Cardiac Output Measurement During Infrarenal Aortic Surgery: Echo-Esophageal Doppler Versus Thermodilution Catheter

Objective: Aortic surgery is associated with various hemodynamic and cardiac output modifications. These disorders may be partly caused by blood flow redistribution between supra-aortic and descending aorta regions during clamping and unclamping. A new echo-esophageal Doppler (Hemosonic 100; Arrow, Reading, PA) calculates cardiac output from a simultaneous measurement of blood flow velocity and diameter of the descending aorta. This calculation may be affected by blood redistribution during aortic clamping. The aim of this study was to compare cardiac output measured by echo-esophageal Doppler and by bolus thermodilution catheter during infrarenal aortic surgery.

Design: Prospective, observational study.

Setting: University hospital, single institution.

Participants: Twenty-two adult patients.

Interventions: Infrarenal aortic surgery.

Measurements and Main Results: Cardiac outputs monitored by both devices were highly correlated during the whole surgical procedure (r² ranging from 0.54 to 0.76). Bland and Altman analysis showed absence of significant bias before and after clamping (ranging from 0.1 ± 0.73 L/min to 0.18 ± 1 L/min, p > 0.05) and a significant bias of 0.5 ± 1.05 L/min (p < 0.05) during aortic clamping. Limits of agreement did not differ significantly during the whole surgical procedure (ranging from −1.36/2.19 to −2.23/2.49). During clamping and unclamping, changes in cardiac output obtained by both methods were positively correlated (r² = 0.7).

Conclusions: Bias between both methods was clinically acceptable, and limits of agreement were not significantly modified by aortic clamping. However, larger studies including homogenous aortic pathologies are necessary to validate this method during infrarenal aortic surgery.

Key words:  aortic surgery , cardiac output monitoring , esophageal Doppler , thermodilution catheter