The purpose of this his post-market, observational study titled Verification of Pulse Oximetry in the Neonatal Population is to gather data to further support the accuracy of Nonin's pulse oximeters when used in the neonate population. Neonates who are currently undergoing arterial blood gas (ABG) sampling, as part of their medical care will be recruited to participate in this study for collecting opportunity samples. Nonin's PureLight® noninvasive sensor will be applied to a foot of the neonate; an adhesive wrap secures the sensor to the neonate. The sensor immediately begins obtaining SpO2 and pulse rate measurements which are sent to the oximeter module for display on the Electronic Data Collection System (EDCS). At the time the prescribed ABG is drawn, the EDCS must have a marker captured to identify the end of the ABG for SpO2 comparison. The SpO2 accuracy of pulse oximeter will be measured by comparing SpO2 readings of the pulse oximeter to values of SaO2 (opportunity samples) determined by a CO-oximeter.