What are the rules for compression part of CPR?

In CPR, chest compressions should be performed at a rate of 100 to 120 compressions per minute, with a depth of about 2 to 2.4 inches (5 to 6 cm) for adults. Compressions should allow the chest to fully recoil between compressions, and rescuers should minimize interruptions during the process. If possible, aim for a compression-to-ventilation ratio of 30:2 for adults, and ensure that compressions are delivered in a straight, firm manner. For infants and children, adjustments in compression depth and technique may be necessary to suit their size.