[Pulmonary blood volume. Definition, measurement, normal values].

We propose a simplification of the double-injection method whereby left atrial catheterization is made unnecessary by use of injection of indicator in the pulmonary wedge position instead of into the left atrium. Normal values of PBV range between 204 +/- 51 ml. m-2 and 326 +/- 51 ml. M-2. Such a large scatter is due in all likelihood partly to techniques themselves, partly to the small number of studied subjects, which precludes standardization of normal values according to age, sex and body build. Determination of PBV may help in assessing the overall distensibility of the pulmonary vascular bed, but is of no avail to assess separately the distensibility of arteries, microcirculation, and veins whose respective volumes cannot be measured in vivo for lack of undisputable methods. Morphometric and physiological observations suggest that the measurement of PBV is no avail to estimate changes in caliber of pulmonary arterioles caused by vasoactive stimuli.