Bender, Janelle EShang, Allan BMoretti, Eugene WYu, BingRichards, Lisa MRamanujam, Nirmala2011-06-212009-12-21https://hdl.handle.net/10161/4243We conducted a pilot study on 10 patients undergoing general surgery to test the feasibility of diffuse reflectance spectroscopy in the visible wavelength range as a noninvasive monitoring tool for blood loss during surgery. Ratios of raw diffuse reflectance at wavelength pairs were tested as a first-pass for estimating hemoglobin concentration. Ratios can be calculated easily and rapidly with limited post-processing, and so this can be considered a near real-time monitoring device. We found the best hemoglobin correlations were when ratios at isosbestic points of oxy- and deoxyhemoglobin were used, specifically 529/500 nm. Baseline subtraction improved correlations, specifically at 520/509 nm. These results demonstrate proof-of-concept for the ability of this noninvasive device to monitor hemoglobin concentration changes due to surgical blood loss. The 529/500 nm ratio also appears to account for variations in probe pressure, as determined from measurements on two volunteers.en-USBiomarkersBlood Chemical AnalysisBlood Loss, SurgicalDiagnosis, Computer-AssistedFeasibility StudiesHemoglobinsHumansOxygenPilot ProjectsPostoperative HemorrhageReproducibility of ResultsSensitivity and SpecificitySpectrophotometry, Ultraviolet