Dec. 1, 2005 — The American Heart Association (AHA) has published new guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC) in the Nov. 28 Rapid Access issue of Circulation . The guidelines are available at:
www.americanheart.org/presenter.jhtml?identifier=3035517. In revising the 2000 guidelines, the AHA has attempted to simplify existing guidelines and apply newly available evidence reviewed at the 2005 International Consensus Conference on CPR and ECC Science With Treatment Recommendations, hosted by the AHA and held in Dallas, Texas, from Jan. 23 - 30.
"The most important determinant of survival from sudden cardiac arrest [SCA] is the presence of a trained rescuer who is ready, willing, able, and equipped to act," the guidelines note. "Any improvements resulting from advanced life support therapies are less substantial than the increases in survival rate reported from successful deployment of lay rescuer CPR and automated external defibrillation (AED) programs in the community."
The objective of these revised recommendations is to improve survival from SCA and acute, life-threatening cardiopulmonary problems. Compared with previous guidelines, the 2005 guidelines are based on the most extensive evidence review of CPR yet published; they were developed using a new structured and transparent process for ongoing disclosure and management of potential conflicts of interest, and they have been streamlined to reduce the amount of information that rescuers need to learn and remember and to clarify the most important skills that rescuers need to perform.
The evidence evaluation process underlying these guidelines relied on the International Liaison Committee on Resuscitation (ILCOR), which was formed to systematically review resuscitation science and develop an evidence-based consensus to guide resuscitation practice worldwide. The 6 task forces of ILCOR include basic life support, advanced life support, acute coronary syndromes, pediatric life support, neonatal life support, and an interdisciplinary task force to address overlapping topics. The AHA added 2 more task forces on stroke and first aid.
Based on available evidence, the AHA classified its recommendations as class I (high-level prospective studies support the action or therapy, and the risk substantially outweighs the potential for harm); class IIa (the weight of evidence supports the action or therapy, and the therapy is considered acceptable and useful); and class IIb (the evidence documents only short-term benefits from the therapy, or positive results were documented with lower levels of evidence).
"The 12 AHA CPR and ECC algorithms contained in these guidelines highlight essential assessments and interventions recommended to treat cardiac arrest or a life-threatening condition," the authors write. "These algorithms have been developed using a template with specific box shapes and colors. Memorizing the box colors and shapes is not recommended, nor is it necessary for use of the algorithms."
The most significant changes in the guidelines attempt to simplify CPR instruction, to increase the number of chest compressions delivered per minute, and to reduce interruptions in chest compressions during CPR. Some of the most significant new recommendations are as follows:
* The lay rescuer no longer needs to assess signs of circulation before beginning chest compressions but should instead be taught to deliver 2 rescue breaths to the unresponsive victim who is not breathing and to then begin chest compressions immediately.
* Instructions for rescue breaths are simplified: all breaths, whether delivered mouth-to-mouth, mouth-to-mask, bag-mask, or bag-to–advanced airway, should be given over 1 second with sufficient volume to achieve visible chest rise.
* The lay rescuer no longer needs to be trained in rescue breathing without chest compressions.
* A single (universal) compression-to-ventilation ratio of 30:2 is recommended for single rescuers of victims of all ages, except for newborn infants. This recommendation should simplify teaching and provide longer periods of uninterrupted chest compressions.
* For application of pediatric basic life support guidelines for healthcare providers, the definition of "pediatric victim" is modified to preadolescent (prepubescent) victim. However, there is no change to the lay rescuer application of child CPR guidelines (1 to 8 years).
* The importance of chest compressions is emphasized. Rescuers will be taught to "push hard, push fast" (at 100 compressions per minute), to allow complete chest recoil, and to minimize interruptions in chest compressions.
* For unwitnessed arrest, Emergency Medical Services providers may consider provision of about 5 cycles (or about 2 minutes) of CPR before defibrillation, particularly when the interval from the call to the Emergency Medical Services dispatcher to response at the scene is more than 4 to 5 minutes.
* During treatment of pulseless arrest, about 5 cycles (or about 2 minutes) of CPR should be provided between rhythm checks. Instead of checking the rhythm or a pulse immediately after shock delivery, rescuers should immediately resume CPR, beginning with chest compressions, and they should check the rhythm after 5 cycles (or about 2 minutes) of CPR.
* All rescue efforts, including insertion of an advanced airway, administration of medications, and reassessment of the patient should be performed in a manner that minimizes interruption of chest compressions. Pulse checks should be limited during the treatment of pulseless arrest.
* For treatment of ventricular fibrillation or pulseless ventricular tachycardia, there should be only 1 shock, instead of 3 stacked shocks, followed immediately by CPR (beginning with chest compressions). This change is based on the high first-shock success rate of new defibrillators and the knowledge that if the first shock fails, intervening chest compressions may improve oxygen and glucose delivery to the myocardium, making the subsequent shock more likely to result in defibrillation.
* For resuscitation of the newborn infant, there is greater emphasis on the importance of ventilation and less emphasis on the importance of using high concentrations of oxygen.
* The guidelines reaffirm that intravenous administration of fibrinolytics (tPA) can improve outcome in patients with acute ischemic stroke who meet the National Institute of Neurological Disorders and Stroke eligibility criteria. This should be done by physicians following a clearly defined protocol, as part of a knowledgeable team, and at an institution committed to stroke care.
* The guidelines include new first aid recommendations.
"The recommendations in the 2005 AHA Guidelines for CPR and ECC confirm the safety and effectiveness of many approaches, acknowledge that other approaches may not be optimal, and recommend new treatments that have undergone evidence evaluation," the authors write. "These new recommendations do not imply that care involving the use of earlier guidelines is unsafe. In addition, it is important to note that these guidelines will not apply to all rescuers and all victims in all situations."
Future directions recommended by the guideline authors include improvement of lay rescuer education and continuous quality improvement of resuscitation programs.
In an accompanying editorial, Mary Fran Hazinski, RN, MSN, and colleagues note that there was unanimous support for ensuring that rescuers deliver high-quality CPR, even though high-level evidence is insufficient to support many recommendations.
"Although researchers continue to try to identify therapies that may improve short-term outcomes, the goal of resuscitation research remains the identification of interventions that improve neurologically intact survival to hospital discharge following cardiac arrest," the editorialists write. "A striking finding of the 2005 Consensus Conference was the contrast of data that showed the critical role of early, high-quality CPR in increasing rates of survival from cardiac arrest with data that showed that few victims of cardiac arrest receive CPR, and even fewer receive high-quality CPR."
The editorial summarizes several key changes in resuscitation skills and sequences recommended by the new guidelines, often based on consensus opinion and bolstered by laboratory, clinical, and educational research and outcome data rather than by level 1 evidence.
"Simply put: rescuers should push hard, push fast, allow full chest recoil, minimize interruptions in compressions, and defibrillate promptly when appropriate," the editorialists conclude. "In the final analysis, the most important determinant of survival from sudden cardiac arrest is the presence of a rescuer who is trained, willing, able, and equipped to act in an emergency. Our greatest challenge and highest priority is the training of lay rescuers and healthcare providers in simple, high-quality CPR skills that can be easily taught, remembered, and implemented to save lives."
Circulation. Posted online Nov. 28, 2005.
Learning Objectives for This Educational Activity
Upon completion of this activity, participants will be able to:
* Identify the rate of survival of out-of-hospital CPR and the means to improve survival.
* Specify the new recommended ratio of compressions to ventilation for adults receiving CPR.
Clinical Context
Only 6% of patients who have SCA outside of the hospital survive the event. And, despite the fact that a total of approximately 250,000 out-of-hospital deaths in the United States due to SCA occur each year, the ideal treatment of SCA remains elusive. This is mainly due to a lack of quality research, as studies have generally been limited by short-term outcome endpoints, inadequate statistical power, or lack of randomization.
Nonetheless, there is hope that CPR may become more effective. The use of community-based AEDs by trained personnel has improved survival rates of SCA secondary to ventricular fibrillation to 49% to 74%. The current guidelines emphasize CPR goals that can be achieved particularly by lay persons. The authors of the guidelines note that these individuals can have the biggest impact on SCA outcomes, but few patients currently receive high-quality CPR.
Study Highlights
* The AHA developed the current guidelines in coordination with the ILCOR. These groups formed 8 task force committees responsible for review of the evidence and generation of reports. These reports were discussed and refined through 7 consensus conferences.
* Most recommendations from the panel were labeled as recommended because of some evidence of benefit outweighing risk, as opposed to strong evidence.
* No human data exist for the optimal ratio of ventilations to compression during CPR for all patients. However, compressions appear to be more important than ventilation in the first few minutes of SCA. Therefore, the new guidelines recommend an increase in the ratio of compression:ventilation to 30:2 for lone rescuers treating patients from infancy to adulthood. The 30:2 ratio holds for 2-rescuer CPR for adults, but a ratio of 15 compressions to 2 breaths should be maintained in 2-rescuer CPR for infants and children, as these patients are at higher risk for arrest secondary to asphyxia and would benefit from greater degrees of ventilation.
* Effective chest compressions are paramount in CPR. The chest should be pushed hard and fast (100 compressions per minute) and should be allowed to recoil completely between compressions. Chest compressions should be interrupted no more than every 2 minutes to check for a pulse.
* AED devices should be used as soon as possible for patients with SCA secondary to ventricular fibrillation or pulseless ventricular tachycardia. However, emergency personnel should give about 5 cycles (2 minutes) of CPR prior to application of AED for cases of ventricular fibrillation or pulseless ventricular tachycardia when an arrest is unwitnessed or the call-to-response time exceeds 4 minutes.
* Modern biphasic defibrillators have a first-shock efficacy of more than 90%, so the new guidelines recommend continuation of chest compressions in cases in which the first shock is ineffective in terminating ventricular fibrillation or pulseless ventricular tachycardia. Even when these rhythms are terminated, the rescuer should continue CPR for about 5 cycles, as most patients do not have adequate tissue perfusion in the postshock interval.
* The recommended energy for an initial shock is 150 to 200 J with a defibrillator featuring a biphasic truncated exponential waveform or 120 J for a machine with a rectilinear biphasic waveform. The recommended energy for the initial shock in children is 2 J/kg, with up to 4 J/kg administered in subsequent shocks.
* There is little evidence that vasopressors or other medications given during CPR significantly increase the rate of survival to hospital discharge. Basic life support should not be compromised to administer vasopressors or other medications during CPR.
* tPA can improve outcomes in patients with acute stroke who meet criteria for this therapy. This medication should be used according to an established protocol by a knowledgeable team.
Pearls for Practice
* Most patients with SCA do not receive high-quality CPR, and the survival rate of out-of-hospital cardiac arrest is only 6%. However, new technology and the greater use of lay persons to perform CPR may improve outcomes of cardiac arrest.
* The current guidelines emphasize the need for chest compressions in CPR, calling for a compression:ventilation ratio of 30:2 for adults and the resumption of chest compressions immediately after a single defibrillation in patients with cardiac arrest secondary to ventricular fibrillation or pulseless ventricular tachycardia.
www.medscape.com/viewarticle/518206?src=mp
