The Role of EMS in STEMI Management

 

 
 
 

Keith Wesley, MD, FACEP | | Wednesday, January 14, 2009


Review of: Brown JP, Mahmud E, Dunford JV, et al: "Effect of Prehospital 12-Lead Electrocardiogram on Activation of the Cardiac Catheterization Laboratory and Door-to-Balloon Time in ST-Segment Elevation Acute Myocardial Infarction." American Journal of Cardiology. 101(2):158-161, 2008.

The Science

This study from San Diego examined the effect of obtaining a prehospital 12-lead ECG and activating the cath lab for patients with suspected ST-elevation myocardial infarctions (STEMI). The time from arrival at the hospital to cath lab (door to balloon) was compared to that of patients who presented on their own to the emergency department (ED) (control group) who were diagnosed with a STEMI.

In this study, 25 prehospital patients were felt to be STEMI patients, and the cath lab was activated. Five were excluded as three 12-leads indicated an old bundle-branch block, and two had left-ventricular hypertrophy. The door-to-balloon time for the EMS patients was 73 +- 19 minutes and 130 +- 66 minutes for the control group. EMS scene times increase an average of 73 seconds for 12-lead acquisition.

The majority of patients with field STEMI achieved door-to-balloon times of <90 minutes (80% field STEMI, 25% controls).

The Street

This study is almost four years old, and I suspect it was a "proof of concept" study. It clearly demonstrated that prehospital 12-leads coupled with cath lab activation leads to faster entry of the patient into the system. The goal for reperfusion using interventional procedures (balloon, stents, etc.) is 90 minutes from arrival at the hospital. It has long been recognized that a large percentage of acute MIs do not call 9-1-1 opting instead to drive themselves to the hospital after waiting prolonged periods for their symptoms to improve or for family members to convince them to seek medical attention. Once at the hospital, they may or may not be properly triaged quickly and further delays may result in them not receiving a diagnostic ECG in a timely manner.

Although the number of EMS STEMI cases in this study is relatively small, it's interesting to note that they inappropriately activated the cath lab five times for a false positive rate of 20%. This is much higher than many other studies have reported. While over-triage of trauma tends to be 20-30%, the fiscal impact of calling in a cath lab can be a major impediment to a highly effective prehospital STEMI program. Some have advocated mandatory telemetry of 12-leads to lower the false positive rate.

The Allina Medical Transport program in Minneapolis/St. Paul will soon release an abstract of its experience, which shows similar times savings to this study with a false-positive rate of less than 5%. Although this study didn t explain how the medics determined what constituted a STEMI, I suspect they relied on the machine-generated interpretation, which tends to be fooled by bundle-branch blocks and ventricular hypertrophy. Various strategies to improve provider education along with the use of very stringent STEMI criteria have proven that EMS providers can accurately diagnose STEMI with low false-positive rates.




Connect: Have a thought or feedback about this? Add your comment now
Related Topics: Cardiac and Circulation, Research

 
What's Your Take? Comment Now ...

Buyer's Guide Featured Companies

Featured Careers & Jobs in EMS

Get JEMS in Your Inbox

 

Fire EMS Blogs


Blogger Browser

Today's Featured Posts

 

EMS Airway Clinic

Mechanical CPR is Producing Resuscitation Results Beyond Expectations

Discover why clinical studies are finding mechanical CPR just as effective as optimally-performed CPR.
More >

Multimedia Thumb

New York First Responders Take Extraordinary Steps to Help Residents

Snow causes fire and EMS crews to go beyond call of duty.
Watch It >


Multimedia Thumb

Raw Video: Explosion and Fire at California Business

Over a dozen hurt in Santa Paula blaze.
Watch It >


Multimedia Thumb

Four Workers Killed at Texas Chemical Plant

Five employees exposed to methyl mercaptan in La Porte.
Watch It >


Multimedia Thumb

Worker Killed in North Carolina Bridge Collapse

A fatal construction site collapse occurred in Wake County.
Watch It >


Multimedia Thumb

Plane Crashes into Chicago Home

Pilot reported engine trouble after takeoff.
More >


Multimedia Thumb

Switzerland Landslide Kills Two, Injures Four

Slide hits residential building near Lugano.
More >


Multimedia Thumb

World Trade Center Rescue

Technical rescue work is done at nation’s tallest skyscraper.
More >


Multimedia Thumb

Braun Ambulances' EZ Door Forward

Helps to create a safer ambulance module.
Watch It >


Multimedia Thumb

LMA MAD Nasal™

Needle-free intranasal drug delivery.
Watch It >


Multimedia Thumb

VividTrac offered by Vivid Medical - EMS Today 2013

VividTrac, affordable high performance video intubation device.
Watch It >


Multimedia Thumb

Field Bridge Xpress ePCR on iPad, Android, Kindle Fire

Sneak peek of customizable run forms & more.
Watch It >


More Product Videos >