Introduction: Washington University in St. Louis research shows 53% of EMS time last normal (TLN) for wake up strokes differ by 208 minutes (mean) from Stroke Neurologists' TLN. Multiple factors contribute to this discrepancy. We hypothesized a major factor is misunderstanding differences between TLN and the time of first awareness (TFA) of symptoms communicated by patients, family and others. We hypothesized EMS understanding could be improved for TFA, TLN and other confounders by a 20 minute education module.
Method: 179 EMS medics in Polk (n=87) and Seminole (n=92) counties in West Central Florida received a 20 minute lecture and 4 pre/post-test questions on 4 different stroke scenarios with potentially discordant TLN and TFA: Wake up strokes, TLN Uncertain, "Found" strokes (defined as: initially absent historian returns to find non-verbal patient with new stroke symptoms) and "waxing/waning strokes" (defined as: new symptoms BOTH fully resolve to baseline AND recur > 1 time in a 24 hour period). Instruction was 100% live for Polk EMS and 70% pre-recorded for Seminole EMS.
Results: Response rates were 74% pre-test and 85% post-test. EMS Pretest comprehension was initially low, but tripled after education on Wake up, Found, and TLN Uncertain stroke scenarios (Pre: 29% vs Post: 76%, p <0.001). The improvement was slightly greater for Wake up strokes (Pre: 18% vs Post: 72% p <0.001) than for Found or TLN uncertain strokes (Pre: 28%, 39% vs Post: 79%, 78%, respectively, p <0.001 for both). Comprehension of these 3 stroke scenarios was slightly higher with live rather than pre-recorded instruction (85% vs 74%). Unfortunately, the doubling of pre/post comprehension for the waxing/waning stroke scenario (24% vs 53% p <0.01) still left comprehension levels unacceptably low.
Conclusion: Baseline EMS comprehension of TLN with possible discordance between TLN and the time of first awareness (TFA) of symptoms communicated by patient, family or caregivers is likely low, but improves with a 20 minute education module that is most effective live rather than pre-recorded. Additional research is needed to further improve EMS comprehension of TLN in waxing/waning strokes and to prove that improved comprehension will lead to more accurate EMS TLN assessment in the field.