Rescue breaths are a technique used in CPR (cardiopulmonary resuscitation) to provide oxygen to someone who is not breathing. This method involves sealing your lips around the person's mouth and blowing air into their lungs. Each breath should last about one second and make the chest rise visibly. In a typical CPR scenario, rescue breaths are given after 30 chest compressions. It's important to ensure the airway is open by tilting the head back slightly. If trained, rescuers may also use a barrier device to reduce the risk of infection while delivering rescue breaths.