This story combines two of our favorite things: lasers and cerebral perfusion. From Duke University, researchers report on the use of near-infrared lasers that penetrate scalp and skull, to measure cerebral hemoglobin concentration. When combined with pulse oximetry, this co-oximetry system can approximate cerebral venous oxygenation — without cutting into the head.
Designed by CAS Medical Systems, Inc., the monitor, called a cerebral oximeter, uses one or more sensors attached to the forehead that emit non-harmful, low-level laser light through the skin and skull into the brain. Since the near-infrared light absorption characteristics of the hemoglobin in red blood cells are known, the system can calculate the brain tissue oxygen saturation by measuring the differences in intensity of light as it passes through the brain. When combined with pulse oximetry, the cerebral oximeter may be used to estimate the cerebral venous oxygen saturation.
“It has always been a challenge to directly measure the oxygen levels in the brain,” said Duke anesthesiologist David MacLeod, M.D., who presented the results of the Duke study Oct. 22, 2005, at the annual scientific sessions of the American Society of Anesthesiologists in Atlanta. “The main issues with the invasive approach are that it does not provide specific information in real time, and it is of course invasive, which can carry some risk to the patient.
“This new technology, which is non-invasive and provides real-time information, appears to be an accurate means for measuring cerebral oxygenation and indirectly cerebral perfusion,” MacLeod said. “As anesthesiologists, protecting the brain from potential harm is one of the main functions we perform during a surgical procedure.”
We also think this would be of benefit during resuscitation and in Emergency Medicine.
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