Preductal

Aortic coarctation is congenital focal narrowing of the aorta in the region of the ductus arteriosus. It may be preductal (proximal to the ductus, illustrated on the right [in the original]), periductal, or postductal.

Criteria for endotracheal intubation were dissatisfying response to non-invasive ventilation defined as absent or insufficient increase in HR and/or preductal oxygen saturation (SpO₂) despite supplemental oxygen.