Fiber-optic light delivery method monitors blood during surgery in real time

An optical fiber works to beam light through blood and interpret the signals that bounce back for real-time monitoring.

A University of Central Florida (UCF; Orlando, FL) professor has developed a way to use light to continuously monitor a surgical patient's blood, providing a real-time status during life-and-death operations. The technology, developed by Aristide Dogariu, Pegasus Professor in UCF's College of Optics & Photonics, uses an optical fiber to beam light through blood and interpret the signals that bounce back. The work could someday—in some situations—replace the need for doctors to wait while blood is drawn from a patient and tested.

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During surgery, physicians are wary of the patient's blood coagulating (clotting) too quickly. A clot can lead to life-threatening conditions such as stroke or pulmonary embolism. Coagulation is of particular concern during cardiovascular surgery, when a clot can shut down the heart-lung machine used to circulate the patient's blood. So, doctors administer blood-thinning medication to prevent coagulation—however, every 20-30 minutes, blood must be withdrawn and taken to a lab for a test that can take up to 10 minutes.

Recognizing this, Dogariu developed a machine with an optical fiber that can tap directly into the tubes of the heart-lung machine. The optical fiber beams light at the blood passing through the tube and detects the light as it bounces back. The machine constantly interprets the light's backscatter to determine how rapidly red blood cells are vibrating. Slow vibration is a sign blood is coagulating and a blood-thinner may be needed.

The technology can alert doctors at the first sign of clotting, and provide nonstop information throughout a long procedure. "It provides continuous feedback for the surgeon to make a decision on medication," Dogariu says.

Dr. William DeCampli, who is chief of pediatric cardiac surgery at Arnold Palmer Hospital for Children and a professor at the UCF College of Medicine, helped develop the technology. Over the past year, DeCampli tested the technology during cardiac surgeries on 10 infants at Arnold Palmer Hospital for Children.

A larger study is in the works, the researchers say.

Full details of the work appear in the journal Nature Biomedical Engineering; for more information, please visit http://dx.doi.org/10.1038/s41551-017-0028.

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