Echocardiographic measurement of cardiac output with automated software analyses of spectral curves in the left ventricular outflow tract has been introduced. This study aimed to assess the precision and accuracy of cardiac output measurements as well as the ability to track cardiac output changes over time comparing the automated echocardiographic method with the continuous pulmonary artery thermodilution cardiac output technique and the manual echocardiographic method in cardiac surgery patients. Cardiac output was measured simultaneously with all three methods in 50 patients on the morning after cardiac surgery. A second comparison was performed 90–180 min later. Precisions for each method were measured. Bias and limits of agreement (LoA) between methods were assessed and concordance- and polar plots were used for evaluating trending of cardiac output. When comparing the automated echocardiographic method with the thermodilution technique, the mean bias was 0.72 L/min with LoA − 1.89; 3.33 L/min corresponding to a percentage error of 46%. The concordance rate was 47%. The mean bias between the automated- and the manual echocardiographic methods was − 0.06 L/min (95% LoA − 2.33; 2.21 L/min, percentage error 42%). The concordance rate was 79%. The automated echocardiographic method did not meet the criteria for interchangeability with the thermodilution technique or the manual echocardiographic method. Trending ability was poor when compared to the continuous thermodilution technique, but moderate when compared to the manual echocardiographic method.
Trial registry number: NCT03372863. Retrospectively registered December 14th 2017.
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Continuous cardiac output
Coefficient of variation
Limits of agreement
Left ventricular outflow tract
Pulmonary artery catheter
Region of interest
Velocity time integral
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The authors wish to thank the staff at the postoperative intensive care unit, Aarhus University Hospital, for their invaluable assistance in patient inclusion and execution of the protocol. Likewise, the authors thank GE Healthcare for making available a Venue R1 ultrasound system for the study.
Conflict of interests
Peter Juhl-Olsen has received minor funds from GE Healthcare and Novartis for teaching courses on critical care. GE Healthcare provided the Venue R1 ultrasound system free of charge for the study without influence on study design, study execution, data interpretation or any aspect of the manuscript writing. All other authors declare that they have not conflict of interests.
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Juhl-Olsen, P., Smith, S.H., Grejs, A.M. et al. Automated echocardiography for measuring and tracking cardiac output after cardiac surgery: a validation study. J Clin Monit Comput 34, 913–922 (2020). https://doi.org/10.1007/s10877-019-00413-w
- Cardiac output
- Thoracic surgery