Early Stroke Recognition: Developing an Out‐of‐hospital NIH Stroke Scale

Abstract

Objective: To develop an abbreviated and practical neurologic scale that could assist emergency medical services or triage personnel in identifying patients with stroke. Methods: A prospective, observational, cohort study was performed at university-based EDs. Participants were 74 patients treated in a thrombolytic stroke trial and 225 consecutive non-stroke patients evaluated during 4 random 12-hour shifts in the ED. Scores on the NIH Stroke Scale were obtained for all patients by physicians. Items of this scale were modified and recoded to a binomial (normal or abnormal) scale. Serial univariate analyses using x2 were performed to rank items. Recursive partitioning was then performed to develop the decision rule for predicting the presence of stroke. Results: Three items identified 100% of patients with stroke: facial palsy, motor arm, and dysarthria. An Abbreviated NZH Stroke Scale based on these items had a sensitivity of 100% and a specificity of 92%. A proposed Out-ofhospital NZH Stroke Scale consisting of facial palsy, motor arm, and a combination of dysarthria and best language items (abnormal speech) had a sensitivity of 100% and a specificity of 88%. Conclusion: Using the derivation data set, a proposed Out-ofhospital NZH Stroke Scale had a high sensitivity and specificity for identifying patients with stroke when performed by physicians in this group of 299 ED patients. Prospective studies of other health care professionals using the scale in the out-of-hospital arena are needed. Key words: out-of-hospital; emergency medical services; EMS; paramedic; stroke; cerebral ischemia; diagnosis; score. are 30% more likely to have excellent neurologic recovery at 3 months than are those treated with placebo.' The mobilization of a stroke team is an effective method of treating patients within this narrow therapeutic window.' Often the first step in mobilizing a stroke team is advance notification of the receiving ED by emergency medical services (EMS) personnel or other nonphysician medical personnel."-5 Developing a rapid, accurate method for EMS or triage personnel to identify patients with stroke could reduce the time to physician evaluation for patients with potentially treatable strokes who present to the ED. Currently, a nonstandardized history and physical examination are the primary tools used to identify potential stroke patients in the field.The NIH Stroke Scale is a 15-item measure of neurologic function used in clinical stroke trials.6 This scale assesses neurologic deficits and was designed to provide a reliable, valid, and easy-to-perform alternative to the standard neurologic examinati~n.'.~ The goal of this preliminary study was to develop an abbreviated and practical neurologic scale, derived from the NIH Stroke Scale, that could assist EMS or other medical personnel in identifying patients with stroke.

Prehospital triage to stroke centres: Is it a solution to the problem?

“…Most patients triaged as a "falsepositive" stroke have serious medical problems such as urosepsis, aspiration, uremia, drug overdose, seizure and syncope. 11,18 These patients frequently require hospitalization, usually by a general internal medicine service rather than a neurology service. As well, no research has been published to indicate how many "true-positive" stroke patients actually meet current thrombolytic guidelines; however, it is probably a small minority.…”

“…An abnormality in at least one of these items was found to have a sensitivity of 100% and a specificity of 88% when tested by an emergency physician on a group of patients in which the prevalence of acute stroke was 25%. 11 The CPSS is also said to have excellent reliability when used by prehospital personnel and physicians to evaluate ED and neurology service patients. 10 In this study, where the prevalence of acute stroke or transient ischemic attack (TIA) was 29%, the scale was 63% sensitive and 88% specific.…”

“…The recently proposed Cincinnati Prehospital Stroke Scale 10,11 (CPSS) is a 3-item scale that was derived from the 15-item National Institutes of Health stroke scale. The items of the CPSS include the presence or absence of facial droop, arm drift and abnormal speech.…”

Telemedicine in Stroke: Potentials, Limitations and Ongoing Issues

“…Two screening tools exist; both designed to aid the pre-hospital identification of stroke by EMS. These are the Los Angeles Pre-hospital Stroke Screen (LAPSS) (Kothari et al 1997) and the Cincinnati Pre-hospital Stroke Scale (Kidwell et al 2000). Through use of the LAPSS in both California and Houston, Texas, the sensitivity of stroke diagnosis increased substantially.…”

EMS Management of Acute Stroke—Prehospital Triage (Resource Document to NAEMSP Position Statement)

“…Without a clear time of symptom onset, most recanalization (intravenous tPA) strategies may be precluded. 28,29,40 Furthermore, EMS providers should have specific basic knowledge of, and document the proper use of, important principles of stroke management as embodied in acute stroke guidelines, 5,11−13 such as treatment of glucose and hypoxia.…”