Person: Franceschini, Maria
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Franceschini
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Maria
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Franceschini, Maria
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Publication Validation of a novel wearable, wireless technology to estimate oxygen levels and lactate threshold power in the exercising muscle(John Wiley and Sons Inc., 2018) Farzam, Parisa; Starkweather, Zack; Franceschini, MariaAbstract There is a growing interest in monitoring muscle oxygen saturation (SmO2), which is a localized measure of muscle oxidative metabolism and can be acquired continuously and noninvasively using near‐infrared spectroscopy (NIRS) methods. Most NIRS systems are cumbersome, expensive, fiber coupled devices, with use limited to lab settings. A novel, low cost, wireless, wearable has been developed for use in athletic training. In this study, we evaluate the advantages and limitations of this new simple continuous‐wave (CW) NIRS device with respect to a benchtop, frequency‐domain near‐infrared spectroscopy (FDNIRS) system. Oxygen saturation and hemoglobin/myoglobin concentration in the exercising muscles of 17 athletic individuals were measured simultaneously with the two systems, while subjects performed an incremental test on a stationary cycle ergometer. In addition, blood lactate concentration was measured at the end of each increment with a lactate analyzer. During exercise, the correlation coefficients of the SmO2 and hemoglobin/myoglobin concentrations between the two systems were over 0.70. We also found both systems were insensitive to the presence of thin layers of varying absorption, mimicking different skin colors. Neither system was able to predict the athletes’ lactate threshold power accurately by simply using SmO2 thresholds. Instead, the proprietary software of the wearable device was able to predict the athletes’ lactate threshold power within half of one power increment of the cycling test. These results indicate this novel wearable device may provide a physiological indicator of athlete's exertion.Publication Non-invasive Assessment of Cerebral Blood Flow and Oxygen Metabolism in Neonates during Hypothermic Cardiopulmonary Bypass: Feasibility and Clinical Implications(Nature Publishing Group, 2017) Ferradal, Silvina L.; Yuki, Koichi; Vyas, Rutvi; Ha, Christopher G.; Yi, Francesca; Stopp, Christian; Wypij, David; Cheng, Henry; Newburger, Jane; Kaza, Aditya; Franceschini, Maria; Kussman, Barry; Grant, P.The neonatal brain is extremely vulnerable to injury during periods of hypoxia and/or ischemia. Risk of brain injury is increased during neonatal cardiac surgery, where pre-existing hemodynamic instability and metabolic abnormalities are combined with long periods of low cerebral blood flow and/or circulatory arrest. Our understanding of events associated with cerebral hypoxia-ischemia during cardiopulmonary bypass (CPB) remains limited, largely due to inadequate tools to quantify cerebral oxygen delivery and consumption non-invasively and in real-time. This pilot study aims to evaluate cerebral blood flow (CBF) and oxygen metabolism (CMRO2) intraoperatively in neonates by combining two novel non-invasive optical techniques: frequency-domain near-infrared spectroscopy (FD-NIRS) and diffuse correlation spectroscopy (DCS). CBF and CMRO2 were quantified before, during and after deep hypothermic cardiopulmonary bypass (CPB) in nine neonates. Our results show significantly decreased CBF and CMRO2 during hypothermic CPB. More interestingly, a change of coupling between both variables is observed during deep hypothermic CPB in all subjects. Our results are consistent with previous studies using invasive techniques, supporting the concept of FD-NIRS/DCS as a promising technology to monitor cerebral physiology in neonates providing the potential for individual optimization of surgical management.Publication Near-infrared Spectroscopy Assessment of Cerebral Oxygen Metabolism in the Developing Premature Brain(Nature Publishing Group, 2012) Roche-Labarbe, Nadege; Fenoglio, Angela Joyce; Aggarwal, Alpna; Dehaes, Mathieu; Carp, Stefan; Franceschini, Maria; Grant, Patricia EllenLittle is known about cerebral blood flow, cerebral blood volume (CBV), oxygenation, and oxygen consumption in the premature newborn brain. We combined quantitative frequency-domain near-infrared spectroscopy measures of cerebral hemoglobin oxygenation \((SO_2\)) and CBV with diffusion correlation spectroscopy measures of cerebral blood flow index \((BF_{ix}\)) to determine the relationship between these measures, gestational age at birth (GA), and chronological age. We followed 56 neonates of various GA once a week during their hospital stay. We provide absolute values of \(SO_2\) and CBV, relative values of \(BF_{ix}\), and relative cerebral metabolic rate of oxygen (\(rCMRO_2\)) as a function of postmenstrual age (PMA) and chronological age for four GA groups. \(SO_2\) correlates with chronological age (r=−0.54, P value \(\leq\)0.001) but not with PMA (r=−0.07), whereas \(BF_{ix}\) and \(rCMRO_2\) correlate better with PMA (r=0.37 and 0.43, respectively, P value \(\leq\)0.001). Relative \(CMRO_2\) during the first month of life is lower when GA is lower. Blood flow index and \(rCMRO_2\) are more accurate biomarkers of the brain development than \(SO_2\) in the premature newborns.Publication Assessment of the Frequency-Domain Multi-Distance Method to Evaluate the Brain Optical Properties: Monte Carlo Simulations from Neonate to Adult(Optical Society of America, 2011) Dehaes, Mathieu; Grant, P.; Sliva, Danielle D.; Roche-Labarbe, Nadege; Pienaar, Rudolph; Boas, David; Franceschini, Maria; Selb, Juliette JThe near infrared spectroscopy (NIRS) frequency-domain multi-distance (FD-MD) method allows for the estimation of optical properties in biological tissue using the phase and intensity of radiofrequency modulated light at different source-detector separations. In this study, we evaluated the accuracy of this method to retrieve the absorption coefficient of the brain at different ages. Synthetic measurements were generated with Monte Carlo simulations in magnetic resonance imaging (MRI)-based heterogeneous head models for four ages: newborn, 6 and 12 month old infants, and adult. For each age, we determined the optimal set of source-detector separations and estimated the corresponding errors. Errors arise from different origins: methodological (FD-MD) and anatomical (curvature, head size and contamination by extra-cerebral tissues). We found that the brain optical absorption could be retrieved with an error between 8-24% in neonates and infants, while the error increased to 19-44% in adults over all source-detector distances. The dominant contribution to the error was found to be the head curvature in neonates and infants, and the extra-cerebral tissues in adults.