by Susan Fitzgerald
Houston is getting a “stroke ambulance” that is equipped with a CT scanner, laboratory, and neurologist ready to administer intravenous tissue plasminogen activator (tPA) on the way to the hospital to stroke patients who could benefit from the clot-busting drug.
The ambulance is modeled after units operating in Germany, where researchers reported encouraging results in reducing the amount of time that passes between when an ambulance is summoned and administration of tPA. The study, Prehospital Acute Neurological Treatment and Optimization of Medical care in Stroke Study (PHANTOM-S), compared use of specially outfitted ambulances designed to take full advantage of the so-called “golden hour,” the critical period right after stroke symptoms appear when it is most possible to limit brain damage, with conventional ambulance transports.
A team of researchers in Berlin reported in the April 23/30 edition of Journal of the American Medical Association (JAMA) that there was, on average, a 25-minute reduction in alarm-to-treatment time (95% CI, 20-29; p< .001); 51.8 minutes (95% CI, 49.0-54.6), with tPA when the mobile stroke unit responded to a call as compared with 76.3 minutes (95%CI, 73.2-79.3) when a regular ambulance service was in place. Also, the rate of tPA usage was 33 percent with the mobile stroke unit, significantly higher than the 21-percent rate during weeks of conventional emergency response.
“Our experience is that our pre-hospital stroke thrombolysis service is frequently used and safe,” Heinrich Audebert, MD, a professor of neurology at Charité University Hospital in Berlin and coauthor of the JAMA study, told Neurology Today. “It increases the thrombolysis rate and shortens the time to treatment.”
The Houston project is the brainchild of James Grotta, MD, FAAN, formerly the chair of neurology at University of Texas Health Science Center and the director of its stroke program. He is now based at Memorial Hermann-Texas Medical Center, where he is coordinating the launch of the stroke-response ambulance to service the Houston area. He became intrigued with the idea after learning of the initiatives in Germany.
“To me, the most effective way we can improve on what we are already doing with stroke care is to get patients to treatment earlier,” Dr. Grotta told Neurology Today, for which he serves as an editorial advisory board member. “No matter what we do, we’ve got to do it faster.”
Despite a number of public health campaigns to increase the awareness of stroke and its symptoms, many people are slow to call for help and do not show up at the emergency department until after the treatment window for tPA has closed, Dr. Grotta noted.
The JAMA study reported on an emergency response vehicle named STEMO — the stroke emergency mobile — that is equipped with a CT scanner, point-of-care laboratory, telemedicine connection, a stroke identification algorithm at the dispatcher level, and a prehospital stroke team that includes a neurologist, paramedic, and radiology technician. The point-of-care laboratory offers tests for blood count, electrolytes, creatinine, glucose, and international normalized ratio.
“Compared with usual care, the use of ambulance-based thrombolysis resulted in decreased time to treatment without an increase in adverse events,” the researchers reported. “Further studies are needed to assess the effects on clinical outcomes.”
For a full analysis of the project and its feasibility, see the May 15 issue of Neurology Today. For now, read our previous articles on administering tPA in the ambulance: http://bit.ly/strokeamb.