Barrett et al., 201759 | USA |
Feasibility study1
Simulation and ‘live’ phase
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Audio-visual communication (iPad)
EMS clinician supporting ambulance clinician assessment of patient
| Stroke patients (live phase) |
Completion of NIHSS assessment
Time to conduct NIHSS assessment
Staff satisfaction
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NIHSS completed in 13/14 cases
Video signal dropped periodically
NIHSS assessment completed in average of 7.6 minutes
Both neurologists and ambulance clinicians reported high satisfaction with prehospital video triage
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Bergrath et al., 201161 | Germany | Feasibility study |
Transmission of vital signs and 12-lead ECG data
Audio-visual communication
EMS physician in teleconsultation centre supporting assessment of patient in ambulance
| 157 emergency ambulance calls |
Completion of assessments
Clinicians assessed technical performance of system (quality of audio and visual signal, background noise, etc.)
Degree of cooperation between ambulance and hospital EMC physicians
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97% of video calls completed successfully
Quality of video signal rated highly
EMS clinician contributed to decisions on several occasions
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Bergrath et al., 201360 | Germany | Prospective, observational study |
Transmission of blood pressure, 3-lead ECG, 12-lead ECG data
EMS physician in teleconsultation centre supporting assessment of patient in ambulance (either by ambulance clinician or EMS physician)
| 35 emergency ambulance calls (i.e. many not stroke), used audio-visual consultation |
Duration of consultation
Patient conditions addressed
Stage at which consultation commenced (e.g. without onsite EMS physician, while awaiting one, or once one arrived)
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Mean duration of consultations 24.9 minutes
3/35 calls involved a diagnosis of neurological emergency
26/35 calls commenced without or while awaiting on-scene EMS clinician
Conclusion that this approach is feasible for a range of emergency conditions
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Chapman Smith et al., 201663 | USA |
Feasibility study
Simulation
| Audio-visual communication (using iPad) between trained NIHSS assessors and either prehospital clinicians or study investigators | Actors performing scripted stroke scenarios |
Signal reliability
Completion of NIHSS assessment
Reliability of NIHSS scoring (ambulance vs. bedside)
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All 27 calls and NIHSS assessments completed without significant interruption
High correlation of ambulance and bedside NIHSS ratings (0.96)
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Chapman Smith et al., 201962 | USA |
Feasibility study
Simulation
| Audio-visual communication between neurologists using tablets and ambulance fitted with dedicated audio-visual system | Actors performing scripted stroke scenarios |
Interruptions of signal
Clinician ratings of audio-visual quality and acceptability of service
Obtaining clinical data and NIHSS score (compared with bedside/script-based NIHSS assessments)
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91% of calls were completed
Variable assessment of signal quality stability, and safety
Moderate agreement between remote vs. script-based NIHSS scores
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Eadie et al., 201564 | Scotland | Feasibility study | Audio-visual communication to support stroke clinicians conduct remote assessments in different parts of the rural highlands, with a focus on mobile vs. static calls | Healthy volunteers performing scripted stroke scenarios |
Reliability of signal
Accuracy of decision about eligibility thrombolysis
Time to decision about thrombolysis
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Drops in signal in 47% of calls, but resumed in all cases, with delays of 2–3 minutes in assessment
No difference in accuracy or time taken in completing remote assessments in mobile and static calls
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Felzen et al., 201765 | Germany | Feasibility study |
Transmission of vital signs and 12-lead ECG data
Consultation report printout in ambulance
Audio-visual communication and still images to allow EMS physician in teleconsultation centre supporting assessment of patient in ambulance (either by ambulance clinician or EMS physician)
| 539 ambulance emergency calls (33 stroke cases) |
Reliability of different transmissions (e.g. malfunctions, impact on quality of communication)
Clinical value of communication sources, quality of audio-visual signals, background noise
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Transmissions of all information types successful in > 90% of cases
Clinicians rated images and videos as being of significant clinical value
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Joseph et al., 202166 | USA |
Feasibility study
Simulation
| Audio-visual communication (via laptops at each end) to let a neurologist and nurse support ambulance clinician in simulated assessment | 13 simulated stroke consultations |
Communication (verbal/non-verbal) between ambulance clinician, neurologist, nurse and patient
Types of interaction (requests for information/confirmation, giving instruction, repetition, camera movement, hand or facial gestures)
Responses to disruptions in communication
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82% communication verbal
Neurologist, ambulance clinician and patient equally involved in discussion
Disruption in 8% of all interactions, with 44% of these being communication-related
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Lippman et al., 201667 | USA |
Feasibility study
Simulation
| Audio-visual communication (via iPad) with portable Wi-Fi. Permitting communication between hospital and ambulance to permit NIHSS assessment | 30 simulation sessions |
Sustained audio-visual signal
Audio-visual signal quality
| Signal was sustained and audio-visual signal was of sufficient quality to permit NIHSS assessment |
Mort et al., 201668 | Scotland |
Feasibility study
Simulation; preliminary findings
| Ambulance technology to send live transcranial ultrasound images and audio-visual stream to stroke unit (to assess potential for prehospital thrombolysis) | 23 simulation sessions | Feasibility of transmission of ultrasound and audio-visual signals | Variable data transfer rate, but suggesting transmission feasible |
Rogers et al., 202169 | USA |
Feasibility study
Simulation
| Audio-visual communication to let neurologist, nurse and ambulance clinician conduct full neurological assessment in ambulance | 13 simulation sessions | Observation by three human factors experts assessing usability and performance of system from human factors perspective, including error types |
Issues with usability of interface (e.g. incorrect data entry, clicking the wrong buttons, inappropriate menu selections); errors most commonly made by nurses, then neurologists
Recommendations for clearer system design, including clear labelling, highlighting errors, interface layout, system automation
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Torres Zenteno et al., 201670 | Spain |
Feasibility study
Simulation
| System to let ambulance clinicians alert stroke team, including videoconferencing to let neurologist perform NIHSS assessment | 3 simulation sessions | Capturing times taken for each stage of information-sharing | System seems feasible; technical issues include mobile network coverage |
Valenzuela Espinoza et al., 201671 | Belgium | Feasibility study | Audio-visual communication letting stroke specialists provide 24/7 remote assessment of suspected stroke patients in the ambulance | 187 emergency calls (16 with suspected stroke) |
Completion of calls
Consultation time
Information transfer
Diagnosis
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94% of calls completed successfully
Median consultation lasted 9 minutes (IQR 8–13 minutes)
12 patients identified as having stroke or TIA; 10 confirmed by in-hospital diagnosis
Information was transferred safely and reliably from ambulance to hospital
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Van Hooff et al., 201372 | Belgium |
Feasibility study
Simulation
| Audio-visual communication using laptops and cameras to let stroke clinician perform remote assessment of suspected stroke using UTSS | 41 simulated calls from ambulance exhibiting different symptoms |
Audio-visual and network signal reliability
Examination times
Consistency of scoring of stroke symptoms
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Signal mostly reliable (5 video freezes, but nothing preventing the assessment)
Mean examination using UTSS was 3.1 minutes
High inter-rater reliability
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Yperzeele et al., 201439 | Belgium | Feasibility study | Audio-visual communication between ambulance and hospital using laptops, plus transmission of patient vital signs | 41 emergency calls of which 5 were suspected stroke (3 confirmed stroke) |
Data transfer of patient characteristics
Patient diagnosis (prehospital and in-hospital)
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Prehospital diagnosis reached in 37/41 cases
High agreement between prehospital and hospital diagnosis
No adverse incidents or safety issues reported
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Wu et al., 202178 | China | Observational study | Smartphone platform ‘Green’ to enable prehospital notification and communication between prehospital and ED clinicians | 8457 acute ischaemic stroke patients who underwent thrombolysis | Time from arrival at hospital to administration of thrombolysis | Significant reductions in time to administration of thrombolysis observed in patients transferred using Green system vs. patients who arrived by themselves (i.e. without prehospital notification) |
Al Kasab et al., 202173 | USA | Pilot study | Audio-visual communication to let stroke clinicians assess suspected stroke patient remotely, including medical history, demographics, and NIHSS | 67 stroke patients who received thrombolysis: 15 patients who underwent prehospital video triage compared with 52 patients who underwent standard transfer processes (which included telephone consultation) |
Stroke onset to hospital
Time from arrival at hospital to thrombolysis decision
Time from arrival at hospital to thrombolysis administration
| Patients who underwent prehospital video triage had no significant difference in time to hospital, but had significantly shorter time to thrombolysis decision and administration of thrombolysis |
Belt et al., 201674 | USA | Pilot study | Audio-visual communication, using high-definition camera, microphone and screen to let stroke clinicians work with ambulance clinicians to assess suspected stroke patients and coordinate care with acute setting | 89 suspected stroke patients |
Reliability of connection
Length of remote consultation
Time from when patient was last well to thrombolysis administration
Time from arrival at hospital to thrombolysis administration
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Connection adequate for all but two cases
Remote consultations lasted around 7 minutes for thrombolysis cases and around 4 minutes for non-thrombolysis cases
Patients who underwent prehospital video triage had shorter times to thrombolysis
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Johansson et al., 201975 | Sweden | Pilot study | Audio-visual communication to let neurologist and prehospital emergency nurses work together to support assessment of suspected stroke patients, e.g. using NIHSS | 11 suspected stroke cases |
Clinician perceptions of image and sound quality, and consistency of assessment
Qualitative research with nurses
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Clinicians felt images were good or very good and were confident in uniformity of assessments
Nurses split on whether to develop service further owing to operational interference and unclear efficacy
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Liman et al., 201276 | Germany |
Pilot study
Simulation
| Audio-visual communication system built into ambulance (including head and body camera) to permit remote assessment by stroke physician | Actors displaying different stroke symptoms |
Completion of NIHSS
Reliability of remote NIHSS assessment vs. stroke physician assessment of video recorded in-ambulance
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NIHSS completed in 12 of 30 calls
Moderate reliability of remote NIHSS assessment in remaining 12 calls
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Wu et al., 201477 | USA |
Pilot study
Simulation
| Audio-visual communication to let vascular neurologists conduct assessment (e.g. using NIHSS) of suspected stroke patients while being conveyed by fire department | 40 simulated scenarios performed by actors in ambulance |
Reliability of technology (i.e. to permit completion of assessment)
Reliability of assessment (i.e. agreement between remote assessments vs. independent neurologist assessment of scripted scenarios)
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85% of assessments completed without major technological interruption
90% agreement between remote assessment and independent assessment of scripts
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Bergrath et al., 201279 | Germany | Prospective study | Audio-visual communication, plus transmission of still pictures and vital data, letting emergency physician support assessment of patient in ambulance | 18 stroke patients undergoing prehospital video triage; 46 control stroke patients attended by a prehospital emergency car and ambulance |
Timings of assessments
Technical assessment of system
Diagnosis
| No significant difference between patients undergoing prehospital triage and control group in terms of time onsite, time to hospital and time to scan |
Drenck et al., 201980 | Denmark | Prospective study | Prehospital assessment of suspected stroke patients, including onsite ECG, consultation with neurologist in hospital | 520 suspected stroke cases | Factors contributing to increased/decreased on-scene time | On-scene time lower when ECG conducted in hospital, other processes conducted in transit rather than onsite and when communication with hospital neurologists was rated as good |
Eder et al., 202181 | Germany | Prospective study | Audio-visual communication (using hand held and desktop PCs) to support communication between stroke clinicians and ambulance clinicians in assessing suspected stroke patients | 845 acute ischaemic stroke patients |
Time from arrival at hospital to brain scan
Time from arrival at hospital to thrombolysis administration
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Arrival to brain scan was significantly lower in people who underwent prehospital video triage
No significant difference in arrival to thrombolysis times
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Mazya et al., 202084 | Sweden | Prospective study | Telephone-only consultation between ambulance and stroke clinicians, to support diagnosis of potential for mechanical thrombectomy and decision-making on patient destination (i.e. to primary stroke centre or comprehensive stroke centre) | 2905 suspected stroke patients |
Accuracy of diagnosis of large-artery occlusion (i.e. suitable for mechanical thrombectomy)
Delivery of mechanical thrombectomy (time from onset)
Delivery of thrombolysis (time from onset)
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87% accuracy of diagnosis of large-artery occlusion
Prehospital telephone triage associated with significantly lower time from onset to thrombectomy, no significant change in onset to thrombolysis
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Felzen et al., 201982 | Germany | Retrospective study | 24/7 service, including transmission of vital signs and 12-lead ECG data. Audio-visual communication and still images to allow EMS physician in teleconsultation centre supporting assessment of patient in ambulance (either by ambulance clinician or EMS physician) | 6265 emergency calls (of which 1049 neurological conditions; stroke unspecified) |
Number of teleconsultations
Number of complications
Number of transmission malfunctions
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Use of prehospital triage increased over time
Only 6 adverse events reported
Transmission malfunctions were uncommon, with the highest occurring in audio communication (1.9%)
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Quadflieg et al., 202085 | Germany | Retrospective study | 24/7 service, including transmission of vital signs and 12-lead ECG data. Audio-visual communication and still images to allow emergency physician in teleconsultation centre supporting assessment of patient in ambulance (either by ambulance clinician or EMS physician) | 1218 emergency calls (including 584 patients who underwent prehospital video triage and 634 patients treated by onsite emergency physician) | Concordance of prehospital diagnosis with diagnosis at end of hospital stay | No significant difference between concordance of diagnoses provided by onsite emergency physician and remote emergency physician |
Schröder et al., 202186 | Germany | Retrospective study | 24/7 service, including transmission of vital signs and 12-lead ECG data. Audio-visual communication and still images to allow emergency physician in teleconsultation centre to support assessment of patient in ambulance (either by ambulance clinician or EMS physician) |
10,362 emergency calls using prehospital video triage
Of these, 2007 life-threatening calls (of which 890 involved stroke)
| Change in vital signs, pre and post prehospital video triage consultation |
Significant improvements in vital signs overall
96% of 890 stroke cases could be managed by the remote emergency physician
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Verma et al., 201087 | Canada | Retrospective study | ‘Patching’ to let stroke clinicians support ambulance clinicians in decision-making about ‘false positives’, including stroke patients who are not eligible for thrombolysis | 2966 stroke patients conveyed by ambulance | Proportion of ‘false positive’ stroke patients, comparing patients where there was prehospital patch with stroke clinician and where ambulance clinicians applied assessment alone | Proportion of false positives was significantly higher when ambulance clinicians did not receive prehospital input from stroke clinicians |
Valenzuela Espinoza et al., 201741 | Belgium | Cost-effectiveness model | Prehospital video triage allowing prenotification of stroke clinicians and a range of patient data from the ambulance | 2282 stroke patients from Brussels stroke registry | Cost-utility model measuring costs and quality-adjusted life-years, driven by assumptions about reduced time to key interventions and resultant improvements in patient outcomes | If time gains are greater than 6 minutes, the model estimates that prehospital video triage is cost-effective. If time gains exceed 12 minutes, it becomes dominant (i.e. saving cost and improving outcomes) |
Hölscher et al., 201383 | – | Concept paper |
Discussion of potential of prehospital transcranial ultrasound scans
Brief discussion of evidence related to prehospital video triage
| – | – | Proposal that prehospital ultrasound may be less costly than mobile stroke units and less technologically challenging than prehospital video triage |
Seah et al., 201988 | – | Concept paper | Description of development of online platform to allow all clinicians associated with stroke pathway to communicate | – | – |
Outline of communication, principally involving instant text-messaging, but with function of sharing images or videos
Summary of key roles across stroke pathway
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Amadi-Obi et al., 201489 | – | Review | Telemedicine (not just prehospital video triage) related to trauma, myocardial infarction, and stroke | Studies from 1970–2014 | Outcomes of interest included cost-effectiveness, feasibility and clinical outcome |
5 studies covered communication between ambulance and hospital
Review found limited conclusive evidence for effectiveness of telemedicine for emergency generally
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Aude Bert et al., 201347 | – | Review | Prehospital management of stroke patients (not just video triage) | Review process unclear | Current approaches to prehospital stroke management, noting risks and potential benefits | Alongside other interventions, prehospital video triage discussed as feasible, but noting the limitations of 3G networks and the potential of 4G to carry a stable signal between ambulance and stroke clinicians |
Chowdhury et al., 202190 | – | Review |
Improved triage for thrombolysis
Identification of patients with large arterial occlusion (i.e. eligible for diversion to centre that provides thrombectomy)
Mobile stroke units
| Systematic review and meta-analysis of papers from 2005 | Analysed impact on time to key interventions, including thrombolysis (time from onset; time from arrival at hospital) and patient outcomes (function; mortality) |
27 articles included in analysis
Improved triage for thrombolysis associated with increased thrombolysis rates, reduced time to thrombolysis
No impact of interventions on functional outcome or mortality
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Fassbender et al., 201391 | – | Review | Approaches to improve timely access to acute stroke care, principally thrombolysis | Review process unclear | Role of patients/public, ambulance services (e.g. ambulance clinician triage, prenotification), future directions (including prehospital video triage) | Prehospital video triage is seen as of potential value, but mobile transmission from ambulance is identified as a significant obstacle |
Fassbender et al., 202092 | – | Review | Approaches to improve timely delivery of mechanical thrombectomy | Review process unclear | Role of different stakeholders in timely pathway to thrombectomy, including patients/public, ambulance services and acute hospitals | Prehospital video triage discussed in relation to prenotification, noting potential for two-way communication between ambulance and stroke clinicians. The technology is described as reliable, although impact on outcomes yet to be established |
Guzik et al., 202193 | – | Review | Use of telemedicine in different parts of the stroke pathway during the COVID-19 pandemic | Review process unclear | Use of telemedicine from prehospital through to long-term rehabilitation | Prehospital triage by remote stroke clinician has potential to support screening process, permit ambulance clinicians to focus more on COVID-19 control (e.g. PPE), and help ensure appropriate patient destination. However, evidence is required on how best to deliver these services |
Hubert et al., 201453 | – | Review | Prehospital management of stroke in developing countries. Interventions include mobile stroke units and remote prehospital triage | Systematic review of papers from 2014 onward | In the context of prehospital video triage, main outcome was reliability of signal |
25 articles included in analysis
Studies reported variable stability of signal, but noted potential of 4G networks
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Lumley et al., 202016 | – | Review |
Technology to support ambulance clinicians in assessing suspected stroke
Interventions included blood biomarkers, prehospital imaging and ‘mobile telestroke’ (including prehospital video triage)
| Scoping review of papers between 2000 and 2019 | In terms of prehospital video triage, accuracy of diagnosis, acceptability of technology, impact on delivery of interventions and patient outcomes |
19 articles included in analysis
Most studied found good agreement between prehospital and final assessments
Most studies reported high satisfaction with technology and a view that it was reliable
No robust evidence on patient acceptance reported
Some evidence suggested that time to interventions either improved through, or was not affected by, prehospital triage
Little evidence reported on outcomes
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Martinez-Gutierrez et al., 201994 | – | Review | Approaches to improve time to thrombectomy, focusing on detection, evaluation, triage and transport of patients | Review process unclear | In terms of prehospital video triage, reliability of signal and quality of communication between ambulance and stroke services |
Signal reliability reported as poor in earlier years, but indications of improvement with advances in technology
Describes importance of appropriate transfer to thrombectomy-capable centres, and the potential of prehospital triage to support this
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Mazighi et al., 201095 | – | Review |
Approaches to improve timely access to acute stroke care, principally thrombolysis
Main focus on inter-hospital communication and prenotification of stroke services from ambulance
Limited focus on prehospital triage
| Review process unclear | In terms of prehospital video triage, there is a brief focus on feasibility | Purely identified as a future development, dependent on improvements in image quality and signal reliability |
Rogers et al., 201748 | – | Review | Telemedicine to support prehospital emergency care, including stroke | Systematic review of articles between 2000 and 2016 | Feasibility, diagnostic accuracy, and impact on treatment timings (time to thrombolysis) |
23 articles were selected, of which 6 focused on stroke
Generally positive views of usability and quality of images
High accuracy of remotely conducted NIHSS ratings
Prehospital assessments associated with shorter time to thrombolysis
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van Gaal et al., 201896 | – | Review |
Discusses approaches to improve access to thrombectomy, importantly noting that diagnosis is ‘primarily a means to support transport decision-making, not an end’
Range of interventions discussed, including real-time involvement of stroke clinicians
| Review process unclear | Potential impact on appropriate diagnosis (via NIHSS), wider eligibility for thrombectomy and destination decision-making |
Describes no evidence conducted on thrombectomy settings
Draws on previous research on thrombolysis to suggest prehospital triage services are likely to be reliable and support accurate decision-making
Makes a general point for implementation, relating to local requirements for sensitivity and specificity of processes, and the need to consider under- and over-triage
Notes that prehospital triage is likely to disrupt ambulance and stroke clinicians’ other duties
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Weber et al., 201597 | – | Review | Prehospital stroke care, focusing on telemedicine, thrombolysis and outcomes | Systematic review covering 2004–2015 | In terms of prehospital video triage, focus on reliability of signal to permit assessment (e.g. via NIHSS) | Reported many issues with 3G-based systems, but greater reliability of assessment via 4G systems |
Winburn et al., 201840 | – | Review | Prehospital telemedicine, focusing on different types of care. Interventions include audio communication, transmission of data (images, patient vital data), videoconferencing, and remote monitoring | Systematic review covering 2000–2017 | Covers the trends, scope and type of telemedicine used in prehospital emergency medicine. Outcomes were not discussed | 68 papers included, of which 19 related to stroke and 12 related to prehospital video triage (i.e. videoconferencing more common in stroke than other conditions) |
Yperzeele et al., 201439 | – | Review | Approaches to prehospital care to improve access to stroke care. Interventions include education of different stakeholders and prehospital triage | Review process unclear | In terms of prehospital video triage, accuracy of decision-making, reliability of connection, journey times and time to clinical intervention |
Reports limited evidence on prehospital video triage, with most studies simulations with healthy volunteers and relatively few ‘real-world’ studies
Video consultations more accurate than telephone alone
Improvements in technology suggest it is likely that prehospital triage may be delivered reliably
Notes clear potential of prehospital video triage, but that data security, privacy and regulatory issues remain to be addressed
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