I'm going to shift gears for a moment and focus my discussion away from baseball and on to medicine.
IMPORTANT: This blog entry is based on preliminary research as I understand it. Please read the links at the bottom before drawing your own conclusions. DO NOT WITHHOLD CPR from your cardiac arrest patients in any circumstance. Alternative treatments do not yet exist outside of the research and clinical trial setting. CPR is still your patient's best chance of survival in a cardiac arrest situation. Please refer to your local protocol and AHA CPR guidelines.No matter what you do for a living odds are you are in some way familiar with Cardiopulmonary Resuscitation (CPR). Whether your knowledge comes from a formal source such as the American Heart Association or from Hollywood, you probably know that it is the gold standard in the treatment of cardiac arrest.
Now what if I told you that new research suggests that our original thinking may be wrong? What if I told you that CPR kills? Now imagine my dismay when one of the program coordinators at the UCLA Center for Prehospital Care told me just that.
So I decided to a little research of my own. Since I don't have the education or the resources to perform my own clinical studies I opted to let Google do the research for me, and that is when I came across several fascinating articles that supported what the UCLA instructor had told me during my EMT refresher class.
Of course, saying that CPR kills is a gross generalization. However, the research does show that CPR may only be effective within the first 10 minutes of a cardiac arrest. Beyond 10 minutes, CPR becomes fatal. In the next few paragraphs I'm going to attempt to explain why this is in simplistic terms.
Three Phases of Cardiac ArrestAccording to Dr. Lance B. Becker and Dr. Myron L. Weisfeldt, cardiac arrest can be divided into three time-sensitive phases:
Phase 1: The Electrical PhaseThe first four minutes of a cardiac arrest are the most critical. During this phase the damage to cells and organs is minimized and the heart is likely to respond to defibrillation ("shocking"). Dr. Becker points out that the high success rate of implantable cardioverter defibrillators (ICD) (like the one that Vice President Dick Cheney has) underscores the importance of this period of time as well as early defirbrillation. During this phase difibrllation (if indicated) should precede CPR.
The growing availability of Automated External Defibrillators (AEDs) is a very important aspect of increasing survivability from cardiac arrest. By the time paramedics arrive on scene a person has usually been without a pulse for significantly longer than this phase and the odds of their survival decrease with each passing minute.
Phase 2: The Criculatory PhaseFrom four minutes to approximately 10 minutes of ventricular fibrillation (VF) the patients best chances for recovery lie in receiving traditional CPR and defibrillation per current standards. It's important to note that the AHA CPR guidelines that took effect in 2005 address the recommendations for this phase of resuscitation.
Phase 3: The Metabolic PhaseThis is where it gets really interesting, and where the shocking reality of CPR takes hold. "After 10 minutes of cardiac arrest, the effectiveness of both immediate defibrillation and CPR followed by defibrillation decreases rapidly and survival rates appear poor." (Becker)
At this point, cells begin to go into what can be understood as a sort of hibernation state. As they become oxygen-deprived the cells begin to die, but it seems that new evidence shows that the process of cell death from oxygen deprivation occurs much more slowly than has always been believed.
The Real Killer: OxygenAlthough counter-intuitive, research is showing that the real damage to cells occurs largely after they are re-oxygenated. During CPR the oxygen level in the blood increases (especially if performed correctly). Cells that were in the process of dying are now reinvigorated with oxygen and their metabolic activities resume. The problem is that cells are inherently designed to commit suicide when they become damaged. This process of programmed cell death is known as apoptsosis.
It is be lived that apoptosis can occur as part of body's natural defense against cancer. When cells sense that they are damaged they sacrafice themselves in order to protect the rest of the body. Normally this works very well because cells don't tend to die en masse. However, during cardiac arrest all of the body's cells suffer from what is known as ischemia, or damage due to oxygen deprivation. Once oxygen is restored (reperfusion), large groups of cells realize that they have been damaged and initiate the process of apoptosis simultaneously. Obviously, this isn't a good thing.
The Bottom LineWhen all is said and done the bottom line is that rapid reperfusion (which can occurred as a result of CPR and successful resuscitative efforts) actually causes cells to die more quickly than if they were deprived of oxygen.
So how do you resuscitate someone without killing their cells?
The answer seems to be surprisingly simple: keep them cold...induce hypothermia.
Studies are showing that an approach involving induced hypothermia (lowering the body's core temperature to around 95 degrees Fahrenheit) as well as other therapies which reperfuse the body in a more controlled manner can raise survivability to as high as 80%.
Of course, more research is needed before we know what the best approach to resuscitation is. However, one thing is for sure, over the next few years we will be forced to rethink what it means to be dead.
*****
Links:
http://www.msnbc.msn.com/id/19751440/site/newsweek/http://www.msnbc.msn.com/id/18368186/site/newsweek/http://erc.uchicago.edu/documents/ResuscitationafterCA.pdf
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