Disclosed is a device, method and computer readable media for determining the adequacy of Cardiopulmonary Resuscitation (CPR). The device comprises an electrical source generator, an electrical signal sensor receiving a signal from the electrical source generator and a microprocessor. The microprocessor determines changes in impedance of the patient based on the signal received from the electrical signal sensor. Software executing on the microprocessor determines at least one of intrathoracic volume, change in intrathoracic volume, rate of compression, depth of compression, respiratory volume, and respiratory rate based on the change of impedance of the patient and outputs a signal indicating the adequacy of ventilation and compressions.