The purpose for this study is to measure the physiology of human undergoing a Lower Body
Negative Pressure usea non-invasive low-power optical technique, near-infrared diffuse
optical spectroscopy measurement and compare these measurement to standard monitoring
procedures delineated in the Brooke Army Medical Center.
The Brooke Army Medical Center can use near-infrared diffuse optical spectroscopy to provide
functional physiologic tissue and organ information without ionizing radiation and without
withdrawing any blood, in a cost-effective and rapid manner. Monitoring for the onset of
circulatory shock in a wounded soldier on the battlefield is typically performed by
measurement of arterial blood pressure, arterial oxygen saturation, or simple auscultation
of the pulse. Shock is typically recognized by non-specific signs and subjective symptoms
such as cold clammy skin, pallor, weak thready pulse, unstable vital signs, and diminished
The near-infrared diffuse optical spectroscopy can measure tissue regions deeper below the
skin surface and reports on larger tissue volumes in muscle and brain. The near-infrared
diffuse optical spectroscopy instrument generate harmless amounts of low-level non-ionizing
near-infrared ligh can measure the tissue absorption and scattering properties at depths of
1 cm or more below the skin surface include larger tissue volumes in muscle and brain. The
absorption properties of tissue provide and can determine absolute concentrations of
deoxygenated hemoglobin, oxygenated hemoglobin, and water, as well as the total hemoglobin
- Healthy nonsmoking normotensive males or females.
- Age 18 to 55 years old, Military or civilian.
- Active duty military members who are 17 years old
- Age <18 and >55 years, except for 17 year old active duty military members.
- History of hyperthyroidism,hypertension, cardiovascular abnormalitY, respiratory
illnesses,anaphylaxis,pre-syncopal/syncopal episodes,abnormal blood clotting,
- Taking drugs to alter autonomic function
- History of alcohol or drug abuse