Measurement of cardiac output using improved chromatographic analysis of sulfur hexafluoride (sf₆)

A constant current variable frequency pulsed electron capture detector has been incorporated into the gas Chromatographic analysis of trace amounts of sulfur hexafluoride (SF ₆) in water and blood. The resulting system offers a broader effective operating range than more conventional electron capture units and has been utilized for measurements of cardiac output employing constant-rate infusion of dissolved SF ₆. The SF ₆ technique has been validated against direct volumetric measurements of cardiac output in a canine right-heart bypass preparation and used subsequently for rapidly repeated measurements in conscious animals and man.