Speed of 911 Alarms and EMS Care in Hyperacute Intracranial Hemorrhage and Cerebral Ischemic Patients

Introduction: Among all stroke patients, intracranial hemorrhage (ICH) patients activate the 911 system sooner than cerebral ischemia (CI) patients. However, the temporal profiles of EMS alarm and response among hyperacute patients who may be enrolled in prehospital treatment trials has not been well delineated. Methods: We analyzed all final diagnosis acute cerebrovascular disease patients enrolled in the NIH Field Administration of Stroke Therapy-Magnesium (FAST-MAG) trial, in 315 ambulances transporting to 60 receiving stroke centers. Results: Among 1632 hyperacute cerebrovascular disease patients, final diagnosis was ICH in 23.7% and CI in 76.3%. Compared with CI patients, ICH patients were younger (65.3 vs 70.9, p < 0.001), less often female (33.3% vs 45.3%, p<0.001), and had greater deficits in the field (LAMS 4.1 vs 3.7, p<0.001), and upon ED arrival (NIHSS median 12 vs 7, p<0.001). Intervals from last known well to 911 call (LKW-to-alarm) did not differ between ICH and ACI patients (median 15 vs 16 mins, p=0.32); however, fewer ICH patients had prolonged LKW-to-alarm times ≥ 30 mins (25.1% vs 30.3%, p = .049). Intervals from symptoms first observed to 911 call (SFO-to-alarm) did not differ (11 vs 12 mins, p=0.40). Times from 911 call to paramedic arrival (alarm-to-on patient) were similar for ICH and CI patients (median 6 vs 6 mins, p=0.80), as were times from paramedic arrival on patient to ED arrival (scene-to-door) (median 32 vs 33 mins, p=0.46) and overall 911 call to ED arrival (alarm-to-door) (median 39 vs 39 mins, p=0.51). The nationally recommended alarm-to-on patient interval ≤ 8 minutes was achieved in 76% of ICH and 78% of CI patients. Conclusion: Speed of prehospital care is swift among hyperacute cerebrovascular disease patients, including 911 calls at 15 minutes after last known well, paramedic arrival on patient 6 minutes after 911 activation, and ED arrival 39 minutes after 911 activation. In the hyperacute window, ICH patients call 911 only slightly faster than ACI patients, and subsequent prehospital intervals of care are similar. In a busy metropolitan region, national alarm-to-on patient time targets were achieved in more than three-quarters of patients.