COLUMBIA — Three hours after ischemic stroke symptoms begin, parts of the brain can be damaged beyond repair.
So when it comes to stroke, "time is brain," Columbia neurologist Allyn Sher said.
A study published in the April issue of the The Journal of the American Medical Association found that equipping ambulances with portable CT scanners and intravenous tissue plasminogen activator, or tPA — a blood thinner designed to break down blood clots — would enhance treatment in ambulances and increase survival rates.
The study, conducted in Berlin, analyzed response and treatment times of stroke patients during weeks when specially equipped stroke-response ambulances were in use compared to weeks when current emergency medical service teams responded.
The specially equipped ambulances in this study carried a point-of-care laboratory and a specialized pre-hospital stroke team. Using those resources resulted in a 25-minute decrease in treatment time for patients — a significant time reduction when dealing with strokes.
According to the American Heart Association, a person has a stroke every 40 seconds in the United States. A person dies of stroke every four minutes. That's more than 130,000 Americans every year.
Only 26.6 percent of the 795,000 yearly stroke patients will receive the potentially life-saving tPA within the recommended time of one hour, the American Heart Association estimates. The percentage would significantly increase if tPA were administered in the ambulance.
"I've always jokingly said I need to invent a CT helmet so we can put it on the patient in the ambulance," said Donna Pond, coordinator for the Stroke Center at Boone Hospital Center. "Then we can know right away if there's a bleed (in the brain) and we can begin mixing the tPA."
If the patient doesn't receive the drug within three hours of the stroke, more invasive measures must be taken, including surgery, which increases the risk of disability.
"Stroke is the fourth leading cause of death, but it's the No. 1 cause of disability," Sher said.
The National Stroke Association has created an acronym, FAST, to help people remember and identify the symptoms of stroke.
- F (face): Is your face drooping on one side?
- A (arm): Is one arm dropping lower than the other when you hold them forward?
- S (speech): Is your speech slurred? Can you speak at all?
- T (time): If any of these symptoms are observed, it's time to call emergency medical services.
Medical diagnosis of a stroke requires a computed tomography, or CT, scan when the patient arrives at the hospital, although the AMA recommends that emergency medical responders begin the treatment.
If the CT scan shows that the brain is bleeding, the patient cannot be given tPA and must be taken to surgery. If the brain is not bleeding, tPA can be given if the patient is seen within three hours.
"Those (first) three hours are the most important," Pond said. "There are still some things you can do after that, but after six hours they're pretty much done."
Although the patient may survive after six hours, parts of the brain will die without fast treatment.
"The penumbra (a level of brain tissue) is still salvageable if we can still get circulation back there; that's why it's so high-speed," Pond said. "Every minute that treatment is delayed — nearly 2 million neurons die."
Portable CT scanners and tPA are not yet a part of EMS treatment, but calling an ambulance when signs of stroke are first noticed can save lives.
Columbia Fire Department Battalion Chief Brad Fraizer said the department's ambulances are not equipped with CT scanners or tPA.
But that's the norm. According to the AMA study, no specialized ambulances are in use.
However, ambulance personnel can still begin treatment, Fraizer said.
"They can check blood sugar levels; they can establish an IV; they can determine heart arrhythmia," he said. "The IV allows them to administer certain medications on the way to the hospital where a more advanced treatment can take over."
Emergency responders also call ahead to alert a stroke team at the hospital that a patient is on his way in to ensure fast action.
"I don't care what hospital they go to as long as they get treatment," Pond said.
The AMA is conducting further clinical trials on specially equipped stroke-response ambulances before they can be used by EMS in everyday situations.
Supervising editor is Katherine Reed.