1990 Fiscal Year Final Research Report Summary
Inhomogeneous Distribution of Pulmonary Gas Transport Caused by Mechanical Ventilation and Asymmetric Lung Pathophysiologies.
| Project/Area Number |
63440057
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
麻酔学
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| Research Institution | University of Tokyo |
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Principal Investigator |
NUMATA Katsuo Dept. of Otolaryngclogy, University of Tokyo, Professor., 医学部・附属病院, 教授 (40048947)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIKAWA Kouki Dept. of Otolaryngology, University of Tokyo. Assistant Professor, 医学部附属病院, 講師 (40114714)
SAWAMURA Shigehito Dept. of Otolaryngology, University of Tokyo. Assistant, 医学部附属病院, 助手
SUZUKAWA Masayuki Dept. of Otolaryngology, University of Tokyo, Assistant Professor, 医学部附属病院, 講師 (00162917)
YAMADA Yoshitsugu Dept. of Otolaryngology, University of Tokyo, Assistant, 医学部附属病院, 助手 (30166748)
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| Project Period (FY) |
1988 – 1990
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| Keywords | inhomogeneous lung pathophysiology / distribution of pulmonary gas transport / high frequency ventilation / constant flow ventilation / asymmetric airway constriction / asymmetric lung lavage / augmented dispersion / 力学的様互作用 |
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| Research Abstract |
The effects of various modes of mechanical ventilation on the distribution of pulmonary gas transport were assessed from the washout of nitrogen-13 by positron emission tomography. During conventional ventilation at 10 /min, vertical gradients of regional ventilation were observed in all levels of transverse sections with dependent regions more ventilated than nondependent regions. During high-frequency ventilation (HFV) over 3 Hz, a central region at the base of the lungs was highly ventilated, with peripheral regions less ventilaed. This characteristic pattern in HFV strongly supports the hypothesis that direct convection of fresh gas is an important mechanism of gas transport. Constant flow ventilation (CFV) had a very inhomogenous distribution of gas transport with a preferential ventilation to dorsal lung regions. This distribution was caused by deeper energy penetration into the bronchial tree in the direction of jet stream, while cardiogenic oscillation facilitated gas transport mainly in pericardial regions. We also developed the experimental system in which the distributions of ventilatory flow (VT) and gas transport (VA) could be simultaneously measured in asymmetric lung disease models (predominantly increased resistance or decreased compliance, respectively). This system proved that inhomogeneous lung pathophysiologies mechanically interact with the ventilatory settings and alter the distribution of VT differently in various ventilatory modes. In spite of inhomogeneous distribution of VT, the distribution of VA became homogeneous with f in high f range, suggesting that dispersive gas transport mechanism was increasingly important with f in HFV.
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