ORi is a unitless index that could help clinicians with their assessments or normoxic and hyperoxic states by scaling the measured absorption information between 0.00 and 1.00. An ORi of 0.00 corresponds to PaO2 values of 100mmHg and below and an ORi of 1.00 corresponds to PaO2 values of 200mmHg and above. In this study, the PaO2 is varied by controlling the concentration of oxygen the study volunteer breathes. Changes in ORi values are analyzed by comparing it to corresponding changes in PaO2 measurements from blood samples.

Inclusion Criteria:

• Subject weighs a minimum of 110 lbs and no more than 250 lbs unless subject is over 6 feet tall.
• Hemoglobin value is greater than or equal to 11 g/dL.
• Baseline heart rate > 45 bpm and < 85 bpm.
• Carbon monoxide (CO) value less than or equal to 2.0% fractional carboxyhemoglobin (FCOHb)
• Subject has a physical status of ASA I or II (American Society of Anesthesiology Class 1; Healthy subjects without any systemic disease at all. American Society of Anesthesiology Class II; subjects with mild systemic disease) as it applies to the systemic disease portion of the classification.
• Systolic Blood Pressure less than or equal to 140 mmHg and Diastolic Blood Pressure less than or equal to 90 mmHg.
• Subject is able to read and communicate in English and understands the study and risks involved.

Exclusion Criteria:

• Subject is pregnant.
• Subject smokes (smoking includes e-cigarette use)
• Subject has a BMI > 35 and has been classified as morbidly obese or at an increased risk for participation by a medical professional.
• Subject has a history of fainting (vasovagal), blacking out or losing consciousness during or after a blood draw.
• Subject has open wounds, inflamed tattoos or piercings or any visible healing wounds.
• Subject experiences frequent or severe headaches and/or migraine headaches.
• Subject has known drug or alcohol abuse or uses recreational drugs.
• Subject has experienced a concussion or head injury with loss of consciousness within the last year.
• Subject has any chronic bleeding disorders (i.e. hemophilia)
• Subject has any history of a stroke, myocardial infarction, seizures or heart attack.
• Subject has any cancer or history of cancer (not including skin cancer).
• Subject has a chronic neurological disease (i.e. multiple sclerosis, Huntington's disease).
• Subject has any cardiac dysrhythmia(s) (i.e. atrial fibrillation) and has not received clearance from their physician to participate.
• Subject has known neurological and/or psychiatric disorder (i.e. schizophrenia, bipolar disorder) that interferes with the subjects' level of consciousness.
• Subject has any medical condition which in the judgment of the investigator and/or medical staff, renders them ineligible for participation in this study (Discretion of investigator).
• Subject has Wolff-Parkinson-White Syndrome or Stokes - Adams syndrome.
• Subject who has taken anticoagulant medications within the last 30 days.
• Subject has taken opioid pain medication within 24 hours of start of study.
• Subject has any type of infectious disease (i.e. 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, gallbladder, heart, appendix, major fracture repairs (involving plates/ screws), jaw surgery, urinary tract surgery, plastic surgery, major ENT surgery, joint replacement or gynecological surgeries, heart surgery or thoracic surgery.
• Subject has donated blood within the last 2 weeks.
• Subject has symptoms of congestion, head colds, flu or other illnesses.
• Subject experiences claustrophobia or has generalized anxiety disorder.
• Subject has been in severe car accident(s) or a similar type of accident(s) requiring hospitalization within the last 12 months.
• Subject has had a concussion within the past 12 months.
• Subject has chronic unresolved asthma, lung disease or respiratory disease.
• Subject is allergic to lidocaine, latex, adhesives, or plastic.
• Subject has heart conditions, insulin-dependent Diabetes or uncontrolled hypertension.
• Subject has given vaginal delivery, had a pregnancy terminated, a miscarriage with hospitalization, or had a C-section within the past 6 months.
• Subject intends to participate in any heavy lifting, repetitive movement of their wrist (including riding a motorcycle) or exercise (working out, riding a bike, riding a skate board etc.), or any activity that will put additional stress on the wrist within 24 hours of the study.
• Discretion of investigator/study staff.

1 to 5 hours