Taking the stroke unit to the patient reduces time from alarm to therapy decision


A randomised controlled trial published in The Lancet Neurology in May has shown that for patients with suspected stroke, treatment in a mobile stroke unit substantially reduced median time from call for help to therapy decision. However, there was no substantial difference in the number of patients who received intravenous thrombolysis, or in neurological outcome.

The lead author of the study, Klaus Fassbender, University of the Saarland, Homburg, Germany, and colleagues set out to assess the efficacy of a new approach, developed in Germany to reduce pre-hospital delays and initiate treatment at the earliest. A new mobile unit, dispatched when stroke is suspected, contains all the equipment needed to diagnose stroke and start thrombolysis in the van, starting at the emergency site, rather than waiting until the patient arrives in hospital. “Only 2–5% of patients who have a stroke receive thrombolytic treatment, mainly because of delay in reaching the hospital,” the authors wrote.

Fassbender and colleagues carried out a randomised single-centre controlled trial to compare the time from emergency call to therapy decision between mobile stroke unit and hospital intervention.

Patients needed to be aged between 18 and 80 years and have one or more stroke symptoms that started within the previous 2.5h to be included in the study which was carried out between 2008 and 2011. “In accordance with our week-wise randomisation plan, patients received either prehospital stroke treatment in a specialised ambulance (equipped with a CT scanner, point-of-care laboratory, and telemedicine connection) or optimised conventional hospital-based stroke treatment (control group) with a seven day follow-up. Allocation was not masked from patients and investigators,” the authors wrote.

The investigators set the primary endpoint as time from alarm to therapy decision, which was analysed with the Mann-Whitney
U test. The secondary endpoints included times from alarm to end of CT and to end of laboratory analysis, number of patients receiving intravenous thrombolysis, time from alarm to intravenous thrombolysis, and neurological outcome. The team also assessed safety endpoints.

The researchers halted the trial after the planned interim analysis at 100 of 200 planned patients (53 in the prehospital stroke treatment group, 47 in the control group), because they had met the prespecified criteria for study termination. 

The results of the study revealed that prehospital stroke treatment reduced the median time from alarm to therapy decision substantially from 35min (interquartile range 31–39) vs. 76min (63–94), p<0.0001 with a median difference of 41min (95% CI 36–48 min).

The authors of the paper also wrote that they found similar gains in times from emergency call to end of CT, and from initial alarm to end of laboratory analysis, and to intravenous thrombolysis for eligible ischaemic stroke patients, although there was no substantial difference in number of patients who received intravenous thrombolysis or in neurological outcome. “Safety endpoints seemed similar across the groups,” they wrote.

They concluded that for patients with suspected stroke, treatment by the mobile stroke unit substantially reduced median time from alarm to therapy decision. “The mobile stroke unit strategy offers a potential solution to the medical problem of the arrival of most stroke patients at the hospital too late for treatment,” they wrote.

In an associated comment, Peter Rothwell and Alastair Buchan from Oxford University, UK, noted that the trial was set in an urban area with a median distance from the patient to the hospital of 7km and median alarm to arrival times of 8min for the standard ambulance versus 12 minutes for the mobile unit. The mobile stroke unit would potentially work less well in rural areas in which a hospital-situated mobile stroke unit might have difficulty in matching time with a local ambulance service.