Let's Keep Grownups in the White House

My recent post about Rachel Maddow garnered an interesting comment. Rather than post my reply there, where it would be buried down below the fold, I thought I'd share it here.

Paa said:

Let's see if I understand...
Katrina was a kitten, rather than a man eating lion, OK.
Bush was Edward Scissorhands rather than Indiana Jones.
Wonder how radiologists look running a real code?

@ Paa:

We will apparently have to agree to disagree concerning the wit of Rachel Maddow. However, I'm pretty sure that her point was that Bush handled the response to Katrina very badly -- not the more concrete interpretation that Katrina was a wimpy storm.

On the other hand, I could be wrong. Maybe she did mean to suggest that Bush's isolation from real life and real people is frighteningly close to that of Edward Scissorhands. If so, she crafted her simile with such subtlety that it went whiffling right over my head. If this is the case, my respect for Rachel Maddow has only deepened.

You may have intended your final question to be rhetorical, but I'll give it a shot anyway. How do radiologists look running a real code? Hopefully, like we're grownups giving it all we've got.

If "real" means doing CPR at a car crash 20 miles from town with no in-house amenities such as drugs, crash carts, and on-call specialists, I know exactly how that feels. If "real" means restarting a friend's heart with an AED on an island way too far from a hospital, I also know how that feels. Compared to these two events, every one of the in-house codes I ran my during internship was a walk in the park.

What if the code in question is a 300 year hurricane called Katrina? I'm pretty sure the country would be a lot better off with even a bottom-feeding radiologist running the disaster response than it has been following Bush's paltry effort.

So, here's my inauguration day wish for all of us: regardless of which way we lean politically, let's do our best to keep grownups in the White House from now on, starting today at noon, Eastern Standard Time.

Grand Rounds - Vol 5, no. 4

Cost-saving automated external defibrillator storage. (A) Vending machine. (B) Advertising box. (figure used with permission)

This week's edition of Grand Rounds is up, hosted this week by the Anesthesioboist.

She groups this week's posts into a movie theme. My contribution, AED Lessons from Japan, appears under the heading of Educational Materials (our section's personal movie theme: Elf).

AED Lessons from Japan

For some years now, automated external defibrillators (AED) have greatly increased the likelihood of surviving a cardiac arrest in the U.S. In Japan, however, lay usage of AEDs was not authorized until July 2004.

Hideo Mitamura (2008). Public access defibrillation: advances from Japan. Nature Clinical Practice Cardiovascular Medicine DOI:10.1038/ncpcardio1330

This recent article by Hideo Mitamura details some of the societal, legal and attitudinal changes in Japanese society since 2000 that led to this change. The U.S. Federal Aviation Administration seems to have gotten the ball rolling there in 2001, by making AEDs mandatory on all US domestic and international flights (including those of Japan Airlines). The well-publicized 2002 squash court death of Prince Takamodo of the Imperial family probably also played a role. After lay-use AED legalization in 2004, Japan adopted the devices avidly, and is now the second largest market for AEDs after the U.S.

The Japanese AED deployment has included several innovative approaches that would be quite swell to import back to the U.S. My favorite: siting AEDs inside vending machines. Assuming that vending machine users there are just as fanatical as Americans, I'll bet that every Japanese over the age of 6 now knows where to find an AED in a hurry.


Cost-saving automated external defibrillator storage. (A) Vending machine. (B) Advertising box. (figure used with permission)

Another Japanese innovation is to put AED locations on lots of internet maps. Better yet, GPS-equipped cell phones there can now lead their users right to the nearest AED.


(A) Each red dot represents an AED location in Aichi Prefecture. (B) A magnified view showing AEDs (red hearts) within buildings. (C) Display of AED location on the screen of a cellular phone. (figure used with permission)

So, hats off to the Japanese for a fine job in AED adoption. After learning a lot from the early U.S. experiments in AED usage and deployment, they now have a few things to teach us.

Surviving Cardiac Arrest: Location, Location, Location

Some places are just safer to live than others.

A study by Nichol et al in the latest issue of the Journal of the American Medical Association estimates one's chances of surviving a cardiac arrest in 10 different sites in North America: Regional Variation in Out-of-Hospital Cardiac Arrest Incidence and Outcome.

Nichol G, Thomas E, Callaway CW, Hedges J, Powell JL, Aufderheide TP, Rea T, Lowe R, Brown T, Dreyer J, Davis D, Idris A, Stiell I. (2008). JAMA, 300 (12), 1423-1431

Their study population included 20,520 patients with out-of-hospital cardiac arrest (OHCA), and concluded that there are significant regional differences in survival.

This study estimated 3 different survival rates: all cardiac arrests, all arrests in which resuscitation was attempted, and all arrests with shockable rhythms. I've summarized these 3 rates for 9 of the 10 centers in the bar chart below.

The top of the red bar is the survival rate for all cardiac arrests.

Many of the 20,520 arrests were not resuscitated, for various reasons (do-not-attempt-resuscitation directives, terminal illness, etc.). The top of the green bar represents survival for those who did receive resuscitation.  As one can see, it's a lot better to be resuscitated than not resuscitated.

Not all cardiac arrests are equal. Patients with arrest due to ventricular fibrillation and other shockable rhythms have a much better chance of survival than arrests from other causes. The top of the blue bar represents their survival rate.


The Pacific Northwest has a reputation of being a great place to live. The plot above suggests it is also a great place to survive a cardiac arrest.

Nichol et al conclude:

These findings have implications for prehospital emergency care. The 5-fold variation in survival after EMS-treated cardiac arrest and 5-fold variation in survival after ventricular fibrillation demonstrate that cardiac arrest is a treatable condition. However, only 31.4% of treated cardiac arrests (84.8% of bystander-witnessed) received bystander CPR. Therefore, ongoing efforts are necessary to encourage the public to be ready, willing, and able to provide CPR when necessary.

Further improvements in outcome could be achieved by reducing the time to arrival of EMS providers capable of advanced cardiac life support by improving early detection of cardiac arrest, dispatch protocols, deployment of existing vehicles, number of vehicles available to respond, quality of CPR, and real-time or postevent quality assurance.

The same issue of JAMA also includes an editorial by Sanders and Kern, from which I have filched the title of this post. Their editorial puts Nichol's study nicely in perspective. As they point out, although OHCA has a dismal prognosis in many communities, even small improvements in survival translate into thousands of lives saved.

From the graph above, it's apparent that someone in Seattle deserves enormous props for achieving the survival rates shown. However, as Sanders and Kern note:

...protocol and technique can be more important than location for survival of OHCA. Focused attention and improvements to identified local issues within the chain of survival can significantly influence survival.

In other words, similar rates of survival should be achievable by any community that cares enough to do so. Sanders and Kern conclude:

It is time to work to overcome barriers in each community, devote appropriate resources, and optimize survival of all patients so that location by city becomes a minor factor in survival of cardiac arrest.

Home AED Use for Precocious Geezers

As we precocious geezers contemplate the various ways we will someday exit this globe, one means looms large: cardiac death. Fortunately, this specter of heart disease can be exorcised somewhat by appropriate technology, such as coronary stents, cardiac pacemakers, and automated external defibrillators (AED). All of these devices have done a great deal to prevent some cardiac deaths.

I'm currently reasonably healthy, but remain a bit sensitized to this issue due to a friend having a cardiac arrest before my eyes at a dance last year. As I posted earlier this year, prompt CPR and a nearby AED got my friend's heart started again. My spouse and I now own a personal AED unit, and take it with us to dances and other events. We also keep it readily accessible at home.

Therefore, I read this article from the current issue of the New England Journal of Medicine with particular interest. It's titled Home Use of Automated External Defibrillators for Sudden Cardiac Arrest, and presents the findings from a randomized study of home AED use in 7,001 subjects with prior anterior-wall myocardial infarction (a specific variety of heart attack). The gist of the article:

For survivors of anterior-wall myocardial infarction who were not candidates for implantation of a cardioverter–defibrillator, access to a home AED did not significantly improve overall survival, as compared with reliance on conventional resuscitation methods.

These results are mildly disappointing if you own your own AED, as we do. They are even more disappointing if you are Philips corporation, who currently sells the only AED on the market that is FDA-approved for home use (and may have been hoping to use the results of this study to sell a zillion more home AED's).

The demographics of this study population don't extrapolate well to our house, since none of us have any prior history of cardiac disease. However, neither did the friend we helped to resuscitate last year. Furthermore, I take heart, so to speak, in the following details from the study:

AEDs were used in 32 patients. Of these patients, 14 received an appropriate shock, and 4 survived to hospital discharge.

A simple analysis of these numbers: 4/14 (29%) of those who were shocked were long-term survivors. If there had been no AED available, this survival rate would have been much lower -- like zero. We won't be putting our AED on eBay anytime soon.

Other points of interest from this study: 83% of the subjects were men, and 88% of the rescuers were married to the subject.

Putting all of these factoids together, here's the Secret Master Plan™ I would suggest for surviving a home cardiac event:

1. keep an AED around the house
   
2. have a significant other
   
3. be really, really nice to your S.O.
   
4. make sure they know CPR
   
5. make sure they know how to use your AED
   

Is a Radiologist Doing CPR Like a Pig with a Wristwatch?

I've been taking cardiopulmonary resuscitation (CPR) classes periodically since medical school many years ago. For me, one of the hardest part of these classes has been keeping track of the ever-changing Official Ratio™ of chest compressions to breaths. Is it 5:1? 15:2? That's one reason why the following recent study in the Journal of the American Medical Association (JAMA) caught my eye:

Bobrow, B.J. (2008). Minimally Interrupted Cardiac Resuscitation by Emergency Medical Services for Out-of-Hospital Cardiac Arrest. JAMA, 299(10), 1158-1165.

This study compared standard advanced life support with a new protocol known as minimally interrupted cardiac resuscitation (MICR). The results: patients treated with MICR were at least 3 times more likely to survive their cardiac arrest than patients treated with the standard life support protocol.

Just what is MICR and why should it make such a difference?

The main idea behind MICR is that the "C" in CPR is a whole lot more important than the "P" part. Unlike the mixture of chest compressions and assisted breaths given in standard CPR, the MICR protocol starts off with 200 uninterrupted chest compressions. Electrical defibrillation was not performed until after these initial 200 chest compressions. Why do it this way? As the authors state:

During resuscitation efforts, the forward blood flow produced by chest compressions is so marginal that any interruption of chest compressions is extremely deleterious, especially for favorable neurological outcomes. Excessive interruptions of chest compressions by prehospital personnel are common. Therefore, MICR emphasizes uninterrupted chest compressions.

In other words: CPR is a very poor substitute for an actual heart. Interrupting chest compression downgrades this "poor" to "piss poor".


But what's the benefit of not ventilating a patient?  How does a patient get any oxygen if one omits the "pulmonary" part of CPR?

...positive pressure ventilations during cardiac arrest may be harmful because they increase intrathoracic pressure, thereby decreasing venous return and subsequent myocardial and cerebral blood flow. Probably due to the excitement and stress of resuscitation efforts, excessive ventilations by both physicians and EMS personnel are common.

Immediately after a sudden VF cardiac arrest, aortic oxygen and carbon dioxide concentrations do not vary from the prearrest state because there is no blood flow and oxygen consumption is minimal. Therefore, when chest compressions are initiated, the blood flowing from the aorta to the coronary and cerebral circulations provides adequate oxygenation at an acceptable pH. At that time, myocardial oxygen delivery is limited more by blood flow than oxygen content. Adequate oxygenation and ventilation can continue without rescue breathing because the lungs serve as a reservoir of oxygen that allows adequate oxygen exchange with the limited pulmonary blood flow during cardiopulmonary resuscitation...

In addition, substantial ventilation occurs from chest compression–induced gas exchange (ie, small volumes exhaled with each compression and inhaled with chest recoil) and spontaneous gasping by the patient in cardiac arrest during cardiopulmonary resuscitation.

Is it time to change the way we do CPR? Maybe. Maybe not.

This is a nicely designed prospective study with a large sample size (n = 883), and published in an English-language major medical journal. I commend the authors for this excellent work and am impressed by their results. However, this JAMA article has a major flaw: the CPR protocols used were not randomized. Lack of randomization can allow all sorts of bias to creep into a study. For example, the effects seen in this study could even represent an example of the Hawthorne effect. I don't think I can improve on the authors' own conclusion:

These results need to be confirmed in a randomized trial.

I agree. If a randomized controlled trial corroborates the findings in this study, I expect to see a lot of changes in official CPR protocols. For an excellent further commentary on this study, please see this JAMA editorial.

At this point, you might be wondering: "How can CPR possibly matter to a radiologist?"

If so, 5 points for Gryffindor for raising that question. But just 5.

A fair number of radiology procedures involve injecting some contrast agent (lay term = "dye") into a patient. Cardiac arrythmias are an uncommon but known complication of these agents. Thus, these studies are only performed when a radiologist is around to monitor the exam and treat any adverse reactions, including cardiac arrest.

I haven't had to do CPR on a patient since I entered radiology. However, a friend had a cardiac arrest before my eyes at a dance last year. Fortunately, CPR and a nearby automatic external defibrillator (AED) were enough for me, my spouse and several other pals to restart my friend's heart, which is still beating strong at local dances 15 months later.

I guess you could say this event made CPR really, really relevant to me -- relevant not only as a physician, but also as a precocious geezer and potential CPR customer myself. These days I travel to local dances with a personal AED just in case cardiac lightning strikes again in my vicinity. If it does, I'm also going to pay a lot more attention to my chest compressions, and keep them as uninterrupted as possible.