Related Experiment Videos
Elevated O2 cost of ventilation contributes to tissue wasting in COPD
E T Mannix1, F Manfredi, M O Farber
1Division of Pulmonary, Allergy, Critical Care and Occupational Medicine, Indiana University Department of Medicine, The National Institute for Fitness and Sport, Indianapolis 46202, USA. EMANNIX@IUPUI.EDU
Chest
|March 20, 1999
Summary
The elevated oxygen cost of ventilation (O2 COV) in COPD patients is linked to increased metabolic rate and tissue wasting. This study found a significant correlation between O2 COV, resting energy expenditure, and body mass index in malnourished COPD patients.
Area of Science:
- Pulmonary Medicine
- Metabolic Research
- Respiratory Physiology
Background:
- Chronic Obstructive Pulmonary Disease (COPD) affects 30-50% of patients with tissue wasting.
- The cause of hypermetabolism and perturbed metabolic state in COPD is not fully understood.
- Elevated oxygen cost of ventilation (O2 COV) is hypothesized as a contributing factor.
Purpose of the Study:
- To investigate the relationship between O2 COV and metabolic state in stable COPD patients.
- To determine if O2 COV contributes to tissue wasting in COPD.
- To explore correlations between O2 COV, nutritional status, and lung function.
Main Methods:
- Studied 10 hypoxemic stable COPD patients and 5 healthy controls.
- Divided COPD patients into malnourished (Group 1) and normally nourished (Group 2) based on BMI.
- Measured O2 COV by assessing changes in oxygen consumption (VO2) and minute ventilation (VE) during CO2-induced hyperventilation.
Main Results:
- Malnourished COPD patients (Group 1) exhibited significantly higher O2 COV compared to normally nourished patients (Group 2) and controls.
- Group 1 also showed higher resting VO2 and resting energy expenditure (REE) % predicted.
- Significant negative correlations were found between O2 COV and BMI, and positive correlations between O2 COV and REE % predicted.
Conclusions:
- Elevated O2 COV is associated with increased metabolic rate in COPD patients.
- The increased metabolic rate, driven by O2 COV, adversely affects nutritional status and contributes to tissue wasting.
- O2 COV is also correlated with impaired lung function (FEV1/FVC ratio) in COPD.