ABSTRACT
INTRODUCTION: The optimal pathway for ultra-early diagnostics and treatment in patients with acute stroke remains uncertain. The aim of this study was to investigate how three different methods of simulated, rural prehospital computed tomography (CT) affected the time to prehospital treatment decision in acute stroke. MATERIALS AND METHODS: In this pragmatic, simulation, pilot study of prehospital CT we investigated a conventional ambulance with transport to a standard care rural stationary CT machine managed by paramedics, a Mobile Stroke Unit (MSU), and a helicopter with a simulated CT machine. Each modality completed 20 real-life dispatches combined with simulation of predetermined animated patient cases with acute stroke symptoms and CT images. The primary endpoint of the study was the time from alarm to treatment decision. RESULTS: Median time from alarm to the treatment decision differed significantly between the three groups (p = 0.0005), with 38 min for rural CT, 33 min for the MSU, and 30 min for the helicopter. There was no difference in time when comparing rural CT with MSU, nor when comparing the MSU with the helicopter. There was a difference in time to treatment decision between the rural CT and the helicopter (p < 0.0001). The helicopter had significantly lower estimated time from treatment decision to hospital (p = 0.001). DISSCUSSION/CONCLUSION: Prehospital CT can be organized in several ways depending on geography, resources and need. Further research on paramedic run rural CT, MSU in rural areas, and helicopter CT is needed to find the optimal strategy.
ABSTRACT
BACKGROUND: Timely treatment of acute stroke depends on early identification and triage. Improved methods for recognition of stroke in the prehospital setting are needed. We aimed to assess whether use of the National Institutes of Health Stroke Scale (NIHSS) by paramedics in the ambulance could improve communication with the hospital, augment triage, and enhance diagnostic accuracy of acute stroke. METHODS: The Paramedic Norwegian Acute Stroke Prehospital Project (ParaNASPP) was a stepped-wedge, single-blind, cluster-randomised controlled trial. Patients with suspected acute stroke, who were evaluated by paramedics from five ambulance stations in Oslo, Norway, were eligible for inclusion. The five ambulance stations (defined as clusters) all initially managed patients according to a standard stroke protocol (control group), with randomised sequential crossover of each station to the intervention group. The intervention consisted of supervised training on NIHSS scoring, a mobile application to aid scoring, and standardised communication with stroke physicians. Random allocation was done via a simple lottery draw by administrators at Oslo University Hospital, who were independent of the research team. Allocation concealment was not possible due to the nature of the intervention. The primary outcome was the positive predictive value (PPV) for prehospital identification of patients with a final discharge diagnosis of acute stroke, analysed by intention to treat. Prespecified secondary safety outcomes were median prehospital on-scene time and median door-to-needle time. This trial is registered with ClinicalTrials.gov, NCT04137874, and is completed. FINDINGS: Between June 3, 2019, and July 1, 2021, 935 patients were evaluated by paramedics for suspected acute stroke. 134 patients met exclusion criteria or did not consent to participate. The primary analysis included 447 patients in the intervention group and 354 in the control group. There was no difference in PPV for prehospital identification of patients with a final discharge diagnosis of acute stroke between the intervention group (48·1%, 95% CI 43·4-52·8) and control group (45·8%, 40·5-51·1), with an estimated percentage points difference between groups of 2·3 (95% CI -4·6 to 9·3; p=0·51). Median prehospital on-scene time increased by 5 min in the intervention group (29 min [IQR 23-36] vs 24 min [19-31]; p<0·0001), whereas median door-to-needle time was similar between groups (26 min [21-36] vs 27 min [20-36]; p=0·90). No prehospital deaths were reported in either group. INTERPRETATION: The intervention did not improve diagnostic accuracy in patients with suspected stroke. A general increase in prehospital time during the pandemic and the identification of smaller strokes that require more deliberation are possible explanations for the increased on-scene time. The ParaNASPP model is to be implemented in Norway from 2023, and will provide real-life data for further research. FUNDING: Norwegian Air Ambulance Foundation and Oslo University Hospital.
