EMS EKGs Don't Increase Onscene, Transport Time

 Scene times & bumpersticker philosophy
To the guy who came up with the phrase "Golden Hour;" thanks for nuthin'.

"There is a golden hour between life and death. If you are critically injured you have less than 60 minutes to survive. You might not die right then; it may be three days or two weeks later -- but something has happened in your body that is irreparable."    Attributed to Dr. Adam Cowley  Reference

Catchy phrases always seem to win out over nuanced discussion, and we are left in the position of having to justify any increment in pre-hospital time intervals. Given the very real dangers of traveling lights & sirens, we instead should have to justify speeding, running red lights, and other ways of "expediting" transport.

"I wonder if it was worth it to encourage all that risky driving..." Not attributed to Dr. Adam Cowley

Nonetheless, there are medical situations where rapid transport is indicated, and most people agree that a STEMI is one of them. And although prehospital ECG acquisition has been shown improve various outcomes, some people may still harbor the concern that taking the time to do the ECG is delaying definitive treatment.

The study

With that in mind, a study of prehospital time intervals was recently published by the folks out in San Diego. The authors of Pre-Hospital Electrocardiography by Emergency Medical Personnel: Effects on Scene and Transport Times for Chest Pain and ST-Segment Elevation Myocardial Infarction Patients. studied scene time and transport time for patients with chest pain. They used a before & after design to look at the differences in times after EMS implemented prehospital ECG acquistion.

They found a statistically significant increase in scene time and transport time after they started doing ECGs. The increases in times, however, were trivial,  accounting for an additional 14 and 12 seconds, respectively. It just goes to show that, if you have over 20,000 subjects in a study, you are going to find statistical differences that just don't matter.

Interestingly, if they only looked at the subset of patients whose Marquette interpretation was *** ACUTE MI ***, they found that those same time intervals decreased, such that the total scene-to-hospital time was almost 3 minutes faster than in the pre-ECG days. So, it appears that, if anything, EMS care is speeding up the care of the specific patient population in question. In particular, the transport time was almost a minute faster, leading the authors to comment: 

"It is possible that once identified, obvious and suspected STEMI patients were treated with greater urgency resulting in expedited transport to the closest STEMI center."

A note of caution

 While the paramedics likely treated the identified STEMI patients with "greater urgency," as the authors suggest, I am paradoxically concerned about such a large drop in transport time. How was this achieved? The study wasn't designed to answer that question, but another recent study suggests it was unlikely to be because a bunch of new cath labs were built in the area.

Instead, I am concerned that the dramatic reading of *** ACUTE MI *** prompted the drivers of the ambulances to "expedite" transport by driving warp factor 10. The problem is that, when the view through the windshield looks like this:

Pictured: about to bounce too close to a supernova.

... the next view could be something like this:

Aaaannnd, supernova. *

Let's be careful out there. Just getting the ECG is probably saving lives - don't risk them during transport, "golden hour" or not.

*Reference. Note that picture this is used for illustration, but the EMS crew apparently was neither responding nor transporting, and a car ran into them.