Retinal Oximeter for Detection of Brain Tissue Hypoxia in TBI
Developing a potential non-invasive means of monitoring brain tissue oxygenation
Project at a Glance
Product Type:
Device
Project Start Date:
7/1/2022
Principal Investigators:
Wei Zhang, PhD
Yannis Paulus, MD
Joseph Myers, OD
Solution Sheet:
Available soon
Funding History:
$165,639 in non-dilutive funding • 2022 $165,639 Massey Grand Challenge • Substantial departmental, school and center based support
Overview
To create a non-invasive means of monitoring brain tissue oxygenation (pBTO2), the team has developed an innovative tool for retinal oximetry (RO). A specialized camera obtains a real time photograph of the retinal vasculature using 2 different wavelengths of light. One wavelength, the control, results in a signal that is independent of oxygen saturation while the other wavelength will produce a signal or color change in vasculature that is sensitive to the level of hemoglobin saturation.
The team has also developed an algorithm that uses the signals obtained in this paradigm to create a map of the optical densities of the retinal vasculature under the two lighting conditions. The algorithm then compares the two signals for each blood vessel to produce a calculated optical density ratio (ODR). The ODR has previously been shown to be linearly related to the oxygen saturation of hemoglobin.
Image credit: Shutterstock
Significant Need
A major obstacle in treating severe TBI is the ongoing need for invasive monitoring due to the lack of accurate noninvasive monitoring options, especially within the “golden hours” after injury.
Currently, there are no means of non-invasively measuring the oxygenation of brain tissue. A variety of techniques have been proposed in the past, but none have been validated for widespread clinical use to date.
Competitive Advantage
Though most commonly considered a part of the eye, the retina is a key part of the central nervous system. The retina receives its blood supply from the intracranial internal carotid artery, which also provides the anterior circulation of the brain. As such, oxygenation of the retina may be susceptible to global intracranial pathology that would affect cerebral blood flow, such as high intracranial pressure, increased cerebral edema, or the secondary cascade of TBI. RO utilizes the color difference between oxygenated hemoglobin and deoxygenated hemoglobin, similar to the widely used peripheral pulse oximeter, in order to calculate retinal tissue oxygenation.
The team hypothesizes that non-invasive RO can be used as a surrogate for pBTO2 and will provide a non-invasive means of directing clinical care for severe TBI within the golden hours of injury and beyond.
Funding Organization(s)
Publications
None at this time