Hyperspectral Near Infrared Assessment Of The Brain In Cardiac Arrest
thesisposted on 22.05.2021, 16:13 by Thu Nga Nguyen
Two-thirds of out-of-hospital cardiac arrest patients, who survive to hospital admission, die in the hospital from neurological injuries related to cerebral hypoperfusion. Hyperspectral near infrared spectroscopy (hNIRS) is a non-invasive technique that measures the major chromophores in the brain, such as oxygenated hemoglobin, deoxygenated hemoglobin and cytochrome C oxidase (CCO), an intracellular marker of oxygen consumption. We have demonstrated that hNIRS can detect changes in cerebral oxygenation and metabolism in patients undergoing transcatheter aortic valve insertion (TAVI) – a procedure that temporarily induces sudden hypotension and hypoperfusion that mimics cardiac arrest. Using multi-distance hNIRS, we found that while measured regional oxygen saturation (rSO2) changes resulted mainly from the extra-cerebral tissues, CCO changes during cardiac arrests occurred mainly in the brains of patients. We also applied the hNIRS algorithm based on the “2-layer model” to the data to measure cerebral oxygen saturation and CCO in patients during the procedure. We found that changes in all the parameters scale with the thickness of the extra-cerebral layer. Finally, the results of the comparison of breath holding measurement by using multispectral NIRS algorithm with the selected wavelength combinations from a previous study on animal suggests that changes in CCO could be measured, however wavelengths need to be further optimized for the adult patients.