The heart is an incredible organ. The average American's heart will beat nearly 2.5 billion times over the course of a lifetime.1 But eventually, often prematurely and unexpectedly, it will stop. At least once per minute in the United States, a beating heart stops.2 Many are rushed to the nearest emergency department (ED), and most will never beat again.
Despite numerous updates and changes to national CPR guidelines, the published survival rate of patients with out-of-hospital cardiac arrest averages only 7.6% and has remained unchanged for 3 decades.3,4 Therefore, in June 2015, the Institute of Medicine (IOM) issued a call to improve cardiac arrest survival.5 Bentley Bobrow, MD, FACEP, et al. answered with an article in the Annals of Emergency Medicine outlining 3 specific interventions designed to improve cardiac arrest survival in any community:6
- Measurement
- Encouraging bystander CPR and 911 telecommunicator CPR programs
- Fostering high-performance CPR by medical professionals
The simplest of these interventions, and the area where the greatest impact can be made in the shortest period of time, is the delivery of high-performance CPR. Dr. Bobrow defines this as "the delivery of minimally interrupted chest compressions with the proper target rate, depth, and release, synchronized with appropriate ventilations and attempts at defibrillation."6 Despite the development of various gadgets to assist with this process, few have been shown to decrease mortality, and no drug has been shown to improve neurologically intact survival.7 The best thing we can do for our patients is to become more efficient at the steps we are already taking. While appropriate defibrillation receives much attention, there is room for improvement in the oft-neglected areas of chest compressions and ventilations - improvements that can save lives in our EDs today.
Quality Chest Compressions
With many responsibilities competing for the team leader's attention during a code, it can be easy to neglect the person delivering chest compressions. These individuals often have varying levels of training and experience. It is important to check the quality of compressions periodically, and do not hesitate to give feedback. Studies have shown that many responders deliver compressions too fast, and almost all fail to achieve the recommended depth of at least 2 inches.8-10 There is an inverse relationship between compression rate and depth, with rates of >120/min resulting in suboptimal depth and recoil.9 This decreases the filling time of the heart and leads to lower pressures and poor perfusion.11,12 Optimal compression rate has been consistently shown to be between 100 and 120 per minute.13,14 Going too slow, or too fast, will decrease survivability.
Appropriate Ventilation
Quality chest compressions may help to perfuse vital organs, but circulating deoxygenated blood will only get us so far. When a cardiac arrest patient arrives in the ED, establishing and/or maintaining a patent airway is a top priority. Whether that means endotracheal intubation, a supraglottic airway, or simply an airway adjunct and bag-valve mask, we must ensure that we are using the airway to deliver appropriate and effective ventilation. Several studies have shown that providers consistently hyperventilate patients at a rate of 20-30 breaths per minute, with as few as 10% receiving the appropriate rate of 8-10.15-18 This is understandable in the chaos of a resuscitation where 6 seconds between breaths can feel like an eternity. Hyperventilation, however, significantly raises mean intrathoracic pressure and diminishes coronary perfusion pressure, making chest compressions ineffective and rendering the oxygen trying to be delivered useless.17 One study showed a tremendous increase in mortality when pigs received 30 breaths per minute during CPR compared to those receiving 12.19 Many variables have been shown to affect the quality of ventilations during CPR, but the factor most strongly associated with proper ventilation is not additional training, but rather a simple comment from the team leader.20 So let's speak up.
Conclusion
The IOM issued quite the challenge in its call to improve cardiac arrest survival. We cannot implement a national registry or train an entire community overnight. We can, however, strive to maximize the efficiency and effectiveness of the skills we already have. With a little vigilance and attention to detail, high-performance CPR is possible in every ED across the country starting today. We are told early in our training to "check our own pulse.” Let us then turn our attention to the patient, check their compression and ventilation rate, and be sure to communicate with our team. It just might mean life or death.
References
- Amazing Heart Facts. NOVA Online. http://www.pbs.org/wgbh/nova/heart/heartfacts.html. Accessed February 12, 2017.
- Benjamin EJ, Blaha MJ, Chiuve SE et al. Heart Disease and Stroke Statistics—2017 Update: A Report From the American Heart Association. Circulation. 2017;135(10):e146-e603.
- Ewy GA, Bobrow BJ. Cardiocerebral Resuscitation: An Approach to Improving Survival of Patients With Primary Cardiac Arrest. J Intensive Care Med. 2016;31(1): 24-33.
- Sasson C, Rogers MA, Dahl J, Kellermann AL. Predictors of survival from out-of-hospital cardiac arrest: a systematic review and meta-analysis. Circ Cardiovasc Qual Outcomes. 2010;3(1):63-81.
- Institute of Medicine of the National Academies. Strategies to improve cardiac arrest survival: A time to act. National Academies Press, Washington, DC; 2015.
- Bobrow BJ, Eisenberg MS, Panczyk M. The Institute of Medicine Says Time to Act to Improve Cardiac Arrest Survival: Here's How. Ann Emerg Med. 2015;67(4):492-495.
- Jentzer JC, Clements CM, Wright RS, White RD, Jaffe AS. Improving Survival From Cardiac Arrest: A Review of Contemporary Practice and Challenges. Ann Emerg Med. 2016;68(6):678-689.
- Idris AH, Guffey D, Aufderheide TP, et al. Relationship Between Chest Compression Rates and Outcomes From Cardiac Arrest. Circulation. 2012;125:3004-3012.
- Stiell IG, Brown SP, Christenson J, et al. What is the role of chest compression depth during out-of-hospital cardiac arrest resuscitation? Crit Care Med. 2012;40(4):1192-8.
- Abella BS, Alvarado JP, Myklebust H, et al. Quality of cardiopulmonary resuscitation during in-hospital cardiac arrest. JAMA. 2005;293(3):305-10.
- Nolan JP, Perkins GD, Soar J. Chest Compression Rate: Where Is the Sweet Spot? Circulation. 2012;125:2968-2970.
- Zuercher M, Hilwig RW, Ranger-Moore J, et al. Leaning during chest compressions impairs cardiac output and left ventricular myocardial blood flow in piglet cardiac arrest. Crit Care Med. 2010; 38: 1141”“1146.
- Meaney PA, Bobrow BJ, Mancini ME, et al. Cardiopulmonary Resuscitation Quality: Improving Cardiac Resuscitation Outcomes Both Inside and Outside the Hospital. Circulation. 2013;128: 417-435.
- Idris AH, Guffey D, Pepe PE, et al. Chest compression rates and survival following out-of-hospital cardiac arrest. Crit Care Med. 2015;43(4):840-848.
- Maertens VL, De Smedt LE, Lemoyne S, et al. Patients with cardiac arrest are ventilated two times faster than guidelines recommend: An observational prehospital study using tracheal pressure measurement. Resuscitation. 2013;84(7):921-926.
- McInnes AD, Sutton RM, Orioles A, et al. The first quantitative report of ventilation rate during in-hospital resuscitation of older children and adolescents. Resuscitation. 2011;82(8):1025-1029.
- Aufderheide TP, Lurie KG. Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation. Crit Care Med. 2004;32(9 Suppl):S345-51.
- O'Neill JF, Deakin CD. Do we hyperventilate cardiac arrest patients? Resuscitation. 2007;73(1):82-85.
- Aufderheide TP, Sigurdsson G, Pirrallo RG, et al. Hyperventilation-induced hypotension during cardiopulmonary resuscitation. Circulation. 2004;109(16):1960-1965.
- Park SO, Shin DH, Baek KJ, et al. A clinical observational study analyzing the factors associated with hyperventilation during actual cardiopulmonary resuscitation in the emergency department. Resuscitation. 2013;84(3):298-303.