Journal of Applied Physiology, Vol 61, Issue 1 198-209, Copyright © 1986 by American Physiological Society
An analysis of estimation of pulmonary blood flow by the single-breath method
R. Srinivasan
The single-breath method of determining pulmonary blood flow is a simple
technique involving no inert gas or special maneuvers such as rebreathing
or breath holding. The use of this elegant technique has been limited,
however, largely because of questions regarding its accuracy. Previous
analyses of the method have indicated that large errors in the estimated
blood flow could result if data reduction is not handled carefully. In
addition, an uncertain amount of error is introduced, if the CO2 retained
by the lung tissue while measurements are being made is not taken into
account in the calculations. This paper presents a rigorous approach for
estimating the pulmonary blood flow by the single-breath method, which
would minimize considerably the effects of measurement errors and would
also allow for possible CO2 absorption by the lung tissue. It is based on
the exact solution of the underlying equations that describe the dynamics
of gas exchange in the lung. The analytic solution provides insight into
the difficulties involved in extracting the desired information from the
experimental data.
