Continuous Monitoring of Mixed Venous Oxygen Saturation in a Pediatric Cardiac Surgical Patient

By inserting a 4-French Opticath catheter into the pulmonary artery through the right atrium and right ventricle during cardiac surgery in a 2-year-old boy, we could continuously monitor blood pressure and mixed venous oxygen saturation in the pulmonary artery. Because mixed venous oxygen saturation reflects instantly the balance between oxygen supply and demand, continuous monitoring can detect subtle changes in cardiopulmonary function immediately. We found this technique to be simple, safe, and effective, and considered the measurement of mixed venous oxygen saturation to be a reliable indicator of cardiopulmonary stability with the potential to replace many of the other tests currently employed to monitor the critical care of small cardiac surgical patients.