When performing chest compressions for CPR on adults, the chest should be pressed down about 5 to 6 centimeters (2 to 2.4 inches) deep. This depth is necessary to create sufficient blood flow to vital organs. It is important to use enough force to compress the chest at least 2 inches but avoid excessive depth beyond 2.4 inches to prevent injury. Compressions should be delivered at a rate of 100 to 120 per minute, allowing the chest to fully recoil after each compression.
For children, chest compressions should be about 4 to 5 cm deep, and for infants around 2 inches (about 5 cm) deep.
In summary, for adult CPR chest compressions, the key is pressing down around 5-6 cm or 2-2.4 inches deeply at 100-120 compressions per minute for effective resuscitation.
