Non-Invasive Cardiac Output Determination by Two-Dimensional Independent Doppler During and After Cardiac Surgery

Purpose This study was to compare noninvasive measurement of cardiac output (CO) using a novel Doppler technique with invasive CO measurements in the postcardiac surgical intensive care unit. Description Thirty-six patients (67.2 ± 10 years, New York Heart Association functional class 3.1 ± 0.3) undergoing coronary revascularization were prospectively examined postoperatively. One hundred eighty paired CO and stroke volume measurements were compared from the noninvasive USCOM device (Sydney, Australia) and the invasive Swan-Ganz catheter at varying COs. Eighteen measurements were performed intraoperatively by direct insonation of the right ventricular outflow tract. Evaluation Mean noninvasive and invasive CO values were 5.15 ± 1.98 L/min and 4.92 ± 2.0 L/min, respectively (r = 0.870; p< 0.01). The mean difference between methods was −0.23 ± 1.01 L/min greater than a range of CO values from 2.5 to 9.9 L/min. Mean central venous saturation percentage was 72 ± 9%, correlating with both noninvasive and invasive CO (r = 0.474 and 0.606, respectively, p< 0.01). Intraoperatively, both direct and invasive CO were identical. Conclusions Using the ultrasonic cardiac output monitoring (USCOM) device it is possible to determine noninvasive beat-to-beat CO in postcardiac surgery patients without the possible complications associated with invasive right heart catheterization. The USCOM CO and stroke volume showed a very good agreement with invasive Swan-Ganz measures and correlated with central venous saturation percentage.