Prospective Prehospital Evaluation of the Cincinnati Stroke Triage Assessment Tool

A simple, easily adoptable scale with good performance characteristics is needed for EMS providers to appropriately triage suspected stroke patients to comprehensive stroke centers (CSC). Many existing tools are complex, require substantial training, or have not been prospectively validated in the prehospital setting. We describe the feasibility and effectiveness of prehospital implementation of our previously retrospectively derived and validated Cincinnati Stroke Triage Assessment Tool (C-STAT) to identify subjects with severe stroke (NIHSS ≥15) among all prehospital patients with clinical suspicion of stroke/TIA. Secondarily, we evaluated the tool's ability to identify subjects with NIHSS ≥10, large vessel occlusion (LVO), or needing services available only at a CSC.

Without formalized training, Cincinnati Fire Department providers performed standard stroke screening ("face, arm, speech, time;" FAST) and C-STAT as part of their assessment of suspected stroke/TIA patients. Outcomes for patients brought to the region's only CSC or assessed by the regional stroke team were determined through structured chart review by a stroke team nurse. C-STAT test characteristics for each outcome were calculated with 95% confidence intervals.

Complete prehospital and outcome data were available for 58 FAST-positive subjects among 158 subjects with prehospital suspicion for stroke/TIA. Subjects were excluded if FAST was negative (n = 22), FAST or C-STAT was incompletely documented (n = 24), if the patient was taken to a non-CSC and did not receive a stroke team consult (n = 48), or if outcome data were missing (n = 6). C-STAT sensitivity and specificity for each outcome were: NIHSS ≥ 15, 77% (95% CI 46-95) and 84% (95% CI 69-93); NIHSS ≥10, 64% (95% CI 41-83) and 91% (95% CI 76-98); LVO, 71% (95% CI 29-96) and 70% (95% CI 55-83); overall CSC need 57% (95% CI 34-78) and 79% (95% CI 61-91).

In this pilot prospective evaluation performed in the prehospital setting by EMS providers without formalized training, C-STAT is comparable to other published tools in test characteristics and may inform appropriate CSC triage beyond LVO ascertainment alone.