Continuous Estimation of Cardiac Output in Critical Care: A Noninvasive Method Based on Pulse Wave Transit Time Compared with Transpulmonary Thermodilution

Ulrike Ehlers; Rolf Erlebach; Giovanna Brandi; Federica Stretti; Richard Valek; Stephanie Klinzing; Reto Schuepbach

doi:10.1155/2020/8956372

Continuous Estimation of Cardiac Output in Critical Care: A Noninvasive Method Based on Pulse Wave Transit Time Compared with Transpulmonary Thermodilution

Crit Care Res Pract. 2020 Jul 20:2020:8956372. doi: 10.1155/2020/8956372. eCollection 2020.

Authors

Ulrike Ehlers^{1

2}, Rolf Erlebach¹, Giovanna Brandi¹, Federica Stretti¹, Richard Valek¹, Stephanie Klinzing¹, Reto Schuepbach¹

Affiliations

¹ Institute of Intensive Care, University Hospital of Zurich, Raemistasse 100 CH-8091, Zurich, Switzerland.
² Intensive Care Unit, Kantonsspital Glarus, Burgstrasse 99, CH-8750, Glarus, Switzerland.

Abstract

Purpose: Estimation of cardiac output (CO) and evaluation of change in CO as a result of therapeutic interventions are essential in critical care medicine. Whether noninvasive tools estimating CO, such as continuous cardiac output (esCCOTM) methods, are sufficiently accurate and precise to guide therapy needs further evaluation. We compared esCCOTM with an established method, namely, transpulmonary thermodilution (TPTD). Patients and Methods. In a single center mixed ICU, esCCOTM was compared with the TPTD method in 38 patients. The primary endpoint was accuracy and precision. The cardiac output was assessed by two investigators at baseline and after eight hours.

Results: In 38 critically ill patients, the two methods correlated significantly (r = 0.742). The Bland-Altman analysis showed a bias of 1.6 l/min with limits of agreement of -1.76 l/min and +4.98 l/min. The percentage error for CO_esCCO was 47%. The correlation of trends in cardiac output after eight hours was significant (r = 0.442), with a concordance of 74%. The performance of CO_esCCO could not be linked to the patient's condition.

Conclusion: The accuracy and precision of the esCCOTM method were not clinically acceptable for our critical patients. EsCCOTM also failed to reliably detect changes in cardiac output.