A system for determining probability of tissue damage is disclosed. The system includes an electrosurgical generator adapted to generate an electrosurgical current and a plurality of return electrodes adhered to a patient and adapted to couple to the electrosurgical generator. Each of the return electrodes includes an impedance sensor attached thereto. The system also includes a current monitor connected in series with each of the plurality of the return electrodes to measure the electrosurgical current passing therethrough and a processor coupled to each of the current monitors. The processor is configured to calculate a cooling factor and a heating factor for each of the plurality of the return electrodes. The processor further configured to determine probability of tissue damage for each of the plurality of the return electrodes as a function of the cooling factor and the heating factor.