Sudden cardiac arrest results in an instant stoppage of blood flow through the blood vessels. This stoppage of blood flow means that fresh, oxygenated blood is not transported to the brain, which will die within four minutes.
There is a significant amount of oxygen in the bloodstream capable of sustaining brain tissue for several minutes, even without breathing. Proponents of doing CPR without rescue breathing argue that continuous chest compressions get blood flowing better than chest compressions interrupted by rescue breaths, and that blood flow is the only way oxygen can reach vital organs such as the brain.
Proof that circulated blood holds enough oxygen to sustain life without taking a breath lies in examples of breath-holding. Freediver Tom Sietas of Germany holds the world record for holding his breath, lasting 8 minutes and 47 seconds. How could he do that unless his bloodstream was capable of sustaining his brain?
Opiate overdoses cause respiratory arrest - victims completely stop breathing while their hearts continue to pump blood. In my experience as a paramedic, I've seen many opiate overdose victims (usually victims of heroin overdose) respond well to the drug that reverses opiate intoxication and wake up without any brain damage - despite not breathing for several minutes.
Studies published in the American Journal of Medicine and The Lancet have indicated better survival rates for victims of cardiac arrest resuscitated by lay rescuers and EMS professionals using chest compressions only.
Dr. Gordon Ewy, director of the Sarver Heart Center at the University of Arizona, has said that training the public to perform CPR without rescue breathing is easier than training in traditional CPR. He has also published research that indicates the public is more likely to do CPR if mouth-to-mouth is not included.
Not all cardiac arrests are from a diseased heart. Sometimes, drowning or drug overdoses cause respiratory arrest that leads to cardiac arrest. In those cases, rescue breathing is an important part of resuscitation efforts.
Research is constantly being published on all manner of healthcare issues and treatments. Changing the guidelines is a process that takes all current research into account. If the guidelines changed regularly, or if there were no standards, public understanding of CPR would be diminished.
It's also very important to make sure everyone is taught the same standard in order to accurately measure the affect changes in CPR have on survival rates. The American Heart Association makes every effort to simplify CPR training while keeping it effective.
Where It Stands
Those who teach and research CPR have always been very passionate. Any changes in CPR have been met with resistance, especially when changes suggest deemphasizing airway and breathing from an emergency medical procedure.
The AHA has publicly stated no intention to change the guidelines immediately. Dr. Ewy, in a commentary published in The Lancet, called for a change in the CPR guidelines. He believes that compression-only CPR would be much easier for lay rescuers to perform.
Undoubtedly, more research is on the way for this prickly issue. CPR performed outside the hospital has not traditionally had a very good success rate. Any potential improvements should be examined.
References:Kellum, MJ, KW Kennedy and GA Ewy. "Cardiocerebral resuscitation improves survival of patients with out-of-hospital cardiac arrest." Am J Med. Apr 2006
Nagao, Ken, The SOS-KANTO Committee. "Cardiopulmonary resuscitation by bystanders with chest compression only (SOS-KANTO): an observational study." The Lancet. 17 Mar 2007