A modular, power augmented medical infusion apparatus to provide rapid transfusion of relatively large quantities of blood, blood components, colloid, and fluids to patients. All components of the infuser that contact blood are sterlie, disposable, and easily assembled. Disassembled or partially assembled the components are also easily transportable. The major components comprise a pair of filtered cardiotomy reservoirs, an air embolus sensor, a modular double roller pump, a heat exchanger, a bubble trap-filter and disposable fluid conduits. The bubble trap-filter is located in the distal most location of the recirculating loop just upstream of the Y-connector to the patient and the air sensor just downstream of the cardiotomy reservoir in the proximal location of the recirculating loop. The experimental infuser has been safely and successfully used with patients undergoing liver transplantation, combined liver and kidney transplantation, major vascular surgery, and other operations associated with large rapid transfusion requirements.