A method and apparatus for a defibrillating system is disclosed that monitors the patient during treatment and then uses the information it gathers to adjust treatment protocols during treatment based on the patient's response. The protocols may include adaptive rhythm analysis intervals, adaptive CPR intervals, and adaptive shock stacks. A method of operating a defibrillator may include the steps of: obtaining a data set on at least one physiological parameter of a patient in a first data gathering interval； performing an analysis of the data set； and determining a time interval between the analysis of the first data set and a second data set, or the duration of a CPR interval, or the number of shocks in a shock stack, based on the result of the analysis of the data set.
