Near-infrared spectroscopy during lower body negative pressure

Near-infrared spectroscopy during lower body negative pressure - NIRS during LBNP

Status

Active, not recruiting

Phases

Unknown

Study type

Observational

Source

NL-OMON

Registry ID

NL-OMON33113

Enrollment

Registered

2009-09-14

Start date

2009-03-01

Completion date

Unknown

Last updated

2024-05-06

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Hemorrhagic shock Hypovolemia

Interventions

None listed

Eligibility

Age

18 Years to 99 Years

Inclusion criteria

Inclusion criteria: Healthy Normotensive Non-smoking > 18 years

Exclusion criteria

Exclusion criteria: Smoking Diabetes Hypertension Cardiovascular disease

Design outcomes

Primary

Measure	Time frame
Hemodynamic measurements Heart rate, beat-by-beat SBP, diastolic blood pressure, and stroke volume will be measured non-invasively using an infrared finger photoplethysmograph (Finometer Blood Pressure Monitor, TNO-TPD Biomedical Instrumentation, Amsterdam, The Netherlands) and a bio-impedance measurement system (Cheetah BioImpedance Cardiography). The Finometer blood pressure cuff will be placed on the middle finger of the left hand which, in turn, will be laid at heart level. Mean arterial pressure will be calculated by dividing the sum of SBP and twice diastolic blood pressure by 3. Non-invasive measurement of forearm and thenar oxygen saturation All patients will be tested with one multi-depth InSpectra device on the forearm and one multi-depth InSpectra device on the thenar, simultaneously. StO2 will be continuously and non-invasively measured using two InSpectra Tissue Spectrometers (Multi-depth Model, Hutchinson Technology Inc., Hutchinson, MN), which use reflectance mode probes which have one 1.5 mm optical fiber to illuminate the tissue and 3 optical fibers to detect the backscattered light from the tissue. The spatial separation between the illumination fiber and the 3 detection fibers will be 2.5, 15, and 25 mm. The relative optical attenuation of the backscattered light at four wavelengths (680, 720, 760, and 800 nm) is measured to calculate two second-derivative attenuation values, one centered at 720 nm, and the other at 760 nm. A ratio of the 720 nm to 760 nm second derivative values is directly related to StO2, defined as [HbO2]/[Hb]+[HbO2], via a calibration table. The calibration table relating StO2 to the second derivative attenuation ratio is stored permanently within the monitor and common to each monitor and probe used. The NIRS devices were calibrated before the first measurement in each subject using a light-scatter calibrator. The devices are both equipped with two temperature sensors: one for core temperature mea	—

Measure

Time frame

Hemodynamic measurements Heart rate, beat-by-beat SBP, diastolic blood pressure, and stroke volume will be measured non-invasively using an infrared finger photoplethysmograph (Finometer Blood Pressure Monitor, TNO-TPD Biomedical Instrumentation, Amsterdam, The Netherlands) and a bio-impedance measurement system (Cheetah BioImpedance Cardiography). The Finometer blood pressure cuff will be placed on the middle finger of the left hand which, in turn, will be laid at heart level. Mean arterial pressure will be calculated by dividing the sum of SBP and twice diastolic blood pressure by 3. Non-invasive measurement of forearm and thenar oxygen saturation All patients will be tested with one multi-depth InSpectra device on the forearm and one multi-depth InSpectra device on the thenar, simultaneously. StO2 will be continuously and non-invasively measured using two InSpectra Tissue Spectrometers (Multi-depth Model, Hutchinson Technology Inc., Hutchinson, MN), which use reflectance mode probes which have one 1.5 mm optical fiber to illuminate the tissue and 3 optical fibers to detect the backscattered light from the tissue. The spatial separation between the illumination fiber and the 3 detection fibers will be 2.5, 15, and 25 mm. The relative optical attenuation of the backscattered light at four wavelengths (680, 720, 760, and 800 nm) is measured to calculate two second-derivative attenuation values, one centered at 720 nm, and the other at 760 nm. A ratio of the 720 nm to 760 nm second derivative values is directly related to StO2, defined as [HbO2]/[Hb]+[HbO2], via a calibration table. The calibration table relating StO2 to the second derivative attenuation ratio is stored permanently within the monitor and common to each monitor and probe used. The NIRS devices were calibrated before the first measurement in each subject using a light-scatter calibrator. The devices are both equipped with two temperature sensors: one for core temperature mea

—

Secondary

Measure	Time frame
n.v.t	—

Countries

Netherlands

Outcome results