How long should each rescue breath last during CPR?

Each rescue breath during CPR should last about 1 second. This duration is critical as it allows enough time for the chest to rise visibly, indicating that the breath has been delivered effectively into the lungs. The key is to administer the breath gently to prevent any unnecessary pressure that could cause complications such as barotrauma. Delivering the breath over the period of roughly 1 second ensures that there is a sufficient volume of air provided to the patient without overwhelming their system, thus promoting the best chance for oxygenation and supporting the resuscitation effort.

Other durations suggested, such as approximately 2 seconds or longer, might lead to ineffective ventilation and can potentially result in airway obstruction or gastric inflation. A minute or 30 seconds would be excessively long, as it would interrupt the crucial cycles of rescue breathing and compressions needed to circulate blood and oxygen effectively during a cardiac arrest scenario.