The effect of recirculation on the shape of the arterial concentration curve after an instantaneous injection of indicator

Document Type

Article

Publication Date

1-1-1959

Publication Title

The International Journal Of Applied Radiation And Isotopes

ISSN

0020708X

Abstract

We present our observations on 15 patients at cardiac catherization showing by two-site sampling that recirculating indicator begins to influence the downslope on the cardiac output curve from 1 to 9 sec before the point of obvious recirculation. The concentration points of the last 38 per cent of the exponential portion of the downslope were slightly increased resulting in a decreased slope. The result is a false low value for the cardiac output estimated at 1·2 ± 1·5 per cent. This is well within the limits of tolerance for the method and less than that proposed on theoretical basis by other investigators. The total error is probably greater when the injection is made into a vein rather than into the heart because of the slower rate of decline of the downslope, but insufficient data are available in this study for statistical evaluation. A comparison was made of the various portions of the arterial concentration curves. The vein-right ventricle, right ventricle-brachial artery, and vein-brachial artery arterial concentration curves are compared as to appearance time, peak concentration time, mean transit time, cardiac output, and central volume as measured by both the mean transit time and slope method. This comparison shows that the cardiac output measurement as calculated from the vein-right ventricle curve and right ventricle-brachial artery curve are larger than that calculated from an arterial concentration curve of the circulation from vein-brachial artery. The values of the central volumes by the MTT method of these two portions of the circulation when summed average slightly larger than that measured by the vein-brachial artery curve. © 1959.

Volume

7

Issue

2

First Page

97

Last Page

100

DOI

10.1016/0020-708X(59)90154-1

PubMed ID

13812653

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