Cerebral Oxygenation Values in Healthy Adults Volunteers Measured With RheoPatch and NIRO-200NX

Study Overview
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Brief Summary
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Noninvasive measurement of cerebral tissue oxygen saturation levels by near infrared spectroscopy (NIRS) is clinical routine in perioperative medicine. One of the main technical challenges of NIRS measurements is to eliminate the influence of signals of the skin and skull. A new device (RheoPatch, Luciole Medical AG, Zurich) has been developed by a company that also developed an intracranial NIRS probe, which allowed measurements directly in the brain and thus improved algorithms for elimination of the extracranial signals. The investigators aim to determine baseline values and performance of the new device (RheoPatch) compared with a more established NIRS device (NIRO-200NX, Hamamatsu Phototonics, Hamamatsu City, Japan)

Detailed Description
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Primary objective is to compare the RheoPatch NIRS device with the NIRO-200NX NIRS device in volunteers at rest in supine position. As secondary objectives, repeatability of the measurements will be tested with optode reapplications. With measurements in Trendelenburg position, the investigators evaluate the influence of body (head) position on the NIRS signals. Primary outcome are the baseline values of cerebral oxygenation levels measured by RheoPatch (SbtO2 (%)) and NIRO-200NX (Tissue oxygenation index: TOI (%)). Secondary endpoints are the repeatability of the measurements with sensor reapplications (coefficient of repeatability, 5 repeats with each device) and changes of the measurements of cerebral oxygenation saturation level in the Trendelenburg position. Measurements of baseline cerebral oxygenation values are obtained in supine position with 10 measurements, alternating between devices. Combined with 5 min measurement phase for equilibration and power adjustment, this will require 33 minutes per participant.

Official Title
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Comparison of Cerebral Oxygenation Values in Healthy Adults

Conditions
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Healthy, Adults

Intervention / Treatment
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* Device: Cerebral oximetry using Rheopatch
* Device: Cerebral oximetry using NIRO-200NX


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects fulfilling all of the following inclusion criteria are eligible for the investigation: Informed Consent signed by the subject Subjective good health Exclusion Criteria: The presence of any one of the following exclusion criteria will lead to the exclusion of the subject Age (<18, > 65 yrs.) Forehead skin disease Allergy to skin contacting components of NIRS-sensors Known cerebrovascular and heart diseases

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Device: Cerebral oximetry using Rheopatch|On the study visit, baseline demographic data (age and gender, BMI) are collected. In supine position the sensor patches (left and right) of the device are applied to the forehead and the cerebral oxymetry values are recorded during 120sec. The sensor patches are then removed and the patches of the second device are applied on the same position on the forehead and the measurement is carried out as described before. For the first measurement of each sensor, a total of 5 minutes equilibration and sensor output power adjustment is allowed. A total of 10 measurements are taken, 5 with each device. The volunteer is then placed in Trendelenburg position and another 4 measurements are made (2 with each device) as previously described.|
|Device: Cerebral oximetry using NIRO-200NX|On the study visit, baseline demographic data (age and gender, BMI) are collected. In supine position the sensor patches (left and right) of the device are applied to the forehead and the cerebral oxymetry values are recorded during 120sec. The sensor patches are then removed and the patches of the second device are applied on the same position on the forehead and the measurement is carried out as described before. For the first measurement of each sensor, a total of 5 minutes equilibration and sensor output power adjustment is allowed. A total of 10 measurements are taken, 5 with each device. The volunteer is then placed in Trendelenburg position and another 4 measurements are made (2 with each device) as previously described.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cerebral oxygen saturation level | Primary endpoint is the cerebral oxygen saturation level measured by RheoPatch (SbtO2 (%)) and NIRO-200NX (Tissue oxygenation index: TOI (%)). This is the value used for clinical decision making in the daily routine when NIRS measurement devices are used in perioperative medicine or intensive care applications and therefore the most relevant value. | One day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes of the measurements of cerebral oxygenation saturation level (SbtO2 (%) and TOI (%)) | SbtO2 and TOI changes are measured | One day | 
| nTHI_NIRO | Normalized tissue hemoglobin index: nTHI (absolute value in arbitrary unit) | One day | 
| ΔO2Hb_NIRO | Oxygenated hemoglobin change: ΔO2Hb (μmol/L) | One day | 
| ΔHHb_NIRO | Deoxygenated hemoglobin change: ΔHHb (μmol/L) | One day | 
| ΔcHb_NIRO | Total hemoglobin change: ΔcHb (μmol/L) | One day | 
| aH2O_RP | Absolute concentration of brain tissue water: aH2O (mmol/L) | One day | 
| aHbDeoxy_RP | Absolute concentration of deoxygenated hemoglobin: aHbDeoxy (μmol/L) | One day | 
| aHbOxy_RP | Absolute concentration of oxygenated hemoglobin: aHbOxy (μmol/L) | One day | 
| aHbTotal_RP | Absolute concentration of total hemoglobin: aHbTotal (μmol/L) | One day | 
| ΔO2Hb_RP | Oxygenated hemoglobin change: ΔO2Hb (μmol/L) | One day | 
| ΔHHb_RP | Deoxygenated hemoglobin change: ΔHHb (μmol/L) | One day | 
| ΔcHb_RP | Total hemoglobin change: ΔcHb (μmol/L) | One day |