Improving Cardiac Arrest Survival Rates
By Jamie Santa Cruz
Nationwide concerted efforts to improve system response are needed to improve survival rates in cases of cardiac arrest.
About 600,000 people in the United States experience cardiac arrest each year, according to figures cited in a new report from the Institute of Medicine (IOM).1 But survival rates are alarmingly low: while 24% of patients survive in cardiac arrests that occur in a hospital, about two-thirds of cardiac arrests occur outside of hospitals, and less than 6% of those patients survive, according to the report. Those dismal chances for survival make cardiac arrest the third leading cause of death in the United States.
But while those statistics are discouraging, the main message of the report is that survival rates can be improved—dramatically—through a concerted national effort. "Cardiac arrest is a huge public health burden in the United States," says Tom Aufderheide, MD, MS, a professor of emergency medicine and associate chair of research affairs at the Medical College of Wisconsin. "[But] there are benchmark communities that have two to three times higher survival rates, and therefore we know it is possible to improve survival and save more lives," he says.
In general, there is wide disparity in survival rates across the United States. In one study cited in the report, survival for out-of-hospital cardiac arrests ranged from 7.7% to 39.9% across 10 different US sites. Those disparities, Aufderheide says, stem from several factors, including variations in patient demographics, variations in patient health status, geographic characteristics, and system-level factors that affect the quality and availability of care.
For instance, one significant variable that substantially impacts a community's statistics is the rate of bystander cardiopulmonary resuscitation (CPR) performance, which doubles or triples the chance of survival after cardiac arrest, according to Aufderheide. On a national level, only 3% of Americans are trained in CPR every year, according to the report, but some communities have lower training rates while others have far better rates. That reality is the basis for one of the IOM's new recommendations, which is the implementation of a nationwide campaign to train the American public on the essential steps to take following a cardiac arrest, including calling 911, performing CPR, and using an automated external defibrillator (AED).
But simply improving rates of bystander CPR is not a solution in itself, Aufderheide says. For cardiac arrest patients to survive, an entire system of response must be in place: The arrest needs to be witnessed and recognized as cardiac arrest; the witness needs to call 911, perform CPR, and use a publically available AED; and the patient must receive high performance professional responder resuscitation followed by good quality postresuscitation care in the hospital. Each link in the chain has to be strong, Aufderheide says.
The first step in strengthening the chain, according to Lance Becker, MD, division chief of emergency critical care and laboratory manager in the Center for Resuscitation Science at the University of Pennsylvania's Perelman School of Medicine, is measuring survival rates—a practice common in communities where survival rates are comparatively high. "They know how they're doing," Becker says. "They have a system where they actually follow whether a person who has a cardiac arrest survives or not. That's not true in most American cities and communities."
Becker says once individual communities begin measuring survival rates, they can then identify where to direct efforts at improvement. In some communities that have begun measurement campaigns, the resulting data have pointed toward a lack of AEDs in the appropriate places as the main problem. Meanwhile, other communities find that their real need lies in improving their emergency response system, such as more ambulances on the street, better training for first responders, or better connections between ambulances and hospitals. Still others find that a key weakness is 911 operators failing to provide callers with appropriate instructions about how to start CPR after a cardiac arrest.
"Every community is different. They have their unique strengths and weaknesses," Becker says. But he stresses that measurement is the key to improvement in all cases. Accordingly, the IOM's first recommendation on cardiac arrest is the establishment of a national cardiac arrest registry to track survival rates across the country.
If communities across the United States were to begin measuring their results and then make targeted improvements in their systems of response, they could anticipate dramatic results, Becker says. Judging from the gains seen in benchmark communities, it would be entirely realistic to expect an improvement of 10 percentage points in survival rates nationwide, he says. Thus, communities that are currently seeing survival rates of just 2% could easily jump to 12%, and those currently at 6% would likely improve to a survival rate of 16% or more.
While the bulk of the IOM report focuses on recommendations for better implementation of practices already known to improve cardiac arrest survival, the report also stresses the need for additional research on cardiac arrest, which could lead to even greater improvements in survival. According to Becker, investment in cardiac arrest research has been curtailed in the United States to such a degree that researchers don't know the answers to some very basic questions—such as the best rate of CPR during cardiac arrest, the appropriate amount of oxygen to give cardiac arrest patients, and the right temperature at which to keep patients following cardiac arrest. "These are things that people have wondered about for the last 10 years, 20 years, and there has not been adequate investment in research to just answer the simple questions," Becker says.
But while the IOM encourages additional research, Aufderheide stresses that much is already known about how to improve survival, and physicians, patients, and communities need to make good use of the knowledge that is available now. "There is a national responsibility to […] implement what we know already is effective," he says.
Implications for Physicians
• Don't assume cardiac arrest patients can't survive. The most important takeaway for clinicians, according to Becker, is that patients can survive at much higher rates than they currently do. "Many clinicians think that a cardiac arrest is just a hopeless condition," says Becker. "What we know is it's not."
In particular, according to Aufderheide, clinicians should not discount the elderly and their chances for survival. He cites the example of ventricular fibrillation cardiac arrest: When older adults receive timely attention and all links in the chain of response are in place, they have a similar chance of survival and a similar chance at high quality of life as younger patients.
• Talk with patients of all ages, but especially older patients, about the importance of CPR and AEDs. Physicians have a huge role in educating patients and the community about the part they play in improving survival. The IOM report recommends CPR training across the lifespan, beginning in high school as a requirement for graduation, but the report points to a special need to train individuals aged 65 and over and their caregivers. Therefore, according to Becker, clinicians need to ask patients whether they know CPR, and older adults should also be asked whether caregivers have received CPR training. Similarly, older patients should be asked whether they know how to operate an AED and whether they would like to have one in their home.
• Educate patients on the difference between cardiac arrest and heart attacks. Despite the medical differences between the two terms, the general public routinely conflates these terms, which only exacerbates the public health problem, Aufderheide says. Physicians should clarify for patients the nature of each medical event: a heart attack is a sudden obstruction of blood flow in an artery in the heart that supplies the heart muscle with blood, whereas a cardiac arrest is an electrical problem of the heart in which the heart suddenly stops beating. Physicians should also help patients understand how the conditions manifest differently: with a heart attack, patients remain awake, whereas in a cardiac arrest patients will collapse immediately and will require intervention within seconds or minutes.
• Advocate in the community for measurement of survival rates. Physicians who live in areas where cardiac arrest survival rates are not currently measured can and should speak up in favor of better tracking and data collection at the community level, Becker says.
"If we [implement the IOM's recommendations on a national level,] there is every scientific basis to expect a huge impact on public health," Aufderheide says.
— Jamie Santa Cruz is a freelance writer based in Englewood, Colorado.