, partially independent of the degree of airflow limitation. Therefore, reducing LH has become a major target in the treatment of COPD over the last decades. Advances were made in the diagnostics of LH and several effective interventions became available. Moreover, there is increasing evidence suggesting that LH is not only an isolated feature in COPD but rather part of a distinct clinical phenotype that may require a more integrated management. This narrative review focuses on the pathophysiology and adverse consequences of LH, the assessment of LH with lung function measurements and imaging techniques and highlights LH as a treatable trait in COPD. Finally, several suggestions regarding future studies in this field are made.

Measuring intensity during free-living physical activities in people with chronic obstructive pulmonary disease: a systematic literature review

BACKGROUND

Measuring intensity of physical activity (PA) is important to ensure safety and the effectiveness of PA interventions in chronic obstructive pulmonary disease (COPD).

OBJECTIVE

This systematic review identified which outcomes, outcome measures and instruments have been used to assess single free-living PA-related intensity in people with COPD and compared the intensity level (light, moderate, vigorous) obtained by different outcome measures.

METHODS

PubMed, Scopus, Web of Science, Cochrane Library and EBSCO were searched for original studies of COPD and assessing single free-living PA-related intensity were included. Agreement was calculated as the number of agreements between 2 measures [same intensity level]/ number of comparisons using both measures*100.

RESULTS

We included 43 studies (1282 people with COPD, mean age 66 years, 65% men, 49% FEV_1%pred) and identified 13 outcomes, 46 outcome measures and 22 instruments. The most-reported outcomes, outcome measures and instruments were dyspnoea with the Borg scale 0-10; cardiac function, via heart rate (HR) using HR monitors; and pulmonary gas exchange, namely oxygen consumption (VO₂), using portable gas analysers, respectively. The most frequently assessed PAs were walking and lifting, changing or moving weights/objects. Agreement between the outcome measures ranged from 0 (%VO_2peak vs metabolic equivalent of task [MET]; %HR_peak vs Fatigue Borg; MET vs walking speed) to 100% (%HR_reserve vs dyspnoea Borg; fatigue and exertion Borg vs walking speed). %VO_{2peak/reserve} elicited the highest intensity. Hence, Borg scores, %HR_reserve and MET may underestimate PA-related intensity.

CONCLUSIONS

Various methodologies are used to assess single free-living PA-related intensity and yield different intensity levels for the same PA. Future studies, further exploring the agreement between the different outcome measures of PA-related intensity and discussing their advantages, disadvantages and applicability in real-world settings, are urgent. These would guide future worldwide recommendations on how to assess single free-living PA-related intensity in COPD, which is essential to optimise PA interventions and ensure patient safety.

The effect of unsupported arm elevations on regional chest wall volumes and thoracoabdominal asynchrony in patients with chronic obstructive pulmonary disease

Objective: To compare the effect of unsupported arm elevation (UAE) in different planes on chest wall volumes, thoracoabdominal asynchrony (TAA), ventilatory demands, dyspnea, and arm fatigue in patients with chronic obstructive pulmonary disease (COPD) and healthy subjects. Methods: Twenty-one patients with COPD and healthy-matched subjects performed UAE in shoulder flexion, scaption, abduction, and resting. Pulmonary total and regional chest wall volumes (V_RCp), abdominal rib cage volume, abdominal volume, TAA, and ventilatory demands during arm positions were measured using optoelectronic plethysmography. Results: In both groups, V_RCp and TAA were significantly affected during UAEs compared with the resting position. The healthy subjects had significantly decreased V_RCp (L) (p < 0.05) during scaption (0.14 ± 0.07) and abduction (0.15 ± 0.06) than during flexion (0.18 ± 0.07) and no significantly different TAA between UAEs. The COPD group had no significantly different V_RCp between UAEs, had significantly increased TAA (p < 0.05) during scaption (31.1°±9.5°) and abduction (32.3°±9.9°) than during flexion (29.7°±9.1°); and had significantly worse V_RCp (p = 0.007), TAA (p = 0.0001), ventilatory demands (p < 0.05), dyspnea ((p = 0.03), and arm fatigue (p = 0.002). Conclusions: In patients with COPD, UAE in different planes similarly restricted the upper chest wall volume. Shoulder scaption and abduction significantly impaired TAA, ventilation, dyspnea, and arm fatigue compared with flexion. These results may help to select the appropriate UAE during physical activities.

Dynamic Hyperinflation Impairs Cardiac Performance During Exercise in COPD

PURPOSE

To investigate the correlation between a plateau in minute ventilation (Equation is included in full-text article.)E during cardiopulmonary exercise tests (CPETs) and its impact on cardiac performance.

METHODS

This retrospective study analyzed 2575 CPETs of patients with chronic obstructive pulmonary disease. The study randomly selected 10 patients with a plateau in the (Equation is included in full-text article.)E curve, suggesting dynamic hyperinflation, 10 patients with normal pattern for the (Equation is included in full-text article.)E curve, and 10 healthy persons. Classic CPET variables, the new ventilation hyperinflation index, and the dynamic cardiac constraint index were analyzed.

RESULTS

The patients with dynamic hyperinflation presented with lower ventilation at 100% work rate (P < .0001), without significant differences in (Equation is included in full-text article.)E at 50% and 100% work rate. Patients with dynamic hyperinflation also presented with a lower oxygen pulse (O2 pulse) at 100% (P < .0001), without significant difference in O2 pulse at 50% and 100% work rate. The subjects with dynamic hyperinflation had a higher ventilation hyperinflation index (P < .0001) and dynamic cardiac constraints index (P < .0001). The ventilation hyperinflation index correlated with the dynamic cardiac constraints index (r = 0.81, P < .0001); oxygen pulse variation (r =-0.63, P < .001); (Equation is included in full-text article.)E/(Equation is included in full-text article.)CO2 slope (r =-0.57, P < .01); work rate (r =-0.86, P < .0001); (Equation is included in full-text article.)O2 (r =-0.80, P < .0001), and (Equation is included in full-text article.)E (r =-0.83, P < .0001).

CONCLUSION

There is a correlation between a plateau in the (Equation is included in full-text article.)E during CPET, suggesting hyperinflation, and it has an impact on cardiac performance.

Systemic inflammation in patients of chronic obstructive pulmonary disease with metabolic syndrome

Context:

India has 18% of the global population and an increasing burden of chronic respiratory diseases. The prevalence of Metabolic syndrome (MS) was found to be as high as 39.7% among Indian population. Metabolic syndrome is found to be more common in Chronic Obstructive Pulmonary Disease (COPD) when compared to the general population. This study was done to assess the prevalence of metabolic syndrome in COPD and the association of systemic inflammation in COPD patients with metabolic syndrome.

Methodology:

This study enrolled 150 consecutive consenting patients of stable COPD attending the outpatient pulmonology department. Detailed history, clinical examination, spirometry, and relevant routine laboratory investigations including complete blood count, fasting blood sugar, and lipid profile were done. In addition, hsCRP, Serum lactate and Vitamin D level was assessed in all patients. Diagnosis of COPD and Metabolic syndrome was done according to GOLD guidelines, 2018 and the International Diabetes Federation criteria respectively.

Result:

The prevalence of metabolic syndrome was found to be 27.3% in our COPD patients. The frequency of metabolic syndrome in GOLD stage I, II, III, and IV was 75%, 32%, 17%, and 13.5%, respectively. Logistic regression analysis showed a significant relationship of blood leucocyte count (OR = 0.342, CI = 0.171-0.686), hs-CRP (OR = 0.020, CI = 0.003-0.122), pack years (OR = 1.083, CI = 1.026-1.14) and vitamin D levels (OR = 1.219, CI = 1.093-1.359) with metabolic syndrome in COPD patients.

Conclusion:

Metabolic syndrome is a co-morbidity that is very often overlooked in patients of COPD. Systemic inflammation which is a common characteristic of both COPD and Metabolic syndrome has been found to be an important contributor towards cardiovascular morbidity and mortality.

Can a physical activity similar to activities of daily living cause dynamic hyperinflation and change the thoracoabdominal configuration in patients with chronic obstructive pulmonary disease?

Introduction: COPD is characterized by the ventilatory limitation, with reduction of the inspiratory reserve volume and dynamic hyperinflation (DH), which changes the configuration of the thoracic compartment, resulting in a disadvantage in respiratory muscle kinetics, and reduced functional capacity. The optoelectronic plethysmography (OEP) has been used to monitor changes in thoracoabdominal mobility. The Glittre-ADL test is a short battery of functional tests that simulate activities of daily living. In mild and moderate COPD, the effect of Glittre-ADL on thoracoabdominal kinetics and DH is understudied. Objective: The aim of our study was to evaluate the acute effects of the Glittre-ADL test on lung function and thoracoabdominal mobility using OEP in patients with mild and moderate COPD. Materials and methods: Twenty-five male and female patients between 45 and 80 years of age with COPD were submitted to the exercises that simulated Glittre-ADL test. Spirometry and OEP were performed before and after the test. Results: After the Glittre test, increases were found in EV (p=0.005), percentage of contribution of the abdominal compartment (p=0.054) and expiratory reserve volume (ERV) (p=0.006) and reductions were found in the contribution of the upper thoracic compartment (p=0.008) and inspiratory capacity (IC) (p=0.040). Conclusion: The acute effect of ADL was a change in thoracoabdominal kinetics, especially the percentage of contribution of the abdominal compartment, as demonstrated by OEP. These findings, together with the reduction in IC and increase in ERV, after the Glittre-ADL test suggest the occurrence of DH, even in patients with mild to moderate COPD according to the GOLD classification.

Effect of pulmonary rehabilitation with assistive use of short-acting β2 agonist in COPD patients using long-acting bronchodilators

Background: Assistive use of short-acting β2 agonists (SABAs) reportedly improves exercise tolerance, activities of daily living, and health-related quality of life (HRQOL) in patients with chronic obstructive pulmonary disease (COPD). However, the effect of SABA on physical activity (PA) is unclear.Objective: This study aimed to determine whether assistive use of SABA increases PA and whether additional pulmonary rehabilitation (PR) can aid further improvement.Methods: Twelve outpatients with COPD and dyspnea during daily activities despite regular use of long-acting bronchodilators were enrolled. This study comprised a 2-week pre-intervention investigation, a 12-week investigation of SABA effects, and an 8-week investigation of the additional effects of PR. Assistive use of SABA was allowed up to 4 times per day after the pre-intervention period. PA was measured for 14 consecutive days using an accelerometer sensor. Dyspnea, exercise tolerance, and HRQOL were evaluated at entry, at 4 and 12 weeks after initiating SABA use, and after completing PR.Results: Assistive use of SABA improved breathlessness during daily activities and increased PA (p < .001). PA and HRQOL were also improved following PR (p < .001 and p = .013, respectively).Conclusions: Combined therapy of SABA and PR can increase PA and HRQOL in COPD patients.

Physiopathological relationship between chronic obstructive pulmonary disease and insulin resistance

PURPOSE

Chronic obstructive pulmonary disease (COPD) is characterized by persistent and progressive airflow obstruction that is associated with an abnormal chronic inflammatory response in the airways and lungs to noxious particles. COPD often leads to physical inactivity and deconditioning that added to inappropriate/excessive inflammatory responses leads to systemic consequences. Studies have shown that metabolic syndrome and manifested diabetes are more frequent in COPD than in healthy subjects; a possible explanation is that different pathophysiological aspects of COPD can lead to insulin resistance. Thus, this mini-review aims to present the main studies suggesting a pathophysiological relationship between COPD and insulin resistance.

METHODS

A review of literature was conducted using PubMed and Web of Science databases with the aim of searching for studies supporting a relationship between COPD and insulin resistance.

RESULTS

A physiopathological relationship between COPD and insulin resistance was found, supported in part due to common risk factors presented by these two conditions, such as smoking and physical inactivity. Also, systemic effects (worsening of physical inactivity and sedentary behavior, inflammation and oxidative stress, body composition abnormalities) and the corticosteroid treatment of patients with COPD may play a role.

CONCLUSION

Patients with COPD should be screened for abnormalities in insulin sensitivity in order to reduce morbidity and improve health status in this population.

Physiological Responses and Dynamic Hyperinflation Induced by Unsupported Arm Activities Involved in Multiple-Task Activities of Daily Living Test in Patients With COPD

PURPOSE

This study aimed to analyze the isolated role of unsupported arm activities and the physiological responses and dynamic hyperinflation (DH) induced by activities of daily living in patients with chronic obstructive pulmonary disease. Physiological responses and DH were compared using the Glittre activities of daily living test (TGlittre) and a modified protocol that emphasized unsupported arm activities and excluded squats and bending down to move objects on shelves (TGlittre-M). Data were also compared from the isolated shelf tasks of TGlittre (TSHELF) and TGlittre-M (TSHELF-M).

METHODS

This cross-sectional study included 30 patients with chronic obstructive pulmonary disease who performed the TGlittre, TGlittre-M, TSHELF and TSHELF-M. The physiological responses were evaluated during the 4 protocols and inspiratory capacity was measured before and immediately after the tests for evaluation of DH.

RESULTS

Patients had higher oxygen uptake, ventilatory demand, dyspnea, and DH in the TGlittre than in the TGlittre-M (mean differences: 123 ± 119 mL/min; 0.11 ± 0.10, 1 [-1 to 3], and - 0.14 ± 0.22, respectively; P < .05 for all). Oxygen uptake, ventilatory demand, and dyspnea were also higher in the TSHELF than in the TSHELF-M (mean differences: 408 ± 185 mL/min; 0.26 ± 0.17; 1 [-1 to 3], respectively; P < .05 for all). However, DH was similar for both tasks (P > .05).

CONCLUSIONS

In patients with chronic obstructive pulmonary disease, the physiological demands during unsupported arm activities were lower than during the task performed with squatting and bending down; however, the magnitude of DH did not differ between them. These results suggest that the isolated arm activities contribute less to the TGlittre's physiological requirement than the lower-limb and trunk activities.

Test-retest reliability of the unsupported upper-limb exercise test (UULEX) and 6-min peg board ring test (6PBRT) in healthy adult individuals

BACKGROUND

The unsupported upper-limb exercise (UULEX) and 6-min peg board ring tests (6PBRTs) have been developed to measure peak unsupported arm exercise capacity and arm endurance, respectively, in individuals with chronic obstructive pulmonary disease. These tests are valid and reproducible in this population; however, the reproducibility of healthy adults is currently unknown.

OBJECTIVE

To determine the within-day test-retest reliability of the UULEX and 6PBRT in healthy adults.

METHOD

The study included 41 healthy adults, aged 38.3 ± 17.9 years old, who performed both tests, twice each on the same day, with a 30-min rest in between. Before and immediately after the tests, blood pressure (BP), heart rate (HR), perception of exertion, and arm fatigue were measured. Time to perform the test and number of rings moved were recorded for the UULEX and 6PBRT, respectively.

RESULTS

The UULEX was reproducible on Bland-Altman analysis with lower and upper limits of agreement: 2.40 and -2.49 min, respectively (bias = -0.05; p = 0.817) and intraclass correlation coefficient (ICC) = 0.85 (p < 0.0001) for time in minutes for the first and second tests. The 6PBRT was not reproducible on Bland-Altman analysis with lower and upper limits of agreement of 31.64 and -114.54 (bias = -41.45; p < 0.0001) and ICC = 0.91 (p < 0.0001) for the number of rings moved.

CONCLUSION

UULEX is a reliable test in healthy adults. Only one test is adequate when measuring peak unsupported arm exercise capacity using the UULEX in healthy adults, while more than two tests may be needed to measure arm endurance using the 6PBRT.

Agreement of different reference equations to classify patients with COPD as having reduced or preserved 6MWD

BACKGROUND

Interpretation of the six-minute walk distance (6MWD) is enhanced by using recommended reference equations. Whenever possible, the choice of equation should be region-specific. A potential problem is that different equations for the 6MWD may have been developed for the same population, and it may be complicated to choose the most suitable.

OBJECTIVE

To verify the agreement of different reference equations in classifying patients with Chronic Obstructive Pulmonary Disease (COPD) as having reduced or preserved 6MWD.

METHODS

159 patients with COPD performed the six-minute walk test according to international standardization. They were classified as having reduced 6MWD if it was below the lower limit of normal. Five Brazilian equations (Iwama; Britto1; Britto2; Dourado; Soares) and the two non-Brazilian equations most cited worldwide (Troosters; Enright) were used. The agreement for patients classified as reduced or preserved 6MWD was verified by Cohen's Kappa (pair-to-pair) analysis. The proportion of patients classified as having reduced walked distance was compared by the Chi-squared test.

RESULTS

Agreement between equations varied largely in classifying subjects as having reduced or preserved 6MWD (Kappa: 0.10-0.82). Brazilian equations with the highest agreement were Iwama, Britto1 and Britto2 (Kappa>0.75). The proportion of patients classified as having reduced 6MWD was statistically similar only between equations in which the agreement was higher than 0.70.

CONCLUSION

Even reference equations from the same country vary considerably in the classification of reduced or preserved 6MWD, and it is recommended that the region-specific ones be used as they give with higher agreement for similar and comparable interpretation of the patients' functional exercise capacity.

Brazilian studies on pulmonary function in COPD patients: what are the gaps?

BACKGROUND

COPD is a major cause of death and morbidity worldwide, and is characterized by persistent airflow obstruction. The evaluation of obstruction is critically dependent on sensitive methods for lung-function testing. A wide body of knowledge has been accumulated in recent years showing that these methods have been significantly refined and seems promising for detection of early disease.

OBJECTIVES

This review focuses on research on pulmonary function analysis in COPD performed in Brazil during this century.

MATERIALS AND METHODS

The literature was searched using a systematic search strategy limited to English language studies that were carried out in Brazil from the year 2000 onward, with study objectives that included a focus on lung function.

RESULTS

After we applied our inclusion and exclusion criteria, 94 articles addressed our stated objectives. Among the new methods reviewed are the forced-oscillation technique and the nitrogen-washout test, which may provide information on small-airway abnormalities. Studies investigating the respiratory muscles and thoracoabdominal motion are also discussed, as well as studies on automatic clinical decision-support systems and complexity measurements. We also examined important gaps in the present knowledge and suggested future directions for the cited research fields.

CONCLUSION

There is clear evidence that improvements in lung-function methods allowed us to obtain new pathophysiological information, contributing to improvement in our understanding of COPD. In addition, they may also assist in the diagnosis and prevention of COPD. Further investigations using prospective and longitudinal design may be of interest to elucidate the use of these new methods in the diagnosis and prevention of 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.

Reproducibility of Ventilatory Parameters, Dynamic Hyperinflation, and Performance in the Glittre-ADL Test in COPD Patients

BACKGROUND

This study aimed to investigate the reproducibility of the ventilatory parameters and dynamic hyperinflation (DH) induced by the Glittre ADL-test (TGlittre) in chronic obstructive pulmonary disease (COPD) patients.

METHODS

Twenty-three patients with COPD underwent anthropometry, spirometry, TGlittre (TGlittre1 and TGlittre2) and pre- and post-test slow vital capacity. During the tests the ventilatory response was evaluated.

RESULTS

Regarding the TGlittre reproducibility, 87% of patients had a better performance in TGlittre2, and reduced on average 0.34 minute ± 0.62 (p = 0.01) from TGlittre1 time to TGlittre2, showing a learning effect of 6.34%. The difference average between tests was correlated with the time spent in TGlittre1 (r = -0.52; p < 0.05). The TGlittre time was statistically reproducible (intraclass correlation coefficient = 0.97; p < 0.001). Final ventilation parameters and their variations presented low-to-high reproducibility, except respiratory rate. The DH was similar (p > 0.05) in both tests, with low reproducibility in percentage, while in liters it was not reproducible.

CONCLUSIONS

The TGlittre time and ventilatory parameters are reproducible, while DH is variable in COPD patients. A 6-7% learning effect was shown, and it is recommended to perform two tests.

Postural control in chronic obstructive pulmonary disease: a systematic review

Patients with chronic obstructive pulmonary disease (COPD) fall frequently, although the risk of falls may seem less important than the respiratory consequences of the disease. Nevertheless, falls are associated to increased mortality, decreased independence and physical activity levels, and worsening of quality of life. The aims of this systematic review was to evaluate information in the literature with regard to whether impaired postural control is more prevalent in COPD patients than in healthy age-matched subjects, and to assess the main characteristics these patients present that contribute to impaired postural control.

Dynamic hyperinflation during activities of daily living in COPD patients

The objective of this study was to investigate whether some activities of daily living (ADLs) usually related to dyspnea sensation in patients with chronic obstructive pulmonary disease (COPD) are associated with dynamic lung hyperinflation (DH) and whether the use of simple energy conservation techniques (ECTs) might reduce this possible hyperinflation. Eighteen patients (mean age: 65.8 ± 9.8 years) with moderate-to-severe COPD performed six ADLs (walking on a treadmill, storing pots, walking 56 meters carrying a 5-kilogram weight, climbing stairs, simulating taking a shower, and putting on shoes) and had their inspiratory capacity (IC) measured before and after each task. The patients were moderately obstructed with forced expiratory volume in 1 second (FEV1): 1.4 ± 0.4 L (50% ± 12.4); FEV1/forced vital capacity: 0.4 ± 8.1; residual volume/total lung capacity: 52.7 ± 10.2, and a reduction in IC was seen after all six activities ( p < 0.05): (1) going upstairs, 170 mL; (2) walking 56 meters carrying 5 kilogram weight, 150 mL; (3) walking on a treadmill without and with ECT, respectively, 230 mL and 235 mL; (4) storing pots without and with ECT, respectively, 170 mL and 128 mL; (5) taking a shower without and with ECT, respectively, 172 mL and 118 mL; and (6) putting on shoes without and with ECT, respectively, 210 mL and 78 mL). Patients with moderate to severe COPD develop DH after performing common ADLs involving the upper and lower limbs. Simple ECTs may avoid DH in some of these ADLs.

Examining the role of activity, exercise, and pharmacology in mild COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide and, although it is a preventable and treatable disease, it often remains undiagnosed in patients with mild disease. It is now evident that pathologic changes and physiologic impairment start early in disease progression, and even patients with mild airflow limitation have impairment in the form of exertional dyspnea, general fatigue, and exercise intolerance. Primary care physicians are optimally positioned to recognize these progressive activity restrictions in their patients, usually involving little more than a detailed patient history and a simple symptom questionnaire. Once a patient with persistent activity-related dyspnea has been diagnosed with COPD, bronchodilators can effectively address expiratory airflow limitation and lung hyperinflation that underlie symptoms. These pharmacologic interventions work in conjunction with nonpharmacologic interventions, including smoking cessation, exercise training, and pulmonary rehabilitation. Although the benefits of exercise intervention are well established in patients with more severe COPD, a small amount of new data is emerging that supports the benefits of both pharmacologic treatment and exercise training for improving exercise endurance in patients with mild-to-moderate COPD. This review examines the growing body of data that suggests that early identification-most likely by primary care physicians-and appropriate intervention can favorably impact the symptoms, exercise tolerance, health status, quality of life, hospitalizations, and economic costs of COPD.

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.

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.