The present invention relates to a multilayer fluid heat exchanger container 1 comprising a thermo-conductive sheet 7, said sheet comprising at least a first outer layer comprising a metal foil and at least a second internal layer comprising a biocompatible plastic material. The outer metal layer may be aluminium and about 45 microns thick. The inner plastic layer may be PVC and about 60 microns thick. There may be a further layer of oriented polyamide film, less than 25 microns thick. There may be an inlet port 2 connected to a fluid source such as blood, and an outlet port 3 connected to a patient. The present invention further relates to a multilayer sheet for the container, a system for heating/cooling a fluid comprising the container, a method for heating/cooling a therapeutic fluid using the container and a process for manufacturing the container.
