Prehospital Administration of Tenecteplase for ST-segment Elevation Myocardial Infarction in a Rural EMS System.

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Get a reprint here.

For the inaugural posting for Mill Hill Ave Command, I selected a recent publication that suggests the potential of what EMS can be. It isn't great science, maybe it didn’t save any lives, and as for cost-effectiveness - I have no idea. But this sort of project that Crowder et al. describe here is nonetheless exciting, and is the sort of thing that excites all of us, whether we’re the ones giving the patch, or the one who is taking it.

The author, a paramedic, describes the 9-year experience that his EMS agency and their local hospital have had with giving TNK in the rig for STEMI. Evidently Wilkes EMS is located in a fairly rural part of North Carolina, and it takes about an hour to transport to the nearest PCI-capable hospital. Business-as-usual used to involve transporting the (EMS identified) STEMI patients to the local hospital, where they would administer lytics in the ED. This would typically be followed by transfer to the regional PCI center afterwards. This seemed like a waste of both petrol and myocardium to all involved, and so they started a program that permitted direct transport to the PCI-facility, as well as the administration of fibrinolytics by paramedics, often in the patient’s home.

“The plural of anecdote” is a retrospective case series, which is how they describe this paper. Essentially, they just want to talk about their project, and that’s fine. Heck, they earned some bragging rights with this. And besides, not every cardiology study needs 10,000 Italians.

They describe the results they had with “consecutive patients presenting with an onset of chest pain that met criteria for prehospital thrombolytics and received tenecteplase between January 1, 2001, and April 1, 2010...” This is a fairly select group, as the numbers will bear out in the results. I’ll just point a few items that will limit (probably appropriately) the percentage of STEMI patients that could have been enrolled.

First off, not all STEMI patients have chest pain, as we all know. Before everyone yells out “Women present atypically!” let me just say that I will tackle that chestnut in a later posting. Diabetics and the elderly, however, are well known to present with “tombstones” in the anterior leads, and “just some indigestion.”

I actually don’t believe that the chest pain requirement was followed strictly. I know too many good medics who will slap on the 12 leads, following their clinical gut, and I’m sure that’s how they roll in NC as well – I expect a good number of the “chest pain” patients were actually calls for SOB or nausea that the medics picked up.

As for exclusion criteria, I wonder how many potential field lysis patients were disqualified based on an initial high BP that subsequently came down, or because of unequal blood pressures in their arms. Fun fact: About 20% of people have at least a 20 point difference in their upper arm blood pressures.

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After 9 years they had treated 75 patients through this process. Unfortunately, the prehospital ECG was only available for 66 of them. Now, there is no real valid way to pull any good outcomes data out of this study – the plural of anecdote, and all that. But the authors are able to legitimately discuss how appropriate it was for each of the patients to have been treated by this process.

A nice point of the paper is that they use both an EP and a cardiologist to review the initial ECG and history, and, not surprisingly, they disagree in some measure. The EP thought that 89% of the patients were, in retrospective, accurately diagnosed with a STEMI, while the cardiologist found that only 82% were. Statistically, that's fair. Eventually, they all came to a “consensus” that the lytics were correctly given 86% of the time. Eleven percent, though, were found to have been lysed inappropriately.   

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There is also a lot of discussion in the paper about how this process probably saves a lot of time, and how this likely helps the patient, and that’s all well and good. Maybe it does, maybe it doesn’t. You could even argue, perhaps, that the cost and increased oversight needed to treat this relatively small number of patients (about 3 every 2 months) can’t be justified in a cost-benefit analysis. Going further, you have to wonder about the STEMIs they didn’t enroll or catch, the patients who had lytics inappropriately withheld. They don’t have that data to share with us, and you can be tempted to start pointing out flaws and omissions that weaken the paper.

That’s all sort of missing the point, though. I actually don’t care that much if this program can be justified based on the number of muscle cells saved, or proper allocation of resources, or dollars spent. Doesn’t matter. Even if it turns out to be a small boondoggle (and there is no way it can be worse than helicopter EMS), it is emblematic of a system that relies on the intelligence and the initiative of both paramedics and physicians. It only works for 9 years if both parties have learned to expect a high degree of professionalism from each other, and are working to maintain the processes. These kinds of behavior and attitude don’t just manifest on the STEMI calls, or even just the cardiac calls. One would hope that even the lowly altered LOC from the nursing home is being assessed with a bit more care, that the EPs are relying more heavily on information from the field. Stuff to aspire to!