The Forgotten Fetal Channel: Guidewire Entry Into Umbilical Vein During Central Line Placement in a Neonate.

Central venous catheterization in neonates presents unique challenges due to transitional circulatory physiology and potential persistence of fetal vascular structures. We describe a rare intraoperative observation in a 4-day-old baby boy weighing 1.8 kg, diagnosed with a large retroperitoneal mass causing abdominal compartment syndrome. The patient underwent emergency exploratory laparotomy. During ultrasound-guided internal jugular vein catheterization in the setting of an open abdomen, the guidewire was unexpectedly visualized emerging through the umbilical vein. This unusual finding indicated the presence of a patent ductus venosus, a fetal vessel that normally closes soon after birth but may remain patent for days or weeks in some neonates. The patent ductus venosus provided an anomalous communication between the umbilical and systemic venous systems, creating a potential pathway for guidewire misdirection. This case highlights the importance of understanding neonatal vascular anatomy, especially the persistence of fetal circulatory structures that may alter expected catheter trajectories. Awareness of such variations, coupled with real-time ultrasound and fluoroscopic confirmation, is essential to prevent inadvertent catheter misplacement and associated complications. This observation reinforces the need for heightened vigilance and imaging guidance during central venous access in critically ill neonates with altered hemodynamics and developmental vascular anomalies.