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Updated: Jul 13, 2026

Determination of Cardiac Output in a Porcine Model for Ex Vivo Pulmonary Perfusion
Published on: June 28, 2024
Lack of agreement between thermodilution and electrical velocimetry cardiac output measurements
Matthias Heringlake1, Ulrich Handke, Thorsten Hanke
1Department of Anesthesiology, University of Luebeck, Ratzeburger Allee 160, 23538 Luebeck, Germany. heringlake@t-online.de
Objective:
The modified algorithm for the non-invasive determination of cardiac output (CO) by electrical bioimpedance-electrical velocimetry (EV)-has been reported to give reliable results in comparison with echocardiography and pulmonary arterial thermodilution (PA-TD) in patients either before or after cardiac surgery. The present study was designed to determine whether EV-CO measurements reflect intraindividual changes in CO during cardiac surgery.
Design:
Prospective, observational study.
Setting:
Operating room (OR) and intensive care unit (ICU) of a university hospital.
Patients:
Twenty-nine patients undergoing elective cardiac surgery.
Interventions:
None.
Measurements:
CO was determined simultaneously by PA-TD and EV after induction of anesthesia (t1) and 4.9+/-3.5 h after ICU admission (t2).
Results:
TD-CO was 3.9+/-1.4 and 5.4+/-1.1 l/min at t1 and t2 (p < 0.0001). EV-CO was 4.3+/-1.1 and 4.9+/-1.5 l/min at t1 and t2 (p = 0.013). Bland-Altman analysis showed a bias of -0.4 l/min and 0.4 l/min and a precision of 3.2 and 3.6 l/min (34.3% and 67.4%) at t1 and t2, respectively. Analysis of the individual pre- to postoperative changes in CO with both methods revealed bidirectional changes in n = 12 patients and unidirectional changes with a difference greater than 50% and less than 50% in n = 9 and n = 8 patients, respectively.
Conclusions:
The disagreement between PA-TD and EV-CO measurements after anesthesia induction and after ICU admission, as well as the fact that thoracic bioimpedance did not adequately reflect pre- to postoperative changes in CO, questions the reliability of EV-CO measurements in cardiac surgery patients and contrasts sharply with previous studies.
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