Читать книгу Emergency Medical Services - Группа авторов - Страница 415

Some regions are trialing the concept of mobile stroke units in an effort to improve the time to tPA or other intervention. A mobile stroke unit ambulance allows for the early administration of tPA in a prehospital setting through the ability to perform the neurologic evaluation and obtain CT imaging in a mobile unit. Most exist in urban areas, though the need for timely stroke evaluation and intervention points to significant potential in rural settings as well. Rural areas may use a rendezvous approach, in which EMS clinicians from a rural site bring the patient toward a stroke center, but meet and transfer care of the patient to the mobile stroke unit along the way. The mobile stroke unit crew often has telemedicine capabilities, linking EMS clinicians to additional resources within the affiliated stroke center [42].

One of the earliest such programs on the east coast of the United States was established by New York Presbyterian Hospital in 2016. This particular mobile stroke unit crew consisted of two paramedics, one radiology technologist, and one vascular neurologist. During the 7‐month pilot, 49 patients were transported, with diagnoses of acute ischemic stroke among 49% of those patients; tPA was administered to 32.6% of the patients transported. This program focused on the complete integration of the affiliated stroke centers’ information systems into a mobile unit, the first of its kind known to do so [43].

In February of 2017, the Edmonton Stroke Program in Canada implemented a rural mobile stroke unit, affiliated with the University of Alberta Hospital in Edmonton. The crew consisted of a stroke fellow, a radiology technologist, a registered nurse, a primary care paramedic, and an advance care paramedic. The unit was dispatched to rendezvous with EMS crews arriving from rural scene calls or rural EDs. The patient was then transferred into the mobile stroke unit for neurologic evaluation and CT imaging; the unit had the ability to administer tPA if appropriate. At last published report, 68 patients had been evaluated and 17 (25%) received tPA. An additional 28 patients were transferred to the stroke center for further evaluation [42].

Initial experiences indicate that mobile stroke units, in the settings in which they have been deployed, result in earlier administration of tPA. No increased additional risk of complicating ICH has been noted. It remains difficult to determine the long‐term clinical outcome benefit, primarily due to the small patient numbers in most studies. Interest in broadening the use of mobile stroke units continues, including the introduction of CT angiography and perfusion, as well as the treatment of other neurological emergencies. Additionally, with advancements in telemedicine technologies, the ability to transition mobile stroke unit staffing to paramedics may also exist [42].

Emphasis is growing on endovascular thrombectomy for patients with LVO strokes. Current evaluations are focusing on the direct transport of select patients to thrombectomy‐capable and comprehensive stroke centers. However, although bypassing a closer primary stroke center reduces the time to potential thrombectomy, it may also delay the administration of IV thrombolytics. If there is a paucity of stroke centers capable of performing thrombectomy in a given geographical area, EMS transport times may be prolonged when using a bypass strategy. In addition, the optimal stroke scale for EMS identification of LVO stroke patients who may benefit from direct transport to a thrombectomy‐capable center needs additional research. Recent investigation suggests that patients with suspected LVO stroke may benefit from being redirected to a comprehensive stroke center if additional transport time is <30 minutes in urban areas and <50 min in rural settings. Additional research is needed to define the acceptable time delay in administration of IV thrombolytics for these patients when bypassing closer primary stroke centers [44].