Translação de um sistema de óptica de difusão para monitoramento de pacientes neurocríticos

Author(s)

Rodrigo Menezes Forti

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin
• Defense date: 2020-01-28

Examining board members

Rickson Coelho Mesquita; Alessandra Tomal; Mônica Alonso Cotta; Cristina Kurachi; William Andrew Kofke

• Advisor: Rickson Coelho Mesquita

Abstract

Cerebrovascular diseases are one of the main causes of death and disability worldwide. In 2015, there were more than 590.000 patients hospitalized due to cerebrovascular diseases in Brazil, with approximately 100.000 deaths. Prevention of secondary damage is an important goal in the treatment of severe neurological conditions, such as head trauma and stroke. However, there is currently a lack of non-invasive methods for continuous monitoring of cerebral physiology in real-time. More recently, diffuse optical spectroscopy (DOS) and diffuse correlation spectroscopy (DCS) have been proposed as noninvasive and continuous bedside monitors capable of providing neurophysiology information in neurocritical patients. By shining near-infrared light from the scalp, DCS can measure microvascular cerebral blood flow (CBF), and DOS can measure oxy- and deoxy-hemoglobin concentrations. The combination of DOS and DCS has been previously explored to monitor patients in several clinical scenarios, such as neonatal monitoring, during cerebrovascular interventions, and for monitoring of neurocritical patients. However, the reliability of the technique to provide accurate real-time information during longitudinal (i.e., across multiple days) measurement as well as during a few different clinical interventions remains largely unaddressed. The main goal of this thesis was to show that diffuse optics can reliably aid in monitoring cerebrovascular diseases, in real-time. To that end, we have translated a diffuse optical system to different clinic environments: during long-term monitoring of patients inside an intensive care unit, as well as during an endovascular treatment of stroke. First, we reported the construction and translation of a hybrid diffuse optical system combining DOS and DCS for real-time monitoring of cerebral physiology in a neuro intensive care unit. By presenting two representative case-studies, we show that the neurophysiological parameters measured by diffuse optics at the bedside are consistent with the clinical evolution of the patients. Then, we reported the translation of diffuse optics to monitor frontal-lobe cerebral hemodynamic changes during endovascular treatment of two patients with ischemic stroke due to internal carotid artery occlusions. The monitoring instrument identified a recanalization-induced increase in ipsilateral CBF with little or no concurrent change in contralateral CBF and extracerebral blood flow. Taken together, our results showed that diffuse optics holds promise for monitoring secondary damage in neurocritical patients, with minimal interference with current clinical practices. Additionally, our results suggest that cerebral hemodynamic monitoring with diffuse optics has the potential to guide therapy based on the individual physiology of neurocritical patients. Last, to improve the reliability of the diffuse optical techniques, we have also proposed the implementation of improved algorithms for data analysis. We showed that by using a two-layer model for DOS/DCS, we can improve the accuracy of diffuse optics in recovering the cerebral hemodynamic changes (AU)

• FAPESP's process: 14/25486-6 - Construction and evaluation of a frequency-domain diffuse optical spectroscopy device for brain monitoring in the clinic
• Grantee: Rodrigo Menezes Forti
• Support Opportunities: Scholarships in Brazil - Doctorate