1) PUSH FAST!
American Heart Association guidelines for high quality CPR start with the basics. The first question asked (and answered!) is how fast to push. The guidelines sate “at least 100 beats per minute.” Notice that they don’t say ABOUT 100 beats, but AT LEAST 100 beats per minute. Pushing faster is generally better. At 110-120 (117 to be EXACT!) more people achieve Return of Spontaneous Circulation (ROSC, which is the whole point of CPR!) Patients die if the rate is too slow (say 80 beats per minute or less.)
2) PUSH HARD!
How deep to push on the chest is question number two. The guidelines suggest pushing MUCH deeper now than they used to, at least 2 inches in an adult (Notice the AT LEAST again!) When you push on a real chest, there is a distinct ‘bottoming out’ sensation, and the chest has been compressed at that point all that it can. More pressure at that point will not really squeeze the chest down any farther. This is where you want to be- AT LEAST 2 inches in an adult, ABOUT 2 inches in a child (1 year to puberty) and ABOUT 1.5 inches in an infant. – bottom the chest out.
Pushing down- creating positive pressure- on the chest on the lower half of the breastbone squeezes blood out of the heart’s ventricles (at BEST- 30% of the heart’s normal output) and delivers it to the vital organs of the body (think brain!)
3) ALLOW COMPLETE CHEST RECOIL!
As discussed above, pushing down (creating positive pressure) on the chest drives blood out of the ventricles and feeds the brain and vital organs. Just as important is letting up on the chest ALL the way between down strokes. This creates a vacuum (negative pressure) in the chest cavity, which PULLS blood from the veins back into the heart and primes the pump for the next down stroke. When people get tired, they get ‘lazy’ and tend to still push down all the way, but only let up half way, (in other words, people stay leaning on the chest all the time) which means less blood gets circulated with each down stroke.
This is an important concept, because in CPR, blood flow is not so much a ‘this is great flow’, and ‘that is not as good,' - as it is an all or nothing proposition. Either blood is circulating through the system, and all the way to the head, or it is not! Complete chest recoil helps ensure that blood flows on the down stroke.
continued here: http://www.carpentercprsolutions.com/-blog/key-components-of-high-quality-cpr-continued-part-2