Knowra Near-infrared spectroscopy Near-infrared spectroscopy Near-infrared spectroscopy estimates tissue oxygenation by measuring how near-infrared light is absorbed as it passes through tissue. Its readings reflect changes in oxygenated and deoxygenated hemoglobin.
Near-infrared light : Electromagnetic radiation with wavelengths just beyond visible red light, commonly defined as about 700–2500 nanometers. These wavelengths penetrate tissue deeply enough for oxygen-sensitive measurements.
Cerebral oximetry : Monitoring of regional oxygen saturation in brain tissue, often using near-infrared spectroscopy. It is a prominent clinical use of NIRS during surgery and critical care.
Pulse oximetry : A noninvasive method that estimates arterial oxygen saturation from light absorption, usually at a fingertip or earlobe. It estimates arterial saturation, whereas NIRS samples a mixture of arterial, venous, and capillary tissue blood.
Optical scattering in biological tissue : The redirection of light by microscopic structures within living tissue. Scattering changes photon paths and makes the sampled volume difficult to define.
Hemoglobin : The oxygen-binding protein in red blood cells that carries most oxygen through the blood. Its oxygenated and deoxygenated forms absorb near-infrared light differently.
Muscle oxygenation : The balance of oxygen supply and consumption in skeletal muscle. NIRS can track local changes during exercise and recovery.
Arterial blood gas test : A blood test measuring oxygen, carbon dioxide, and acidity in an arterial sample. It gives direct blood-gas measurements rather than a continuous local tissue estimate.
Extracerebral contamination : Influence of superficial tissues, such as scalp and skull, on optical measurements intended to reflect brain tissue. These tissues can contribute substantially to signals labeled cerebral oxygenation.
Beer–Lambert law : A relation connecting light attenuation to the concentration of absorbing substances and the distance light travels through them. It underlies estimates of chromophore changes from measured light attenuation.
Neonatal monitoring : Clinical observation of newborns’ physiological status, including oxygen delivery to organs. NIRS can monitor regional oxygenation in vulnerable newborns.
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