一种校正气体密度对最大呼气流量率影响的方法。

A method to correct for the influence of gas density on maximal expiratory flow rate.

作者信息

Nielsen T M, Pedersen O F

出版信息

Acta Physiol Scand. 1976 Sep;98(1):123-30. doi: 10.1111/j.1748-1716.1976.tb10311.x.

DOI:10.1111/j.1748-1716.1976.tb10311.x

Abstract

Maximal expiratory flow rate (Vmax) was measured at 20, 35, 50, 65, and 80% vital capacity in 4 young healthy subjects breathing air, SF6/O2, and He/O2 mixtures. The flows of SF6/O2 and He/O2 were corrected to normal alveolar gasflow by means of only the density of the gases. The values for normal alveolar gasflow and corrected SF6/O2 flow were identical at 35% VC and larger volumes while the values for normal alveolar gasflow and corrected He/O2 flow were not. The results indicate that in young healthy subjects it is possible to correct Vmax at lung volumes above 35% VC for the changes induced by an increase in density of the gas breathed, provided viscosity is not much changed. Without correction, Vmax after O2-breathing will be underestimated by about 6%, compared with Vmax for normal alveolar gas, whereas a change in alveolar CO2 concentrations between 3 and 9% only causes a 1% decrease of Vmax.

摘要

在4名年轻健康受试者呼吸空气、SF6/O2和He/O2混合气时，于肺活量的20%、35%、50%、65%和80%处测量最大呼气流量（Vmax）。SF6/O2和He/O2的流量仅通过气体密度校正为正常肺泡气流。正常肺泡气流值与校正后的SF6/O2流量值在肺活量35%及更大容积时相同，而正常肺泡气流值与校正后的He/O2流量值则不同。结果表明，在年轻健康受试者中，若气体黏度变化不大，对于高于肺活量35%的肺容积，因所呼吸气体密度增加引起的变化，有可能校正Vmax。未经校正时，与正常肺泡气体的Vmax相比，吸氧后的Vmax将被低估约6%，而肺泡二氧化碳浓度在3%至9%之间的变化仅导致Vmax降低1%。