The ESO EMS Index: In 2019, data and metrics matter more than ever

In its second year, the benchmark report based on EMS national data digs deeper into five key metrics and adds two additional measures

By Drs. Brent Myers and Remle Crowe

The value of using data to make informed decisions at both clinical and operational levels is being increasingly recognized in EMS. In other words, agencies are seeing a need to track, measure, assess and implement changes to continuously improve performance.

The advent of the electronic patient care record (ePCR) has put more data than ever before within fingertips’ reach. In theory, having this much data readily available should be a good thing. However, there is such a thing as having too much data. Data overload is defined as the state of feeling overwhelmed when presented with more information than can reasonably be digested and used to make decisions. When presenting clinical performance metrics, it may be tempting to report on the hundreds of measures available with the click of a few buttons. Yet, carefully selecting a small set of measures that matter is far more likely to bring big results in quality improvement.

Agencies are seeing a need to track, measure, assess and implement changes to continuously improve performance.
Agencies are seeing a need to track, measure, assess and implement changes to continuously improve performance. (Photo/

Of course, the appropriate metrics for evaluating the success of any EMS organization will vary depending upon a number of factors, including the size of the population served, availability of resources and geographic location. However, an objective look at aggregate data from across the United States can provide a good starting point for understanding how an organization is performing compared to its peers.

For the second year running, ESO has identified a specific set of measures likely to apply to a wide variety of EMS practice settings and made the published findings freely available in the form of an annual index. The 2019 ESO EMS Index is based on analysis of more than 7.58 million patient encounters contributed from approximately 1,200 EMS agencies for the complete calendar year of 2018. Based on feedback received after the publication of last year’s ESO EMS Index, we made some refinements to the original five metrics and added two new metrics:



  • Opioid overdose
  • Influenza surveillance

The purpose of this Index is to serve as a point of reference for EMS organizations to identify which areas are in alignment and which areas represent opportunity for improvement, more intensive local monitoring or, at least, further assessment and evaluation. This quantitative approach to measuring performance gives EMS organizations a framework to start with and adapt in order to continually refine tactics, improve efficiency and outcomes, and guidance for where to potentially allocate limited resources.

Here is what we found in 2019 and how it differs from the 2018 findings.

1. Stroke assessment

We updated the stroke assessment performance measure to account for the additional screening tools being employed, as well as focusing only on 911 patients. We opted to exclude interfacility transfers and other run types, to provide a better evaluation of stroke assessment screening practices for patients suspected to be experiencing a stroke in the prehospital setting.

In our 2018 EMS Index, we discovered that a complete stroke assessment was not documented nearly 50% of the time (representing nearly 75,000 encounters). The good news is that in the 2019 EMS Index, we see a nearly 15 percentage point jump – meaning that a complete stroke assessment was documented in nearly 65% of cases (nearly 84,000 encounters). These results suggest that EMS providers are either completing the stroke assessment more frequently or documenting the assessment more regularly after a primary impression of stroke is identified.

Two of the main reasons for unsuccessful completion of a stroke screen are partial completion and narrative-only documentation. Basically, one element of a stroke screen was positive and further stroke screen documentation was abandoned and, frequently, the stroke screens was only included in the narrative and not on the specialty form.

Not documenting, or worse, not doing the full screen limits the ability to assess the severity of the stroke. By completing and documenting all elements of a stroke screen, field personnel enable substantially stronger research and performance improvement activities. Additionally, narrative-only inclusion inhibits the ability to query data and easily make comparisons with in-hospital vs. out-of-hospital stroke findings.

2. Aspirin administration

There is still work to be done around administration and appropriate documentation of aspirin administration to adult patients with non-traumatic chest pain. In the 2018 EMS Index, we saw that aspirin administration was documented in only 55% of cases (out of nearly 182,000 encounters). That number fell slightly in the 2019 EMS Index to 52% (out of more than 270,000 encounters).

Two of the main reasons for lack of compliance with this measure (or seeming lack of compliance) can be attributed to miscategorization and narrative-only documentation.

Often, in cases where aspirin was not administered, a deeper dive into the record revealed that the chest pain was clearly non-cardiac. In nearly 30% of cases where aspirin was not documented in the medications field, mention of aspirin administration was noted in the patient narrative section. Choosing an appropriate primary impression and documenting treatments (even those performed prior to EMS arrival) in discrete queryable fields are critical for quality improvement and research efforts.

3. 12-Lead ECG performance

While 12-lead ECG performance for adult patients experiencing chest pain increased slightly in the 2019 EMS Index (77% based on more than 305,000 encounters) compared to the 2018 EMS Index (76% based on approximately 209,000 encounters), there is still room for improvement.

We have seen different studies show that door-to-balloon time can be reduced by as much as 30 minutes with minimal impact on transport time, highlighting the value of the 12-lead ECG for all adult patients exhibiting non-traumatic chest pain. The 77% raises the question as to why more than 20% of the patients in the dataset that met the inclusion criteria did not receive an ECG (or an ECG was performed and not documented) and why has this number remained unchanged.

4. ETCO2 after advanced airway

The good news is that the vast majority of records examined in this category complied with best practice. In the 2018 EMS Index, we saw a nearly 95% utilization rate for ETCO2 after advanced airway (in approximately 30,000 cases). In the 2019 EMS Index, that number increased to 96% (in more than 42,000 cases).

At the risk of stating the obvious, measuring and monitoring ETCO2 levels to ensure they remain within the acceptable range after an advanced airway is placed is critical. Moreover, given the need to move patients and the generally more austere environment in the out-of-hospital vs. the in-hospital settings, EMS airways in all types of patients have an increased risk of becoming dislodged. Thus, continuous monitoring of EtCO2 remains essential.

5. Overdose (and opioid overdose)

Overdose patients accounted for 1.65% of all encounters in our 2018 EMS Index (about 83,000 encounters), which is exactly the same percentage in our 2019 EMS Index (more than 125,000 encounters). Overdose continues to represent a public health problem, with overdose encounters accounting for nearly 40% more encounters than stroke as a primary impression.

While overdoses in general remain a steady concern, we may be seeing some positive signs regarding opioids – specifically, prescription opioids. Based on our data, we see that nearly 94% of opioid overdoses involved illicit drugs, while only 4% involved prescription opioids (2% did not include documentation of substance type). What we are seeing is that opioid overdoses are very different from other types of overdoses and this might be some of the first good news regarding this epidemic.

While we suspect some of the downward trend in opioid overdose incidents may be due to self or buddy treatment with the widely distributed intranasal naloxone kits, the trend toward a decrease in opioid overdose events is encouraging and, if it continues, may signal that the entirety of the national efforts towards opioid overdose reduction is beginning to produce the desired outcome.

6. Influenza surveillance

Flu-like primary impressions accounted for 1% of all encounters (a little more than 78,000 encounters), with the majority coming in the months of January and February. The 2018 flu season was particularly severe and affected all age groups.

Based on the seasonality we see in the data, getting ready for the flu as early as August is a good approach. We suggest arranging for flu vaccines for staff in the October/November timeframe and encourage vaccinations for family members. Review supply availability and place orders of high in-demand items, such as IV fluids and surgical masks ahead of time.

Look for ways to leverage data to improve

Data and the insights gleaned are only as valuable as the actions we take. The Index we created is simply a start to quality improvement conversations. This document is intended to serve as a way for organizations to look at their own performance and gauge where opportunities exist for improvement and where recognition for outstanding work is in order for areas of high performance.

Take a look at the full Index here.

About the authors

Dr. Brent Myers is the chief medical officer for ESO and one of the authors of the 2019 ESO EMS Index. He can be reached at

Dr. Remle Crowe is the research scientist and performance improvement manager for ESO and one of the authors of the 2019 ESO EMS Index. She can be reached at

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