In its latest round of changes, AHA has adjusted the protocols in areas that will not affect many AEDs.

Push Harder

The AHA's new 2010 Guidelines focus on chest compressions.

Every five years, the American Heart Association (AHA) updates the "Guidelines for Emergency Cardiac Care." This time around, the changes are slight but very focused on CPR chest compressions. In the past, effects on rescue protocols and the workings of automated external defibrillators (AEDs) have called for more obvious changes. The regular reassessment and improvement of resuscitation therapies for the immediate treatment of cardiac arrest victims actually takes place globally through an organization called the International Liaison Committee on Resuscitation, or ILCOR.

AHA is one of eight regional bodies that participate in ILCOR's process of revising Emergency Cardiac Care therapies and protocols by arriving at an international consensus in which 365 researchers from 29 countries have sifted through and reviewed all of the latest research to determine what it all must mean. The latest result, published in October, constitutes evidence-based medicine at its best.

The changes introduced back in 2005 brought new emphasis to the importance of cardiopulmonary resuscitation (CPR) when resuscitating a victim of cardiac arrest. They doubled the chest-compression-to-rescue-breathing ratio from 15-to-2 to 30-to-2. They doubled the CPR interval between heart analyses from one minute to two, and they got rid of "three stacked shock" technology in favor of a single shock (with no further analysis to see if a second, or even a third, shock might be needed). These changes caused all AEDs to undergo some level of modification to accommodate the new changes.

The New 2010 Guidelines
In its latest round, AHA has adjusted the protocols in areas that will not affect many AEDs. Clearly, however, AHA intends to change significantly the behavior of rescuers by calling on them to start chest compressions sooner, do more of them, and, most important, push harder with every compression.

Ever since 1992, AHA has said CPR chest compressions should be 1.5 to 2 inches deep. I was once asked by a scientist well versed in the evidence on which the Guidelines rest if I knew how the compression depth of 1.5 to 2 inches was arrived at. I admitted I did not know. "Well, let me tell you," he responded. "They were pulled out of thin air. Good research may one day prove us right or wrong, but we had to start somewhere. Rescuers need protocols, and they can't always wait on the evidence. People's lives are at stake."

Well, the evidence has now begun to present itself. In its Executive Summary, AHA presents what it considers the key changes for lay-rescuer Basic Life Support.1

First, when presented with an unresponsive adult who is not breathing normally (where gasping should not be considered normal), rescuers should begin CPR immediately without making any attempt to "look, listen, and feel" or clear the airway before starting chest compressions. The reason: Inconsistent performance by rescuers and loss of early chest compressions reduces the quality and quantity of chest compressions.

Second, "hands only" CPR (compression only without any rescue breathing) should be encouraged among untrained rescuers. The reason: Research shows that survival improves when untrained, or unsure, rescuers are encouraged to do only chest compressions without any rescue breathing.

Third, whenever CPR is performed, chest compressions should always precede clearing the airway, checking breathing, and delivering rescue breath. The "A-B-C" rescue (Airway-Breathing-Compression) has now become the "C-A-B" rescue. The reason: Chest compressions are more important than rescue breathing and need to be started as soon as possible.

Fourth, "there is an increased focus on methods to ensure that high-quality CPR is performed. . . . The recommended depth of compressions for adult victims has increased from a depth of 1½ to 2 inches to a depth of at least 2 inches." The reason: Research shows survival improves when rescuers compress 2 inches or more, compared with those who compress only more than 1.5 inches. What a difference a half inch makes.

Further, AHA also cites as a key point of continued emphasis that rescuers should "minimize interruptions in effective chest compressions" because "any unnecessary interruptions in chest compressions . . . decreases CPR effectiveness."

The overall thrust of these recommendations is clear: Research shows that more than anything else, what can improve survival from cardiac arrest is chest compressions, especially ones that are "high quality." If you want to, forget about rescue breaths. Don't waste time checking circulation or taking a pulse. Start compressions immediately. If you try to open the airway and check breathing, do so only after completing at least 30 all-important chest compressions.

But the most important new element in these recommendations is the move to deeper chest compressions "at a depth of at least two inches." The evidence has begun to show (from both animal studies and patient survival studies) that compressions at 2 inches and beyond lead to significantly better outcomes than those that reach only an inch and a half. Some animal studies show that this difference of only one half inch can literally make the difference between life and death.

As the scientist I referred to above said, ILCOR and AHA "had to start somewhere" when they came up with their original protocol in 1992, but now we know more. Henceforth, all rescuers should achieve compressions of at least 2 inches on every compression.

The key, major, most important, number one Guideline change for 2010 is therefore simple: Do as many chest compressions as possible, and push harder! This change applies even when using an AED.

Indeed, in the chapter on "Electrical Therapies" in a section headlined "Defibrillation Plus CPR: A Critical Combination," the Guidelines note that:

"In the 1990s, some predicted that CPR could be rendered obsolete by the widespread development of AED programs. However, as . . . more first responders were equipped with AEDs, survival rates from Sudden Cardiac Arrest unexpectedly fell. This decline was attributed to reduced emphasis on CPR, and there is growing evidence to support this view."2 [Emphasis added.]

The new 2010 Guidelines make it very clear that what saves lives is the combination of CPR with the use of an AED, that the most important part of CPR is chest compressions, and that chest compressions need to be at least 2 inches deep. In short: Push harder.

Automated External Defibrillator Compliance
But what about AED compliance? Will AEDs have to be modified to comply with the latest 2010 Guidelines?

Philips announced in November 2010 that its AEDs are already compliant without any changes to what it offers currently. Its Advanced Life Support (ALS) defibrillator -- the MRx used by medical professionals -- will, Philips indicates on its website, need some minor modifications to become compliant. All of Zoll's defibrillators -- the E Series® and R Series® for Advanced Life Support professionals and the AED Pro® and AED Plus® for EMTs and lay rescuers -- also will need to be modified to comply fully with the 2010 Guidelines.

These defibrillators need modification because they can detect chest compression depth (using "accelerometer" technology much like that used by smartphones to sense changes in position). Unlike other AEDs, these defibrillators let users see the quality of their CPR by indicating visually, in real time on the display screen, the depth of every compression and by audio prompting for adjusting the rate and depth of their chest compressions. (Actually, rescuers using one of these defibrillators can today adjust their compression depth to be more than 2 inches, and therefore be 2010 compliant, merely by watching the compression depth gauge present on the display screen.)

Clearly, compared to what occurred in 2005, the changes for 2010 are rather slight, although the move to compressions that at least 2 inches deep is radical -- particularly if you happen to be the rescuer called on to perform them. Less clear is whether other AED manufacturers will follow Philips' lead or not by announcing that what they offer today is already compliant. It seems likely most will, since they do not provide real-time feedback on the depth of compressions. Some other AEDs, though they cannot detect chest compression depth, do provide rhythmic audio prompting to help rescuers with their rate of chest compressions. For depth, however, they provide only a prompt that notes how deep to push. These prompts may need to be modified very slightly.

The 2010 changes will change things somewhat, particularly in the area of training (where the rules for clearing the airway and checking breathing have been simplified and rearranged). The 2010 Guidelines will not, however, rock the world of AEDs. Most of those in place today will need no modification to comply. Those that do require modification will undergo changes that focus on chest compression depth. Moreover, the modification process can, for most manufacturers, be accomplished in a few minutes using a PC or memory card at the user's site.

Actions Needed?
Naturally, users who are concerned about the accuracy and effectiveness of their training and their equipment will want to comply as fully as possible and as soon as possible. However, no one should expect an immediate transformation.

Manufacturers may need several months to introduce changed products. Based on the experience of 2005, in many cases upgrades will be easily applied to AEDs purchased prior to the recent changes. Those who already have AEDs in place should visit their manufacturer's website. If all questions cannot be answered currently, most of these sites offer the opportunity to sign up for notification when the changes and schedules are known.

The American Heart Association itself has announced that training materials required for compliant training will not be available until the April-June 2011 timeframe. In the meantime, its website cautions there is nothing "wrong" about following the previous 2005 Guidelines:

"The recommendations in the 2010 AHA Guidelines for CPR & ECC confirm the safety and effectiveness of many existing approaches, acknowledge that some may not be optimal, and introduce new treatments that have undergone intensive evaluation. These new recommendations do not imply that care involving the use of earlier Guidelines is either unsafe or ineffective. . . . People should continue to perform CPR just as they were last trained and follow the prompts of the AED that they are using."

Though the new Guidelines may improve Emergency Cardiac Care, the same techniques and practices that saved lives yesterday can still save lives today and tomorrow. No one should hesitate to establish or extend an AED Program because newly issued Guidelines may not yet have been incorporated. No one should postpone training in CPR and Emergency Cardiac Care until the very latest version is available from the AHA. No one should hesitate to buy an AED today because of concern about its ultimate compliance with the new Guidelines. A victim of cardiac arrest needs the same defibrillating shock today that was needed yesterday. Acquiring the ability to deliver that shock, and to perform the best possible CPR, is much less dangerous than waiting for the "perfection" provided by the new 2010 Guidelines.

Note: For more information about the AHA's 2010 Guidelines, visit its website at and select the link for Learn more about the new CPR guidelines.

1. 2010 American Heart Association Guidelines for CPR and Emergency Cardiovascular Care. Circulation 2010;122;S643.
2. Ibid. S706.

This article originally appeared in the January 2011 issue of Occupational Health & Safety.

About the Author

Hank Constantine is Director of Marketing for AEDs at ZOLL Medical Corporation, a medical device company focused on resuscitation technology and located in Chelmsford, Mass. (

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