Abstract
In the practice of cardiac catheterization, it is difficult to obtain a correct pulmonary arterial wedging partly because the pulmonary arteries narrow down fairly steeply before reaching peripheries, partly because these arteries are rich in ramifications. Therefore, as Dexter already pointed out, it is necessary to establish the criteria, enabling the indentification of true pulmonary arterial wedge pressure (W. P.). The author have investigated such criteria for W. P. in 18 patients and 10 normal adults.1) For correct wedge pressure measurement the following conditions should be fulfilled : blood samples, obtained from wedged catheter after discarding at least the first 5 cc of the blood should have a slightly higher value in oxygen content and quite equal value in hematocrit percentage in comparing with that of systemic arterial blood. The W. P. curve should show typical venous a, c and v-waves.2) In many cases there have been distortion in the W. P. curve caused by the dumping effect of pulmonary vascular beds and by the heart sound or the displacement of catheter due to the ventricular contraction. These distorting effects may be avoided by the correction of the catheter position in the heart, and by the utilization of the manometer, having adequate pressure charateristics or dumping.3) In such criteria, the author have measured normal wedge pressure in 10 normal adults.
