An Enhanced Method for Measuring Cardiac Output Using Doppler Color Flow Echocardiography

Abstract

An enhanced method for determining cardiac output using Doppler color flow imaging techniques to measure mitral orifice diameter was developed and validated in an experimental model and in clinical patients. In an in vitro circuit model, color jet width correlated well with actual orifice dimension from 12 to 24 mm (r = 0.99). In the clinical application, mitral valve area was calculated as a X b X pi/4 where a and b represent the width of the color flow stream in the mitral orifice just distal to the annulus in apical long-axis (short-diameter) and 4-chamber (90 degrees rotated, long-diameter) views, respectively. Cardiac output was then computed as the product of mitral valve area and time-velocity integral of transmitral flow from the same site. Cardiac output was also measured by thermodilution and conventional echocardiographic methods using diameters and time-velocity integrals from the left ventricular outflow tract. In 30 patients with nonvalvular heart disease, cardiac output measured by thermodilution ranged from 3.40 to 8.40 L/min. Cardiac output was determined in 28 of 30 patients (93%) by the Doppler color flow imaging technique; it ranged from 3.00 to 8.36 L/min and correlated well with thermodilution: y = 0.90x + 0.63, r = 0.91. Cardiac output was determined in 24 of 30 patients by the conventional left ventricular outflow method (80%). The cardiac output measured by the conventional method correlated less closely with thermodilution (r = 0.84), although there was no statistical difference in correlation coefficiencies between the 2 methods. These results indicate that the Doppler color flow imaging technique can be used to enhance the determination of cardiac output by echocardiography, particularly when the conventional method has resulted in technically inadequate recordings.

Emergency department non-invasive cardiac output study (EDNICO): a feasibility and repeatability study

“…Non-invasive cardiac output monitoring methods which can rapidly identify fluid responsiveness and guide fluid therapy are emerging in the ED and in the pre-hospital environment [12, 13]. These methods include left ventricular outflow tract velocity time integral (LVOT VTI) [14, 15], common carotid artery blood flow monitoring (CCABF) [16], suprasternal aortic Doppler (SSAD) [17, 18], plethysmography using the vascular unloading technique (PVUT) [19, 20], and thoracic bioreactance [21–23]. Inferior vena cava collapsibility index (IVCCI), while not measuring cardiac output, may be an indicator of fluid responsiveness [23–25].…”

Emergency department non-invasive cardiac output study (EDNICO): an accuracy study

“…Inferior vena cava collapsibility index (IVCCI), while not measuring cardiac output, has been studied as an indicator of fluid responsiveness [25][26][27]. Stroke volume measured by left ventricular outflow tract velocity time integral (LVOT VTI) [28,29] is the most widely studied of these techniques, including validation against the PAC, which is widely referred to as the gold standard for cardiac output monitoring. LVOT VTI is widely accepted as a non-invasive method to assess stroke volume and cardiac output, and guide fluid therapy [30][31][32][33][34][35].…”