Please could you give a brief introduction to cardiac arrest?
Cardiac arrest is an important clinical challenge. The event is unexpected and surprising; the patients are challenging, and the outcomes are poor.
In the United States each year approximately 200,000 hospitalized patients will suffer a cardiac arrest. Only half of them survive the arrest and fewer than 20% survive to hospital discharge.
Is a cardiac arrest the same thing as a heart attack?
A cardiac arrest is not the same thing as a heart attack.
A cardiac arrest is when the heart stops beating, or goes into a rhythm that cannot circulate blood effectively. Patients usually lose a pulse, become unresponsive, and stop breathing. A heart attack specifically refers to a process where there is an obstruction in one of the coronary arteries (which supplies oxygen to the heart itself), often as a result of atherosclerosis. A heart attack can cause a cardiac arrest—sometimes at the same time, or sometimes years later.
How does resuscitation help to revive patients who have had a cardiac arrest?
The process of resuscitation involves chest compressions, medicines that affect the circulation, and often providing an airway when the patient has stopped breathing. The aim is to externally restore circulation to the body, because the heart itself is not doing the job.
How long does this process normally take?
It varies. Sometimes the patient goes into cardiac arrest and it is as simple as giving one electric shock to restore the regular rhythm. Often the cardiac arrest is sustained and resuscitation has to go on for a long time before you have a response.
On average, how successful is this process?
The fact is that only half of patients survive the cardiac arrest itself. Even though the science of resuscitation has improved dramatically over the past 30 years, outcomes are generally poor.
How do medical professionals decide that it is time to stop attempting resuscitation of a patient?
One of the challenges that we face during in-hospital cardiac arrest is determining how long to continue resuscitation before stopping, if the patient remains unresponsive.
The conventional wisdom has been that resuscitation shouldn’t be considered for a long time because if patients don’t survive early on, because their prognosis is poor.
This was the impetus to conduct our study. There really have been no guidelines to guide practitioners on determining when to stop resuscitating a cardiac arrest patient once resuscitative efforts have begun.
What was previously thought to be the problem with long duration resuscitations?
The problem is we don’t have a lot of published evidence about sustained cardiac arrests.
When studies look at this, most of patients do survive within the first few minutes, therefore longer efforts are felt to be futile.
What has your recent research found?
We found a few things. Basically, our study explored the issue of long resuscitation further. We hypothesized that:
- There is significant variation in the amount of time hospitals continue efforts because there are no formal guidelines.
- The length of attempts might be related to the survival rates.
We found several things. Firstly, we looked at survivors and found that about 50% of patients survived a cardiac arrest. 87% of those patients that survived were able to get a pulse back by 30 minutes.
It was largely known that most patients who do survive, survive early on; but we were actually surprised that this percentage wasn’t higher. We expected that the number of patients that survived that got a pulse back by 30 minutes would be closer to 90% or 100%. This was not the case. There was a non-trivial number that required resuscitation for longer than 30 minutes.
Then we focused on the non-survivors – the patients who didn’t survive the cardiac arrest. We found that fewer than 25% of the patients who died were only resuscitated for 30 minutes.
This means that there are clearly a non-trivial number of patients that need more than 30 minutes of resuscitation to achieve a pulse. Secondly, attempts in most patients are rarely extended for longer than 30 minutes.
This suggests a big opportunity for extending the length of resuscitation in patients that might benefit.
The final thing that we found, and this is the main overall finding of the study, is that the hospitals that tended to practice longer duration resuscitations had a higher survival rate than those that didn’t. This means that hospital practice patterns matter in these situations.
What impact do you think this research will have?
There are several things that we hope people will take away from this study.
First and foremost, our study cannot identify an optimal duration of resuscitation for any particular patient. We’re not defining an optimal duration for resuscitation and we are hesitant to do so. The amount of time spent resuscitating any particular individual will always remain bedside decision based on clinical judgment.
The second thing to take away is that we should be a little bit more open minded about longer resuscitations, because for some patients, long duration resuscitations may result in survival.
In our sample, we found that hospitals that increased their median resuscitation time by 10 minutes had improved survival rates.
Finally, it is important to note that we are not trying to say that every single patient needs a longer resuscitation, but that there is a chance for a systems-level improvement. If we could standardize the length of resuscitation, perhaps by setting a minimum time, then that could increase survival rates for a large number of patients.
How do you think the process of resuscitation will develop in the future?
We hope that our research will lead to further research which will identify for which patients longer resuscitation would be useful.
It is not clear from our research that the extended duration was responsible for improved outcome in the patients. There may actually be other factors involved in the hospitals that tend to resuscitate for longer having better survival rates. They may have better co-team leadership, better compressions etc. It is hard to know, but we hope this paper will spur further work in the area.
Do you have any plans for further research into this field?
We think that it is certainly a very interesting field and that our group will continue to research in this area and I hope to be a part of that.
Would you like to make any further comments?
We just want to emphasize again that we hope our findings aren’t misunderstood. We are not trying to say that everyone should have a long duration resuscitation.
We do think though that this research may shift the paradigm and it will make people think about whether patients necessarily should be stopped being resuscitated after a certain period of time. We should also be very mindful of the patients that we choose to resuscitate. A lot of patients who are very sick will obviously have a worse outcome.
Where can readers find more information?
Readers can find more information on our paper: http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2812%2960862-9/abstract
About Zach Goldberger
Dr. Goldberger received his undergraduate degree with Honors in English and American Literature from Brown University in 1998. He received his medical degree from Yale School of Medicine in 2004, an internship and residency in Internal Medicine at the University of Washington Medical Center in 2007, and fellowship in Cardiovascular Disease at the University of Michigan Health System. In addition, he was a 2010-2012 Robert Wood Johnson Foundation Clinical Scholar at the University of Michigan, receiving a Master of Science degree in Health and Health Care Research. He is a Fellow of the American College of Physicians.
He has published over 20 peer-reviewed papers, including first-author papers in the New England Journal of Medicine, JAMA, Lancet, and Journal of the American College of Cardiology.
In addition, he is the co-author of two textbooks. He is currently a cardiologist at Harborview Medical Center / University of Washington School of Medicine, in Seattle, Washington.