| 摘要 |
A method for determining pulmonary functional residual capacity (FRC). A given amount of indicator gas is delivered into the breathing gases flowing into the lungs of a subject in a selected number of sequential breaths. The amounts of indicator gas delivered during the selected number of breaths are summed to provide a cumulative total ( SIGMA Vin). The amount of indicator gas exhaled in the number of sequential breaths is summed to provide a cumulative total ( SIGMA Vout). An indication of the concentration of indicator gas in the lungs of the subject (FET) is obtained for said two or more breaths. Using the quantities ( SIGMA Vin), ( SIGMA Vout), and (FET) as measured variables, at least two measured value data sets are formed in which the product of the indicator gas concentration (FET) and a regression coefficient comprising the functional residual capacity (FRC) plus the product of the cumulative total of exhaled indicator gas ( SIGMA Vout) and a regression coefficient K equals the cumulative total of the delivered indicator gas ( SIGMA Vin). Multi dimensional regression analysis is carried out using the data sets to obtain values for K and FRC fitted to said data sets. The value FRC so obtained is a determination of function residual capacity.
|
