Introduction: Simple prehospital assessment tools for identifying patients with large vessel occlusion remains a challenge. This study evaluated the mnemonic BE FAST with modified designations for the detection of large vessel occlusion by evaluation of select symptoms (Balance/Coordination, Eye Deviation, Facial Weakness, Arm/Leg Weakness, Slurred Speech/Sensory Deficits, Time of Onset).
Methods: Retrospective chart review for all patients (July 2014 to June 2015) with discharge diagnosis of ischemic stroke was performed excluding hemorrhagic stroke and TIAs. Presenting symptoms, physical findings and NIH score were used to determine a BE FAST score. Imaging was evaluated for presence of large vessel occlusion (LVO) and stroke. Comorbidities and interventions were recorded. A presumptive BE FAST cut-off value for identifying LVO was made and confirmed using Two-step Cluster Technique and data dichotomized based on the cut-off. Chi-Square Tests were then used to determine if an association existed between dichotomized BE FAST scores and rates of LVO. Diagnostic sensitivity, specificity, and accuracy were then calculated using this cut-off value.
Findings: 526 patient charts were identified and 455 patient charts remained after application of exclusion criteria. Of 108 patients with LVO, 18 patients had a BE FAST score <4 (16.7%) and 90 patients had a score ≥4 (83.3%). Of the 347 patients without LVO, 260 (74.9%) had a score <4 and 87 (25.1%) had a score of ≥ 4. Differences in the rates of LVO based on this cut-off were significant (p<0.001). Only atrial fibrillation and BE FAST score ≥4 were predictive of LVO, odds ratios of 1.89 (95% CI: 1.035 - 3.456; p=0.038) and 19.5 (95% CI: 10.474 - 36.293; p<0.001), respectively. The sensitivity for the BE FAST score in the detection of LVO was calculated as 83%. The diagnostic accuracy of the BE FAST score with a threshold of 4 was calculated as 77%.
Conclusion: The modified BE FAST score, as defined here, may serve as a useful prehospital assessment tool for identifying patients with large vessel occlusion. The simplicity of the tool may reduce time to appropriate intervention. Prospective research is needed to confirm these findings and to determine inter- and intra-rater reliability of this modified BE FAST score.