The invention is a process and system, consisting of a reinjection pump, connecting tubing, a reinjection cannula and a recipient site, with fluid management features including a peristaltic pump head and controls for pressure limits, flow rates and flow distribution wherein the process of controlling the reinjected fat and fluid is unique because of the control of flow rates, pressures, matching cannula hole sizes, and maintaining a closed continuous system where the harvesting and reinjection is done all together with a completely closed system. The process utilizes a method and control system to manage pressure levels during reinjection procedures of viable soft tissue. Although this case specifically relates to its use in the reinjection of adipose fat and other tissue back into the body during liposuction procedures, it can be applied to any medical procedure of introducing or re-introducing materials into the body.