[Noninvasive cardiac output determinations]

The thermodilution determination of cardiac output (CO) by pulmonary arterial catheterization is considered to be the gold standard. However, a diversity of complications associated with the insertion and use of a catheter has made for the design of CO-measuring devices in a mini- or noninvasive mode. This prospective controlled study has been conducted to compare various CO determination techniques by the shape of the arterial curve (ART), as shown by the use of a transesophageal Doppler ultrasonic sensor (TEDUS) determining the blood flow velocity in the descending thoracic aorta by the Fick's backward equation with partial CO2 recirculation, by measuring thoracic bioimpedance (Tbio) by bolus thermodilution as the reference method (CO BT). In all the study examined, the mean CO values are lower than those in the reference method. In addition, there was a wide scatter of the CO values calculated by alternative methods. The mean difference and its standard deviation are 1.27 +/- 2.26 (ART); 0.87 +/- 1.57 (TEDUS); 1.01 +/- 1.46 (Fick); and 1.46 +/- 1.70 (Tbio). The errors of the methods, as compared to CO BT have the following values: APT, 27% (24-31% conference interval (CI)); TEDUS, 19% (17-21% CI); Fick, 20% (19-22%); Tbio, 25% (22-27%). By taking into account the findings, it should be stated that there is not any accurate mini- or noninvasive CO determination method that could completely substitute for the classical thermodilution technique.