Adaptive defibrillator: new approach to implementing an automated defibrillator energy delivery

It is well established that successful defibrillation depends on the energy selected and the transthoracic resistance (TTR) of the patient. To achieve an effective and safe defibrillation, the TTR should be measured accurately during the defibrillator pulse where the breakdown phenomenon of the skin resistance occurs, followed by the adjustment of the defibrillator parameters to ensure the correct current flow through the heart to completely depolarise all myocardial cells without any associated tissue damage being caused by heating. In this paper, an online technique is described which determines the dynamic TTR and adjusts the defibrillator current to ensure safe operation regardless of patient variability.