Should commuter trains carry defibrillators?

The Chicago Tribune (http://www.chicagotribune.com/health/chi-metra-defibs-09-oct09,0,5601601.story) reported on October 9, 2009, that a commuter suffered a heart attack during his commute the previous day and despite efforts to administer CPR on board the train, the man died. Would an AED (automated external defibrillator) have saved his life? And, policy wise, should Metra and other operators of commuter trains be required to have AEDs aboard?

The article reports that defibrillators cost between $1200 and $2500. Is that a lot of money to spend on reviving a person in cardiac arrest? Of course, posing the question that way is too easy--of course if we see a person in cardiac arrest, we are likely to think we should spend $2500--or $25,000, or $250,000--to provide the medical care needed to take care of that person.

But that isn't the right way to pose that question, because ex post, or after an cardiac incident occurs, we will want to spend whatever it takes to care for the individual. It's a bit like waiting until a house fire breaks out and then asking the homeowner if he is willing to contribute money towards the local fire department. I"m guessing the answer to that one would be "yes."

So what is the right way to pose the question? We need an ex ante approach: we need to say, what is it worth to lower the risk of a certain event happening?

In this case, we can ask, how many lives would be saved if we required AEDs on Metra's commuter trains? What would it cost to install and maintain these AEDs? And is that expense worth paying, given the likely impact on fatalities averted?

Some evidence suggests that AEDs are as cost-effective as many other health interventions:

• A somewhat dated (1998) article by Nichol et al. in the journal Circulation (http://www.circ.ahajournals.org/cgi/content/full/97/13/1315 ) offers some evidence that public (lay) use of AED's would be cost effective by "usual" U.S. standards: the authors estimate a median cost of $44,000 per QALY (quality adjusted life year) saved by use of the devices.
  

• A study of the use of AEDs on commercial aircraft (2001, Groeneveld et. al; http://gateway.nlm.nih.gov/MeetingAbstracts/ma?f=102273455.html ) of AEDs' cost effectiveness found that "Placing AEDs on all passenger aircraft with concurrent BLS [basic life support] training would cost $49,800 per QALY gained compared to no AEDs and no BLS training."
  

• A more recent study (2009, by Nichol et al., here: http://www.annemergmed.com/article/S0196-0644(09)00101-2/abstract ) estimated a mean cost of $46,700 per QALY saved by use of AEDs by lay responders.
  

In the U.S., we often apply a "rule of thumb" in which interventions or treatments that cost less than $50,000 per QALY saved are cost effective, and by that measure, these studies suggest that AEDs meet that standard.

What does that mean for Metra or other operators of commuter trains? Well, the impact of the devices on lives saved will depend in part on how many people ride the train and are at risk of going into cardiac arrest. If a train only carries 10 people all day long, it's hard to believe that installing an AED would be worth it--meaning, the likely effect on averted fatalities (reflecting 10 people, 24 hours a day, having some underlying risk of going into cardiac arrest) would be small, so that the cost per QALY saved is likely pretty high. But if a train carries 1000 people--or 4000 people--or ???? people--all day long, then the number of expected averted deaths will be greater and, consequently, the $ cost of per each gained QALY will be lower.

So, my recommendations would be:

• Require Metra to install AEDs on trains that meet some sort of minimum usage standard.
  

• Allow Metra to recoup the cost of the AEDs through its ticket prices. After all, the beneficiaries of the installation are quite clearly the passengers.
  

While these steps would not prevent every death from cardiac arrest in public spaces, they would mean higher survival rates and better outcomes for a reasonable outlay of dollars.