4-.Medical device for the delivery and/or the extraction of fluid to and/or from a patient, said medical device comprising a pumping unit (1) for pumping a fluid, a warming chamber (2) with an inlet (3) and an outlet (4) and containing a heating element (5) for warming said fluid, fluid volume measuring means (13-18) and a fluid line crossing said pumping and warming units (1,2), characterized by the fact that said heating element (5) is adapted to be fully immersed in the fluid which is crossing said warming chamber (2) and by the fact that said fluid measuring means comprise temperature sensing means adapted to measure the fluid temperature on at least two separate points and electrical parameter measuring means for determining at least one electrical parameter such as current, power or frequency applied to said heating element (5). The invention also includes a method for using this device.
