RELIABILITY OF BIOREACTANCE AND PULSE POWER ANALYSIS IN MEASURING CARDIAC INDEX DURING OPEN ABDOMINAL AORTIC SURGERY

Abstract

<h3>Objective</h3> Pulmonary artery catheter (PAC) is considered as the gold standard for measuring cardiac output, but less invasive monitors have recently been developed. We compared the accuracy, precision and trending ability of non-invasive bioreactance-based Starling SV and mini-invasive pulse power device LiDCOrapid to bolus thermodilution technique with pulmonary artery catheter (TDCO) when measuring cardiac index (CI) in the setting of open abdominal aortic surgery. <h3>Design and Methods</h3> Forty-one patients undergoing open abdominal aortic surgery were monitored with Starling SV, LiDCOrapid and TDCO during surgery, resulting in 627 simultaneous CI measurements. We used the Bland-Altman method and percentage error to investigate the agreement between the devices and four-quadrant plots with error grids to assess the trending ability. <h3>Results</h3> The agreement between TDCO and Starling SV was associated with a bias of 0.18 L/min/m2 (95% confidence interval, 95% CI 0.13 to 0.23), wide limits of agreement (LOA, -1.12 to 1.47 L/min/m2) and a percentage error (PE) of 63.7 (95% CI 52.4-71.0). (Figure 1a) The agreement between TDCO and LiDCOrapid was associated with a bias of -0.15 L/min/m2 (95% CI -0.21 to -0.09), wide LOA (-1.56 to 1.37) and PE of 68.7 (95% CI 54.9-79.6). (Figure 1b) Trending abilities were not acceptable, since with Starling SV only 33.6% and with LiDCOrapid only 41.2 % of the measurements changed in the same direction to the same extent as with TDCO. <h3>Conclusions</h3> CI measurements with Starling SV and LiDCOrapid were not interchangeable with TDCO, and their ability to track changes in CI was poor. These results do not support their use in monitoring CI reliably during open abdominal aortic surgery.