The proposed Phase I work will deliver a noninvasive, small, portable functional pulse oximeter based finger prototype device capable of heartbeat-to-heartbeat estimation of: 1) closeness to hemodynamic decompensation of injured warfighters for the purpose of triage; 2) effectiveness of fluid resuscitation in a bleeding or a potentially bleeding patient; and, 3) fluid volume required by a bleeding patient to prevent over or under resuscitation. In addition, the device will be capable of transmitting this information wirelessly to a tablet, laptop and/or workstation. This project will also investigate the application of pulse oximeter type sensors to other areas of the body including but not limited to the forearm area, to determine optimal placement for effective and robust portable resuscitation monitoring. This work effort will utilize simulated bleeding and resuscitation data gathered at the USAISR as well as data gathered in related human hemorrhage studies involving a liter or less of blood loss, all of which are being conducted under existing Flashback projects that are synergistic to this proposed effort. The deliverables of this 6 month project will include the working resuscitation monitoring device, as well as a rigorous statistical analysis of its effectiveness based on existing data.