Continuous intraoperative noninvasive cardiac output monitoring using a new thoracic bioimpedance device

Objectives: To compare a new noninvasive bioimpedance device with the standard thermodilution method during the intraoperative period in high-risk patients undergoing oncological surgery. Design: Prospectively collected data with retrospective analysis. Setting: The study was undertaken at a university hospital, single institution. Participants: Twenty-three selected adults undergoing extensive, ablative oncological surgery. Interventions: Simultaneous measurements of cardiac output by a new bioimpedance method and the standard thermodilution method during the intraoperative and immediate postoperative periods. Measurements and Main Results: The correlation coefficient between the two methods was r = 0.89, p < 0.001. Bias and precision analysis between the two techniques showed a mean bias of 0.1 L/min and SD of the bias (precision) of 1.0 L/min (95% level of agreement +2.1 L/min to -1.9 L/min). After software enhancement, data from the last 11 monitored patients showed improved correlation between the two methods; r = 0.93, mean bias -0.1 L/min, and precision 0.8 L/min,Electrical and motion induced interference only transiently impaired the performance of the new impedance method. Conclusion: This new impedance device is a safe, reliable, clinically acceptable alternative to the invasive thermodilution method in the operating room environment. Copyright (C) 1997 by W.B. Saunders Company.