Correlation of Cardiac Output Measurement with Transoesophageal Echocardiography andBolus Termodilution Technique in Patients with Various Degree of Tricuspid Regurgitation

Overview

Objective:
The aim of the article is to suggest a practical approach to the cardiac output (CO) measurement with combineduse of echocardiography and thermodilution in patients with various valve disorders.Design: Prospective observational study.Setting: 20-bed general intensive care unit in the university hospital.Material and Methods: 27 mechanically ventilated patients with no significant aortic valve disease were included. Patientswere measured twice using simultaneously transesophageal echocardiography (TEE) and pulmonary artery catheter (PAC)for CO.Results: Continuous doppler measurements were taken in the left ventricular outflow tract (LVOT) at the level of the aorticvalve.CO was calculated bymultiplying velocity-time integral (VTI) with aortic valve area (AVA) and heart rate. SimultaneousPAC measurements were taken averaging the results of the three 10 cc boluses of iced saline. The difference between themethods expressed as mean ± 2 SD was 0.5 ± 1.1 l/min in the first group of patients (N = 8) with no or the 1st degree tricuspidregurgitration (TR), r = 0.96. A mean difference of 0.8 ± 2.0 l/min was found in the second group (N = 9) with the 2nd degreeTR, r = 0.92. The difference was 1.9 ± 2.3 l/min in the third group (N = 10) with the 3rd degree TR, r = 0.69. Only in the thirdgroup the statistic bias was different from zero (T = 6.83, P < 0.0001).Conclusions: The presence of significant aortic valve disease on echocardiographic investigation impairs validity of COmeasurement in LVOT. In those cases thermodilution may become the method of choice. On the other hand a high degreeof TR is associated with an underestimation of CO measurement by thermodilution. Echocardiography is more accuratemodality for CO assessment in those patients.

Key words:
tricuspid regurgitation – cardiac output – echocardiography – doppler-ultrasonography – pulmonary arterycatheter – thermodilution