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At least three U.S. medical centers are evaluating the benefits of deploying specially equipped mobile stroke units to respond to emergency calls for patients with suspected strokes. Most of these units contain CT scanners, lab facilities, and other functionality capable of determining whether a patient would benefit from clot-busting therapy. Such drugs can then be administered to appropriate patients before a patient even arrives in the ED. Early findings from the approach show that care can be accelerated, potentially improving stroke outcomes and reducing longer-term costs.
With the primary goal of improving outcomes for stroke victims, a handful of medical centers are deploying mobile stroke units. This new emergency response vehicle is equipped with a CT scanner, laboratory, telemedicine capability, and other critical functionality so that brain-saving treatment, such as clot-busting drugs, for example, can be administered to patients even before they are transported to an ED.
It’s an idea borrowed from medical innovators in Germany who have implemented the world’s first mobile stroke units in recent years.1 There, researchers found they could slash the time between an EMS call and the administration of clot-busting medication from 73 minutes to 38 minutes, savings that should translate into preserved neurons in the brain and better outcomes, according to experts.
Recognizing the potential upside of bringing stroke care to the patient, James Grotta, MD, director of stroke research in the Clinical Institute for Research and Innovation at Memorial Hermann-Texas Medical Center in Houston, led the effort to deploy the first mobile stroke unit in the United States in May 2014. Another mobile stroke unit has since been deployed by the Cleveland Clinic, with a third unit scheduled to divide its time between Denver and Colorado Springs, CO, starting this month.
While investigators in Houston are still in the midst of a multi-year study on the effect of the first U.S. mobile stroke unit, their early experiences are encouraging, according to Stephanie Parker, BSN, RN, project manager of the mobile stroke unit at the University of Texas Health Science Center (UT) in Houston.
“We have embedded ourselves with the Houston Fire Department dispatch system,” Parker notes, adding that the unit is also working with both the Bellaire and West University Fire Departments. “We are dispatched for 911 stroke patients within the city of Houston and the surrounding 10-mile radius of our dispatch center in the Texas Medical Center.”
Parker explains that when the mobile stroke unit was first deployed, it only responded to calls within a three-mile radius of the dispatch center because investigators wanted to make sure the unit could arrive on the scene without delaying anyone.
“It has expanded because we have been so successful,” she says. “We respond with Houston Fire. If it is not a stroke, they move forward with their standard management of patients. It is still their patient until we both collaborate and deem that [the patient] has stroke symptoms. Then we put [the patient] in our unit.”
In addition to responding immediately to emergency calls for suspected strokes, the mobile stroke unit also dispatches when a first responder arrives on the scene of an emergency call and only then recognizes symptoms of stroke from his or her assessment.
“They will not delay their care to wait for us. If they are ready to leave the scene and we are not on the scene yet, then they will rendezvous with us,” Parker explains. “We have radio contact.”
Parker adds that the mobile stroke unit dispatches when first responders arrive at the scene of a suspected stroke that is outside of the 10-mile radius.
“If they see that it is a stroke, they will actually request that we rendezvous with them,” she says.
The main advantage of being able to perform a CT scan on patients in the field is that clinicians can quickly determine if the patient is having a stroke caused by a blood clot and is a candidate for tissue plasminogen activator or tPA, a drug that works to dissolve blood clots. The mobile stroke team can then administer the drug before the patient even reaches the hospital. This is important because tPA must be given within three hours of the onset of symptoms to be most effective, and experts maintain that the earlier the drug is administered the better.
While outcome research takes time, a handful of early findings are encouraging. For instance, presenting at the American Stroke Association’s International Stroke Conference in February 2015, Parker reported that during a nine-week period, UT’s mobile stroke unit team treated about two patients per week with tPA, and 40% of these patients received this treatment within the first hour of onset. Further, none of the patients who received tPA experienced intracerebral hemorrhage, and half of them recovered fully from their strokes within 90 days.
Parker notes that roughly one in every seven calls that the mobile stroke unit responds to involves a patient the mobile stroke team treats with tPA. She also observes that the team is trained to work quickly.
“Our average on-scene time from putting the unit in park to performing the CT scan, labs, IV, starting the drugs, and driving [the patient] to the hospital is 21 minutes,” she explains. “A large percentage of our patients receive tPA within less than 60 minutes [from the onset of symptoms].”
Parker adds that the average door-to-needle time for stroke patients who were brought to a hospital in the United States last year was 62 minutes, so she notes that it is clear that the mobile stroke unit is accelerating treatment.
“Experienced clinicians are definitely assessing patients faster. That is obvious. [Patients] are also receiving treatment faster,” she says. “What we are looking at now are the outcomes. Do patients have better outcomes?”
Currently, there is not a lot of data on patients who receive tPA in less than 60 minutes from symptom onset, Parker observes. She notes that most eligible stroke patients receive the drug within 90 minutes to three hours.
“One advantage to [the mobile stroke unit] is that you are putting that experienced staff out there to [patients] who have those smaller strokes that will require clot-busting medication,” she says. “[Patients] could then go to a primary stroke facility where they will do just fine.”
Further, Parker notes that the unit team is also able to identify patients who are having a hemorrhagic stroke as well as patients with large vessel occlusions who will require higher level stroke care.
“You can drive a little bit longer to get them to that comprehensive stroke center where they have more opportunities for endovascular or neurosurgery and more treatment options,” she explains.
To assess the effectiveness of this approach, investigators are utilizing the mobile stroke unit every other week. During off weeks, first responders are managing stroke cases in a standard fashion, where the patients are brought to the ED for further evaluation and treatment. Investigators will be comparing the outcomes of stroke patients from both groups for a year following their original EMS call.
There are just three EDs in Houston that work with the mobile stroke unit: Memorial Hermann-Texas Medical Center, Houston Methodist Hospital, and CHI St. Luke’s Medical Center. Samuel Prater, MD, medical director of the ED at Memorial Hermann-Texas Medical Center, observes that implementation of the unit has been pretty seamless from the ED’s point of view.
“Any time we are notified by the mobile stroke unit, by our life flight helicopters, or by the ambulance agencies who are bringing [stroke patients] in, we do what is called our code stroke activation,” he explains. “All ED nurses, ED physicians, and techs who run the CT scanners are notified. Physicians and nurses on the stroke team are also notified.”
Typically, any patients brought to the ED with symptoms of stroke will immediately go to a CT scanner, Prater says.
“With the mobile stroke unit patients, the only difference is that some of these patients have already received tPA, so they will not receive a repeat CT,” Prater observes.
However, most of these patients will undergo other types of evaluations, such as a CT angiogram with perfusion (CTA), to determine if the patients would benefit from interventional therapy.
Sometimes the CT that is administered in the mobile stroke unit determines that the patient is having a hemorrhagic stroke.
“Those patients will stop in the ED, we will make sure they are stable, and then admit them to the ICU,” Prater adds.
One reason why implementation of the mobile stroke unit has been so easily assimilated into the ED is because emergency clinicians have developed a good working relationship with the hospital’s stroke team, Prater offers.
“It is the same physicians we have always worked with that are on the [mobile stroke unit]. For us, it has been a very seamless transition,” he says.
Further, Prater says that the approach is definitely accelerating care for stroke victims. For instance, he recalls one recent case in which the ED was notified ahead of the arrival of a woman who had suffered a severe stroke.
“As soon as she came through, she didn’t stop in the ED. She basically passed through. I went with the patient and the mobile stroke team into the CT scanner and performed a CTA with perfusion. I saw that she still had a big clot and lots of potentially salvageable brain tissue. So from the CT scanner, she went directly into the angio [angiography] suite,” Prater recalls. “This was a woman who … had a stroke scale [score] greater than 20, and she walked out of the hospital with almost no deficits.”
Currently, a paramedic, nurse, CT technician, and a neurologist staff UT’s mobile stroke unit, but Parker anticipates that the neurologist consult will soon occur via telemedicine rather than in person. Both approaches are currently under investigation, although Parker acknowledges that to be cost effective, the telemedicine option will have to come into play.
“It’s not realistic to have a vascular neurologist for all of these calls,” she says. “But a telemedicine physician can cover five of these units. That makes things more cost effective and realistic.”
In fact, the University of Colorado Health in Aurora, CO, is preparing its own mobile stroke unit for deployment, and clinicians there will rely on virtual neurological consults right away, according to Brandi Schimpf, BSN, RN, CSN, the program manager for UC Health’s mobile stroke unit.
“We have been working closely with Aurora Fire,” she explains. “We will simultaneously dispatch on all stroke symptom-type calls for the Aurora region.”
When service begins later this month, the mobile stroke unit team at UC Health will become part of the same multi-site study already underway in Houston.
“The one thing that is a little bit different for us is we will be operating in research mode Thursday through Tuesday with one day off every week, which is Wednesday,” Schimpf says.
However, the mobile stroke unit team will hardly be sitting idle during this so-called maintenance and transition day.
“After our go-live, we will shortly thereafter work toward a second go-live with our system partner in Colorado Springs at Memorial [Hospital],” Schimpf says.
There is only one unit, so it will operate every other week at each site, Schimpf explains.
“We need to [produce results] and show quality outcomes in the patients to which we deliver care. Eventually, our goal is to have one of these units in every one of our [five] regional system hospitals,” she explains. “And maybe even more than one at every facility.”
Schimpf acknowledges that gearing up for the launch of the new unit has been challenging.
“This is basically another unit for our hospital in a sense,” she explains. “Not many people have started this type of project, so there [are no guidelines].”
However, the University of Colorado team has consulted with the mobile stroke unit teams in both Houston and Cleveland, and Schimpf is working with key management at area hospitals to make sure processes are in place to work with the new unit.
“We are trying to identify key members [in hospitals], such as stroke coordinators and stroke neurologists … so that we are able to communicate with them on how our process works, how our efforts in the field benefit them, and what to expect from us,” Schimpf explains.
While processes are finalized, the personnel who will man the mobile stroke unit are receiving added training.
“They know how to be a nurse, a paramedic, or a CT tech, but we need to educate them on how to do their jobs on this unit,” Schimpf observes. “For some of the nurses or CT techs, for example, we are completely taking them out of the element of the hospital … and they are not necessarily used to being mobile.”
Personnel also need to be familiar with what the criteria are to be a patient accepted onto the mobile stroke unit, how these patients should be cared for in the unit, and how all the proper steps align, Schimpf adds.
Financial Disclosure: Author Dorothy Brooks, Executive Editor Shelly Morrow Mark, Associate Managing Editor Jonathan Springston, and Nurse Planner Diana S. Contino report no consultant, stockholder, speaker’s bureau, research, or other financial relationships with companies having ties to this field of study. Executive Editor James J. Augustine discloses he is a stockholder in EMP Holdings and U.S. Acute Care Solutions and is a retained consultant for Masimo.