title: Detection of intracardiac left-to-right shunting in adults: a prospective analysis of the variability of the standard indocyanine green technique in patients without shunting.
abstract: Intracardiac left-to-right shunting may be detected and quantitated by an oximetric analysis of blood from the right-sided cardiac chambers and prominent early recirculation of indocyanine green after it is injected into the central venous circulation and sampled from a systemic artery. Although the variability of oximetric measurements has been established in patients without shunting and a range of normal has been determined for the technique, the variability of the indocyanine green method among persons without shunting has not been clarified; as a result, a range of normal for indocyanine green has not been established. In 66 adult patients in whom hydrogen inhalation (an extremely sensitive technique for detecting even very small intracardiac left-to-right shunts) revealed no shunting, indocyanine green curves were generated by injection into the pulmonary artery as blood was sampled from a systemic artery. In these patients the percentage left-to-right shunt (that is, the percentage of pulmonary blood flow reaching the lungs through an intracardiac shunt) (determined with the equation of Carter et al) ranged from -9% to +26% (+7 +/- 8%, mean +/- standard deviation). There was no definable relation between the percentage left-to-right shunt and the indicator dilution measurement of cardiac output. Thus, these data establish a range of normal for the indocyanine green technique of detecting and measuring intracardiac left-to-right shunting. If this technique is to be used reliably to detect shunting, its results must demonstrate a percentage shunt in excess of +26%.
authors.forename: E H
authors.initials: EH
authors.lastname: Niggemann
authors.forename: P T
authors.initials: PT
authors.lastname: Ma
authors.forename: K P
authors.initials: KP
authors.lastname: Sunnergren
authors.forename: M D
authors.initials: MD
authors.lastname: Winniford
authors.forename: L D
authors.initials: LD
authors.lastname: Hillis
mesh_terms: D000328:Adult; D000368:Aged; D002302:Cardiac Output; D004395:Dye Dilution Technique; D005260:Female; D006343:Heart Septal Defects / Q000175:diagnosis*; D006801:Humans; D006859:Hydrogen; D007208:Indocyanine Green; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D011446:Prospective Studies; D012016:Reference Values
chemical_list: D006859:Hydrogen; D007208:Indocyanine Green