VCU researchers develop novel method for measuring oxygen level in tissues

By Joe Kuttenkuler

Virginia Commonwealth University researchers have developed and patented a new means of measuring blood oxygen levels in tissue – a key barometer of how well the body is functioning, especially during a trauma as inadequate oxygenation can lead to organ failure and death.

The new technology uses a low-energy laser light that is shone under the tongue to measure how well the tissues are receiving and using oxygen. Researchers believe the technology, once moved from the lab to the clinic, potentially could be used with burn, cardiac arrest, heart failure, sepsis, traumatic brain injury, sickle cell and wound care patients.

Researchers in VCU’s Reanimation Engineering Shock Center, VCURES, modified a decades-old technology called resonance Raman spectroscopy to track changes in hemoglobin oxygen saturation in tissues.

The modified use of the Raman spectroscopy represents one of the first real-time biomedical tissue applications of the technique, according to Kevin Ward, M.D., associate professor in the Department of Emergency Medicine at the VCU Medical Center, who co-authored one of two studies on the technique and is a co-inventor.

During emergencies, time is critical and medical personnel have few tools to assess tissue oxygenation in patients, according to Ward.

“Failure to recognize inadequate tissue oxygenation and correct it in a timely manner can lead to severe complications such as organ failure and death,” said Ward. “This noninvasive spectroscopy technique may give healthcare providers the ability to rapidly diagnose, treat and track how effectively they are treating patients.” 

Two recent VCU studies found the modified Raman spectroscopy technology was as accurate as directly measuring the level of hemoglobin oxygen saturation. One of these studies – using an animal model of hemorrhagic shock – demonstrated that the Raman technique detected inadequate tissue oxygenation as well or better than drawing blood from a vessel near the right atrium of the heart – a much more invasive and time-consuming procedure.  

“The possibility of being able to obtain the same critical data in a few seconds by shining a light under a patient’s tongue versus a lengthy and potentially dangerous procedure to place a catheter into a major vessel near the heart is very exciting,” said Ward.  

Ward also indicated the technique may prove extremely valuable in the laboratory study of how oxygen is transported from capillaries to tissues and in the development of blood substitutes.

The studies were funded by the Office of Naval Research’s Combat Casualty Care Program. The first was published July 2005 in American Journal of Physiology-Heart and Circulatory Physiology. The second study will appear next month in the journal Critical Care Medicine. 

The U.S. Patent and trademark Office has issued VCU a patent for the method.

Other members of the VCURES team include Ivo Torres Filho, M.D., Ph.D. and Leonardo Somero III, VCU Department of Anesthesiology; James Terner, Ph.D., VCU Department of Chemistry; R. Wayne Barbee, Ph.D., Hakam Tiba, M.D., Penny Reynolds, Ph.D., VCU Department of Emergency Medicine; Roland Pittman Ph.D., and Luciana Torres Ph.D., VCU Department of Physiology; and Rao Ivatury M.D., VCU Department of Surgery. VCURES is a multidisciplinary center dedicated to improving survival from critical illness and injury. Their Web site is www.vcures.org.