How long should one rescue breath be during CPR?

A rescue breath during CPR should last about 1 second. This duration is critical because it ensures that the breath is sufficient to inflate the lungs without causing excessive pressure or distention. The goal of providing rescue breaths is to deliver enough oxygen to the victim effectively while minimizing the risk of complications, such as gastric inflation and potential aspiration.

Timing the rescue breath to approximately 1 second allows the rescuer to see the chest rise, indicating effective ventilation. It's important to maintain a steady rhythm and to provide the breath in a way that does not overwhelm the patient. Doing so helps to ensure the delivery of adequate oxygen to the bloodstream, which is crucial during a cardiac emergency.