How many cycles of rescue breathing should be given to an adult?

The correct procedure for administering rescue breathing to an adult is to deliver one breath every five to six seconds, which translates to a total of approximately 10 to 12 breaths per minute. Given this rate, performing 20 cycles of rescue breathing would align with the guidelines for effective ventilation, especially in a situation of cardiac arrest or respiratory distress.

In practice, each "cycle" includes two breaths delivered in quick succession. Therefore, 20 cycles refer to 40 individual breaths, which is excessive given the previous standard of 10-12 breaths per minute. Providing an excessive number of breaths can lead to complications such as hyperventilation, which can decrease the venous return to the heart.

Thus, 20 cycles effectively represents a safe and appropriate practice for delivering rescue breathing to an adult, allowing for a steady and controlled approach to ventilation while avoiding potential complications.