Clinical Predictors of Accurate Prehospital Stroke Recognition

Abstract

Background and Purpose-Prehospital activation of in-hospital stroke response hastens treatment but depends on accurate emergency medical services (EMS) stroke recognition. We sought to measure EMS stroke recognition accuracy and identify clinical factors associated with correct stroke identification. Methods-Using EMS and hospital records, we assembled a cohort of EMS-transported suspect, confirmed, or missed ischemic stroke or transient ischemic attack cases. The sensitivity and positive predictive value (PPV) for EMS stroke recognition were calculated using the hospital discharge diagnosis as the gold standard. We used multivariable logistic regression analysis to determine the association between Cincinnati Prehospital Stroke Scale use and EMS stroke recognition. Results-During a 12-month period, 441 EMS-transported patients were enrolled; of which, 371 (84.1%) were EMSsuspected strokes and 70 (15.9%) were EMS-missed strokes. Overall, 264 cases (59.9%) were confirmed as either ischemic stroke (n=186) or transient ischemic attack (n=78). The sensitivity of EMS stroke recognition was 73.5% (95% confidence interval, 67.7-78.7), and PPV was 52.3% (95% confidence interval, 47.1-57.5). Sensitivity (84.7% versus 30.9%; P<0.0001) and PPV (56.2% versus 30.4%; P=0.0004) were higher among cases with Cincinnati Prehospital Stroke Scale documentation. In multivariate analysis, Cincinnati Prehospital Stroke Scale documentation was independently associated with EMS sensitivity (odds ratio, 12.0; 95% confidence interval, 5.7-25.5) and PPV (odds ratio, 2.5; 95% confidence interval, 1.3-4.7). Conclusions-EMS providers recognized 3 quarters of the patients with ischemic stroke and transient ischemic attack;however, half of EMS-suspected strokes were false positives. Documentation of a Cincinnati Prehospital Stroke Scale was associated with higher EMS stroke recognition sensitivity and PPV.

Is It Acute Stroke or Not? - A Prospective Observational Study from a Multidisciplinary Emergency Department

“…Especially in cases of epileptic seizures, a fast assessment by the neurologist is recommended to manage the acute situation. Concordant to another study [17] , we also had a high percentage of migraine with aura (6% of all patients with a neurologic diagnosis), which is a relevant differential diagnosis particularly in younger patients. In patients with unusually prolonged migraine with aura, a differentiation on clinical basis alone is sometimes difficult and MRI can help to exclude ischemia for sure [22] .…”

“…In patients with unusually prolonged migraine with aura, a differentiation on clinical basis alone is sometimes difficult and MRI can help to exclude ischemia for sure [22] . Finally, diagnoses coming from other disciplines like metabolic disorder, infection or syncope were also highly prevalent and confirmed previous observations [15,17,19] . From the ED point of view, we wondered if an overdiagnosis of acute stroke might be associated with the pre-clinical situation, for instance, in patients with a higher mRS or in those living in an institution with a reduced autonomy entailing potential health risks, such as falls.…”

“…Furthermore, their predictive value is strongly investigator-dependent [16] . Most of the studies on accuracy of prehospital acute stroke diagnosis have focussed on missed diagnoses of stroke comparing EMS protocols and final diagnosis at hospital discharge, whereas the problem of overdiagnosis of stroke entailing a fast and extensive patient management has been addressed in a recent study of 441 patients with about 50% of EMS-suspected false positive strokes [17] . Another observation with 558 SAS patients reported about 30% of confirmed cerebrovascular events, 30% of neurological diagnoses and 40% of systemic or other diagnoses [18] , and this finding corresponds roughly with our data.…”

Stroke and the emergency medical services – enhancing performance within the chain of survival

“…Currently, the use of prehospital stroke recognition tools is recommended by both the National Academy of Emergency Medical Service Physicians and the American Stroke Association. , Acker et al 2007) However, it has been estimated that more than 30% of all stroke cases are still missed by prehospital stroke scales and as much as 50% or more of cases designated as suspected stroke have been false positives (Asimos et al 2014, Brandler et al 2014, Oostema et al 2015. This burdens in-hospital stroke teams who at times have to struggle with multiple suspected stroke patients simultaneously.…”

Development and Pilot Testing of 24/7 In-Ambulance Telemedicine for Acute Stroke: Prehospital Stroke Study at the Universitair Ziekenhuis Brussel-Project

“…Furthermore, a considerate level of knowledge and expertise are required to efficiently engage in the complex patientdoctor interactions that are common in acute stroke, and to make appropriate medical decisions under time pressure. For these reasons, stroke diagnosis and patient selection by paramedics may not be the optimal approach [4] .…”