Innovations in Traumatic Hemorrhage

Traumatic hemorrhagic injuries present a great problem to humanity and a challenge to medicine in the modern world. Current methods of treating these injuries in the field are ineffective and often extremely overkill or injurious. These methods are particularly inadequate when applied to the continuous high pressure bleeding that occurs from arterial wounds. Our project focuses on lowering the barriers to entry to innovation in the field of bleeding treatment by creating a low cost model of the human circulatory system. This model can function as a low-cost testing platform for novel bleeding treatments developed by companies and individuals that do not have the resources to regularly purchase extremely expensive cardiovascular simulators. To this end we designed a tripartite model which included a heart-simulating pump, vessel-simulating vasculature, and blood-mimicking fluid. In order to ensure our device functioned as a testing platform, we performed some preliminary solution candidate tests on it which had the ancillary benefit of identifying one effective but biologically unsafe solution that could be translated into a safe and efficacious future solution. Ultimately we found that our system functioned well as a testing platform for traumatic injury treatments and that standard silicone sealant administered by injection into the vessels had the greatest efficacy in stopping bleeding

An ultrasonic system for intravascular measurement and visualisation of anatomical structures and blood flow

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Non-invasive Multimodal Monitoring in Traumatic Brain Injury

Traumatic brain injury (TBI) is a leading cause of death and disability, often resulting in increased intracranial pressure (ICP) and cerebral ischemia. Current ICP measurement methods involve invasive, non-therapeutic procedures. This research aims to develop a non-invasive, continuous optical system for monitoring ICP and cerebral oxygenation. Using backscattered brain optical signals, it leverages cerebral pulsatile photoplethysmograms (PPGs) and non-pulsatile near-infrared spectroscopy (NIRS) signals to assess ICP and oxygenation. The innovation lies in using cerebral NIRS-PPGs to measure ICP, based on the hypothesis that changes in ICP affect cerebral PPG signal morphology. These changes in morphological features, with the support of advanced algorithms including Machine Learning (ML) models, could be utilised in translating the changes in the pulsatile signals in absolute measurements of ICP. The research firstly implemented Monte Carlo simulations to fully understand the effect of multi-source detector separations on brain light tissue interaction. Secondly, a novel reflectance, custom-made TBI multiwavelength and multisource-detector optical sensor and instrumentation, including advanced signal processing algorithms, was designed to acquire, pre-process, and analyse raw PPG signals (AC + DC) from the brain. Thirdly, a novel head phantom and an in vitro brain haemodynamic system were developed for evaluating the sensor. The phantom was the ideal tool for simulating different clinical scenarios that cannot be implemented in real in vivo studies. Fourthly, this research carried out three in vitro studies to investigate the sensor's capability to non-invasively monitor intracranial pressure and oxygenation. The first study evaluated the quality of the optical signals acquired from the developed probe at different source-detector (S-D) separations and multiple wavelengths. It was concluded that the optimal S-D separation to reach the cerebral tissue, and acquire good quality PPG signals, was within 3 cm and 4 cm. The second study assessed the central hypothesis of this research by recording PPG signals from the phantom’s brain at different intracranial pressure levels and implementing ML models utilising pertinent features from the PPG. Results from the second study showed a correlation coefficient of 0.86, mean absolute error of 3.7 mmHg, and limits of agreement of ±4 mmHg, which suggest that NIRS-PPG signals could estimate ICP non invasively. Finally, a third study demonstrated the sensor’s response to in vitro changes in blood oxygenation levels, with less than 33.8% error in half the measurements compared to the reference. This final implementation of spatially resolved spectroscopy algorithms actualize the proposed non-invasive multimodal monitoring sensor for traumatic brain injury. The novel technological developments and the new knowledge acquired from this research paves the way for the development of a transformative non-invasive optical sensor technology for the continuous monitoring of ICP and cerebral oxygenation in TBI patients and beyond