scholarly journals Simple Methods of Estimating Oxygen Consumption of the Respiratory Muscles Used Dead Space

2010 ◽  
Vol 25 (1) ◽  
pp. 45-48
Author(s):  
Kenichi ORIMOTO ◽  
Ayako UEJYO ◽  
Hideaki SENJYU
Keyword(s):  
Oxygen Consumption ◽  
Dead Space ◽  
Respiratory Muscles

Mechanical efficiency of breathing

1960 ◽  
Vol 15 (3) ◽  
pp. 359-362 ◽  
Author(s):  
G. Milic-Emili ◽  
J. M. Petit
Keyword(s):  
Oxygen Consumption ◽  
Tidal Volume ◽  
Dead Space ◽  
Energy Cost ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Mechanical Efficiency ◽  
Mechanical Work ◽  
Closed Circuit ◽  
Simultaneous Measurements

Simultaneous measurements of mechanical work and energy cost of breathing were performed on four normal subjects with ventilation increased by adding dead space. Mechanical work was obtained from simultaneous records of endoesophageal pressure and tidal volume. The associated energy cost was estimated by measuring oxygen consumption of respiratory muscles by means of a closed-circuit spirometer. In all subjects studied and over the range of ventilations involved (ca. 30–110 l/min.), the mechanical efficiency of breathing was found to be in the order of 0.19–0.25. Submitted on July 6, 1959

Aging effect on oxygen consumption of respiratory muscles in humans

1990 ◽  
Vol 69 (1) ◽  
pp. 14-20 ◽  
Author(s):  
T. Takishima ◽  
C. Shindoh ◽  
Y. Kikuchi ◽  
W. Hida ◽  
H. Inoue
Keyword(s):  
Oxygen Consumption ◽  
Dead Space ◽  
Human Subjects ◽  
Minute Ventilation ◽  
Regression Line ◽  
Respiratory Muscles ◽  
Aging Effect ◽  
Forced Expiratory Volume ◽  
Stepwise Multiple Regression ◽  
Wide Range

The first purpose of the present study was to develop a new method to examine oxygen consumption of respiratory muscles (VO2resp) in human subjects. The apparatus consists of an expandable dead space and a respirometer. When the dead space was increased at a constant rate (approximately 100 ml/min), minute ventilation (VE) and VO2resp increased gradually. Because the logarithm of VO2 was found to be approximately linearly related to VE, we characterized this relationship by the slope (logVO2/VE) and the intercept at VE = 0 (VO2met) of the semilog regression line. The second purpose of this study was to examine the relationship between VO2resp and aging. Six anthropometric and spirometric factors (age, height, weight, vital capacity, forced expiratory volume in 1 s, and body surface area) were analyzed in 37 normal subjects by simple and stepwise multiple regression analyses. We found a significant increase in logVO2/VE and a significant decrease in VO2met with age. In conclusion, 1) the present method is convenient to use, and we are able to study VO2resp over a wide range of ventilation without voluntary effort, and 2) age per se is one of the factors accounting for the observed increase in VO2resp with age.

scholarly journals Contribution of Respiratory Muscle Oxygen Consumption to Breathing Limitation and Cyspnea

1997 ◽  
Vol 4 (2) ◽  
pp. 101-107 ◽  
Author(s):  
Pere Casan ◽  
Carlos C Villafranca ◽  
Clive Kearon ◽  
Edward JM Campbell ◽  
Kieran J Killian
Keyword(s):  
Oxygen Consumption ◽  
Dead Space ◽  
Muscle Power ◽  
Sensory Nerve ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Confidence Limits ◽  
Total Oxygen ◽  
Physiological Factors ◽  
Resistive Loading

During exercise, the sustainable activity of large muscle groups is limited by oxygen delivery. The purpose of this study was to see whether the oxygen consumption of the respiratory muscles reaches a similar critical value under maximal resistive loading and hyperventilation. A secondary objective was to see whether dyspnea (estimated discomfort experienced with breathing using the Borg 0-10 scale) and the oxygen consumption of the respiratory muscles are closely related across conditions. This would be expected if intramuscular sensory nerve fibres stimulated as a consequence of metabolic events contributed to this sensation. In six normal subjects the respiratory muscles were progressively activated by the addition of incremental inspiratory resistive loads to a maximum of 300 cm H20×s/L (SD=66.4), and incremental dead space to a maximum of 2638 mL (SD=452), associated with an increase in ventilation to 75.1 L/min (SD=29.79). Each increment was maintained for 5 mins to allow the measurement of oxygen uptake in a steady state. During resistive loading total oxygen consumption increased from 239 mL/min (SD=38.2) to 299 mL/min (SD=52.3) and dyspnea increased to "very severe" (Borg scale 7.5, SD=1.55). During dead space loading total oxygen consumption increased from 270 mL/min (SD=20.2) to 426 mL/min (SD=81.9) and dyspnea increased to "very severe" (7.1, SD=0.66). Oxygen cost of inspiratory muscle power was 25 mL/watt (95% confidence limits 16.7 to 34.3) with dead space loading and 91 mL/watt (95% confidence limits 54 to 128) with resistive loading. Oxygen consumption did not reach a critical common value in the two types of loading, 60 mL/min (SD 22.3) during maximal resistive loading and 156 mL/min (SD 82.4) during maximal dead space loading (P<0.05). Physiological factors limiting the respiratory muscles are not uniquely related to oxygen consumption and appear to be expressed through the activation of sensory structures, perceptually manifested as dyspnea.

Oxygen Consumption of Respiratory Muscles in Patients With COPD

CHEST Journal ◽  
1994 ◽  
Vol 105 (3) ◽  
pp. 790-797 ◽  
Author(s):  
Chiyohiko Shindoh ◽  
Wataru Hida ◽  
Yoshihiru Kikuchi ◽  
Osamu Taguchi ◽  
Hiroshi Miki ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Respiratory Muscles
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