The design, fabrication, and testing of a portable arteriovenous fluid warming system

Hypothermia has historically been a significant cause of death for trauma victims in cold environments. Hypovolemia exacerbates the condition. The topic of this thesis is the design and development of a portable device that rapidly and safely warms blood or intravenous fluid to normal core body temperature, thereby reducing the otherwise high mortality rate. The design has evolved from a proof of concept model using a desktop computer to a completely autonomous prototype involving the use of a microcontroller and integrated electronics. The fluid warmer utilizes a fuel-based catalytic heat exchanger in conjunction with a control system that monitors and modulates fuel flow to control the temperature of the exiting fluid. The fuel-powered fluid warmer is a significant improvement over existing technology found currently in the field. A fuel-based rewarming system would allow trauma victims to receive treatment when they are hours from the nearest hospital facility. Testing performed in a laboratory setting gave promising results, including a change in fluid temperature of approximately 6° C at a flowrate of 300 mL/min. Of greater importance, the control system ensured that fluid outlet temperature did not surpass the maximum safe temperature for blood. Several aspects of the design must be refined or optimized before the device is ready for field use. These include the following: Increase responsiveness of the system during a perturbation in fluid flowrate or inlet temperature -- Stabilize flowrate through inclusion of a pump in the flow circuit -- Reduce or eliminate the effect of condensation inside the heat exchanger -- Provide a proper method of ignition that is both energy efficient and safe.