“Knowing is not enough; we must apply. Willing is not enough; we must do.”
—Johann Wolfgang von Goethe
The impact of out-of-hospital cardiac arrest (OHCA) is enormous, taking the lives of nearly 300,000 people each year in the U.S.(1) Although survival rates vary widely, they are still generally low (less than 10%) in most areas of the country.(2) Yet many communities have significantly improved their survival rates.(3-5)
The common theme in the communities saving the most lives from OHCA is high-quality cardiopulmonary resuscitation (CPR). Growing scientific evidence suggests that simple changes in technique, especially focusing on ensuring the proper compression rate, depth and chest wall recoil, minimizing interruptions and avoiding over-ventilation, markedly improve survival.(3-5)
These concepts are becoming better understood, but there remains a huge gap between what we know and what we consistently do. The 2005 American Heart Association (AHA) Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care (6) stressed the importance of quality CPR. However, an enormous opportunity for improved translation of high-quality CPR into the everyday practice of our EMS systems and hospitals remains. This is why the new 2010 AHA CPR Guidelines (7) clearly advise providers to focus on the quality of CPR delivered throughout resuscitation attempts for adult and pediatric victims of cardiac arrest, both inside and outside the hospital.
The 2010 Guidelines also emphasize that in order to close the knowledge-practice gap and save more lives, emergency medical providers should develop a culture of measuring and ensuring high-quality CPR.
The Physiology of CPR
The goal of CPR is to optimize blood flow to the vital organs, particularly the heart and brain, in order to maximize the chance of return of spontaneous circulation (ROSC) and a good neurologic outcome.
Effective CPR generates blood flow to vital organs until circulation is restored by defibrillation or other therapy. CPR also been shown to prolong the duration of ventricular fibrillation in OHCA victims,(8) thus expanding the window of opportunity for successful defibrillation.
CPR Quality Matters
“CPR is CPR, right?” Absolutely not.
There is a vast difference between the coronary and cerebral perfusion pressures generated by poor-quality and high-quality CPR. It is this critical forward blood flow to the heart and brain during CPR that best determines ROSC and survival.(9)
The Current State of CPR
“Our professional CPR is fine, right?” No, again.
Unfortunately, without any measurement or feedback, CPR quality is usually poor and has been equated with “trying to drive at night with your headlights turned off.” Despite the fact that CPR is a critical link in the chain of survival, it is often unmonitored and performed with inconsistent quality in both the in-hospital
and out-of-hospital settings.(10,11)
Wik demonstrated this during 176 adult OHCAs by continuously monitoring all chest compressions and ventilations using modified defibrillators programmed for CPR data collection in recently retrained paramedics and nurse anesthetists. He found the quality of CPR was dramatically different from that recommended by the AHA Guidelines. Only 28% of the compressions had a depth of 38–52 mm, and chest compressions were given only 48% of the available time during resuscitation.(10) It has been suggested that shallow chest compressions may be identical to interruptions in CPR if the compressions are not deep enough to generate a functional cardiac output.(12)
There are many reasons why manual CPR is difficult to perform, including rapidly occurring physical and mental fatigue (within one to two minutes); changes in chest wall compliance during resuscitation; prioritizing other interventions; and trying to perform CPR on a soft surface or while transporting patients down hallways and stairways, or in moving ambulances. All of these factors make hitting the proper rate, depth and recoil a moving target.(13)
These findings have spurred development of a variety of FDA-approved CPR feedback and mechanical-assist devices. Feedback devices provide rescuers with real-time audio-visual feedback, instruct them on how to deliver Guidelines-quality CPR, give them the opportunity to precisely review their performance and guide training.
CPR Feedback Strategies
Experts propose three strategies to develop a culture of high-quality CPR and improve outcomes from sudden cardiac arrest.
1. Implementation of a continuous quality improvement (CQI) program. As Lord Kelvin said in 1883, “If you cannot measure it, you cannot improve it.”
Standardized data collection tools are now available to accurately monitor cardiac arrest and resuscitation metrics inside and outside the hospital. Some of these tools include the National Registry of CPR (www.nrcpr.org) and the Cardiac Arrest Registry to Enhance Survival (www.mycares.net).
Monitoring, reporting and benchmarking cardiac arrests are fundamental steps to improve survival and, in some ways, are “interventions” themselves.
2. Use of real-time audio-visual CPR feedback. Feedback devices provide audio and visual CPR feedback, along with prompting, to assist providers in delivering AHA-recommended compression depth and rate, and limit interruptions to compressions. Some devices also provide feedback on chest wall recoil and the rate and tidal volume of ventilation.
There is a perception by health care providers that their CPR skills are adequate, but in reality, when CPR is monitored without feedback, that’s often not the case. Even with feedback devices, it has been shown that proper CPR performance must be continually monitored, “coached” by the feedback device and periodically corrected by the provider.
The gap between the perception of performing quality CPR and the reality of inadequate performance only adds to the many reasons why survival rates for this patient population are so dismal. A recent observational study showed that trained health care providers performing actual CPR at one urban hospital became fatigued after roughly 90 seconds and that their chest compression depth decreased accordingly over time.(13)
3. Utilization of CPR data for provider feedback and training. Although CPR monitoring devices with feedback are one solution, they should be used in concurrence with debriefing after arrest events to bolster CPR education. Two different studies, one simulation and one clinical, conducted in the hospital setting demonstrated that debriefing offered in conjunction with CPR monitoring resulted in marked improvement in CPR quality at subsequent CPR events.(14,15)
Fifty years after the introduction of CPR, we clearly know that immediate, uninterrupted and properly performed CPR saves lives. We know how to do CPR; now we must close the gap between knowing how to do CPR and the way we actually perform CPR. Providers now have more opportunity than ever to improve survival from sudden cardiac arrest. The focus must shift from “Do CPR” to “Do CPR right.”
1. Lloyd-Jones D, Adams R, Carnethon M, et al: “Heart disease and stroke statistics—2009 update: A report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee.” Circulation. 2009;119(3):480–486.
2. Nichol G, Thomas E, Callaway CW, et al: “Regional variation in out-of-hospital cardiac arrest incidence and outcome.” JAMA. 2008;300(12): 1423–1431.
3. Rea TD, Helbock M, Perry S, et al: “Increasing use of cardiopulmonary resuscitation during out-of-hospital ventricular fibrillation arrest: Survival implications of guideline changes.” Circulation. 2006;114(25):2760–2765.
4. Kellum MJ, Kennedy KW, Ewy GA: “Cardiocerebral resuscitation improves survival of patients with out-of-hospital cardiac arrest.” The American Journal of Medicine. 2006;119(4):335–340.
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(10):1158–1165.
6. “2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.” Circulation. 2005 Dec 13; 112(24 Suppl).
7. “2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science.” Circulation. 2010 Nov 2; 122(18 Suppl 3).
8. Cummins RO, Eisenberg MS, Hallstrom AP, Litwin PE: “Survival of out-of-hospital cardiac arrest with early initiation of cardiopulmonary resuscitation.” The American Journal of Medicine. 2985;3(2):114–119.
9. Kern KB, Ewy GA, Voorhees WD, et al: “Myocardial perfusion pressure: A predictor of 24-hour survival during prolonged cardiac arrest in dogs.” Resuscitation. 1988;16(4):241–250.
10. Wik L, Kramer-Johansen J, Myklebust H, et al: “Quality of cardiopulmonary resuscitation during out-of-hospital cardiac arrest.” JAMA. 2005;293(3):299–304.
11. Abella BS, Alvarado JP, Myklebust H, et al: “Quality of cardiopulmonary resuscitation during in-hospital cardiac arrest.” JAMA. 2005;293(3):305–310.
12. Edelson DP, Abella BS, Kramer-Johansen J, et al: “Effects of compression depth and pre-shock pauses predict defibrillation failure during cardiac arrest.” Resuscitation. 2006;71(2):137–145.
13. Sugerman NT, Edelson DP, Leary M, et al: “Rescuer fatigue during actual in-hospital cardiopulmonary resuscitation with audiovisual feedback: A prospective multicenter study.” Resuscitation. 2009;80(9):981–984.
14. Dine CJ, Gersh RE, Leary M, et al: “Improving cardiopulmonary resuscitation quality and resuscitation training by combining audiovisual feedback and debriefing.” Critical Care Medicine. 2008;36(10):2817–2822.
15. Edelson DP, Litzinger B, Arora V, et al: “Improving in-hospital cardiac arrest process and outcomes with performance debriefing.” Archives of Internal Medicine. 2008;168(10):1063–1069.
Disclosure: Marion Leary reports that she has received a minimal honorarium for speaking at conferences from the CPR Improvement Working Group.
This article originally appeared in an editorial supplement to December 2010 JEMS, FireRescue, Journal of Emergency Nursing and ACEP News as CPR Performance Counts: Quality Improves Survival.