A system for insertion into a pleural cavity for adjusting the temperature of a body comprising: - a sheath for providing a channel from outside said body to a pleural cavity inside said body - a heat exchange unit comprising: - two sheets having an outer contour between which fluid can flow in an inner fluid channel; and - a fluid inlet, and a fluid outlet between which said inner fluid channel is positioned; where said heat exchange unit is adapted for inserting through the channel of said sheath and into the pleural cavity inside said body in a compressed state, and where liquid entering the fluid inlet and into the heat exchange unit expands the inner fluid channel and eventually expands the heat exchange unit fully corresponding to the outer contour of said sheets, thus enabling liquid to pass through said fluid inlet, into said inner fluid channel and from said channel through said fluid outlet; wherein: - the heat exchange unit comprises at least one elongated and rigid element running in a direction parallel to the inlet tube and outlet tube adapted to at least partially withstand the compression of the heat exchange element on removal of fluid thus forcing the compression to be performed substantially perpendicular to the insertion direction; characterised in that - said compressed state is achieved by the heat exchange unit being folded in a wave-like manner, and in that - said sheath comprises an L-shaped angular guiding section with a rounded corner through which said channel extends. - a sheath for providing a channel from outside said body to a pleural cavity inside said body - a heat exchange unit comprising: - two sheets having an outer contour between which fluid can flow in an inner fluid channel; and - a fluid inlet, and a fluid outlet between which said inner fluid channel is positioned; - two sheets having an outer contour between which fluid can flow in an inner fluid channel; and - a fluid inlet, and a fluid outlet between which said inner fluid channel is positioned; where said heat exchange unit is adapted for inserting through the channel of said sheath and into the pleural cavity inside said body in a compressed state, and where liquid entering the fluid inlet and into the heat exchange unit expands the inner fluid channel and eventually expands the heat exchange unit fully corresponding to the outer contour of said sheets, thus enabling liquid to pass through said fluid inlet, into said inner fluid channel and from said channel through said fluid outlet; wherein: - the heat exchange unit comprises at least one elongated and rigid element running in a direction parallel to the inlet tube and outlet tube adapted to at least partially withstand the compression of the heat exchange element on removal of fluid thus forcing the compression to be performed substantially perpendicular to the insertion direction; - the heat exchange unit comprises at least one elongated and rigid element running in a direction parallel to the inlet tube and outlet tube adapted to at least partially withstand the compression of the heat exchange element on removal of fluid thus forcing the compression to be performed substantially perpendicular to the insertion direction; characterised in that - said compressed state is achieved by the heat exchange unit being folded in a wave-like manner, and in that - said sheath comprises an L-shaped angular guiding section with a rounded corner through which said channel extends. - said compressed state is achieved by the heat exchange unit being folded in a wave-like manner, and in that - said sheath comprises an L-shaped angular guiding section with a rounded corner through which said channel extends.