Mobile Stroke Unit Operational Metrics: Institutional Experience, Systematic Review and Meta-Analysis

Abstract

BackgroundThe available literature on mobile stroke units (MSU) has focused on clinical outcomes, rather than operational performance. Our objective was to establish normalized metrics and to conduct a meta-analysis of the current literature on MSU performance.MethodsOur MSU in upstate New York serves 741,000 people. We present prospectively collected, retrospectively analyzed data from the inception of our MSU in October of 2018, through March of 2021. Rates of transportation/dispatch and MSU utilization were reported. We also performed a meta-analysis using MEDLINE, SCOPUS, and Cochrane Library databases, calculating rates of tPA/dispatch, tPA-per-24-operational-hours (“per day”), mechanical thrombectomy (MT)/dispatch and MT/day.ResultsOur MSU was dispatched 1,719 times in 606 days (8.5 dispatches/24-operational-hours) and transported 324 patients (18.8%) to the hospital. Intravenous tPA was administered in 64 patients (3.7% of dispatches) and the rate of tPA/day was 0.317 (95% CI 0.150–0.567). MT was performed in 24 patients (1.4% of dispatches) for a MT/day rate of 0.119 (95% CI 0.074–0.163). The MSU was in use for 38,742 minutes out of 290,760 total available minutes (13.3% utilization rate). Our meta-analysis included 14 articles. Eight studies were included in the analysis of tPA/dispatch (342/5,862) for a rate of 7.2% (95% CI 4.8–9.5%, I2 = 92%) and 11 were included in the analysis of tPA/day (1,858/4,961) for a rate of 0.358 (95% CI 0.215–0.502, I2 = 99%). Seven studies were included for MT/dispatch (102/5,335) for a rate of 2.0% (95% CI 1.2–2.8%, I2 = 67%) and MT/day (103/1,249) for a rate of 0.092 (95% CI 0.046–0.138, I2 = 91%).ConclusionsIn this single institution retrospective study and meta-analysis, we outline the following operational metrics: tPA/dispatch, tPA/day, MT/dispatch, MT/day, and utilization rate. These metrics are useful for internal and external comparison for institutions with or considering developing mobile stroke programs.

Potential effects of a mobile stroke unit on time to treatment and outcome in patients treated with thrombectomy or thrombolysis: A Danish–German cross‐border analysis

“…Considering the number of thrombolysis and thrombectomy cases, 28 thrombectomy cases and 52 thrombolysis cases per year were estimated. This is well within the range of a recent meta‐analysis evaluating the thrombolysis and thrombectomy treatments of all published MSU studies, rendering 131 (95% confidence interval 79–183) thrombolysis treatments per year and 34 (95% confidence interval 17–50) thrombectomy cases per year [ 34 ]. Because of our hypothetical approach, there are a number of unknown errors possibly interfering with our assumptions, amongst others the actual stroke incidence and its regional heterogeneity.…”

Establishing an MSU service in a medium-sized German urban area—clinical and economic considerations

“…Expected average daily patients treated by MSU ranged from 0.55 (0.44-0.67) to 0.77 (0.61-0.92) in 8-to 16-h operation models. The rate of daily t-PA administration per MSU is expected to be 0.22 (0.18-0.26) per 24 h, which is nearly five-fold lower than the one reported by the well-established MSU service from Houston, TX (12). Whereas MSU programs in rural areas aim to expand the radius of MSU operation up to 250 km (27), in the Mannheim case with a densely populated surrounding area, simulation revealed that a limited increase in driving distance of five more minutes lead to an increase of 30-40% in patient numbers.…”

“…The estimated proportions of patients with ischemic stroke, transient ischemic attack (TIA), hemorrhagic stroke, and stroke mimics typically treated by MSU were taken from recent literature ( 9 , 10 ). MSU-specific metrics such as the number of cancelations, utilization rate, average distance and duration per dispatch, as well as the tPA administration rate were considered ( 11 , 12 ). Assuming an MSU can miss stroke cases on a dispatch-level by inaccuracy of EMS dispatchers and on an MSU-level by not being able to manage simultaneous cases at peak times and by being located too far away from a specific case.…”