This study is designed to evaluate the repeatability and reproducibility of ORi using an investigational Masimo rainbow sensor and FDA cleared rainbow sensors connected to the Masimo Radical-7 pulse oximeter and Masimo Root monitor in healthy volunteers as the subjects undergo a controlled hyperoxygenation protocol.

Inclusion Criteria:

• Subject is 18 to 50 years of age.
• Subject weighs a minimum of 110 lbs.
• Hemoglobin value ≥ 11 g/dL.
• Baseline heart rate ≥ 45 bpm and ≤ 85 bpm.
• Blood Pressure: Systolic BP ≤ 140 mmHg and ≥ 90 mmHg, Diastolic BP ≤ 90 mmHg and ≥ 50 mmHg, and if systolic BP is lower than 100 mmHg and/or diastolic BP is lower than 60 mmHg, subject passes an orthostatic blood pressure test.
• CO value ≤ 3.0% FCOHb.
• Subject is able to read and communicate in English and understands the study and the risks involved

Exclusion Criteria:

• Subject has a positive hCG test.
• Subject has a BMI > 35.
• Subject has a history of fainting (vasovagal syncope), blacking out or losing consciousness during or after a blood draw, or has a fear of blood draws.
• Subject has open wounds, inflamed tattoos or piercings, and/or has any visible healing wounds that a medical professional determines may place them at an increased risk for participation. *
• Subject has known drug or alcohol abuse.
• Subject uses recreational drugs. *
• Subject experiences frequent or severe headaches and/or migraine headaches, migraine auras, altitude sickness, and/or headaches accompanied by visual changes or sensitivity to light or sound.
• Subject has experienced a concussion or head injury with loss of consciousness within the past 12 months.
• Subject has any history of a stroke, myocardial infarction (heart attack), and/or seizures.
• Subject has any chronic bleeding disorder (e.g., hemophilia).
• Subject has taken anticoagulant medication within the past 30 days (excluding nonsteroidal anti-inflammatory drugs (NSAIDS)).
• Subject has donated blood within the past 4 weeks.
• Subject has Wolff-Parkinson-White Syndrome or Stokes-Adams Syndrome.
• Subject has any cardiac dysrhythmia (e.g., atrial fibrillation) and has not received clearance from their physician to participate. *
• Subject has a known neurological and/or psychiatric disorder (e.g., schizophrenia, bipolar disorder, Multiple Sclerosis, Huntington's disease) that interferes with the subject's level of consciousness. *
• Subject has taken opioid pain medication 24 hours before the study.
• Subject has any active signs and/or symptoms of infectious disease (e.g., Hepatitis, HIV, Tuberculosis, Flu, Malaria, Measles, etc.). *
• Subject is taking medications known to treat any type of infectious disease.
• Subject has either signs or history of peripheral ischemia or carpal tunnel syndrome.
• Subject has had invasive surgery within the past year, including but not limited to major dental surgery, appendectomy, plastic surgery, jaw surgery, major ENT surgery, major abdominal and/or pelvic surgery, heart surgery, or thoracic surgery. *
• Subject has symptoms of congestion, head cold, or other illnesses.
• Subject has been in a severe car accident(s) or a similar type of accident(s) requiring hospitalization within the past 12 months.
• Subject has any cancer or history of cancer (not including skin cancer). *
• Subject has chronic unresolved asthma, lung disease (including COPD) and/or respiratory disease.
• Subject is allergic to Lidocaine, chlorhexidine, latex, adhesives, or plastic.
• Subject has a heart condition, insulin-dependent diabetes, or uncontrolled hypertension.
• Subject has delivered vaginally, has had a pregnancy terminated, a miscarriage with hospitalization or had a C-section within the past 6 months.
• Subject intends on participating in any heavy lifting, repetitive movement of their wrist (including riding a motorcycle, tennis), exercise (working out, riding a bike, riding a skateboard, etc.), or any activity that will put additional stress on the wrist within 24 hours following a study that involves an arterial line.
• Subject has any medical condition which in the judgment of the investigator and/or medical staff, renders them ineligible for participation in this study or subject is deemed ineligible by the discretion of investigator/study staff.

1-3 hours