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- SHIBUYA Izumi
- Department of Physiology, Yamagata University, School of Medicine
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- NIIZEKI Kyuichi
- Department of Physiology, Yamagata University, School of Medicine
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- UCHIDA Katsuo
- Department of Physiology, Yamagata University, School of Medicine
抄録
In pertaining to PO<sub>2</sub> dependency of the pulmonary CO diffusing capacity during rebreathing, the O2 uptake (VO<sub>2</sub>) and cardiac output (Q) were measured at three different PO<sub>2</sub> levels between 100 and 500 Torr. Since the VO<sub>2</sub> measured by an O2 injection method is strongly influenced in hyperoxia by a gas exchange ratio (R), a simulation method using a R- PCO<sub>2</sub> relation during rebreathing was developed. Gas volume in the lung-bag-system needed in the computation was measured from the difference in O2 concentration between before and after injecting a known amount of O2 into the rebreathing circuit. The accuracy of the volume was checked by comparing it with the volume measured successively with a body box. The VO<sub>2</sub> was determined by comparing the simulated O2 and CO2 concentrations in rebreathing gas with the measured ones. The VO<sub>2</sub> significantly increased by rebreathing in hyperoxia. To analyze the VO<sub>2</sub> increase, the Q was computed by dividing the VO<sub>2</sub> by the arteriovenous O2 content difference, which in turn was obtained by dividing the slope of the CO2 dissociation curve by that of the R-PCO<sub>2</sub> line. The Q was almost linearly related to the VO<sub>2</sub>. Since there was no difference in VO<sub>2</sub> in steady state breathing between normoxia and hyperoxia, the increase in VO<sub>2</sub> and Q seemed to occur transiently. This finding is very important in evaluating the PO<sub>2</sub> dependency of the pulmonary diffusing capacity for CO.
収録刊行物
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- The Japanese Journal of Physiology
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The Japanese Journal of Physiology 36 (5), 985-1000, 1986
一般社団法人 日本生理学会
