Validation of Brain Oxygenation Monitor on Pediatric Patients

NIRS cerebral oximeters are FDA-approved devices used to measure oxygen saturation within the brain, in a similar manner to pulse oximeters that measure the oxygen saturation in the finger tip. The sensor pads are placed on the surface of the forehead and shine near-infrared light through the skull and brain tissue from which the brain tissue oxygen saturation is estimated. The same principles can be applied when the sensor pads are placed over the internal organs of the abdomen, for example, the liver. Currently the only way to accurately measure the oxygen saturation of internal organs is by the invasive placement of intravenous lines into the blood vessels of that organ. This study will determine if the NIRS sensors can reliably estimate the tissue oxygen saturation non-invasively by placing the pad over the skin of the abdomen. The study will be conducted in pediatric patients who are undergoing cardiac catheterization, a procedure in which invasive lines are placed in order to get information about the heart. The procedure is always conducted under general anesthesia. During the cardiac catheterization procedure blood samples are routinely taken for oxygen saturation analysis. In the study two oximeter sensor pads will be placed on the forehead (one on each side) and two further oximeter sensor pads will be placed on the abdominal wall. The oxygen saturation values from all oximeter sensors will be recorded continuously throughout the cardiac catheterization procedure and will be compared to the oxygen saturation values from the blood samples. In addition to the routine blood samples taken as part of the cardiac catheterization, one blood sample will be taken when the invasive line is within the right hepatic (liver) vein. The information from this study will determine how well the oximeter sensors estimate the oxygen saturation of both the internal organs (StO2) and the blood returning to the heart (mean mixed venous oxygen saturation).