The invention discloses an external defibrillator system, which comprises: a graphical display; one or more sensors for obtaining data regarding chest compressions performed on a patient; and a controller configured to display on the graphical display numeric values for depth and/or rate of the chest compressions based upon the data from the one or more sensors. The invention also discloses an external defibrillator system, which comprises: a display; one or more sensors for obtainining CO2 data of a patient according to a time interval; one or more sensors for obtainining information of cardiomotility of a patient on the time interval; a controller, which is configured for determining CO2 waveform on the time interval according to obtained CO2 data, determining an electrocardiogram track of filters according to the information of cardiomotility of the patient, and displaying the CO2 waveform and the electrocardiogram track of filters.