Abstract: The apparatus pre-treats fluid and then delivers it to a patient during surgery, for example a hyperthermic intra-peritoneal chemotherapy (HIPEC) procedure. It comprises a reservoir (2) for the fluid, a reversible pump (10) and a valve assembly (22). In a recirculation mode, the pump (10) is operated in one direction to draw fluid from the reservoir (2), through the valve assembly (22) and back to the reservoir (2), while the fluid is pre-treated by heating, for example. In a fluid delivery mode, the pump (10) is operated in an opposite direction to draw fluid from the reservoir (2) and deliver the fluid through the valve assembly (22) to a port (30) from which it can be supplied to the patient. A second pump (12) may be provided for drawing fluid from the patient via a return port (48). The pumps (10,12) may be peristaltic pumps integrated with the walls of the reservoir (2).