Accuracy of the ClearSight™ system in patients undergoing abdominal aortic aneurysm surgery

The ClearSight™ device monitors continuous pressure and cardiac output via pulse contour analysis. ClearSight™, however, may not be reliable in patients with reduced peripheral perfusion caused by high peripheral resistance. This study aimed to elucidate the accuracy and trending ability of ClearSight™ in patients undergoing abdominal aortic aneurysm (AAA) surgery by comparing the ClearSight^TM-derived cardiac index (CI_CS) with that measured using three-dimensional echocardiography (CI_3D).

The study included 20 patients who underwent elective AAA surgery. CI_CS and CI_3D were measured simultaneously at eight time points during the surgery. Trending ability was investigated after aortic clamping and unclamping. We used CI_3D as the reference method.

Bland-Altman analysis showed a wide limit of agreement between CI_CS and CI_3D (percentage error 41.3%). Subgroup analysis showed a lower percentage error (33.2%) in patients with CI ≥ 2.5 L/min/m². The cubic splines related to the CI_3D and CI discrepancy were negatively sloped, indicating that CI_3D had significant influence on the CI discrepancy (p < 0.001). Four-quadrant plot analysis showed that the tracking ability of ClearSight™ after aortic clamping and declamping were clinically unacceptable (81.3% and 78.6%, respectively). Also, the polar plot analysis showed that the concordance rate of ClearSight™ after aortic clamping and declamping were clinically unacceptable (58.3% and 66.7%, respectively).

ClearSight™ was not sufficiently accurate in patients undergoing AAA surgery. The tracking ability of ClearSight™ after aortic clamping was below the acceptable limit.