Simultaneous measurement of cardiac output by thermodilution, thoracic electrical bioimpedance and Doppler ultrasound

Abstract

To evaluate the accuracy of two non-invasive techniques for cardiac output (CO) measurement, we have measured CO simultaneously by thoracic electrical bioimpedance (TEB), pulsed Doppler ultrasound (DU) and standard thermodilution methods (TD) under different clinical conditions. Measurements were made in 10 patients: (I) during steady state anaesthesia with controlled IPPV ventilation (n = 131), spread over the entire ventilatory cycle; (II) during apnoea (n = 56); (III) during spontaneous breathing (n = 152) in the intensive care unit. Mean (SD) cardiac output values were: (I) COTD 3.5 (1.0) litre min-1, COTEB 3.4 (0.7) litre min-1, CODU 2.8 (0.7) litre min-1; (II) COTD 3.6 (0.6) litre min-1, COTEB 3.5 (0.4) litre min-1, CODU 2.9 (0.7) litre min-1; (III) COTD 7.7 (1.5) litre min-1, COTEB 7.6 (1.9) litre min-1, CODU 5.2 (1.4) litre min-1. The mean percentage deviation of TEB from TD ranged from -2.2% to 1.4% and that of DU from TD was from -16% to -32%. There were no statistically significant differences between TD and TEB, but TD and DU differed significantly during IPPV, apnoea and spontaneous ventilation (P < 0.0001).

Increased lipopolysaccharide binding protein in cirrhotic patients with marked immune and hemodynamic derangement

“…Although the correlation between both methods is good, echocardiography underestimates the value of cardiac output measured by thermodilution, the latter considered as the clinical standard. 28 This fact explains the greater values of SVR observed in Protocol 1 than in Protocol 2 patients. The profound hemodynamic disturbance of cirrhotic patients with high LBP may in part be caused by the increased amounts of proinflammatory cytokines with a concomitant excess synthesis of nitric oxide.…”

Minimally Invasive Determination of Cardiac Output by Transthoracic Bioimpedance, Partial Carbon Dioxide Rebreathing, and Transesophageal Doppler Echocardiography in Beagle Dogs

“…Transesophageal Doppler echocardiography is increasingly being used as an intraoperative method for assessing cardiac function in humans [4,6,14,16] and horses [24]. In this study, TEECO provided the closest values to TDCO with the narrow limits of agreement and percentage error.…”

Impedance cardiographyThe impact of new technology

“…Several authors have assessed impedance cardiography during anaesthesia and surgery. In peripheral surgery, such as neurosurgery, the BoMed NCCOM3 performs acceptably when compared with thermodilution, with limits of agreement of Ϯ 20-30% [20,28]. Poorer correlation has been found during abdominal surgery, which has been discussed previously [11,40].…”

“…Most significant is that there is no true 'gold standard' method of cardiac output measurement that can be applied clinically and with which comparisons can therefore be made. In general, thermodilution cardiac output is used as the reference method This is only accurate to Ϯ 10-20% [19] and alternatives such as Doppler ultrasound [20], carbon dioxide rebreathing and radio-nuclide angiography are no better at present. This lack of accuracy has led to problems with statistical analysis as traditional regression analysis and quoting correlation coefficients is inappropriate.…”

“…The findings from these studies have been variable. In patients who have suffered acute myocardial infarction [26], undergoing cardiac catheterisation [27] or neurosurgery [20,28], agreement with thermodilution has been acceptable (Ϯ 20-30%). However, unacceptable limits of agreement of Ϯ 40-60% have been repeatedly found in critically ill patients [29][30][31].…”