Research

Pulse contour analysis after normothermic cardiopulmonary bypass in cardiac surgery patients

Michael Sander¹ , Christian von Heymann¹, Achim Foer¹, Vera von Dossow¹, Joachim Grosse¹, Simon Dushe², Wolfgang F Konertz² and Claudia D Spies¹

¹  Department of Anesthesiology and Intensive Care Medicine, University Hospital Charité, Campus Charité Mitte, University Medicine, Schumannstrasse 20/21, 10098 Berlin, Germany

²  Department of Cardiovascular Surgery, University Hospital Charité, Campus Charité Mitte, University Medicine, Schumannstrasse 20/21, 10098, Berlin, Germany

author email corresponding author email

Critical Care 2005, 9:R729-R734doi:10.1186/cc3903

Published:	4 November 2005

Abstract

Introduction

Monitoring of the cardiac output by continuous arterial pulse contour (CO_PiCCOpulse) analysis is a clinically validated procedure proved to be an alternative to the pulmonary artery catheter thermodilution cardiac output (CO_PACtherm) in cardiac surgical patients. There is ongoing debate, however, of whether the CO_PiCCOpulse is accurate after profound hemodynamic changes. The aim of this study was therefore to compare the CO_PiCCOpulse after cardiopulmonary bypass (CPB) with a simultaneous measurement of the CO_PACtherm.

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 (CO_PiCCOtherm) and the CO_PACtherm were determined in all patients. Prior to surgery, the CO_PiCCOpulse was calibrated by triple transpulmonary thermodilution measurement of the CO_PiCCOtherm. After termination of CPB, the CO_PiCCOpulse was documented. Both CO_PACtherm and CO_PiCCOtherm were also simultaneously determined and documented.

Results

Regression analysis between CO_PACtherm and CO_PiCCOtherm 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 CO_PiCCOpulse versus CO_PiCCOtherm and of CO_PiCCOpulse versus CO_PACtherm 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.

Conclusion

We observed an excellent correlation of CO_PiCCOtherm and CO_PACtherm 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.