an apparatus for thermal regulation , or temperature control of intravenous fluid . the apparatus includes four subassemblies to control intravenous fluid temperature during rapid time varying fluctuations in fluid flow rates independent of ambient air temperature and initial fluid temperature . the first subassembly is an intravenous infusion subassembly containing a fluid reservoir , flexible tubing and a syringe for injecting fluid into a human . the second subassembly is a disposable heat exchange subassembly containing a wire heat exchanger and temperature and flow sensors . the heat exchanger is fabricated into the flexible tubing of the infusion subassembly . the third subassembly is a controller subassembly including a microprocessor system to control the heat exchange subassembly and power supplies . the fourth subassembly is the power supply subassembly which uses a variable voltage dc power supply to reduce low level 60 hertz artifact signals that interfere with electronic monitoring systems such as the electrocardiogram .