Mobile Stroke Units

A mobile stroke unit (MSU) is a specialized ambulance that contains a CT scanner, mobile laboratory, and telemedicine connection for treating stroke patients before arrival at a hospital [1]. The proposed benefit of mobile stroke units is to reduce the time between an emergency call and administration of therapy. After German researchers first deployed an MSU in 2010, hospitals in Germany and the United States have deployed their own MSUs [1][2]. Throughout that time, researchers have evaluated the medical benefits and practical considerations of MSUs.

Guidelines for stroke treatment follow the “time is brain” paradigm: the faster a patient is treated, the better their outcomes will be. MSUs have received funding and attention because they are thought to decrease time to treatment. Stroke patients can receive a CT scan and have it analyzed by a neurologist on their way to the hospital. If deemed necessary and appropriate, onboard paramedics can administer intravenous tissue-type plasminogen activator (tPA), a drug that can dissolve blood clots [1]. These steps can happen before the patient arrives at the hospital, potentially improving the patient’s outcomes.

Randomized control trials have investigated the potential benefits of MSUs. One study measured the average time from the emergency call to the specialist’s therapy decision: 76 minutes for a regular hospital, 35 minutes for a hospital with an MSU [1]. Separately, two studies assessed whether the neurologist should be remotely connected or physically onboard the MSU. In both studies, a remote neurologist agreed with an onboard neurologist in over 88% of cases, suggesting that a remote connection is sufficient for good outcomes [3][4]. Overall, MSUs appear to offer the same quality of treatment as standard hospital care (excluding surgical interventions), but much faster.

However, MSUs are complex to assemble and maintain. The researchers behind the first MSU in the United States documented the technical and business challenges to deploy an MSU [5]. For example, a mobile CT scanner requires specialized radiation shielding to protect all passengers in the vehicle. To facilitate its telemedicine capability, an MSU must have on-board communications technology, and the parent hospital must have a base station capable of communicating with the MSU. Onboard paramedics and remote staff need additional training to make full use of the MSU’s capabilities. On the business side, funding and purchasing are key considerations. The hospital running the pilot program had to coordinate licensing and insurance policies for both staff and equipment. Although this paper does not contribute novel findings about MSU as a medical technology, it does present a template for medical stakeholders who want to deploy their own MSU.

Despite the promise of MSUs, two challenges remain in their future. First, MSU research has challenged the “time is brain” paradigm, questioning whether time to treatment is correlated with patient outcomes [1]. Along these lines, not enough MSU research has concretely studied medical outcomes for patients. Second, MSUs are experiencing fundraising challenges. If tPA or other stroke-related drugs are administered inside a hospital building, the provider is eligible for reimbursement through the federal government or private insurance companies. However, if the medicine is administered inside an MSU, the provider is ineligible because no coverage rules exist for MSUs [6]. Today, MSUs rely on funding from private donations and government grants, which is an effective but unsustainable funding source for the long term.

References

[1] S. Walter, et al. Diagnosis and Treatment of Patients with Stroke in a Mobile Stroke Unit versus in Hospital: A Randomised Controlled Trial. The Lancet Neurology 2012; 11: 5. DOI:10.1016/S1474-4422(12)70057-1.

[2] S. Walter, et al. Bringing the Hospital to the Patient: First Treatment of Stroke Patients at the Emergency Site. PLOS One 2010. DOI:10.1371/journal.pone.0013758.

[3] T.-C. Wu, et al. Telemedicine Can Replace the Neurologist on a Mobile Stroke Unit. Stroke 2017; 48. DOI:10.1161/STROKEAHA.116.015363.

[4] R. Bowry, et al. Benefits of Stroke Treatment Using a Mobile Stroke Unit Compared With Standard Management. Stroke 2015; 46. DOI:10.1161/STROKEAHA.115.011093.

[5] S. A. Parker, et al. Establishing the First Mobile Stroke Unit in the United States. Stroke 2015; 46. DOI:10.1161/STROKEAHA.114.007993.

[6] Life-Saving Role of Mobile Stroke Units at Risk Due to Reimbursement Limitations. American Heart Association 2021. URL: https://newsroom.heart.org/news/life-saving-role-of-mobile-stroke-units-at-risk-due-to-reimbursement-limitations.