Today, we take a lot of modern inventions for granted, and one of them is definitely modern medicine as a whole. Cardiology has advanced and now we know how to react efficiently in order to save lives. One of the procedures that often gets overlooked for its brilliant simplicity is cardiopulmonary resuscitation (CPR). How does CPR work and what actually happens inside the body of the person being brought back from certain death?
We’ve all seen it on TV and in films. Someone clutches at their chest or their left arm, they stagger and collapse to the ground either in great pain, or unconscious. In swoops some informed citizen, perhaps a doctor, to take charge. They provide the chest compressions and mouth to mouth assisted ventilation procedure commonly associated with cardiopulmonary resuscitation, or CPR.
Sometimes the emergency medical technicians arrive and take over the basic life saving efforts. Occasionally, usually in the case of drowning, the chest compressions and mouth to mouth is followed by verbal encouragement like “Don’t you die on me, damn it!” at which time the victim gives up a shuddering cough, spits up some water and resumes breathing on their own, sometimes even recovering enough to make it to the final act of the story.
It seems very easy up there on the screen, everything is organized and neat, the first responders are syncopated and never seem to get tired, and the whole thing wraps up in time for late night talk shows. So, while most people can recognize what CPR looks like, and have some familiarity with the process involved, few people ever really bother to ask, how does CPR work in real life?
CPR Facts – Cardiac Events
To understand what cardiopulmonary resuscitation is, a good place to start is to establish what a cardiac event is.
To begin with, an event can take any of a number of different forms. Heart attacks are often mistaken for a sudden cardiac event, but while the two may present similar symptoms, they are not the same. Heart attacks can mimic cardiac arrest in their suddenness, and intensity, but heart attacks can also present fairly mild symptoms that can play out over hours, days or even weeks.
Heart attacks occur when the flow of oxygenated blood from the lungs to the heart is blocked, usually by plaque buildup within the arteries leading to the heart. This condition is known as arteriosclerosis and unless this blockage is removed, the area of the heart serviced by that artery will quickly begin to die.
Heart disease is often connected to incidences of heart attack, but they can also be caused by coronary spasms that interrupt the flow of blood through an artery and into the heart.
When To Do CPR and Why Time Is Of The Essence
During a heart attack, the heart generally does not stop beating completely and it has been shown that symptoms of a heart attack can vary between males and females. Neither of these is the case with actual cardiac arrest. Other causes of cardiac arrest that may not be present during a heart include electrocution, extreme pain, fear, and/or other distress, cocaine and/or other narcotic use, or intense cold.
This difference is a critical one, because once the heart stops beating entirely the victim is only minutes away from irreversible brain injury and death. With a heart attack, there may be time to get a victim to a hospital, or call 911.
Cardiac arrest is an immediate threat and must be handled immediately. Simply put, even a poor attempt to keep oxygen and blood flowing through the victim’s body is better than none at all. A broken rib is relatively easy to fix, a brain that has suffered several minutes of oxygen deprivation is not.
Cardiopulmonary resuscitation is the only way to keep blood and ostensibly some degree of oxygen, flowing through a victim’s body until advanced life saving techniques can be undertaken by trained emergency medical technicians.
It is important to understand the limitations of CPR as a life saving technique.
Despite what popular entertainment would have you believe, even when properly performed within seconds of a cardiac arrest in a hospital with all necessary equipment and capabilities, only about fifty percent of all arrest victims survive the initial event. Fewer still will survive long enough to leave the hospital and a good percentage of those will suffer some degree of neurological impairment.
For victims wherein there is a delay of CPR treatment in any way, the prognosis is even bleaker which begs the question: why doesn’t CPR save more people than it does?
How Often Does CPR Work?
Official data varies, but generally, around 40% of patients brought back from cardiac arrest via CPR procedures survive immediately after being resuscitated and end up in a hospital. However, only 10 – 20% live long enough to get discharged.
Why such a low survival rate? The answer is because as a procedure, it really isn’t designed to be a permanent life-saving solution. It is impossible to know why the person has entered as a state of arrest, and that is a crucial component of proper treatment. Even discounting that, it is unrealistic to expect a given individual to be able to diagnose and properly treat another given individual who just happens to arrest within their vicinity.
Chest compressions and any accompanying rescue breaths are intended only to buy time for the EMTs to arrive and take over life saving efforts.
CPR Guidelines from The American Heart Association (AHA)
Taking all of these factors in mind, in 2005 the American Heart Association (AHA) refined their guidelines on CPR and cardiac arrest to make administering the procedure more streamlined, and less focused on the tools, pharmaceuticals and advanced life saving skills used by professional rescuers.
The AHA has even gone so far as reducing the focus on mouth to mouth assisted ventilation in favor of an emphasis on maintaining blood circulation until EMTs arrive.
These updated recommendations include universal guidelines for compression ratios where there were formerly ranges separated by age. Assuming a single rescuer, the AHA currently recommends 30 compressions at a rate of 100 per minute then two breaths, then repeat until EMTs arrive or the person resumes breathing on their own.
These guidelines represent a significant increase in simplicity as well as the ability to remember and execute.
Official Guideline Updates
In 2008, the AHA doubled down on these guidelines by eliminating the mouth to mouth assisted ventilation component of CPR in favor of compression or “hands-only” CPR. The Association determined hands only was equally effective in terms of basic life support, and also reduced the possible aversion to mouth to mouth contact that might cause some to be less inclined to administer aid.
These new guidelines are thought to make it not just more likely that people will intercede, but that they also be more disposed to learning to provide quality CPR in a crisis situation.
CPR With or Without Rescue Breaths – Which is Better?
This apparent contradiction leads us to another important question: are chest compressions with rescue breaths, or “conventional” CPR demonstrably superior to compression only CPR?
Research indicates both forms of CPR are equally effective when arrest is cardiac in origin, but when the victim is suffering arrest of a non-cardiac origin, victims who are provided hands only CPR fare about the same as arrest victims who receive no treatment at all. This makes it clear that chest compression coupled with rescue breathing yields a significantly greater possibility of a positive outcome.
Oxygen & Blood Flow
While it appears to be a counterintuitive act to not provide oxygen during cardiopulmonary resuscitation (it is in the name, after all) but speaking in terms of physiology, venous or “deoxygenated” blood still carries a pretty good amount of oxygen, about 75%. Then too, blood flowing throughout the body carries a lot more than just oxygen.
The same cells that require oxygen to survive also need the nutrients carried by the blood, oxygenated or not and build up harmful metabolic by products that are moved along by continuing blood flow.
To sum things up, breathing is surely necessary, but the average person can survive far longer without oxygen than they can without blood flow.
Conclusion
We hope this small overview of CPR and its science has helped inform and instruct our readers as to the myths and realities of cardiopulmonary resuscitation. It is an essential life saving technique, but it has its limitations and this is by no means to be considered a comprehensive document of the process of, or science behind CPR.
We encourage all readers to please take the time to learn more about this critical first aid procedure.
Cardiac arrest accounts for over 475,000 deaths in America annually, and globally speaking it is responsible for more fatalities than colorectal cancer, breast cancer, prostate cancer, influenza, pneumonia, auto accidents, HIV, firearms including handguns, and house fires combined.
Contact CPR Northwest to Get First Aid & BLS Training
You could make the critical difference between someone surviving a cardiac arrest event, and someone losing their life. Come to CPR Northwest Washington first for all basic first aid, basic life support, advanced first aid, and AED device training, certification and/or recertification needs.
We offer group classes and corporate rates so contact CPR Northwest Washington to schedule your class today! Visit us online at https://cprnwwashington.com/ for more info!