Preterm infants 32 to 36 weeks will be eligible for this study

At or immediately following an umbilical venous blood draw for CO-oximetry, the FS-II NIRS Small sensor will be briefly placed on the abdominal wall for spot check measurements over the 1) left & 2) right flank, 3) liver and on three intestine locations: just inferior and lateral to the umbilicus in the 4) Right Lower Quadrant (RLQ) and 5) Left Lower Quadrant (LLQ) positions, as well as 6) Mid Lower Quadrant (MLQ). Then a reference FS-I measurement of the 7) flank for 2 minutes will be done.

Following abdominal measurements, the FS-II Small sensor will be placed on the head with the following positions in the following sequence 1) forehead, over the frontal cortex for two minutes; 2) the FS-II sensor is lifted off the head and placed back in the same forehead position to make a repeat measurement for two minutes; and 3) on the side of the head above the ear (frontal and parietal cortex) for two minutes. For reference cerebral measurements, a FDA cleared FS-I Small sensor will be placed on the 4) forehead for two minutes; 5) the FS-I sensor will be removed and replaced on the same forehead position to make a repeat measurement for two minutes. The sensors will take a measurement of 2 minutes in each position and 10 minutes total.

Then two FS-II Small sensors will be attached longer term, one sensor on the forehead and one sensor on the abdomen (RLQ), with neonatal adhesives to allow monitoring for up to 24 hours. Dynamic changes of StO2 at these locations will be observed, along with pulse oximetry SpO2 to capture any acute events such as apnea and bradycardia, which will help in modeling and verifying dynamic StO2 change behavior within the FS-II algorithm. FS-II, and pulse oximetry data will be collected simultaneously on a laptop computer.