What is the correct compression to breath ratio for CPR on an adult or child performed by someone trained in BLS?

The correct compression to breath ratio for CPR on an adult or child performed by someone trained in Basic Life Support (BLS) is 30:2. This means that for every 30 chest compressions delivered, 2 rescue breaths should be given. This ratio is critical as it maximizes the chances of preserving brain function and increasing the likelihood of survival until professional help arrives.

The rationale behind the 30:2 ratio is rooted in the need to provide adequate blood flow through chest compressions while also ensuring that the victim receives oxygen. Chest compressions should be performed at a rate of 100 to 120 per minute, which aligns well with the 30:2 ratio, allowing for a smooth and effective transition between compressions and breaths.

This ratio simplifies the CPR process, making it easier for responders to remember and apply during an emergency. This approach is recommended by organizations like the American Heart Association and aligns with current guidelines on effective CPR techniques.