title: Pulse contour analysis after normothermic cardiopulmonary bypass in cardiac surgery patients.
abstract: BACKGROUND
  Monitoring of the cardiac output by continuous arterial pulse contour (COPiCCOpulse) analysis is a clinically validated procedure proved to be an alternative to the pulmonary artery catheter thermodilution cardiac output (COPACtherm) in cardiac surgical patients. There is ongoing debate, however, of whether the COPiCCOpulse is accurate after profound hemodynamic changes. The aim of this study was therefore to compare the COPiCCOpulse after cardiopulmonary bypass (CPB) with a simultaneous measurement of the COPACtherm.
  
  
  METHODS
  After ethical approval and written informed consent, data of 45 patients were analyzed during this prospective study. During coronary artery bypass graft surgery, the aortic transpulmonary thermodilution cardiac output (COPiCCOtherm) and the COPACtherm were determined in all patients. Prior to surgery, the COPiCCOpulse was calibrated by triple transpulmonary thermodilution measurement of the COPiCCOtherm. After termination of CPB, the COPiCCOpulse was documented. Both COPACtherm and COPiCCOtherm were also simultaneously determined and documented.
  
  
  RESULTS
  Regression analysis between COPACtherm and COPiCCOtherm prior to CPB showed a correlation coefficient of 0.95 (P < 0.001), and after CPB showed a correlation coefficient of 0.82 (P < 0.001). Bland-Altman analysis showed a mean bias and limits of agreement of 0.0 l/minute and -1.4 to +1.4 l/minute prior to CPB and of 0.3 l/minute and -1.9 to +2.5 l/minute after CPB, respectively. Regression analysis of COPiCCOpulse versus COPiCCOtherm and of COPiCCOpulse versus COPACtherm after CPB showed a correlation coefficient of 0.67 (P < 0.001) and 0.63 (P < 0.001), respectively. Bland-Altman analysis showed a mean bias and limits of agreement of -1.1 l/minute and -1.9 to +4.1 l/minute versus -1.4 l/minute and -4.8 to +2.0 l/minute, respectively.
  
  
  CONCLUSIONS
  We observed an excellent correlation of COPiCCOtherm and COPACtherm measurement prior to CPB. Pulse contour analysis did not yield reliable results with acceptable accuracy and limits of agreement under difficult conditions after weaning from CPB in cardiac surgical patients. The pulse contour analysis thus should be re-calibrated as soon as possible, to prevent false therapeutic consequences.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Charité, Campus Charité Mitte, University Medicine, Schumannstrasse 20/21, 10098 Berlin, Germany. michael.sander@charite.de
authors.forename: Michael
authors.initials: M
authors.lastname: Sander
authors.forename: Christian
authors.initials: C
authors.lastname: von Heymann
authors.forename: Achim
authors.initials: A
authors.lastname: Foer
authors.forename: Vera
authors.initials: V
authors.lastname: von Dossow
authors.forename: Joachim
authors.initials: J
authors.lastname: Grosse
authors.forename: Simon
authors.initials: S
authors.lastname: Dushe
authors.forename: Wolfgang F
authors.initials: WF
authors.lastname: Konertz
authors.forename: Claudia D
authors.initials: CD
authors.lastname: Spies
mesh_terms: D002302:Cardiac Output; D006348:Cardiac Surgical Procedures / Q000534:rehabilitation*; D002315:Cardiopulmonary Bypass / Q000534:rehabilitation*; D006339:Heart Rate; D006801:Humans; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D011182:Postoperative Care / Q000379:methods; D011446:Prospective Studies; D011674:Pulse / Q000379:methods*; D012680:Sensitivity and Specificity; D013815:Thermodilution / Q000379:methods; D014655:Vascular Resistance