A fluid circuit for circulating coolant in a closed loop between an intravascular catheter and a heat exchange system includes a buffer IV bag in fluid flow series with the catheter between the catheter and a pump that pumps the coolant to the heat exchange system. A request for registration is sent from a user equipment to the serving controller where after it is determined in a second controller that the user equipment supports another security mechanism than the first security mechanism. In one aspect the shared pixel unit circuitry may include a shared source follower transistor. A range of frequency of a s-parameter is determined and numbers of pole-residue, times for recursion and durable maximum system errors in the equivalent circuit is also determined. Electromagnetic interference affecting the sampling or the input measurement signal is electronically neutralized. The method comprises providing a charge to an intermediate power cell by electrically connecting the intermediate power cell to a power source, disconnecting the intermediate power cell from the power source, and electrically connecting the wireless device to the intermediate power cell.