A simplified method for quantitating left to right shunts from arterial dilution curves

Abstract

This report presents a new, simple and reliable method of quantitating left to right shunts from arterial dilution curves. When indicator (e.g., indocyanine green) is injected centrally (right ventricle or pulmonary artery) and blood is withdrawn rapidly from either the aorta or other central systemic artery, in the presence of a left to right shunt the recorded indicator dilution curve usually shows two discrete peaks: P1 of pulmonary blood flow and P2 of shunt flow. The formula, P2/P1 X 100 has been found to reliably estimate the magnitude of the shunt expressed as percent of pulmonary blood flow. Experimental and clinical data demonstrate that this method is accurate in quantitating shunts from such curves.