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.

Hypoglycemic patients, and refusal of transport.

It's a fairly typical ambulance run - you're called for "low blood sugar," and on arrival the wife points you to a sweaty, pale man who is shaking and speaking nonsense. The finger stick is "LO," but a box of D50 brings him around fairly quickly. You soon determine that he had administered his insulin just prior to lunch, but some distraction prevented him from eating on schedule.

No problem sir, just sign right here!

Probably not the best AMA form to be using...

For such a common practice, you would imagine that this would be a fairly safe encounter. Most EMS providers are careful to ensure that the patient will another person with them, that they eat a meal before the ambulance leaves, etc. Nonetheless, there are still a number of potential pitfalls that await the unwary paramedic.

Let me point out 5 important aspects of the "routine" hypoglycemic patient encounter:

1. In general, this is a safe practice that patients are very satisfied with.
2. Hypoglycemia due to oral hypoglycemics can be prolonged.
3. Accidental ingestions of oral hypoglycemics by children, even if they are just suspected or possible, must always be transported, and admitted to the hospital.
4. Hypoglycemia associated with long-acting insulin is also dangerous, and should also be transported.
5. After a hypoglycemic episode, patients are especially vulnerable to a repeat episode, often showing symptoms at a higher glucose level.

Signing off patients is generally safe.

A number of studies, using a variety of methods and protocols, have shown that treating patients at home, and permitting them to refuse transport is a safe and popular practice. Studies conducted in the U.S. have more often used protocols that used an on-line medical control physician to talk with the paramedic, and often the patient as well. They also have used explicit inclusion criteria, and formal AMA paperwork. One study out of Buffalo used this inclusion check-off sheet:

Patients who met the criteria, and who had discussed refusing transport with the medical control physician, were given this form:

This level of documentation is very thorough, and likely prevents many potential lawsuits. The down-side of this elaborate protocol was that, over 3 years, less than 1/3 of the medics in that EMS system enrolled any patients, and only 36 patients total were enrolled.

Contrast this with one Canadian study, where only 34% of hypoglycemic patients ended up being transported. There was still a requirement for the paramedic to contact medical control, but there were no extensive inclusion criteria to follow. Instead, clinical discretion was expected of the medics. Perhaps that's why, in less than 1 year, 145 patients were found to decline transport - a far higher number than in Buffalo. Nonetheless, the practice was very safe, with recurrence of hypoglycemia happening just as often in the transported group as the refusals.

Even further from the U.S., both in protocol and in geography, is Finland. Researchers examined how well the protocols were working for them. Paramedics only needed to transport if patients "did not regain consciousness, were not able to eat after treatment, were pregnant, had type II diabetes treated with oral medication only or oral medication in addition to insulin, in case of insulin overdosage and variably in case the patient would be left alone or was a child (physician consultation)." In general, paramedics did not contact base physicians. Only 10% of patients ended up being transported!

Hypoglycemia due to sulfonylurea drugs must be transported.

Note that in the Finnish study, despite the willingness to leave many of the hypoglycemic patients at home, they required transport for patients who were taking oral hypoglycemics. Why was that?

Two reasons: duration of action, and underlying causes.

First, you must understand that not all oral diabetic medications are alike. There are five classes of oral medications: sulfonylureas, meglitinides, bigiuanides, alpha-glucosidase inhibitors, and the thiazoladinediones. While they all act in some way to prevent hyPERglycemia, only the first two classes are able to cause hyPOglycemia.

The most common sulfonylureas are glyburide, glimepiride, and glipizide, and they all have pretty long duration of action (24+ hours for both glyburide and glimeride). This means that if the patient accidentally took 2 or 3 pills extra today, 1 box of D50 and a PB&J sandwich may only temporarily bump the glucose, before the levels ground out again. This may not be a patient you can safely leave at home - they may have trouble for the next few hours or days!

Certainly, skipping a meal, or running for an hour longer may also promote hypoglycemia. These causes will be clear from the history. However, there are other causes of hypoglycemia associated with the oral medications, and the history may not be obvious.

Such causes are:

• In patients who are undernourished or abuse alcohol
• In patients with impaired renal or cardiac function or gastrointestinal disease
• Concurrent therapy with salicylates, sulfonamides, gemfibrozil, or warfarin

These comorbidities often play a role in hypoglycemia. If you have a patient taking glyburide who has had an episode of hypoglycemia, realize that this may be just the "tip of the iceberg." We will end admitting a good chunk of these patients, so don't leave them at home. The little evidence we have about the safety of not transporting is not encouraging.

Speaking of the oral medications; this isn't strictly on-topic, but while we're on the topic...

The suspected ingestion of a sulfonylurea by a child gets transported.

Obviously, if a child is symptomatic from such an ingestion, they will be transported. The danger lays with the child whom the caretakers think may have taken a pill or two out of grandmother's purse. Despite normal glucose levels at the time of evaluation by EMS, patients have been known to develop hypoglycemia many hours after ingestion. This delayed effect seems to happen when children are given dextrose or food to prevent hypoglycemia, but it just puts it off for a few hours.

These are simple cases - they will all be admitted, even if there is just the suspicion of an ingestion.

"Kid and glyburide means ambulance ride."

Hypoglycemia associated with a long-acting insulin should be transported.


Lantus (insulin glargine) was approved by the FDA in 2000, and was the first insulin that was effective for 24 hours. This was a great therapeutic development, providing patients a more natural delivery of insulin. Levimer (insulin detemir) is the other commonly-used long acting insulin

Unfortunately, most of the good studies that looked at EMS "treat and release" protocols were conducted either before, or soon after, the release of Lantus. As a result, it is unclear if it would be safe to allow patients on these long acting insulins to refuse transport - we just don't have the data yet.

In the ED, these patients will usually be admitted, so don't think too hard about transporting!


Acute hypoglycemia predisposes patients to more recurrences.


Episodes of severe hypoglycemia seems to make it easier for a patient to have more episodes in the short term. Patients seem to lose both the ability to feel when their sugar is low, and a weaker capability to send out catecholamines to raise the sugar.

As a result, patients may have symptoms of hypoglycemia at a lower glucose level than before. If they developed an altered level of consciousness at a level of 55 mg/dL the first time, they may need to drop down to 35 mg/dL the second time.

For that reason, especially if patients decline transport to the hospital, they need to be educated that they should keep their glucose levels higher than usual for the next few days. In truth, it could take a few months of blood sugars in the 160-180 range to significantly improve their hypoglycemia awareness.

What do the Greater Bridgeport protocols say?

Glad you asked.

This protocol can't cover all the possibilities - we need an educated prehospital practitioner in the field to look at the scene, the patient, and get the history. But when you call in, you'll now have a much better idea of the things we're listening for, and the ways we can avoid the pitfalls.