Introduction:
On April 1 2019, New York City EMS began a triage protocol using a modified Los Angeles Motor Scale (S-LAMS for addition of speech) to identify potential endovascular thrombectomy (EVT) eligible patients in the field (S-LAMS 4-6 with last known well (LKW) <5 hours). These patients are routed to the nearest thrombectomy capable center, driving past potentially closer primary stroke centers.
Methods:
Patients brought by EMS to a large multicenter health system across NYC for the year following April 1, 2019 were extracted from a prospectively collected stroke database. S-LAMS triage positive (STP) patients were assessed for diagnostic accuracy and treatment times. They were compared with a cohort that underwent EVT during the same period, but triaged as S-LAMS triage negative (STN).
Results:
STP patients (N=145) were 56.6% women, mean age of 70, median baseline mRS of 0, S-LAMS score of 5, and arrival NIHSS of 13. Stroke was diagnosed in 110 (75.8%) patients, 32 intracerebral hemorrhage and 78 ischemic. Of the ischemic, 45 were large vessel occlusion stroke (ELVO) and 34 underwent EVT (PPV of 0.31 for ELVO). STN patients (N=65) with LKW of < 5 hours were brought by EMS and underwent EVT; 34 were brought directly to EVT capable centers, and 36 required transfer for EVT. Mean time to hospital arrival from EMS scene arrival was significantly longer for STP patients than STN patients (38 vs. 29 minutes, p<0.01). Mean ambulance travel time was significantly longer for STP patients than STN patients (10 vs. 7 minutes, p<0.01). Mean tPA administration time from EMS scene arrival was not significantly different between STP (N=41) and STN patients (N=40) (90 vs. 91 minutes, p=0.89). Mean arterial access time for EVT from EMS scene arrival was significantly shorter for STP patients than STN patients (137 vs. 200 minutes, p<0.01).
Conclusions:
Pre-hospital stroke triage using the streamlined S-LAMS scale is comparable with other pre-hospital scales in predictive value for ELVO. While pre-hospital evaluation and transport times are longer, they add minimal delay to the hospital arrival, do not affect tPA times, and improve times to EVT in a large, urban environment. Further analysis on effect of the triage protocol on patient outcomes is warranted.
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