The last issue of Prehospital Emergency Care (PEC) published a couple of articles about prehospital ECGs, including this one: A Prospective Evaluation of the Utility of the Prehospital 12-lead Electrocardiogram to Change Patient Management in the Emergency Department. (If you have access to this journal or article, please let me know–I can’t find any way to access it, even after trying several hospital databases).
This article discusses how prehospital ECGs can capture clinically significant abnormalities that aren’t always found in the first ED ECG, and that these prehospital ECGs influence the physician’s treatment plan roughly 20% of the time.
Two questions came to mind after reading that abstract. First, how good are paramedics at interpreting ECGs (specifically those that change the clinical course of a patient), and second, what about lead placement?
The first question is less pertinent to the article, but if the prehospital ECG is the deciding factor in a patient’s clinical course, paramedic providers should also recognize this sign. A quick PubMed search, however, suggests that this might not always be the case. An article from PEC last year concluded that, despite extensive training and a high level of confidence, ED physicians cannot rely solely on paramedic providers to activate the cath lab. That stings a little bit. But that’s a conversation for another time.
More concerning is if prehospital ECGs are truly capturing the “clinically significant” ECG abnormalities that influence physicians’ treatments. One 2012 study looked at how the displacement of electrodes by one intercostal space can affect the ECG interpretation about 20% of the time. Another found that precordial lead displacement significantly affects ECG morphology; however, it did not extrapolate to clinical significance. (This study also commented on the classic over-breast/under-breast dilemma faced with precordial lead placement! Skip to the discussion to see what they say).
Not only does lead placement affect the accuracy of the ECG, but lead displacement is common even in the hospital setting and when done by clinical ‘experts’ identifying correct sites for placement.
Perhaps then, we should put a little more consideration into our ECG skills and lead placement. It’s easy slap some leads on in roughly the right places, but that really isn’t good enough. So here’s some FOAM incase you (or your partner[s]) need a refresher on correct lead placement!