How long should each rescue breath last?

The appropriate duration for each rescue breath during CPR is essential for ensuring adequate ventilation without over-inflating the lungs. A rescue breath lasting around 1 second strikes a balance between providing enough air to the victim and minimizing the risk of complications such as air entering the stomach, which can lead to aspiration.

This one-second breath time allows the responder to effectively fill the lungs with oxygen while maintaining a rhythm that is manageable and consistent with the compression cycles that are being performed in CPR. The objective is to allow for sufficient time to see the chest rise, which indicates that the air is indeed entering the lungs. If breaths were administered too quickly or for too long, it could lead to ineffective ventilation or complications.

The other durations, longer than one second, could disrupt the rhythm of CPR or overwhelm the victim's respiratory system, whereas a duration shorter than one second may not allow for effective inflation of the lungs. Therefore, a rescue breath lasting 1 second is the most appropriate and effective choice.