Figure 5. Examples of the blood flow wave forms recorded in the left pulmonary artery (top panel) and in the ductus arteriosus (DA) in the fetus (before umbilical cord occlusion; BCO) and in the neonate at 5 min and 1 h after the onset of ventilation.

Negative values of pulmonary blood flow indicate retrograde flow away from the lungs, whereas negative blood flow values through the DA indicate flow that is directed from the systemic (aorta) into the pulmonary circulation.