STATE OF THE ART PAPER: COMMENTARY
Cardiocerebral ResuscitationA Broader Perspective
Daniel P. Davis, MD*
Department of Emergency Medicine, University of California San Diego, San Diego, California
Manuscript received June 23, 2008;
revised manuscript received August 15, 2008,
accepted August 20, 2008.
* Reprint requests and correspondence: Dr. Daniel P. Davis, UCSD Emergency Medicine, 200 West Arbor Drive, #8676, San Diego, California 92103-8676 (Email: davismd{at}cox.net).
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Abstract
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Historically, cardiac arrest outcomes have been stagnant with few therapies demonstrating clinical benefit. Recent advances in our understanding of cardiac arrest physiology and therapy have led to improved outcomes and renewed interest in defining the "optimal" approach. Cardiocerebral resuscitation (CCR) represents a bundle of specific therapies designed to enhance perfusion during cardiopulmonary arrest by emphasizing chest compressions over ventilations and "priming" the heart with compressions before and after defibrillation attempts. Implemented in Arizona and Wisconsin in 2003, patients treated using CCR appear to have improved outcomes compared with those treated under the 2000 guidelines from the International Liaison Committee on Resuscitation (ILCOR). This was particularly true in the subgroup of patients with bystander-witnessed collapse, who may represent a group with adequate oxygen reserves at the time of arrest and decreased requirement for immediate positive-pressure ventilation. Many components of CCR have since been incorporated in the 2005 ILCOR guidelines. Beyond the specific treatment approaches that define CCR, this alternative approach may represent the future of resuscitation science in which each institution and emergency medical services agency will define an optimal approach to treatment and training based on the specific resources available and patient population. This may mandate a paradigm shift away from advanced cardiac life support and basic life support, which emphasize standardization of content and format rather than institution- or agency-specific protocols and training.
Key Words: cardiac arrest • resuscitation • cardiopulmonary resuscitation • CPR • cardiocerebral resuscitation • emergency medical services • EMS • ventricular fibrillation
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Abbreviations and Acronyms
| | ACLS = advanced cardiac life support | | AHA = American Heart Association | | BLS = basic life support | | CCR = cardiocerebral resuscitation | | CPR = cardiopulmonary resuscitation | | ILCOR = International Liaison Committee on Resuscitation |
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The current renaissance in resuscitation science has rapidly expanded our understanding of cardiac arrest physiology and identified multiple potential therapeutic targets. Although this carries the promise of improved clinical outcomes from cardiac arrest, which remains a leading cause of death and years of productive life lost, the existing mechanisms of providing clinical guidance and training in this area are quickly becoming inadequate. For the past several decades, a set of consensus guidelines has been generated every 5 years under the auspices of the International Liaison Committee on Resuscitation (ILCOR) (1,2). Within a year, updates are made to the advanced cardiac life support (ACLS)/basic life support (BLS) curriculum, a process overseen by the American Heart Association (AHA). These courses have served as a standard-of-care for both prehospital and in-patient providers, emphasizing uniformity of content and format to ensure a predictable knowledge base and skills performance. The increasing velocity and refinement with regard to our understanding of cardiac arrest physiology and therapeutics may warrant a different approach to training and clinical practice going forward, with the optimal strategy modified for the individual institution or emergency medical services (EMS) agency based on available resources and the patient population served.
In their report in this issue of the Journal, Ewy and Kern (3) are to be commended for their willingness to break from the 2000 ILCOR guidelines and standard ACLS/BLS curriculum to develop an alternative paradigm to cardiopulmonary resuscitation (CPR) that they have termed cardiocerebral resuscitation (CCR). The principal objective of CCR is to enhance perfusion by emphasizing chest compressions over ventilations and to "prime" the heart with compressions before and after defibrillation attempts. Many of the core principles of CCR have since been incorporated into the 2005 ILCOR guidelines and subsequent AHA recommendations. These include the performance of chest compressions without mouth-to-mouth ventilation by laypersons in cases of witnessed cardiac arrest, chest compressions before and after all direct countershocks including the initial defibrillation attempt, de-emphasis on early endotracheal intubation, avoidance of excessive ventilation, and use of hypothermia following return of spontaneous circulation. The authors should be recognized as major architects of these changes, reflecting their substantial scientific contributions over the past decade.
Several important differences remain between CCR and current ILCOR guidelines, the most substantial concerning the role of positive-pressure ventilation in the initial phase of cardiac arrest resuscitation. The authors advocate that chest compressions should be continuous in cases of bystander-witnessed cardiac arrest, with adequate ventilation occurring passively if airway patency is maintained through basic maneuvers. Current ILCOR guidelines recommend 30 chest compressions followed by a pause for 2 positive-pressure ventilations. Available clinical data compare outcomes in patients treated with CCR with those treated under the 2000 ILCOR guidelines, which advocated 15 chest compressions followed by a pause for 2 positive-pressure ventilations (4–7). Thus, the relative benefit of CCR versus current ILCOR guidelines remains unknown.
In addition, the most substantial improvements in outcome with CCR have been observed in patients with bystander-witnessed ventricular fibrillation (4,5). This is a group that is likely to have adequate oxygen reserves at the time of collapse to sustain 6 or more minutes of chest compressions without positive-pressure ventilations. The authors are forthright in stating that CCR is intended to benefit patients with bystander-witnessed collapse, in whom ventricular fibrillation is the most likely arrest rhythm. The benefit—or potential harm—with CCR in nonwitnessed arrests or with other rhythms remains unclear, especially when compared with alternate compression–ventilation strategies, such as the current ILCOR recommendations of 30 compressions interrupted for 2 positive-pressure ventilations or the performance of continuous compressions with interposed positive-pressure ventilations.
The refinement in our understanding of cardiac arrest will likely identify different approaches in various subgroups of patients, which requires that each institution or EMS agency consider the particular patient population being served before defining an optimal approach to treatment and training. Data from my own institution suggest that primary ventricular fibrillation is relatively uncommon in the in-patient setting and generally occurs in monitored environments, where immediate defibrillation is the treatment of choice. In the pre-hospital arena, the incidence of ventricular fibrillation appears to be declining for unclear reasons, which may result in further modifications to the "optimal" treatment approach (8–10).
The use of the term "CCR" seems to imply the desire for a paradigm shift in resuscitation science. However, the approach to resuscitation described by Ewy and Kern (3) is actually more similar to current recommendations than it is different. In addition, the remaining differences identify critical areas for further investigation as described above. Perhaps the critical challenge is not to decide whether CCR should replace CPR but is instead to follow the example set by Drs. Ewy and Kern (3) in creating treatment protocols and training curricula based on available scientific evidence and the unique resources available to their system to optimize outcomes in their specific patient population, even if a break from the existing standard-of-care is required. This warrants a novel approach to training that is appropriately flexible in both content and format to better align with institution- or agency-specific protocols. In addition, the group of patients benefiting from CCR should be identified and alternative treatment approaches for other patients defined to guide others in selecting the optimal approach for their own institutions or EMS agencies.
In summary, it is critical to consider CCR in its proper context—not as a replacement for CPR but as a bundle of specific therapies that target a specific patient population. None of these comments should detract from the achievements of Drs. Ewy and Kern and their colleagues or the importance of CCR in our efforts to improve outcomes from cardiac arrest. History will undoubtedly recognize the authors as important catalysts of change, with early data suggesting that their efforts have saved thousands of lives, either directly or indirectly through their influence on the resuscitation community. Additional data are clearly required to better define whether this approach should be universally or selectively applied, based on the specific resources available and patient population being treated. In the interim, those individuals responsible for cardiac arrest resuscitation performance in their individual institutions and EMS agencies should carefully consider the resources and personnel available and the population that may benefit from a particular approach before deciding whether to adopt CCR or any other resuscitation strategy. A unique training and monitoring strategy should then be implemented to continually reinforce and refine the optimal approach.
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References
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1. The International Liaison Committee on Resuscitation Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care, part 6: advanced cardiovascular life support, 7C: a guide to the International ACLS algorithms Circulation 2000;102(Suppl I):I142-I157.[Medline]2. The International Liaison Committee on Resuscitation 2005 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations. Part 4: advanced life support. Resuscitation 2005;67:213-247.[CrossRef][Medline] 3. Ewy GA, Kern KB. Recent advances in cardiopulmonary resuscitation: cardiocerebral resuscitation J Am Coll Cardiol 2009;53:149-157.[Abstract/Free Full Text] 4. Kellum MJ, Kennedy KW, Ewy GA. Cardiocerebral resuscitation improves survival of patients with out-of-hospital cardiac arrest Am J Med 2006;119:335-340.[CrossRef][Web of Science][Medline] 5. Bobrow BJ, Clark LL, Ewy GA, et al. Minimally interrupted cardiac resuscitation by emergency medical services for out-of-hospital cardiac arrest JAMA 2008;299:1158-1165.[Abstract/Free Full Text] 6. Vadeboncoeur TF, Bobrow BJ, Clark L, Chikani V, Ewy GA. The survival rate from out-of-hospital cardiac arrest is superior with passive oxygen insufflation compared to active assisted ventilation (abstr) Circulation 2007;116(Suppl II):923. 7. Bobrow BJ, Vadeboncoeur TF, Clark L, Chikani V, Ewy GA, Sanders AB. Statewide out-of-hospital cardiac arrest survival improves after widespread implementation of cardiocerebral resuscitation (abstr) Circulation 2007;116(Suppl II):923. 8. Youngquist ST, Kaji AH, Niemann JT. Beta-blocker use and the changing epidemiology of out-of-hospital cardiac arrest rhythms Resuscitation 2008;76:376-380.[CrossRef][Web of Science][Medline] 9. Bunch TJ, White RD, Friedman PA, Kottke TE, Wu LA, Packer DL. Trends in treated ventricular fibrillation out-of-hospital cardiac arrest: a 17-year population-based study Heart Rhythm 2004;1:255-259.[CrossRef][Medline] 10. Polentini MS, Pirrallo RG, McGill W. The changing incidence of ventricular fibrillation in Milwaukee, Wisconsin (1992–2002) Prehosp Emerg Care 2006;10:52-60.[CrossRef][Medline]
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