title: Esophageal Doppler and thermodilution are not interchangeable for determination of cardiac output.
abstract: OBJECTIVE
  This study compares thermodilution cardiac output (TD-CO) and esophageal Doppler cardiac output (ED-CO) during periods of hemodynamic stability and after heart stabilization during off-pump coronary artery bypass (OPCAB) surgery.
  
  
  METHODS
  After Institutional Review Board approval, 58 patients undergoing OPCAB had simultaneous comparison of TD-CO and ED-CO at three time periods. Measurements were recorded, in a blinded manner, after probe insertion (T0), immediately before and after (T1,T2) heart displacement and before starting any pharmacological treatment (if needed) to maintain systolic blood pressure to its value before heart mobilization. Measurements were also taken before sternal closure (Tfinal).
  
  
  RESULTS
  Three hundred and two pairs of data were analyzed using the Bland and Altman method. Bias, standard deviation (SD) of the bias (precision), and degree of agreement (bias +/- 2 SD) were calculated. Based on published literature, we considered that the highest degree of agreement should be < 0.5 L.min(-1) to consider both methods as interchangeable. At T0, bias and SD of bias between TD-CO and ED-CO were -0.1 +/- 1.0 L.min(-1). Immediately before heart stabilization, bias +/- SD was 0.6 +/- 1.0 L.min(-1) and after heart displacement, 0.5 +/- 0.8 L.min(-1). At Tfinal, bias +/- SD was 0.7+/- 0.7 L.min(-1).
  
  
  CONCLUSIONS
  Because the degree of agreement was > 0.5 L.min(-1) at all measurement periods except T0, we conclude that TD and ED are not interchangeable at any time during OPCAB surgery.
authors.affiliation: Department of Anesthesiology, CHUM, Hôpital Notre-Dame, 1560 Sherbrooke East, Montréal, Québec H2L 4M1, Canada.
authors.forename: Sophie
authors.initials: S
authors.lastname: Collins
authors.forename: François
authors.initials: F
authors.lastname: Girard
authors.forename: Daniel
authors.initials: D
authors.lastname: Boudreault
authors.forename: Philippe
authors.initials: P
authors.lastname: Chouinard
authors.forename: Louis
authors.initials: L
authors.lastname: Normandin
authors.forename: Pierre
authors.initials: P
authors.lastname: Couture
authors.forename: Marie-Josée
authors.initials: MJ
authors.lastname: Caron
authors.forename: Monique
authors.initials: M
authors.lastname: Ruel
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output / Q000502:physiology*; D047549:Coronary Artery Bypass, Off-Pump; D004311:Double-Blind Method; D004947:Esophagus / Q000000981:diagnostic imaging*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011229:Preanesthetic Medication; D013815:Thermodilution; D018608:Ultrasonography, Doppler
chemical_list: D002245:Carbon Dioxide