Determination of left ventricularoutput in the human newborn in the first two hours of life

Gessner, Ira H.; Krovetz, L. Jerome; Stenger, Vincent G.; Prystowsky, Harry; Benson, Reuel A.; Eitzman, Donald V.

doi:10.1016/s0022-3476(64)80135-9

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“…The indicator used throughout this study was indocyanine green, (Cardiogreen Left-to-right shunts were calculated by three methods for each patient: (1) oxygen saturations and the formula pulmonary arterymixed venous/systemic artery-mixed venous, (2) indicator-dilution curves following injections of dye into the right heart and Carter's3 formula ( fig. 1), and (3) our newly devised formula, which utilizes information obtained from both right and left heart injections of dye.…”

Section: Methodsmentioning

confidence: 99%

A New Method Utilizing Indicator-Dilution Technics for Estimation of Left-to-Right Shunts in Infants

Krovetz

Gessner

1965

Circulation

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IN INFANTS the short circulatory pathways result in rapid pulmonary and systemic circulation times. So rapid is the transit of blood, that in the presence of a left-toright shunt, an indicator injected into the right heart arrives a second time at an arterial sampling site prior to the inscription of the concentration peak. This then results in the lack of discrimination of left-to-right shunts and also completely negates the usual method of the Stewart Hamilton calculation of cardiac outputs.'During the course of an investigation of the cardiovascular hemodynamics in a group of normal neonates,2 the authors found that the usual method3 for calculating left-to-right shunts by indicator-dilution contour yielded erroneously high magnitudes. The formula to be proposed here is based on a modification of a right-to-left shunt formula,4 applied to left heart injections of indicator. This new formula compares favorably to estimates of left-to-right shunts obtained by oximetry. Materials and MethodsAll the patients included in this report underwent cardiac catheterization for diagnostic purposes. Included are 11 infants ranging from 11 days to 10 months in age and from 2.4 to 7.2 Kg. in weight. Each of these children had only a left-to-right shunt that included two patent ductus arteriosus, six ventricular septal defects, and three atrial septal defects. constant rate infusion-withdrawal pump at rates of 16 or 36 ml./min. through a Waters XC250 A densitometer. Galvanometer deflections were recorded on a Minneapolis Honeywell Visicorder, model 1108. Multiple intracardiac and great-vessel blood samples were drawn in every case through a Waters XC-50B cuvette oximeter. The cuvette oximeter was calibrated for each patient by two or more simultaneous measurements of oxygen determined by the Van Slyke-Neill method.Left-to-right shunts were calculated by three methods for each patient: (1) oxygen saturations and the formula pulmonary arterymixed venous/systemic artery-mixed venous,(2) indicator-dilution curves following injections of dye into the right heart and Carter's3 formula ( fig. 1), and (3) our newly devised formula, which utilizes information obtained from both right and left heart injections of dye. This formula encompasses two areas ( fig. 2). Area 1 of the dye curve is assumed to be proportional to the amount of blood flowing in the normal circulatory pathway and in turn is proportional to the product of peak concentration (C0) and build-up time (T.). Area 2 similarly represents the left-to-right shunt pathway and is proportional to the product of peak concentration of the shunt (C.) and the difference between shunt time (T.) and pulmonary circulation time (PCT). This latter value is obtained from the difference in appearance times of sequential right and left heart injections. Obviously, the presence of an additional right-toleft shunt invalidates this procedure. The magnitude of the left-to-right shunt is obtained by dividing area 2 by the sum of area 1 plus area 2, the result being expressed as per cent of pulmon...

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Section: Methodsmentioning

confidence: 99%