This study involves comparison of the performance of two SpHb sensors in subjects that undergo a hemodilution procedure. The sensors' performance will be assessed by comparison of the measured hemoglobin values against reference values obtained by a laboratory hematology analyzer. Blood samples will be collected from healthy volunteers who undergo a hemodilution procedure wherein blood is repeatedly sampled as the concentration of hemoglobin is reduced by administering intravenous fluids to the volunteer in a controlled manner.

Inclusion Criteria:

• Competent adults between the ages of 18 and 50 years of age
• Must weigh a minimum of 110 lbs and no more than 250 lbs unless subject is over 6 feet tall
• BMI ≤ 35 unless the physician determines that a higher BMI is not due to morbid obesity, to safeguard subject safety during hemodilution
• Must have a hemoglobin value ≥ 11 g/dL at time of screening, to safeguard subject safety during hemodilution
• Baseline heart rate between 45 bpm and 85 bpm
• CO value less than 2.0% FCOHb
• Physical status of ASA I or II (American Society of Anesthesiology Class I; Healthy subjects without any systemic disease at all. American Society of Anesthesiology Class II; subjects with mild systemic disease) The ASA definition strictly applies to the systemic disease portion of the classification
• Systolic BP less than or equal to 140 mmHg and Diastolic BP less than or equal to 90 mmHg
• Able to read and communicate in English

Exclusion Criteria:

• Pregnancy or positive hCG test
• Smokers (including e-cigarette users)
• Subject has known drug or alcohol abuse. Subjects who uses recreational drugs
• Subject has experienced a concussion or head injury with loss of consciousness within the last year
• Any chronic bleeding disorders (i.e. hemophilia)
• Any history of a stroke, myocardial infarction, or seizures
• Any cancer or history of cancer (not including skin cancer)
• Chronic neurological diseases (i.e. multiple sclerosis, Huntington's Disease)
• Any cardiac dysrhythmias (i.e. atrial fibrillation)(without physicians clearance)
• Subject has known neurological and/or psychiatric disorder (i.e. schizophrenia, bipolar disorder) that interferes with the subject's level of consciousness
• Subject has Wolff-Parkinson-White Syndrome or Stokes-Adams Syndrome
• Subjects who have/are currently taking anticoagulant medication
• Subjects who have taken opioid pain medication within 24 hours of start of study
• Subjects who do not understand the study and the risks
• Subjects having either signs or history of peripheral ischemia
• Subjects who have 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
• Subjects that have symptoms of congestion, head colds, flu, or other illnesses
• Subjects with claustrophobia, or generalized anxiety disorder
• Subjects who have been in severe car accident(s) or a similar type of accident(s) requiring hospitalization within the last 12 months
• Subjects with chronic unresolved asthma, lung disease and respiratory disease
• Subjects with allergies to lidocaine, latex, adhesives, or plastic
• Subjects with heart conditions, insulin-dependent diabetes or uncontrolled hypertension
• Subjects who have given vaginal delivery, had a pregnancy terminated, a miscarriage with hospitalization or had a c-section within the last 6 months
• Subjects who intend on participating 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 following a study involving an arterial blood draw and/or arterial line placement
• 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)

1 to 5 hours

Adverse Events were not collected with respect to the interventions, only on participants as a whole.