Cardiac Arrest Management
Since the American Heart Association's first set of CPR and Emergency Cardiac Care guidelines were published in 1974,1 we have all come to eagerly await the updates published every 5-6 years.
The new AHA Guidelines 20102 are now being avidly digested, dissected and debated, and EMS agencies across the country are reviewing and revising their cardiac arrest treatment protocols. As we do this, it's crucial to remember that these are guidelines, not mandates, and we must critically evaluate what specific protocols are optimal for our patients and our personnel.
THE DEVELOPMENT PROCESS
It is also important to recognize how the AHA's guidelines are developed. Most EMS personnel see only the material presented in BLS and ACLS courses, not the actual guidelines publication, worksheets, evidence rankings or journal articles. When EMS protocols do not match AHA course content completely, the result is often confusion and frustration. However, EMS medical directors must consider many factors as they adapt the guidelines to EMS use.
Development of each set of guidelines includes a staggering amount of work by hundreds of resuscitation experts from many organizations, not just the AHA. All available research articles are critiqued and ranked. Worksheets are posted for open comment as the new guidelines are debated. Eventually, an evidence-based consensus recommendation is published as "The Guidelines," where specific interventions are categorized as Class I (should be done), IIa (reasonable to do), IIb (may be considered) or Class III (not helpful and may be harmful). Some are "Class Indeterminate," where not enough research is available to recommend for or against that treatment.
Many answers are not clear-cut, so there are differences in guidelines published by the three main groups (AHA, International Liaison Committee on Resuscitation and European Resuscitation Council). Both medical and educational goals are considered. Overly complex guidelines are therefore avoided, while content and testing have been simplified to accommodate a broad base of learners. For example, we are taught to perform CPR in 2-minute cycles; therefore, the post-shock waiting time prior to a pulse check was set at 2 minutes in 2005 for ease of learning. Eventually, one ACLS course curriculum is created from the AHA Guidelines as a basic, evidence-based approach to cardiac arrest care for all healthcare providers.
Guidelines 2010 provide outstanding emphasis on several high-priority items for EMS to incorporate, such as:
- Simplification of public training and 9-1-1 instructions to focus on chest compressions only
- C-A-B approach, including "Push Hard, Push Fast" high-quality compressions with minimal interruptions
- Team approach to BLS and ACLS
- Waveform capnography peri-resuscitation
- Induced hypothermia after Return of Spontaneous Circulation (ROSC).
However, there are several potential stumbling blocks when translating the guidelines to EMS use. The AHA and authors of each set of guidelines are well aware of this, saying "It is important to note that these guidelines will not apply to all rescuers and all victims in all situations. The leader of a resuscitation attempt may need to adapt application of the guidelines to unique circumstances."3 They made a point of changing the title from "Standards" in 1974 to "Standards and Guidelines" and then to "Guidelines" as of 1992.4
Protocols Should Reflect Practice
New research may suggest a better approach long before the next guidelines are published; EMS can change faster. The "one-size-fits-all" ACLS course is not optimal. EM, ICU and EMS practitioners handle cardiac catastrophes daily and have considerably more education and experience than other ACLS learners, who might see one cardiac arrest every five years but are nonetheless required to complete ACLS courses. We can and should be expected to know more and do more. Treatments that are labeled as "not for routine use in cardiac arrest" in Guidelines 2010 may benefit specific situations, while some options listed in the guidelines may not be included in the ACLS course, so our EMS protocols may include them.
While it is obviously great to treat according to best medical evidence, there are large gaps in resuscitation science where optimal treatment is unclear or simply has never been studied rigorously in humans. Survival from arrests in non-shockable rhythms is extremely poor, and optimal human research trials are therefore extremely difficult and expensive to do (and may never be done!). But there are likely to be subgroups where specific treatments may work. For example, asystole is occasionally the first arrest rhythm, not merely the end result of untreated VF in unwitnessed arrests. Similarly, refractory VF in a 40-year-old with a true sudden cardiac death event merits the addition of a second antiarrhythmic drug (and perhaps 720 joules) if initial ACLS treatment fails, but the guidelines will not address this because good quality human studies have never been done.
There are many examples of treatments that looked fantastic in animal studies, only to be dropped from ACLS use after studies in humans failed to show improvement in long-term outcome. However, if a drug significantly improved initial ROSC but not long-term outcome, does that really mean it should be discarded? Was the problem due to the drug, to other issues (e.g., inadvertent hyperventilation or gaps in compressions during human trials), or to post-resuscitation care (especially lack of induced hypothermia)?
For all of these reasons, it is appropriate for EMS medical directors to consider a "best practice" approach to BLS and ACLS protocols for our EMS systems, based on available evidence, our experience and practicality. The evidence-based recommendations from the AHA Guidelines are a tremendous foundation that we must build upon, with variations that are appropriate for the skills of our EMS personnel and for our patients. Our primary goal must stay focused on what is best for our patients.
At the Gathering of Eagles conference, speakers presented an array of options for EMS to consider, and we learned that none of us chose to fully conform to the AHA Guidelines. Where we differ, we have studied and debated and picked the best choices-the ones we would want done if our loved ones were the cardiac arrest victims. We are passionate about our choices, and each of us considers every EMS run as "my patient." We expect a lot from our EMS personnel and from ourselves, and we all keep learning from each other.
1. Standards for cardiopulmonary resuscitation and emergency cardiac care. JAMA 227 (suppl):833–868, 1974.
2. 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care science. Circulation 122(18) Suppl 3:637–933, 2010.
3. 2005 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation 112 (suppl):IV–4, 2005.
4. Guidelines for cardiopulmonary resuscitation and emergency cardiac care. JAMA 286:2135–2302, 1992.