a device for assisting a caregiver in delivering cardiac resuscitation to a patient , the device comprising a user interface configured to deliver prompts to a caregiver to assist the caregiver in delivering cardiac resuscitation to a patient ; at least one sensor configured to detect the caregiver &# 39 ; s progress in delivering the cardiac resuscitation , wherein the sensor is configured to provide a signal containing information indicative of ventilation ; a memory in which a plurality of different prompts are stored , including at least one ventilation progress prompt to guide the rescuer &# 39 ; s performance of ventilation ; a processor configured to process the output of the sensor to determine a parameter descriptive of ventilation progress and to determine whether the ventilation progress prompt should be selected for delivery . possible parameters descriptive of ventilation progress include ventilation rate , delivered tidal volume , and flow rate .