Invasive Monitoring of Cardiac Output by Pulse Wave Transit Time After Aortocoronary Bypass on the Beating Heart

Goal of the study: to evaluate the accuracy of invasive measurement of cardiac output (CO) by pulse wave transit time (PWTT) (esCCO, Japan) compared to transpulmonary thermodilution (TPTD) (PiCCO 2 , Germany) after aortocoronary bypass (ACB) without cardiopulmonary bypass (ACB without CPB). Methods. 21 patients with ACB without CPB were enrolled into the study. During early post-operative period CO was simultaneously registered at eight stages basing on PWTT (CO PWTT ) and TPTD (CO TPTD ). Statistic analysis included evaluation of congruence of CO absolute values and capability to follow-up changes in CO. Results. In accordance with Bland-Altman analysis the average difference between two methods made 0.3 l/min. with consistency limits of ± 2.1 l/min. and percent error of 40%. Polar chart analysis showed the angular difference of 2.6°, radial consistency limits ± 53.3° and polar concordance of 69%. Conclusion: Lower repeatability of CO measurement by PWTT and insufficient capability to follow the changes in CO after ACB without CPB don not allow recommending this method in its invasive variant for routine practice as an alternative to thermodilution methods.