Umbilical vein catheterization--appropriate and inappropriate placement.

Because of the dangers of inappropriate placement of an umbilical vein catheter (UVC), knowledge of the proper pathway and tip localization is important. The acceptable ductus venosus/hepatic vein/inferior vena cava confluence location is compared to inappropriate localizations below and above the diaphragm, with emphasis on confusion about the position when the UVC tip is in the umbilical vein itself, including the umbilical vein recess. Small amounts of gas can inadvertently accompany initial UVC placement and provide landmarks for position evaluation.