More “Science” from the Popular Media

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As I mentioned in my last post, I came across this article in at the Health Day website.

Special Ambulance Delivers Vital Stroke Care More Quickly

FRIDAY, Nov. 21, 2014 (HealthDay News) — Stroke outcomes are better when patients are treated in an ambulance by a neurologist equipped with a CT scanner and clot-busting drugs, German researchers report.

The first thing to note is that this was from Germany. The EMS system is built differently there and it’s not uncommon for doctors to respond in the field. Usually not in ambulances, but in cars. I’ve heard they have some very fast cars for that purpose, but that’s not the subject of this post. I mention the location because I don’t know what kind of stroke assessment paramedics in Germany are trained to use. That would be good to know, but either the people at Health Day don’t understand that different countries configure the EMS systems differently, or they don’t know much about EMS. Or maybe both.

The sooner patients get the clot dissolver — tissue plasminogen activator (tPA) — the better the outcome after a stroke, the researchers noted. For the best outcome, the drug needs to be given within the first hour after stroke symptoms start, the researchers said.

The sooner the better, which makes sense. In the US for many years the “window” was three hours, but now in most places it has been lengthened to four and a half. After that, TPA doesn’t show any benefit in terms of reversing the effects of a blood clot. I have to question their “golden hour” theory. The article doesn’t tell us what this is based, so I have no way of knowing.

Of the 614 patients who suffered a stroke when a STEMO unit was available, 32.6 percent got tPA in the ambulance. Among the 330 stroke patients seen when the special ambulance was not available, 22 percent were given the drug once they got to the hospital.

What the article doesn’t tell us is why the difference. Is the one hour rule organic to the German system? If so, why? What makes their one hour time frame more valid than the four and a half hour limit in the US?

Dr. Ralph Sacco, chairman of neurology at the University of Miami Miller School of Medicine, said, “Now we have objective evidence that STEMO not only leads to an increase in the proportion of stroke patients treated with tPA, but also can gets it accomplished much faster, with a six-fold increase in the number of stroke patients treated in the golden hour.”

No, we don’t know that at all. First, one study is never definitive in medicine.  Second, we don’t know what causes the delays in the hospital.

I know that in my state there is a push from the Department of Public Health for hospitals to be faster to get patients into CT. Part of that effort is education of EMTs and paramedics on the importance of doing a stroke scale (Cincinnati or similar), doing a blood glucose, documenting Time Last Known Well (TLKW), onset of symptoms and early notification of Emergency Departments so that they can activate their stroke team.

Dr. Steven Warach is executive director of the Seton/UT Southwestern Clinical Research Institute in Austin, Texas, and author of an accompanying journal editorial. He said, “The mobile stroke unit could be a revolutionary breakthrough in treating stroke victims, but more research is needed to understand how and where to deploy this emergency room on wheels.”

Ahh, the popular myth of the “emergency room on wheels”. EMS isn’t that at all, never has been, never will be. Anyone in EMS who says that it is, is full of a Scott’s product.

“But there are many questions still to be answered,” Warach said. “STEMO is expensive and the CT scanner won’t be needed for most ambulances. Where is it best to have STEMO — in a city with many strokes but many hospitals nearby or in rural settings far away from hospitals but with fewer strokes?”

According to Warach, the cost can range from around $750,000 to up to $2 million, depending on the components and whether a standard ambulance truck is used or is customized. The CT scanner itself is about $500,000. Also, the ongoing costs of personnel need to be considered, he said.

“To be financially sustainable, the costs of these units must be offset by the benefits they provide, measured in terms of preventing long-term disabilities and deaths,” Warach said.

Yes, many questions to be answered. First, who is going to pay for this? Second, where in the US are we going to find doctors to staff a specialty ambulance? Third, how long does the CT take in the ambulance? I’m going to go out on a limb and guess that the ambulance has to be standing still for this to be done.

Here is a link to an article about the experimental unit in Houston

 It typically takes roughly an hour once a stroke patient arrives in the emergency room to receive treatment. So if we can actually put the emergency room in the ambulance and take the CT scanner to the patient, we could treat the patient at the scene with the medication and save that hour,” said Dr. James C. Grotta, director of stroke research in the Center for Innovation & Research at Memorial Hermann-TMC and director of the mobile stroke unit consortium made up of stroke teams from Houston Methodist Hospital and St. Luke’s Medical Center, local businesses and philanthropists. “That hour could mean saving 120 million brain cells.

It seems to me that money and effort would be better spent speeding up the process in the hospital as well as improving stroke recognition training of field providers.  That way potentially every stroke patient can benefit, not just the ones that get treated in the “special ambulance”.

Speaking of which, what criteria is used to dispatch the special ambulance? Part of the problem in dealing with Strokes is that the signs and symptoms can be very subtle. Very often the onset appears to be something else and only once EMS is on scene does the situation become apparent. Which brings us back once again to better training for EMS personnel and faster treatment once in the hospital.

Which of course brings up another vexing question. What if the patient rules out of having a Stroke? Is the special ambulance still going to transport that patient or is another not so special ambulance going to be summoned to the scene? Stroke is not the only time critical illness that EMS systems have to deal with.

“We know we can speed up treatment, but we don’t know how much that speed will affect recovery,” said Grotta, co-principal investigator of the study. “We really don’t have data on how receiving tPA within the first hour after symptoms start affects patient outcomes, including the amount of disability. This study will help us determine how much more helpful it is to receive tPA within that first hour.”

That would seem to contradict what the German study says, which is why more studies are needed.

I have to think that there is a far better cost:benefit ratio to improving stroke education for EMS providers as opposed to spending the money on specialty ambulances that will only benefit a few patients. I am reasonably sure that more patients will benefit from the former approach.