Contribution of Respiratory Muscle Oxygen Consumption to Breathing Limitation and Cyspnea

Casán, Pere; Villafranca, C; Kearon, Clive; Campbell, Edward J.; Killian, Kieran J.

doi:10.1155/1997/863215

Cited by 2 publications

(2 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…26,27 Our data further demonstrated an increase in resting V o 2 in our subjects with COPD as compared with individuals without COPD. 28 Breathing at rest in people without pathology requires less than 5% of total V o 2 . 29 -31 This metabolic cost reflects the energy required to support the work of the ventilatory muscles to generate negative pressure in the thoracic cavity for a given combination of airway resistance and lung compliance.…”

mentioning

confidence: 99%

Comparison of the Oxygen Cost of Breathing Exercises and Spontaneous Breathing in Patients With Stable Chronic Obstructive Pulmonary Disease

2003

View full text Add to dashboard Cite

Background and Purpose. The oxygen demand of breathing exercises and the clinical implications have not been studied in detail. In this study, the oxygen cost of 3 common breathing exercises believed to reduce oxygen cost (ie, work of breathing) was compared with that of spontaneous breathing in patients with chronic obstructive pulmonary disease (COPD). Subjects. Thirty subjects with stable, moderately severe COPD participated. Methods. Oxygen consumption (V o 2 ) and respiratory rate (RR) during spontaneous breathing at rest (SB) were recorded for 10 minutes. Subjects then performed 3 breathing exercises in random order, with a rest between exercises: diaphragmatic breathing (DB), pursed-lip breathing (PLB), and a combination of DB and PLB (CB). Oxygen consumption and RR were measured. Results. Mean V o 2 (ϮSD) was lower during the breathing exercises (165.8Ϯ22.3 mL O 2 /min for DB, 164.8Ϯ20.9 mL O 2 /min for PLB, and 167.7Ϯ20.7 mL O 2 /min for CB) compared with SB (174.5Ϯ25.2 mL O 2 /min). Correspondingly, mean RR (ϮSD) was higher during SB (17.3Ϯ4.23 breaths/min), followed by DB (15.0Ϯ4.32 breaths/min), PLB (12.8Ϯ3.53 breaths/min), and CB (11.2Ϯ2.7 breaths/min). Discussion and Conclusion. Given that patients do not spontaneously adopt the breathing pattern with the least V o 2 and the lowest RR, the results suggest that determinants of the breathing pattern other than metabolic demand warrant being a primary focus in patients with COPD. [Jones AYM, Dean E, Chow CCS. Comparison of the oxygen cost of breathing exercises and spontaneous breathing in patients with stable chronic obstructive pulmonary disease. Phys Ther. 2003;83:424 -431 Due to their increased ventilatory demands, people with chronic obstructive pulmonary disease (COPD) have a higher resting oxygen consumption (V o 2 ) than do people without pulmonary disease. 1,2 This higher resting V o 2 may be explained by increased mechanical work of breathing or reduced ventilatory muscle efficiency, or both, in patients with severe COPD. 3 Mechanical work in biological systems is achieved when a force applied to a structure results in movement. The amount of work produced is the product of the force applied and the distance moved. With respect to spontaneous ventilation, the mean pressure generated by the ventilatory muscles is equivalent to the force, and the tidal volume is equivalent to the distance. Ventilatory muscle work is primarily dependent on minute ventilation, airway resistance, and lung compliance, which, in turn, determine ventilatory muscle efficiency and the pattern of breathing. 4 Efficient ventilatory muscle function is equivalent to the attainment of the requisite minute ventilation with the least energy cost.In COPD, the loss of alveolar tethering and elastic recoil contributes to increased lung compliance and impaired lung perfusion. 5 Typically, these changes result from prolonged inhalation of cigarette smoke, which irritates the airways, thus increasing mucous production and airway resistance. Over time, these pathophysiologic chan...

show abstract

mentioning

confidence: 99%

Comparison of the Oxygen Cost of Breathing Exercises and Spontaneous Breathing in Patients With Stable Chronic Obstructive Pulmonary Disease

2003

View full text Add to dashboard Cite

show abstract

“…At the limit, the work and energy costs of breathing differed widely between the conditions. Dyspnea was not uniquely related to the associated energy consumption (56).…”

Section: Dyspneamentioning

confidence: 73%

Research in Exercise Physiology and Dyspnea at McMaster University

Jones

2007

Canadian Respiratory Journal

View full text Add to dashboard Cite

D r EJ Moran Campbell arrived in Hamilton, Ontario, in September 1968, as the founding chairman of the Department of Medicine at McMaster University Medical Centre (Hamilton, Ontario). He had asked me to be the Head of the Regional Respiratory Program, and I followed him two weeks later. We had worked together at the Royal Postgraduate Medical School, Hammersmith Hospital, for several years to develop a system of exercise testing that could be routinely applied to any clinical problem associated with effort intolerance. We also each had our own separate obsessions; Moran's obsession was in dyspnea, and mine was in exercise metabolism. The three research streams-exercise testing, metabolism and dyspnea-gradually gained momentum, largely due to the hard work of graduate students and fellows. In the present brief overview, I hope to acknowledge their contribution as much as the progress we made in these topics.

show abstract

Contribution of Respiratory Muscle Oxygen Consumption to Breathing Limitation and Cyspnea

Cited by 2 publications

References 33 publications

Comparison of the Oxygen Cost of Breathing Exercises and Spontaneous Breathing in Patients With Stable Chronic Obstructive Pulmonary Disease

Comparison of the Oxygen Cost of Breathing Exercises and Spontaneous Breathing in Patients With Stable Chronic Obstructive Pulmonary Disease

Research in Exercise Physiology and Dyspnea at McMaster University

Contact Info

Product

Resources

About