Time intervals and distances travelled for prehospital ambulance stroke care: data from the randomised-controlled ambulance-based Rapid Intervention with Glyceryl trinitrate in Hypertensive stroke Trial-2 (RIGHT-2).

OBJECTIVES: Ambulances offer the first opportunity to evaluate hyperacute stroke treatments. In this study, we investigated the conduct of a hyperacute stroke study in the ambulance-based setting with a particular focus on timings and logistics of trial delivery.

DESIGN: Multicentre prospective, single-blind, parallel group randomised controlled trial.

SETTING: Eight National Health Service ambulance services in England and Wales; 54 acute stroke centres.

PARTICIPANTS: Paramedics enrolled 1149 patients assessed as likely to have a stroke, with Face, Arm, Speech and Time score (2 or 3), within 4 hours of symptom onset and systolic blood pressure >120 mm Hg.

INTERVENTIONS: Paramedics administered randomly assigned active transdermal glyceryl trinitrate or sham.

PRIMARY AND SECONDARY OUTCOMES: Modified Rankin scale at day 90. This paper focuses on response time intervals, distances travelled and baseline characteristics of patients, compared between ambulance services.

RESULTS: Paramedics enrolled 1149 patients between September 2015 and May 2018.

FINAL DIAGNOSIS: intracerebral haemorrhage 13%, ischaemic stroke 52%, transient ischaemic attack 9% and mimic 26%. Timings (min) were (median (25-75 centile)): onset to emergency call 19 (5-64); onset to randomisation 71 (45-116); total time at scene 33 (26-46); depart scene to hospital 15 (10-23); randomisation to hospital 24 (16-34) and onset to hospital 97 (71-141). Ambulances travelled (km) 10 (4-19) from scene to hospital. Timings and distances differed between ambulance service, for example, onset to randomisation (fastest 53 min, slowest 77 min; p<0.001), distance from scene to hospital (least 4 km, most 20 km; p<0.001).

CONCLUSION: We completed a large prehospital stroke trial involving a simple-to-administer intervention across multiple ambulance services. The time from onset to randomisation and modest distances travelled support the applicability of future large-scale paramedic-delivered ambulance-based stroke trials in urban and rural locations.

TRIAL REGISTRATION NUMBER: ISRCTN26986053.