Reduced Mechanical Efficiency in Chronic Obstructive Pulmonary Disease but Normal Peak V̇<scp>o</scp><sub>2</sub>with Small Muscle Mass Exercise

Richardson, Russell S.; Leek, Bryan T.; Gavin, Timothy P.; Haseler, Luke J.; Mudaliar, Sundar; Henry, Robert R.; Mathieu-Costello, Odile; Wagner, Peter D.

doi:10.1164/rccm.200305-627oc

Cited by 153 publications

(197 citation statements)

References 65 publications

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“…There is a large body of evidence, much of which is beyond the scope of this review, which supports the view that skeletal muscle dysfunction is a major contributor to exercise limitation in COPD [50][51][52][53][54]. It could therefore be hypothesised that the effects observed on muscle performance in nonanaemic athletes with EPO may also be seen in COPD patients.…”

Section: Skeletal Muscle Functionsupporting

confidence: 55%

The potential impact of anaemia of chronic disease in COPD

Similowski

Agustí²,

MacNee³

et al. 2006

European Respiratory Journal

148

107

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Anaemia of chronic disease (ACD), with chronically low levels of circulating haemoglobin, is an immune driven abnormality that occurs in many inflammatory diseases, and also in chronic heart failure. Although chronic obstructive pulmonary disease (COPD) is ''traditionally'' associated with polycythaemia, the systemic inflammation that is now recognised as a feature of COPD makes it a possible cause of ACD. If present in COPD, anaemia could worsen dyspnoea and limit exercise tolerance.Preliminary evidence suggests that anaemia in COPD patients may be more prevalent than expected, concerning 10-15% of patients suffering from severe forms of the disease. A database study conducted in 2,524 COPD patients being prescribed long-term oxygen therapy has shown that a low haematocrit is a strong predictor of survival in this population, before body mass index, and is associated with more hospitalisations and a longer cumulative duration of hospitalisation. COPD patients with low haemoglobin levels have a poorer prognosis than COPD patients with normal haemoglobin levels in the event of acute gastrointestinal bleeding or after elective aneurysm repair. Raising haemoglobinaemia through transfusion decreases minute ventilation and work of breathing in COPD patients.These preliminary evidences point to the need to study the prevalence of anaemia, and its physiological and clinical impact in chronic obstructive pulmonary disease. When this body of knowledge is available, the question of the putative benefits of raising haemoglobinaemia in chronic obstructive pulmonary disease will have to be addressed.

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Section: Skeletal Muscle Functionsupporting

confidence: 55%

The potential impact of anaemia of chronic disease in COPD

Similowski

Agustí²,

MacNee³

et al. 2006

European Respiratory Journal

148

107

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“…19,20 They used a large part of their breathing reserves and presented a severe increase of V E /V CO 2 measured at anaerobic threshold, which is indicative of ventilatory inefficiency. In association they also presented an accentuated limitation in expiratory flow, and the majority had dynamic hyperinflation.…”

Section: Discussionmentioning

confidence: 99%

“…[15][16][17][18] The V O 2 /heart rate is a surrogate for the systolic volume by the Fick equation: V O 2 ϭ cardiac output ϫ ⌬C(a-v)O 2 , and circulatory power (%V O 2 max ϫ peak systolic blood pressure) is a surrogate for cardiac power (cardiac output ϫ mean arterial pressure ϫ K). [16][17][18][19][20][21] …”

Section: What This Paper Contributes To Our Knowledgementioning

confidence: 99%

Ventilatory Inefficiency as a Limiting Factor for Exercise in Patients With COPD

Caviedes¹,

Delgado

Soto³

2012

Respir Care

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BACKGROUND: Ventilatory inefficiency increases ventilatory demand; corresponds to an abnormal increase in the ratio of minute ventilation (V E ) to CO 2 production (V CO 2 ); represents increased dead space, deregulation of respiratory control, and early lactic threshold; and is associated with expiratory flow limitation that enhances dynamic hyperinflation and may limit exercise capacity. OBJECTIVE: To evaluate the influence of ventilatory inefficiency over exercise capacity in COPD patients. METHODS: Prospective study of 35 COPD subjects with different levels of severity, in whom cardiopulmonary stress test was performed. Ventilatory inefficiency was represented by the V E /V CO 2 relation. Its influence over maximal oxygen consumption (V O 2 max), power (W), and ventilatory threshold was evaluated. Surrogate parameters of cardiac function, like oxygen pulse (V O 2 /heart rate) and circulatory power (%V O 2 max ؋ peak systolic pressure), were also evaluated. RESULTS: Cardiopulmonary stress test was stopped due to dyspnea with elevated V E and marked reduction of breathing reserve. A severe increase in V E /V CO 2 (mean ؎ SD 35.9 ؎ 5.6), a decrease of V O 2 max (mean ؎ SD 75.2 ؎ 20%), and a decrease of W (mean ؎ SD 68.6 ؎ 23.3%) were demonstrated. Twenty-eight patients presented dynamic hyperinflation. Linear regression showed a reduction of 2.04% on V O 2 max (P < .001), 2.6% on W (P < .001), 1% on V O 2 /heart rate (P ‫؍‬ .049), and 322.7 units on circulatory power (P ‫؍‬ .02) per each unit of increment in V E /V CO 2 , respectively. CONCLUSIONS: Ventilatory inefficiency correlates with a reduction in exercise capacity in COPD patients. Including this parameter in the evaluation of exercise limitation in this patient population may mean a contribution toward the understanding of its pathophysiology.

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“…For instance, one study, in which proper control subjects had similar physical activity levels to those of COPD patients, revealed reductions of quadriceps muscle endurance in the COPD patients that cannot be explained by a mere lack of physical activity since reductions in the proportion of type I fi bers in quadriceps muscles of COPD patients are relatively greater than in the control group (Couillard et al 2002). Indeed, while sedentary lifestyle is associated with reduction of quadriceps muscle type I fi ber proportion, from 60%-65% in healthy active control subjects to about 40% in inactive subjects (Proctor et al 1995;Houmard et al 1998), the proportion of type I fi bers in quadriceps muscles of COPD patients reaches as low as 19% (Gosker et al 2002;Allaire et al 2004;Richardson et al 2004). It is also worth noting that prolonged periods of exercise training exerts a relatively small infl uence on the proportion of type I fi bers in quadriceps muscles of COPD patients, and only partially reverses reductions in oxidative enzyme activities (citrate synthase and 3-hydroxyacyl-CoA dehydrogenase) in the muscle (Maltais et al 1996;Whittom et al 1998).…”

Section: Inactivitymentioning

confidence: 98%

Skeletal Muscle Dysfunction in Patients with Chronic Obstructive Pulmonary Disease

2010

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Chronic obstructive pulmonary disease (COPD) is a debilitating disease characterized by infl ammation-induced airfl ow limitation and parenchymal destruction. In addition to pulmonary manifestations, patients with COPD develop systemic problems, including skeletal muscle and other organ-specifi c dysfunctions, nutritional abnormalities, weight loss, and adverse psychological responses. Patients with COPD often complain of dyspnea on exertion, reduced exercise capacity, and develop a progressive decline in lung function with increasing age. These symptoms have been attributed to increases in the work of breathing and in impairments in gas exchange that result from airfl ow limitation and dynamic hyperinfl ation. However, there is mounting evidence to suggest that skeletal muscle dysfunction, independent of lung function, contributes signifi cantly to reduced exercise capacity and poor quality of life in these patients. Limb and ventilatory skeletal muscle dysfunction in COPD patients has been attributed to a myriad of factors, including the presence of low grade systemic infl ammatory processes, nutritional depletion, corticosteroid medications, chronic inactivity, age, hypoxemia, smoking, oxidative and nitrosative stresses, protein degradation and changes in vascular density. This review briefl y summarizes the contribution of these factors to overall skeletal muscle dysfunction in patients with COPD, with particular attention paid to the latest advances in the fi eld. Keywords: skeletal muscles, chronic obstructive pulmonary disease, diaphragm, quadriceps, fatigue, disuse, atrophy, smoking, exercise It has long been recognized that COPD is a systemic disease in which several extrapulmonary manifestations, including cachexia and skeletal muscle dysfunction, contribute to morbidity and mortality. Functionally, skeletal muscle dysfunction in COPD patients is characterized by signifi cant reduction in muscle strength and endurance. It is structurally characterized by loss of muscle mass and cross-sectional area (muscle atrophy), fi ber type distribution (reduction in the proportion of oxidative fi bers and increases in the proportion of glycolytic fi bers), oxidative metabolic capacity (attenuation of mitochondrial enzyme activities and expression) and capillary distribution (signifi cant loss of capillary density). Although disuse and inactivity are important contributors to the pathogenesis of skeletal muscle dysfunction in COPD patients, several other systemic and local factors are also involved. These include systemic infl ammation, malnutrition, corticosteroid usage, hypoxemia, aging, smoking and local factors such as the production of reactive oxygen (ROS) and nitrogen species (RNS) and enhanced protein degradation inside muscle fi bers, a result of increased activities of the proteasomal and lysosomal pathways and activation of calpains and caspases. Evidence of skeletal muscle dysfunction in patients with COPDIt has been well established that skeletal muscle function (strength and endurance) and s...

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Reduced Mechanical Efficiency in Chronic Obstructive Pulmonary Disease but Normal Peak V̇o₂with Small Muscle Mass Exercise

Cited by 153 publications

References 65 publications

The potential impact of anaemia of chronic disease in COPD

The potential impact of anaemia of chronic disease in COPD

Ventilatory Inefficiency as a Limiting Factor for Exercise in Patients With COPD

Skeletal Muscle Dysfunction in Patients with Chronic Obstructive Pulmonary Disease

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Reduced Mechanical Efficiency in Chronic Obstructive Pulmonary Disease but Normal Peak V̇o2with Small Muscle Mass Exercise

Cited by 153 publications

References 65 publications

The potential impact of anaemia of chronic disease in COPD

The potential impact of anaemia of chronic disease in COPD

Ventilatory Inefficiency as a Limiting Factor for Exercise in Patients With COPD

Skeletal Muscle Dysfunction in Patients with Chronic Obstructive Pulmonary Disease

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Product

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Reduced Mechanical Efficiency in Chronic Obstructive Pulmonary Disease but Normal Peak V̇o₂with Small Muscle Mass Exercise