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Updated: Oct 11, 2025
Author Spotlight: Assessment of Cardiac Output Calculation by Thermodilution in Pigs for Effective Perfusion Flow During EVLP
Published on: June 28, 2024
Extracorporeal Membrane Oxygenation Blood Flow and Blood Recirculation Compromise Thermodilution-Based Measurements
Martin Russ1, Elvira Steiner1, Willehad Boemke1
1From the Department of Anesthesiology and Intensive Care Medicine (CCM, CVK); Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
Abstract:
The contribution of veno-venous (VV) extracorporeal membrane oxygenation (ECMO) to systemic oxygen delivery is determined by the ratio of total extracorporeal blood flow () to cardiac output (). Thermodilution-based measurements of may be compromised by blood recirculating through the ECMO (recirculation fraction; Rf). We measured the effects of and Rf on classic thermodilution-based measurements of in six anesthetized pigs. An ultrasound flow probe measured total aortic blood flow () at the aortic root. Rf was quantified with the ultrasound dilution technique. was set to 0-125% of and was measured using a pulmonary artery catheter (PAC) in healthy and lung injured animals. PAC overestimated () at all settings compared to . The mean bias between both methods was 2.1 L/min in healthy animals and 2.7 L/min after lung injury. The difference between and increased with an of 75-125%/ compared to QEC <50%/. Overestimation of was highest when resulted in a high Rf. Thus, thermodilution-based measurements can overestimate cardiac output during VV ECMO. The degree of overestimation of depends on the EC/ ratio and the recirculation fraction.
