Right Ventricular Output:
This measurement is also relatively well validated, though the valve diameter measurement is vulnerable to error since it relies on lateral rather than axial resolution of the ultrasound beam. In the newborn infant it is confounded by inter-atrial shunting, however since this is generally lower volume than ductal shunting it may actually be a more robust measure of systemic perfusion than left ventricular output in the early newborn period.
Measure the pulmonary valve diameter from the modified parasternal long axis view, with tilting to look over the subject’s left shoulder.
Zoom in on the valve, and try to get the outflow tract to look as broad as possible. Then freeze the image, and scroll back to measure the diameter of the valve hinge points at end systole.
For flow velocity use the same view, with pulsed wave Doppler at the valve hinge points