The Validation of Cardiac Index and Stroke-Volume Variation Measured by the Pulse-Wave Transit Time-Analysis Versus...

To compare the reliability of cardiac index (CI) and stroke-volume variation (SVV) measured by the pulse-wave transit-time (PWTT) method using estimated continuous cardiac output (esCCO) technique with conventional pulse-contour analysis after off-pump coronary artery bypass grafting (OPCAB).

A single-center, prospective, observational study.

At a 1,000-bed university hospital.

A total of 21 patients were enrolled after elective OPCAB.

The study authors performed a method comparison study with simultaneous measurement of CI and SVV based on the esCCO technique (CI_esCCO and esSVV, correspondingly) and pulse-contour analysis (CI_PCA and SVV_PCA, correspondingly). As a secondary analysis, they also assessed the trending ability of CI_esCCO versus CI_PCA. MEASUREMENTS AND MAIN RESULTS: The authors analyzed 178 measurement pairs for CI, and 174 pairs for SVV during the 10 study stages. The mean bias between CI_esCCO and CI_PCA was 0.06 L min/m², with limits of agreement of ± 0.92 L min/m² and a percentage error (PE) of 35.3%. The analysis of the trending ability of CI measured by PWTT revealed a concordance rate of 70%. The mean bias between esSVV and SVV_PCA was -6.1%, with limits of agreement of ± 15.5% and a PE of 137%.

The overall performance of CI_esCCO and esSVV versus CI_PCA and SVV_PCA is not clinically acceptable. A further improvement of the PWTT algorithm may be required for an accurate and precise assessment of CI and SVV.