Real time myoglobin saturation measurement to assess benefit of RBC transfusion

ABSTRACT Clinical thresholds for blood transfusions vary by illness and medical specialty and are largely based on anecdotal experience Measured hematocrit is the most frequent determinant for clinical decisions to transfuse blood often resulting in a one size fits all approach Although lifesaving at times blood transfusions have also been clearly shown to increase morbidity and mortality Thus an objective measure of cellular oxygenation is needed to work toward a patient centered approach to blood utilization A noninvasive and continuous measurement of cellular oxygenation as proposed in this application will alert clinicians to the presence and degree of cellular hypoxia and help direct patient specific clinical decisions By measuring and analyzing full optical spectra in the visible and near infrared regions at three source detector separations Opticyteandapos s CellSat will quantify myoglobin saturation in muscle cells separately from hemoglobin saturation in the vasculature Since the goal of red blood cell RBC transfusion is to improve cellular oxygenation by increasing blood oxygen carrying capacity decisions about whether a transfusion is needed would optimally be based on knowledge of pre transfusion cellular oxygenation If there is no cellular oxygen deficiency a transfusion may be unnecessary In our ongoing Phase I STTR project we have demonstrated the feasibility of measuring cellular oxygen saturation ScO in healthy adults Our Phase II activities will center on demonstrating proof of concept for accurate real time measurement of ScO in healthy and critically ill adults We will build a compact prototype device that can be easily used in a clinical setting With the new prototype we will perform a pilot study in an ICU of a major regional referral hospital in Seattle The Specific Aims of this proposal are to confirm sufficient spectral quality and stability in our next generation prototype the CellSat evaluate the accuracy of real time ScO measurements with the CellSat in healthy adults during ischemia and test the hypotheses that ScO increases following RBC transfusion and that initial high ScO correlates with better patient outcomes in an ICU patient population The CellSat will provide unprecedented information about cellular oxygenation that has major implications for both research and clinical care The long term goal of the company is to market a noninvasive monitor that will provide robust and accurate measurements of ScO The device has broad applicability to critical care and will be useful in ambulances emergency departments intensive care units and operating rooms The CellSat will allow patient specific clinical decisions to be made that prevent prolonged tissue hypoxia leading to improve clinical outcomes PROJECT NARRATIVE This project will develop an optical device as a medical monitor to assess cellular oxygenation in skeletal muscle The approach analyzes spectral or color changes from reflected light through the skin to determine how well oxygen is able to get into muscle cells and will be used to assess the benefits of blood transfusions This project will convert successful technology developed at the University of Washington into a clinically useful medical monitoring device Measurement of muscle cell oximetry may prove very helpful to clinicians caring for anemic patients