Quantitative Studies of the Human Neonatal Circulation

Abstract

SUMMARY Principles and techniques for the application of indicator‐dilution studies to the newborn period are discussed. A simple method for in vivo dye curve calibration is described, and a modification of the forward triangle factor for cardiac output estimation in this age group is presented: Methods of calculation of cardiac output and shunts are given. Many problems unique to the neonatal period are suited to study by careful application of these techniques.

Quantitative Studies of the Human Neonatal Circulation

“…The procedure and technique used to assess the cardiac output has recently been described in detail (9) and shall only be briefly outlined. After appropriate sterile preparation of the umbilical stump, an infant feeding tube size F 5 was advanced through the umbilical vein and the ductus venoms to the right and subsequently to the left atrium.…”

“…Calibration of the instrument was made according to a technique earlier described (9) using the infants own blood. Quantitative evaluation of the dilution curve was made by use of the forward triangle method (lo), revised in this laboratory for application to the newborn infant (9). Left ventricular minute output was computed as the mean of at least three technically acceptable dye dilution curves.…”

Quantitative Studies of the Human Neonatal Circulation

“…The techniques used for the study of the central as well as peripheral circulation have been described in some detail in foregoing communications ( 8 ) . All infants were investigated laying on the extractable tray of an Isolette1 Incubator.…”

“…The left ventricular output (LVO) was estimated by the dye dilution principle according to methods earlier described (8). Indicator material (CardiogreenB) was injected into the left atrium, blood being sampled from the ascending aorta.…”

“…It has been considered of great importance to study, with the aid of earlier described modifications of the Stewart-Hamilton technique ( 8 ) , the central circulatory pattern of the immature infant with and without pulmonary pathology and relate it to the simultaneously assessed peripheral circulation as well as to earlier reported findings in fullterm infants. It was judged equally important from the pathogenetic and possibly also from therapeutic points of view to elucidate possible differences in the circulatory pattern between these three groups of newborn infants.…”