title: The use of live three-dimensional Doppler echocardiography in the measurement of cardiac output: an in vivo animal study.
abstract: OBJECTIVE
  The purpose of this study was to investigate whether cardiac output (CO) could be accurately computed from live three-dimensional (3-D) Doppler echocardiographic data in an acute open-chested animal preparation.
  
  
  BACKGROUND
  The accurate measurement of CO is important in both patient management and research. Current methods use invasive pulmonary artery catheters or two-dimensional (2-D) echocardiography or esophageal aortic Doppler measures, with the inherent risks and inaccuracies of these techniques.
  
  
  METHODS
  Seventeen juvenile, open-chested pigs were studied before undergoing a separate cardiopulmonary bypass procedure. Live 3-D Doppler echocardiography images of the left ventricular outflow tract and aortic valve were obtained by epicardial scanning, using a Philips Medical Systems (Andover, Massachusetts) Sonos 7500 Live 3-D Echo system with a 2.5-MHz probe. Simultaneous CO measurements were obtained from an ultrasonic flow probe placed around the aortic root. Subsequent offline processing using custom software computed the CO from the digital 3-D Doppler DICOM data, and this was compared to the gold standard of the aortic flow probe measurements.
  
  
  RESULTS
  One hundred forty-three individual CO measurements were taken from 16 pigs, one being excluded because of severe aortic regurgitation. There was good correlation between the 3-D Doppler and flow probe methods of CO measurement (y = 1.1x - 9.82, R(2) = 0.93).
  
  
  CONCLUSIONS
  In this acute animal preparation, live 3-D Doppler echocardiographic data allowed for accurate assessment of CO as compared to the ultrasonic flow probe measurement.
authors.affiliation: Clinical Care Center for Congenital Heart Disease, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
authors.forename: James
authors.initials: J
authors.lastname: Pemberton
authors.forename: Xiaokui
authors.initials: X
authors.lastname: Li
authors.forename: Tara
authors.initials: T
authors.lastname: Karamlou
authors.forename: Chloe A
authors.initials: CA
authors.lastname: Sandquist
authors.forename: Karl
authors.initials: K
authors.lastname: Thiele
authors.forename: Irving
authors.initials: I
authors.lastname: Shen
authors.forename: Ross M
authors.initials: RM
authors.lastname: Ungerleider
authors.forename: Antoinette
authors.initials: A
authors.lastname: Kenny
authors.forename: David J
authors.initials: DJ
authors.lastname: Sahn
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D002302:Cardiac Output; D002315:Cardiopulmonary Bypass; D018618:Echocardiography, Doppler, Color; D019560:Echocardiography, Three-Dimensional; D005240:Feasibility Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D023421:Models, Animal; D015203:Reproducibility of Results; D013552:Swine