Non-Invasive Hemoglobin Monitoring during Hemorrhage and Hypovolemic Shock

Serial blood draws for the assessment of a trauma patient's hemoglobin (sHgb) and hematocrit (sHct) is standard practice. In the event of multiple casualties this process can be time consuming and lead to the inefficient use of valuable resources. A device that would allow for continuous real-time, non-invasive monitoring of hemoglobin and tissue perfusion would not only improve the utilization of scarce and valuable resources but would also improve triage efforts. We developed a device utilizing the technology of Diffuse Optical Spectroscopy (DOS) to obtain non-invasive measurements of tissue hemoglobin concentration (THC) and oxygen consumption in an animal model of hypovolemic shock induced by successive blood withdrawals. Measured DOS results were compared against invasive systemic physiological measurements to demonstrate that DOS provides a reliable non-invasive measurement of tissue THC, and also quantifies various degrees of hemorrhage induced systemic hypovolemia and subsequent tissue perfusion decreases. DOS provides a potential platform for reliable non-invasive measurements of tissue oxygenated and deoxygenated hemoglobin and may accurately reflect the degree of systemic hypovolemia and compromised tissue perfusion. Sponsored in part by Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine Grant No. 445574-30133. Paper presented at the RTO HFM Symposium on Combat Casualty Care in Ground Based Tactical Situations: Trauma Technology and Emergency Medical Procedures held in St. Pete Beach, FL on 16-18 August 2004, and published in RTO-MP-HFM-109. See also ADM001795. The original document contains color images.