UBC Theses and Dissertations
Optical monitoring of spinal cord oxygenation and hemodynamics in acute traumatic spinal cord injury Cheung, Amanda
One of the only available treatment options to potentially improve neurologic recovery after acute spinal cord injury (SCI) is to augment the mean arterial blood pressure (MAP) to promote blood flow and oxygen delivery to the injured spinal cord. However, to optimize such hemodynamic management, clinicians would require a method to monitor the physiological effects of these MAP alterations within the injured cord. To address this need, I developed a technique using an implantable optical sensor based on near-infrared spectroscopy (NIRS) to monitor real-time spinal cord tissue oxygenation and hemodynamics after acute SCI. NIRS is an optical technology that uses light in the near-infrared spectrum to monitor changes in the concentrations of oxygenated and deoxygenated hemoglobin, from which changes in tissue oxygenation and perfusion can be inferred. In Chapter 1, I provide an overview of acute SCI and hemodynamic management and discuss the background of NIRS and its application on the spinal cord. In Chapter 2, I use a porcine model of thoracic SCI to study the effect of early vasopressor administration on oxygenation and hemodynamic responses within the spinal cord using intraparenchymal sensors. In Chapter 3, I investigate the feasibility and effectiveness of using an implantable NIRS sensor to monitor real-time spinal cord tissue oxygenation and hemodynamics during the first 7 days post- injury in the porcine model. In Chapter 4, I use the experimental protocol and analytical processes developed in Chapter 3 to evaluate refined and improved versions of the NIRS system for clinical application. In Chapter 5, I assess the accuracy of the clinical NIRS system to gold-standard intraparenchymal sensors and reference NIRS systems in both skeletal muscle and a porcine model. Through these pre-clinical studies, I have established a technique to monitor the oxygenation and hemodynamic status of the injured spinal cord to optimize clinical care. This work lays the foundation for direct monitoring of the spinal cord prior to its clinical translation and provides a broad landscape of oxygenation and hemodynamic responses in the spinal cord as reference for future work, as well as a resource for future studies developing and evaluating such technologies.
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