Canberra pREhospital Stroke Screening Tool (CRESST)

Background: Several pre-notification screening tools have been developed and evaluated for the rapid assessment of acute stroke patients. Each has been designed to accommodate its regional geography and demographics and individual sensitivity and specificity vary considerably (Rudd M et. al 2016). In particular, the existing tools do not detect posterior circulation strokes, nor do they incorporate the fact that strokes are usually of sudden onset. Methods: The Canberra pREhospital Stroke Screening Tool (CRESST) is a new tool designed to assist paramedics with accurate recognition and pre-notification of patients presenting with both anterior and posterior circulation strokes. Results: CRESST has seven components: timing of symptom onset, level of consciousness, speech and language function, facial weakness, arm and leg strength, vertigo, and diplopia. Each component has a variable maximum score reflecting its likely contribution to the diagnosis of stroke. Total scores range from 0 to 15. To activate a stroke call, a patient must score at least 4, including a point for sudden onset of symptoms. A database has been set up to record CRESST scores so that they can be correlated with stroke diagnosis, stroke severity, and stroke topography and vessel occlusion on angiography. Inter-rater reliability between paramedics and stroke physicians will also be assessed. Conclusion: CRESST has been designed with a view to increasing sensitivity and specificity of stroke pre-notification, with particular reference to improving performance in relation to posterior circulation strokes.