title: Beat-to-beat measurement of cardiac output by intravascular pulse contour analysis: a prospective criterion standard study in patients after cardiac surgery.
abstract: OBJECTIVE
  To evaluate the accuracy of a new pulse contour method of measuring cardiac output in critically ill patients.
  
  
  METHODS
  A prospective criterion standard study.
  
  
  METHODS
  Cardiac surgery intensive care unit in a university hospital.
  
  
  METHODS
  Nineteen cardiac surgery patients requiring intensive care treatment with pulmonary artery catheters after surgery.
  
  
  METHODS
  None.
  
  
  RESULTS
  The pulse contour cardiac output monitor uses transpulmonary bolus thermodilution measurements to calibrate the system. In each patient, the pulse contour cardiac output values were compared with conventional thermodilution. The method described by Bland and Altman and linear regression analysis were used for comparison. The mean difference (bias) +/- standard deviation of differences (precision) was 0.31 +/- 1.25 L/min for pulmonary bolus thermodilution cardiac output versus pulse contour cardiac output and 0.21 +/- 0.73 L/min for pulmonary bolus thermodilution cardiac output versus transpulmonary bolus thermodilution cardiac output. Linear regression (correlation) analyses were pulse contour cardiac output = 0.97 thermodilution + 0.53 (r = 0.88), and transpulmonary cardiac output = 0.87 thermodilution + 1.09 (r = 0.96). There was a small increase 60 minutes after recalibration but not a statistically significant difference between pulse contour cardiac output and pulmonary bolus thermodilution cardiac output (p = 0.52).
  
  
  CONCLUSIONS
  Bias and precision are acceptable, and the system provides results that agree with conventional thermodilution. This study demonstrates the clinical applicability of the pulse contour cardiac output monitoring system.
authors.affiliation: Department of Anesthesiology, Ludwig-Maximilians University of Munich, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Zöllner
authors.forename: M
authors.initials: M
authors.lastname: Haller
authors.forename: M
authors.initials: M
authors.lastname: Weis
authors.forename: K
authors.initials: K
authors.lastname: Mörstedt
authors.forename: P
authors.initials: P
authors.lastname: Lamm
authors.forename: E
authors.initials: E
authors.lastname: Kilger
authors.forename: A E
authors.initials: AE
authors.lastname: Goetz
mesh_terms: D000328:Adult; D000368:Aged; D002138:Calibration; D002302:Cardiac Output / Q000502:physiology*; D006348:Cardiac Surgical Procedures; D002407:Catheterization, Swan-Ganz; D003422:Critical Care; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D011446:Prospective Studies; D012044:Regression Analysis; D013815:Thermodilution