Posted on 06/12/2008

We all know that cardiopulmonary resuscitation (CPR) is a lifesaver. Some of us also know how to “pump and blow.” So it’s good news that CPR is now easier to perform.

Recently the American Heart Association (AHA) has accepted the findings of several studies that suggest sudden cardiac arrest (SCA) victims may be better off without mouth-to-mouth resuscitation.

That’s not to say the victims don’t need CPR. The change comes from the realization that it’s critical to immediately get the blood circulating again—which is what continuous-chest-compression (CCC) does if performed correctly—to have any chance of survival.

The March 2008 advisory on AHA CPR guidelines (Circulation Mar 31, 2008) is controversial because it suggests only bystanders, laypeople, or untrained rescuers need use the “new” technique. It’s also controversial because the recommendation comes in between official guidelines conference, without the usual rigorous scrutiny of medical research. And, some fear, the public will only be further confused by mixed messages.

However several emergency medical services (EMS) organizations are already using the new method (and one called cardio-cerebral resuscitation, CCR - Learn More). They are achieving significantly better results than “normal” CPR, even compared to the 2005 CPR guidelines technique of 30 compressions to 2 ventilations.

The AHA has the lead role in defining and recommending the preferred CPR method in the United States. There is also an international body called ILCOR (International Liaison Committee on Resuscitation) that seeks to provide a unified position from all resuscitation councils throughout the world. Neither organization has supported exclusive use of CCC (or CCR) for cardiac arrest victims, despite the improved results in survivability. Is the latest science advisory from the AHA a sign that the move has begun? Or will the ILCOR position rejecting “hands only” win out?

There is of course some bureaucracy at play, as is always the case with large organizations and worldwide bodies. But is the debate about medical science or statistics? It is a challenging situation; animal studies in a laboratory do not exactly match real-world settings. In two recent human studies, research groups from Sweden and Japan found no statistically significant difference in survival rates for cardiac arrest victims where bystanders used either traditional CPR with mouth-to-mouth breathing, or chest-compression-only CPR.

In addition, there is clinical evidence to support the claim that circulation is the key to survival, and that ventilation can actually impede the all-important perfusion pressure. Dr Gordon Ewy, (pronounced “Avy”), Professor and Chief of Cardiology at the University of Arizona Sarver Heart Center, has much experience with the issue of the best CPR technique.

“Most people won’t do bystander CPR because they think they lack the necessary skills and are afraid of doing something wrong. Dr. Ewy’s team investigated the problem and found evidence that supported a change in CPR technique. “We have been advising chest-compression-only CPR since 1993,” he said. They found that bystanders were four times more willing to perform CPR if there was no rescue breathing involved. He went on to say that they, “…had done a number of studies that determined the most important thing for survival was the pressure generated by chest compressions.” An even more surprising finding was that blood oxygen content didn’t seem to be critical. “The most important thing was the perfusion pressure,” Dr. Ewy reiterated.

Lani Clark, Director of Research at the same University of Arizona Sarver Heart Center, is also convinced. She collects the data and analyzes the reports from the Arizona statewide registry (SHARE) for automated external defibrillators (AEDs) and cardiac arrest victims. She has noticed that, “the public prefers that professionals do the CPR, as they are fearful of ‘doing harm, or doing it wrong’, but when shown how to perform CCC they say, ‘Well, I can do that.’ ” Ms. Clark said. “The real target for compression-only CPR is the true layperson. A person in cardiac arrest is in as much trouble as they can get, and you certainly can’t make them any worse.” She commends the AHA for the advisory, believing it will make a big difference in bystander action. “It’s too simple” she says, “I think a lot more people are now going to be willing to jump in and do something.”

Ben Bobrow, MD, Medical Director, Arizona Department of Health Services, emphatically endorses this point, “…you want a bystander to recognize what’s happened and do something. If [they] push hard and fast on the chest, that’s great. Because most of the time they do nothing!” He feels that current therapies are underutilized. “We don’t do what we already know.” Dr. Bobrow says that bystander CPR can dramatically improve survival. “If we just do that, we could save hundreds of thousands of people.”

The problem is that no one is formally trained to manage SCA victims in this way. Instead, we have a technique that interrupts the compressions, although it is beneficial for respiratory arrest and when response to cardiac arrest is delayed. In fact, a SCA victim is typically breathing normally and has normal arterial blood gas just prior to collapse, so there is sufficient oxygen in the blood and lungs to sustain the heart and brain for a few minutes, if only the blood was circulating.

The current CPR training recommendations are based upon giving two quick breaths between sets of 30 compressions with an expected duration of two seconds. Real world observation, however, shows a bystander takes around 16 seconds to resume compressions (i.e. around half the time they are not “pumping”). This causes a harmful drop in the essential perfusion pressure, which then makes defibrillation less effective, with a consequent reduction in survivability. Dr. Ewy explained that during compressions, “the forward blood flow is so marginal, that if you stop for anything, it’s deleterious.” He says that, in reality, “your hands are their heartbeat.”

In addition, dispatch directed CPR (9-1-1 operators instructing the caller on how to perform CPR) includes airway management and pausing for ventilations. Is it time for a universal recommendation for bystander CPR—if for no other reason than to reduce confusion in the minds of the public? The ILCOR 2005 guidelines for dispatch directed CPR specify compression-only. According to their spokesman, Rudy Koster, MD, many European countries have a “substantially higher proportion of cases where bystander CPR is performed, compared to the USA.”

We could remove much of the doubt and reluctance in the mind of a layperson by separating the technique into Basic CPR and Advanced CPR. Anyone (everyone) can do Basic CPR; “call 9-1-1, then start pushing down hard and fast—don’t stop till the EMTs arrive.” And only those with training need be concerned with Advanced CPR including airway and ventilation.

Roger White, MD, FACC, Mayo Clinic and Medical School, and an SCA Foundation adviser, (Bio)considers “the initial intervention in that first several minutes, with or without ventilation, as being equivalent.” He feels that, either way, the bystander is providing life support to the victim. It is in those several minutes that a bystander can make a difference, and whether they act or not is the issue, not the action itself.

The lead author of the AHA science advisory, Michael Sayre, MD, Ohio State University, Department of Emergency Medicine, and founding SCA Foundation Board chairman, (Bio) agrees that we need to lower the barriers to bystander action. “We know they may not be perfect, but they’re certainly better than nothing,” Dr. Sayre said, in explaining that part of the “hands-only” project is to help bystanders be more competent. He reasons that, “for true sudden cardiac arrest, patient outcomes seem to be approximately the same, regardless of the kind of CPR that the victim gets.” The motto should be; when in doubt, do compressions.

A critical factor in “moving the needle” of survival rates is the education and training of bystanders. Dr. Sayre would like to see further investment in the research and measurement of CPR actions. He is confident that just as the increasing emphasis in chest compressions of the 2005 guidelines has had an impact, the hands-only method will too. In fact he mentioned a CDC-sponsored national registry established to collect data on SCA events, that should provide evidence of increased CPR activity, although it isn’t designed to identify which technique was used. (Cardiac Arrest Registry to Enhance Survival, CARES program -

On one point there is no dissention; compressions are king for sudden cardiac arrest victims. Closely following that sentiment is the certainty that bystander action is the key to survivability.

Ipso facto, if the vast majority of witnessed arrests occur outside the hospital—and in the absence of trained rescuers—then the easiest and quickest intervention ought to be the best. Doesn’t that imply that continuous-chest-compression resuscitation is also king?

-Jeremy Whitehead, SCA Foundation

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