Background: Stroke evolution after hospital arrival is well characterized for acute cerebral ischemia and intracranial hemorrhage. But with the advent of patient routing to designated stroke centers, and of prehospital stroke therapeutic trials, it is important to characterize stroke evolution in the earliest, prehospital moments of onset. Initial studies have prehospital evolution using serial Glasgow Coma Scale (GCS) assessment; however, GCS assesses level of consciousness rather than focal deficits.
Methods: In the NIH FAST-MAG trial database, we analyzed patient deficit evolution from time of first paramedic assessment to early post-arrival assessment in the ED, using serial scores on the GCS, serial scores on the Los Angeles Motor Scale (LAMS) (a prehospital stroke deficit measure), and the Paramedic Global Impression of Change (PGIC) score, a 5 point Likert paramedic-clinician score.
Results: Among 1632 acute, EMS-transported neurovascular disease patients, 1,245 (76.3%) had a final diagnosis of acute cerebral ischemia and 387 (23.7%) of acute intracranial hemorrhage. Time of paramedic initial assessment was median 23 mins (IQR 14-41) after onset and time of early ED assessment 58 mins (IQR 46-78). Considering score changes by 2 or more as salient, overall the LAMS and GCS indicated approximately equal frequencies of prehospital deterioration (LAMS 11.1%, GCS 12.0%), but the LAMS indicated higher frequencies of prehospital improvement (LAMS 24.5% vs GCS 5.7%, p<0.001), due to the ceiling constraint of the GCS. The LAMS correlated more strongly than the GCS with the paramedic global impression of change among all patients, r=0.31 vs 0.19, and especially in acute cerebral ischemia patients, r=0.27 vs 0.08). The prehospital course differed by stroke subtype on the LAMS: acute cerebral ischemia: improved 30.7%, worsened 7.1%, stable 62.25%; intracranial hemorrhage: improved 4.5%, worsened 24.2%, stable 71.3%.
Conclusions: Focal deficit scales are superior to the GCS in characterizing prehospital stroke evolution. Change in neurologic status occurs in more than one-third of acute stroke patients during transport and the early ED, with improvement more common in acute cerebral ischemia and deterioration more common in ICH.