Original Article
Prehospital Stroke Identification: Factors Associated with Diagnostic Accuracy

https://doi.org/10.1016/j.jstrokecerebrovasdis.2015.06.004Get rights and content

Background

Stroke patients misdiagnosed by emergency medical services (EMS) providers have been shown to receive delayed in-hospital care. We aim at determining the diagnostic accuracy of Fire Department of New York (FDNY) EMS providers for stroke and identifying potential reasons for misdiagnosis.

Methods

Prehospital care reports of all patients transported by FDNY EMS to 3 hospitals from January 1, 2010, to December 31, 2011, were compared against the American Heart Association Get With The Guidelines (GWTG) database (reference standard) for the diagnosis of stroke. Age-adjusted logistic regression models were generated to explore prehospital patient characteristics which are associated with stroke misdiagnosis.

Results

Of 72,984 patient transports during the study period, 750 had a GWTG diagnosis of stroke, 468 (62%) of which were identified correctly in the field and 282 (38%) were missed. An additional 268 patients were misdiagnosed as stroke when in fact they had an alternative diagnosis. Overall sensitivity was 62.4% (95% confidence interval [CI], 58.9-65.8) and specificity was 99.6% (95% CI, 99.6-99.7). No patients who presented with unilateral weakness, facial weakness, or speech problems were missed, whereas patients with atypical complaints like general malaise, dizziness, and headache were more likely to be missed. Seizures led the EMS providers to both overcall a stroke and miss the diagnosis.

Conclusions

FDNY EMS care providers missed more than a third of stroke cases. Seizures and other atypical presentations contribute significantly to stroke misdiagnosis in the field. Our findings highlight the need for better prehospital stroke identification methods.

Section snippets

Study Design

We performed a retrospective analysis to assess the performance of FDNY care providers in identifying stroke in the prehospital phase. Data used for this assessment were obtained from the FDNY prehospital care reports (ePCRs) and were compared against the local Get With The Guidelines (GWTG) database.19 The study was approved by the State University of New York Downstate Medical Center Institutional Review Board.

Study Setting

Brooklyn (Kings County) is the most populous of New York City's 5 boroughs and is

Results

Of the 72,984 adult patients (45% men, mean age = 47.6 ± 19.9 years) transported to the participating hospitals by FDNY EMS during the study period, 750 had strokes, of which 468 (true positives) were identified in the prehospital phase and 282 were missed (false negatives; Fig 1). Consult Table 1 for the distribution of stroke types. An additional 268 patients were misdiagnosed as having had strokes by EMS but later found to have alternate diagnoses (false positives). Table 1 summarizes the

Discussion

Our study overcomes limitations of previous studies by not relying on a prior suspicion of stroke, rather it considers how well strokes are identified in the entire population of ambulance-transported patients. Furthermore, factors affecting prehospital providers' impression of stroke have not been studied. This gap in our knowledge about prehospital stroke identification is addressed in the present study.

Delays in stroke diagnosis in the field may decrease the likelihood of receiving

Conclusions

FDNY EMTs and paramedics missed approximately one third of all stroke cases. We plan to use these findings to inform and improve our EMS educational methods. Better tools are needed for prehospital stroke screening, including development of more sensitive and specific prehospital stroke scales particularly targeted at identifying posterior circulation stroke syndromes. From our data, it seems prudent to activate in-hospital resources on EMS notification; individual hospitals must balance the

References (27)

  • P. Ramanujam et al.

    Accuracy of stroke recognition by emergency medical dispatchers and paramedics–San Diego experience

    PrehospEmerg Care

    (2008)
  • C.S. Kidwell et al.

    Identifying stroke in the field. Prospective validation of the Los Angeles prehospital stroke screen (LAPSS)

    Stroke

    (2000)
  • J.E. Bray et al.

    Paramedic identification of stroke: community validation of the Melbourne ambulance stroke screen

    Cerebrovasc Dis

    (2005)

    • Cited by (0)

    The study was performed at the Departments of Emergency Medicine, Neurology, and the School of Public Health, State University of New York, Downstate Medical Center. Data were provided partially by the Fire Department of New York, Office of Medical Affairs.

    This study was partially supported by NIH grants 1U01NS044364, R01 HL096944, 1U10NS077378, and 1U10NS080377.

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    Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.