The positive predictive value of an ambulance prealert for stroke and transient ischaemic attack

Craig W. Brown*, Mary J. Macleod

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

OBJECTIVE: Therapeutic options for ischaemic stroke, such as thrombolysis or thrombectomy, are time sensitive. Multiple innovations have been established to reduce the symptom-to-needle time. One such innovation is the prealerting of emergency department (ED) or stroke unit staff by prehospital personnel of suspected stroke patients. The diagnosis of stroke can sometimes be difficult, with stroke mimics being a recognized issue. The prealert mobilizes ED, stroke and imaging personnel, which, for a true-positive, improves door-to-needle times. However, there are a proportion of false-positive prealerts (nonstrokes) that have a significant resource activation implication. The aim of this study was to evaluate the positive predictive value of a prealert for stroke and transient ischaemic attack (TIA).

 METHODS: Ambulance service prealert forms for stroke and TIA collated by the ED were compared with the Scottish Stroke Audit database findings, ED electronic notes and imaging reports to establish whether the prealert was a true-positive or a false-positive. 

RESULTS: A prealert was obtained for 77 patients as query stroke/TIA. The true-positive rate was 52 and the false-positive rate was 25. The positive predictive value was 0.675. The median symptom-to-arrival time for prealerted patients was 97 min and the door-to-needle time for thrombolysis (n=17 patients) was 38 min. 

CONCLUSION: The diagnosis of true-positive stroke can be difficult in the prehospital environment. Although prealert has been shown to improve the patient’s journey in terms of door-to-thrombolysis times, we have identified that the prealert has a significant false-positive rate that has important resource allocation and activation consequences. Further analysis of this may inform paramedic training and improve protocols for information handover.

Original languageEnglish
Pages (from-to)411-415
Number of pages5
JournalEuropean journal of emergency medicine
Volume25
Issue number6
Early online date19 May 2017
DOIs
Publication statusPublished - 1 Dec 2018

Fingerprint

Ambulances
Transient Ischemic Attack
Stroke
Hospital Emergency Service
Needles
Allied Health Personnel
Thrombectomy
Resource Allocation
Databases

Keywords

  • ambulance
  • prealert
  • stroke
  • systems

ASJC Scopus subject areas

  • Medicine(all)

Cite this

The positive predictive value of an ambulance prealert for stroke and transient ischaemic attack. / Brown, Craig W.; Macleod, Mary J.

In: European journal of emergency medicine, Vol. 25, No. 6, 01.12.2018, p. 411-415.

Research output: Contribution to journalArticle

@article{a71c970af15d4645bd487598d0fa4877,
title = "The positive predictive value of an ambulance prealert for stroke and transient ischaemic attack",
abstract = "OBJECTIVE: Therapeutic options for ischaemic stroke, such as thrombolysis or thrombectomy, are time sensitive. Multiple innovations have been established to reduce the symptom-to-needle time. One such innovation is the prealerting of emergency department (ED) or stroke unit staff by prehospital personnel of suspected stroke patients. The diagnosis of stroke can sometimes be difficult, with stroke mimics being a recognized issue. The prealert mobilizes ED, stroke and imaging personnel, which, for a true-positive, improves door-to-needle times. However, there are a proportion of false-positive prealerts (nonstrokes) that have a significant resource activation implication. The aim of this study was to evaluate the positive predictive value of a prealert for stroke and transient ischaemic attack (TIA). METHODS: Ambulance service prealert forms for stroke and TIA collated by the ED were compared with the Scottish Stroke Audit database findings, ED electronic notes and imaging reports to establish whether the prealert was a true-positive or a false-positive. RESULTS: A prealert was obtained for 77 patients as query stroke/TIA. The true-positive rate was 52 and the false-positive rate was 25. The positive predictive value was 0.675. The median symptom-to-arrival time for prealerted patients was 97 min and the door-to-needle time for thrombolysis (n=17 patients) was 38 min. CONCLUSION: The diagnosis of true-positive stroke can be difficult in the prehospital environment. Although prealert has been shown to improve the patient’s journey in terms of door-to-thrombolysis times, we have identified that the prealert has a significant false-positive rate that has important resource allocation and activation consequences. Further analysis of this may inform paramedic training and improve protocols for information handover.",
keywords = "ambulance , prealert, stroke, systems",
author = "Brown, {Craig W.} and Macleod, {Mary J.}",
year = "2018",
month = "12",
day = "1",
doi = "10.1097/MEJ.0000000000000475",
language = "English",
volume = "25",
pages = "411--415",
journal = "European journal of emergency medicine",
issn = "0969-9546",
number = "6",

}

TY - JOUR

T1 - The positive predictive value of an ambulance prealert for stroke and transient ischaemic attack

AU - Brown, Craig W.

AU - Macleod, Mary J.

PY - 2018/12/1

Y1 - 2018/12/1

N2 - OBJECTIVE: Therapeutic options for ischaemic stroke, such as thrombolysis or thrombectomy, are time sensitive. Multiple innovations have been established to reduce the symptom-to-needle time. One such innovation is the prealerting of emergency department (ED) or stroke unit staff by prehospital personnel of suspected stroke patients. The diagnosis of stroke can sometimes be difficult, with stroke mimics being a recognized issue. The prealert mobilizes ED, stroke and imaging personnel, which, for a true-positive, improves door-to-needle times. However, there are a proportion of false-positive prealerts (nonstrokes) that have a significant resource activation implication. The aim of this study was to evaluate the positive predictive value of a prealert for stroke and transient ischaemic attack (TIA). METHODS: Ambulance service prealert forms for stroke and TIA collated by the ED were compared with the Scottish Stroke Audit database findings, ED electronic notes and imaging reports to establish whether the prealert was a true-positive or a false-positive. RESULTS: A prealert was obtained for 77 patients as query stroke/TIA. The true-positive rate was 52 and the false-positive rate was 25. The positive predictive value was 0.675. The median symptom-to-arrival time for prealerted patients was 97 min and the door-to-needle time for thrombolysis (n=17 patients) was 38 min. CONCLUSION: The diagnosis of true-positive stroke can be difficult in the prehospital environment. Although prealert has been shown to improve the patient’s journey in terms of door-to-thrombolysis times, we have identified that the prealert has a significant false-positive rate that has important resource allocation and activation consequences. Further analysis of this may inform paramedic training and improve protocols for information handover.

AB - OBJECTIVE: Therapeutic options for ischaemic stroke, such as thrombolysis or thrombectomy, are time sensitive. Multiple innovations have been established to reduce the symptom-to-needle time. One such innovation is the prealerting of emergency department (ED) or stroke unit staff by prehospital personnel of suspected stroke patients. The diagnosis of stroke can sometimes be difficult, with stroke mimics being a recognized issue. The prealert mobilizes ED, stroke and imaging personnel, which, for a true-positive, improves door-to-needle times. However, there are a proportion of false-positive prealerts (nonstrokes) that have a significant resource activation implication. The aim of this study was to evaluate the positive predictive value of a prealert for stroke and transient ischaemic attack (TIA). METHODS: Ambulance service prealert forms for stroke and TIA collated by the ED were compared with the Scottish Stroke Audit database findings, ED electronic notes and imaging reports to establish whether the prealert was a true-positive or a false-positive. RESULTS: A prealert was obtained for 77 patients as query stroke/TIA. The true-positive rate was 52 and the false-positive rate was 25. The positive predictive value was 0.675. The median symptom-to-arrival time for prealerted patients was 97 min and the door-to-needle time for thrombolysis (n=17 patients) was 38 min. CONCLUSION: The diagnosis of true-positive stroke can be difficult in the prehospital environment. Although prealert has been shown to improve the patient’s journey in terms of door-to-thrombolysis times, we have identified that the prealert has a significant false-positive rate that has important resource allocation and activation consequences. Further analysis of this may inform paramedic training and improve protocols for information handover.

KW - ambulance

KW - prealert

KW - stroke

KW - systems

UR - http://www.scopus.com/inward/record.url?scp=85019646709&partnerID=8YFLogxK

U2 - 10.1097/MEJ.0000000000000475

DO - 10.1097/MEJ.0000000000000475

M3 - Article

VL - 25

SP - 411

EP - 415

JO - European journal of emergency medicine

JF - European journal of emergency medicine

SN - 0969-9546

IS - 6

ER -