The management of persistent fetal circulation (PFC) in 3 neonates was facilitated by continuous monitoring of either pulmonary artery (PAP) or right ventricular pressure using an umbilical catheter with a catheter-tip electrode. The catheter was inserted without fluoroscopy via the umbilical vein, using continuously monitored oxygen tension and pressure waveform to determine entry into the right ventricle in 1 patient and the main pulmonary artery in 2 others. Right ventricular and PAP responses to dopamine, dobutamine, and tolazoline facilitated pharmacologic management, whereas continuous mixed venous oxygen tension (PVO2) provided an index of tissue oxygenation.