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'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'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.