The main goal of this study is to look at the performance of the neonatal, infant, and pediatric Philips SpO2 sensors with the Philips FAST Pulse Oximetry technology. Oxygen saturation measurements (SpO2) will be obtained via pulse oximetry and invasive arterial oxygen measurements (SaO2) will be obtained via arterial blood samples as part of your clinical care and assessed by co-oximetry. The study will aim to enroll a diverse population to help us understand the impact of skin pigmentation.

This is a prospective, multi-center, multi-phase, unblinded, non-randomized. self-controlled, observational study. All data analyses specified below will be calculated and summarized by each of SpO2 sensors under test. Demographics and baseline characteristics, including sex assigned at birth, age, ethnicity, race, baseline height, baseline weight, BMI, skin pigmentation and sensor application site measurements will be summarized with descriptive statistics using the analysis set.

Inclusion Criteria:

• Subject aged 18 years or older or parent/legal guardian of subject aged less than 18 years, willing and able to understand and provide written informed consent/assent.
• Weight and/or age within intended use of at least one SpO2 sensor under test at time of enrollment.
• Willing and able to wear study devices in addition to SoC devices and during SoC procedures.
• In-patient within a neonatal or pediatric intensive care unit (e.g. NICU, PICU, PCICU).
• Has arterial access and ability to have arterial blood samples drawn as part of their SoC and analyzed by CO-Oximetry.

Exclusion Criteria:

• Known pregnancy or lactating females (self-reported)
• Injury, wounds, physical malformation, hyperkeratosis, or compromised/non-intact skin at sensor application site (i.e. fingers, toes, hands, feet, ears, nasal ala). Note: Certain malformations may be allowed if determined it would not affect application of sensor with the pulse oximetry system.
• Self-reported severe contact allergies to standard adhesives or other materials found in pulse oximetry sensors. Note: Subject may be considered eligible if subject can wear non-adhesive sensor.
• Unwillingness or inability to remove nail polish or artificial nails from sensor application site.
• Nail fungus on sensor application site.
• Wearing and unable to remove jewelry from sensor application site.
• Dye injection within 48 hours of enrollment.
• Known dysfunctional hemoglobin levels (COHb >3%, MetHb >2%, and ctHb <10g/dl)
• Undergoing phototherapy for neonatal hyperbilirubinemia during arterial blood sampling

The study will be conducted in neonate, infant, and pediatric patients admitted into an intensive care unit (e.g. NICU, PICU, PCICU).