Elevated O{\textless}sub{\textgreater}2{\textless}/sub{\textgreater} Cost of Ventilation Contributes to Tissue Wasting in {COPD{\textless}xref} {rid={"}AFF1{"}{\textgreater}{\textless}sup{\textgreater}*{\textless}/sup{\textgreater}{\textless}/xref{\textgr

Abstract

Thirty to 50% of all {COPD} patients experience tissue wasting that may be caused by hypermetabolism, but the cause of the perturbed metabolic state is unclear. We hypothesized that the elevated O2 cost of ventilation {(O2} {COV)} may be a contributing factor. All of the data are presented as means {(+/-SEM).} Ten hypoxemic (a {PaO2} of 54+/-3 mm Hg) stable {COPD} patients (an {FEV1/FVC} ratio of 42+/-4%) and five healthy control subjects were studied. The patients were divided into two groups based on nutritional status. Group 1 (n = 6) was malnourished (a body mass index {[BMI]} of 17.6+/-0.7 kg/m2), and group 2 (n = 4) was normally nourished (a {BMI} of 26.0+/-3 kg/m2). The O2 {COV} was determined by measuring the change in the oxygen consumption {(VO2)} and the minute ventilation {(VE)} caused by {CO2-induced} hyperventilation.