How should the surge protection circuit be designed for the vehicle power port of a defibrillator?

It is necessary to construct a multi-stage, energy-coordinated protection network to address high-energy threats such as ISO 7637-2 load dump. The first stage should utilize a gas discharge tube or varistor with strong current-handling capability to discharge the majority of the surge energy. The second stage employs an automotive-grade TVS diode with high clamping capability to finely clamp the residual voltage to a safe level that the subsequent circuitry can withstand. Decoupling components such as common-mode inductors or resistors should be used between the front and rear stages to achieve graded energy discharge. Finally, filtering capacitors should be incorporated to further smooth the voltage, ensuring stable input for the subsequent DC-DC power module.