title: Continuous cardiac output determination using transtracheal Doppler: initial results in humans.
abstract: Transtracheal Doppler, a procedure developed in the authors' laboratory, provides an estimate of cardiac output in endotracheally intubated dogs. The present study reports initial results in humans with a Doppler probe incorporated into an endotracheal tube. The system was first calibrated by empirically determining phi, the angle of the ultrasound beam with respect to the blood velocity vector. For a best least squares fit for phi, aortic diameters can be calibrated over a range of 22-37 mm. The calibration was then tested in a separate group of patients using the same empirically derived angle to calculate cardiac outputs. The transtracheal Doppler cardiac outputs show good correlation with those obtained by thermodilution over a range of cardiac outputs, 2.69-8.62 1/min, R2 = 0.835.
authors.affiliation: Department of Surgery, University of Minnesota, Minneapolis.
authors.forename: J H
authors.initials: JH
authors.lastname: Abrams
authors.forename: R E
authors.initials: RE
authors.lastname: Weber
authors.forename: K D
authors.initials: KD
authors.lastname: Holmen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002302:Cardiac Output; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D013815:Thermodilution; D014463:Ultrasonography / Q000379:methods*