Continuous wave Doppler cardiac output: use in pediatric patients receiving inotropic support

Area of Science:

• Pediatric Cardiology
• Echocardiography
• Hemodynamics

Background:

• Doppler estimates of cardiac output correlate well with invasive methods in stable patients.
• Validation in hemodynamically unstable pediatric patients is lacking.

Purpose of the Study:

• To assess the accuracy of continuous wave Doppler echocardiography for cardiac output estimation in hemodynamically unstable pediatric patients.
• To evaluate the impact of aortic diameter measurement site on Doppler accuracy.

Main Methods:

• 27 simultaneous Doppler and thermodilution comparisons were performed in 12 pediatric patients.
• Doppler cardiac output was calculated using aortic diameter measured at three sites: aortic valve annulus, aortic root, and ascending aorta.
• Patients received inotropic support and afterload-reducing agents.

Main Results:

• A close correlation was observed between Doppler and thermodilution techniques across all measurement sites.
• Aortic valve annulus diameter measurement yielded the best correlation (r = 0.94) and least variability.
• Percent change in Doppler stroke volume correlated well with thermodilution stroke volume (r = 0.87) for serial determinations.

Conclusions:

• Continuous wave Doppler echocardiography is a useful method for estimating cardiac output in hemodynamically unstable pediatric patients.
• Measurement site of aortic diameter significantly impacts accuracy, with the aortic valve annulus being optimal.
• Doppler is effective in detecting changes in cardiac output during hemodynamic support.