STEMI or Not STEMI?
Mencl F, Wilber S, Frey J, et al. Paramedic ability to recognize ST-segment elevation myocardial infarction on prehospital electrocardiograms. Prehosp Emerg Care. 2013;17(2):203–210.
The role of EMS in identifying ST elevation myocardial infarctions (STEMIs) has been repeatedly upheld as a cornerstone of acute care; however, most of the research pertaining to accuracy of identification is from retrospective chart review rather than static identification.
In this study from the Summa Akron City Hospital in Akron, Ohio, researchers held meetings with multiple paramedics from the Northeastern Ohio region in which they were asked to fill out a basic demographic survey and identify 10 ECGs: an inferior STEMI, an anterior STEMI, a lateral STEMI, a paced rhythm, an SVT rhythm, an ECG showing LVH, a left and right bundle branch block, and two normal ECGs.
Results: A total of 472 paramedics from 30 different EMS agencies responded to the survey, with 52% (245) reporting 10 or more years of experience. Nearly all of the respondents (467, or 99%) stated they regularly obtained 12-lead ECGs and 74% (349) stated they were comfortable with their ability to interpret and identify a STEMI.
All respondents were able to identify one of the two normal ECGs while 97% (458) were able to identify the other normal ECG. Most respondents (453, or 96%) were able to identify the inferior STEMI as being an acute myocardial infarction. Only 78% (368) of respondents were able to identify the anterior STEMI and 51% (241) were able to identify the lateral STEMI. An overall sensitivity of 75% (95% confidence interval: 73–77%) and specificity of 53% (95% confidence interval: 51–55%) was reported for paramedic identification of STEMI. Interestingly, there was no correlation between years of service and ability to accurately identify a STEMI, nor was there a correlation between recent education and ability to identify a STEMI.
Discussion: This study presents lower paramedic accuracy rates than we are used to seeing in other articles; however, there are other variables at play. First, the researchers used previously transmitted prehospital ECGs that were then printed and given to the respondents in a static, non-clinical setting. Previously, studies have used computer generated ECGs or retrospective chart review, which may contribute to higher accuracy rates previously. The authors included the 10 ECGs that were presented to respondents in their research paper and, after significant discussion, there were quite a few tough ECGs that we didn’t agree were adequate representations as a group. Lastly, keep in mind that the medics in the study didn’t work in a system that allowed them to activate a cath lab in the field—all ECGs were transmitted to the receiving facility for review. That’s not a statement against the respondent paramedics; however, it leaves us to wonder if this study was designed around that knowledge. The authors feel that more training may be needed on identification of anterior and lateral STEMI identification within this group of paramedics.
Although we love seeing research that challenges prehospital providers’ skill sets, we do caution taking research like this at face value without delving a little deeper into the methods.
What we know: Multiple research studies have assessed and verified paramedic accuracy in obtaining and interpreting prehospital ECGs.
What this study adds: Certain gaps in knowledge, such as identifying lateral and subtle anterior STEMIs, may need to be addressed by future training.
Quick JA, Macintyre AD, Barnes SL. Emergent surgical airway: Comparison of the three-step method and conventional cricothyroidotomy utilizing high-fidelity simulation. J Emerg Med. Nov. 1, 2013. [Epub ahead of print.]
Cricothyroidotomy is a low-frequency, high-acuity skill making its way out of protocols nationally. The authors of this paper, from Columbia, Mo., developed a new, three-step insertion process with the addition of a bougie and an endotracheal tube rather than traditional insertion methods. Twelve flight providers were videotaped and timed performing traditional emergent cricothyroidotomy on a mannequin, and then trained in the new three-step method, which they again performed on a mannequin while being videotaped and timed. The new three-step method yielded a 100% first pass success rate and a significant reduction in time needed to perform cricothyroidotomy. Look for this to pave the way for new airway management techniques and training in the future.