When you’re the sole rescuer using an AED during CPR, and the AED directs a shock, you deliver a single shock and then immediately resume CPR. Giving just one shock minimizes the interruption to chest compressions, which are essential for maintaining blood flow during cardiac arrest. After delivering that one shock, start rescuers’ high-quality CPR right away (continue with chest compressions at a rate of about 100–120 per minute and a depth of about 2 inches/5 cm for adults) and let the AED reanalyze after the next complete CPR cycle (roughly every 2 minutes). Delivering additional shocks without resuming compressions would unnecessarily delay perfusion; thus a single shock followed by immediate resumption of CPR is the best approach.

Regular calibration and maintenance keep CPR feedback readings accurate and reliable over time, preventing sensor drift from distorting guidance. These devices measure metrics like compression depth, rate, and recoil, and small changes in sensors, temperature, or battery can gradually shift what the readings reflect. Calibrating realigns measurements with standardized references, while maintenance keeps hardware and software functioning correctly, so the feedback you receive truly represents your actual performance. This accuracy is crucial for reinforcing proper technique and for producing trustworthy data used in ongoing RQI quality improvement. While faster processing or convenience are helpful, they don’t address the real risk of drift or the need for correct, consistent feedback.

Providing breaths for someone who isn’t breathing requires delivering positive pressure ventilation. The bag-mask device is designed for this: it combines a face mask with a squeezable bag and an oxygen reservoir. When you compress the bag, air is pushed into the lungs under positive pressure, and the reservoir lets you deliver larger breaths with higher oxygen concentration if attached to oxygen. This setup gives you reliable tidal volumes and better chest rise, which are essential for effective ventilation during resuscitation. A pocket mask can deliver breaths but lacks the reservoir, making consistent volumes harder and less efficient, especially in adults or longer CPR. An oxygen mask and a nasal cannula deliver oxygen but do not provide breaths themselves, so they don’t ventilate a non-breathing victim.

The key idea is that CPR skills in RQI are kept fresh through ongoing, brief practice rather than a once-a-year check. This approach combats rapid skill decay by providing regular, short practice sessions with feedback. Because the exact timing of re-demonstrations can depend on the specific program or facility, many RQI implementations use a quarterly cadence. So the best answer reflects both the regular, short practice and the commonly used interval of about every three months. The other options imply fixed, longer gaps (weekly, semiannual, or annual), which don’t align with the RQI emphasis on frequent, ongoing maintenance.