Accuracy of a noninvasive estimated continuous cardiac output measurement under different respiratory conditions: a prospective observational study

Abstract Purpose Recently, the estimated continuous cardiac output (esCCO) system was developed as a noninvasive hemodynamic monitoring alternative to thermodilution cardiac output (TDCO). However, the accuracy of CCO measurements by the esCCO compared with TDCO under different respiratory conditions remains unclear. This prospective study aimed to assess the clinical accuracy of the esCCO by continuously measuring the esCCO and TDCO. Methods This study enrolled 40 patients who had undergone cardiac surgery with pulmonary artery catheterization. We compared the esCCO with TDCO from mechanical ventilation to spontaneous respiration through extubation. Patients undergoing cardiac pacing during the esCCO measurement, those receiving treatment with an intra-aortic balloon pump, and those with measurement errors or missing data were excluded. On the basis of these criteria, 23 patients were included. Agreement between the esCCO and TDCO was evaluated using Bland–Altman analysis with a 20-minute moving average of the esCCO. Results The paired esCCO and TDCO measurements (939 points before extubation and 1112 points after extubation) were compared. The respective bias and standard deviation (SD) values were 0.13 L/min and 0.60 L/min before extubation and − 0.48 L/min and 0.78 L/min after extubation. There was a significant difference in bias before and after extubation ( P < 0.001); the SD before and after extubation was not significant ( P = 0.315). The percentage errors were 25.1% before extubation and 29.6% after extubation, which is the criterion for acceptance of a new technique. Conclusion The accuracy of esCCO measurement is clinically acceptable to that of TDCO under mechanical ventilation and spontaneous respiration. This study was registered with the UMIN Clinical Trials Registry on September 1st, 2021 (identifier: UMIN000044712).