Applying Phase Plane Analysis to Cerebrovascular Autoregulation and Patient Outcome Following Brain Injury

• Main Author: Semkewyc, Courtney Erin
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2019
• Subjects: Biomedical engineering
• ISBN: 9781088328118; 1088328113

Cerebrovascular autoregulation (AR) is an important mechanism within the brain that aims to maintain adequate blood flow to all lobes thus promoting proper brain function. Brain injuries due to a traumatic (TBI) or non-TBI event can damage this internal feedback mechanism leading to an impaired response that can lead to secondary injury in the form of swelling or ischemia. This impaired response is reflected in the intracranial pressure (ICP) waveform in the form of varying peak heights, and enlarged valleys. The ICP waveform could be used as a predictive index of patient cerebrovascular autoregulation state, and outcome through the use of integral phase plane analysis and the phase area ration (PAR). PAR is a method of comparing phase plane areas to assign a numerical value to different waveform shapes, and can be calculated through the use of graphical techniques. To test PAR as a predictive index patients were chosen from a database of hemodynamic data and grouped by injury type (TBI or non-TBI), and outcome (rehab or deceased). PAR was able to determine waveform differences representative of the patient’s physiological state not only in terms of injury type, but outcome as well. PAR can be used as a patient-specific predictor of cerebrovascularautoregulation state and patient outcome through the incorporation of the integral phase plane. PAR provides additional patient information that could aid in improving both patient care and management. To further validate these results and feasibility of the index additional testing is required with an increased patient sample size.