Minimally Invasive Cerebral Blood Flow and Oxygenation Monitoring for Intracranial Hypertension

Contact PD/PI: Floyd, Thomas ABSTRACT/PROJECT SUMMARY Traumatic brain injury, acute ischemic stroke, and intracerebral hemorrhage are frequently complicated by intracranial hypertension leading to progressive ischemia and secondary brain injury. Recent efforts focused on improving outcomes have therefore been focused upon improving cerebral oxygenation and the development of monitoring devices to guide therapy. Current devices designed to measure tissue oxygenation are, however, severely limited in their scope of surveillance and accuracy. Surface oximetry monitors interrogate only superficial brain tissue, with contamination from intervening skin and skull. Intraparenchymal brain tissue oxygen probes survey relatively metabolically less active white matter (compared to gray matter), a volume of less than 3 mm3, and at a single location. Lastly, intraparenchymal tissue oxygen monitors are bulky, incompatible with magnetic resonance imaging, and have yet to demonstrate clinical efficacy. To fill this need, we will finalize the development of a brain-specific, minimally invasive, optical blood flow and oxygenation monitoring system (FLOXBR), then translate this device to humans. The FLOXBR, employing diffuse optical and correlation spectroscopies via a brain surface probe, may offer improved sensitivity and specificity compared to non-invasive probes and will probe larger volumes than currently available invasive probes, such as the LicoxTM tissue pO2 probe. Unlike intraparenchymal probes, this device can lie above or below the dura and will be more sensitive to highly metabolically active gray matter. Its small size and flexibility will permit multiple probes to be placed through a single burr hole, thus allowing for the monitoring of regional differences in flow and oxygenation. Unlike surface oximetry, the FLOXBR is not impacted by superficial trauma or edema, improving reliability and sensitivity. Continuous, easily interpreted, and reliable minimally invasive monitoring of cerebral oxygen delivery may enhance management and outcomes in patients suffering from intracranial hypertension. Our aims are succinctly summarized below. Aim 1) Finalize development & manufacture the FLOXBR brain flow and oximetry monitoring device. Aim 2) Pre-clinical device evaluation, measurement validation, and safety testing of FLOXBR. Aim 3) Complete regulatory and safety requirements to support FLOXBR first-in-humans feasibility testing. Aim 4) Conduct first-in-humans feasibility testing. Project Summary/Abstract Page 7