Definitions and Context
Approximately two-thirds of all patients who seek acute care for stroke arrive at the emergency department by ambulance. Transport by paramedics is safer and enables patients to be triaged to appropriate hospitals that provide stroke services without delays. The current estimated target for transport to hospital by paramedics is in the range of 80% of cases (based on Canadian Stroke 2009 benchmark data).
Two timelines have been established to describe emergency medical services (EMS) in Canada for stroke patients who may be eligible for acute ischemic stroke therapy, including intravenous alteplase and endovascular thrombectomy. These are:
Timeline One: The pre-hospital phase starts with symptom onset and ends with hospital arrival.* This includes on-scene management and transport time. Patients with ischemic stroke who can arrive at hospital and be treated as soon as possible within a 4.5 hour time window from witnessed symptom onset (or when last seen well) may be eligible to receive medical treatment with intravenous thrombolysis; thrombolysis may be offered alone or in combination with endovascular thrombectomy which has a 6 hour time window for most patients. Highly selected patients may be eligible for endovascular thrombectomy up to 24 hours from symptom onset. Refer to Section 4 for more information.
Timeline Two: The emergency department phase starts with hospital arrival and ends with discharge from the emergency department decision time – either with admission to a stroke unit or hospital ward for inpatient care or discharge to the community. This includes the diagnostic evaluation, consideration of treatment options, and initiation of treatment which should be completed in less than 60 minutes, initiation of treatment. Aim for a target 90th percentile for door-to-needle time of 60 minutes (upper limit); and a target median door-to-needle time of 30 minutes or less [Kamal et al CJNS 2015]. Note, the goal is to transfer admitted stroke patients within four hours of arrival where possible; however, many hospitals operate at full capacity and patients may have to remain in the emergency department after they are admitted to inpatient care while waiting for an inpatient bed.
It should be noted that the probability of disability-free survival decreases over time within the treatment window and all phases of patient care should aim for the shortest process and treatment times possible.
- These recommendations cover management of potential stroke patients between the time of first contact with the local emergency medical system to transfer of care to the hospital, as well as care of suspected or confirmed stroke patients who are being transferred between healthcare facilities by paramedics.
- These recommendations are directed to paramedics and those individuals who support emergency medical systems, including communications officers and dispatchers. It also applies to other first responders such as emergency medical responders and primary care paramedics who have been trained to screen for stroke and manage potential stroke patients during transfer.
- These recommendations are intended to be translated into practice by the entire breadth of out-of-hospital healthcare providers within the defined scope of practice of each. This includes emergency medical system professionals such as paramedics and emergency medical dispatchers, but also allied emergency medical system providers such as medical first responders and emergency medical responders.
* Local variations should be taken into consideration for pre-hospital time (e.g., remote locations with poor road access).
3.0 Out-of-hospital patient management should be optimized to meet the needs of suspected acute stroke patients, including recognition, management and rapid transport, usually done concurrently [Evidence Level C].
3.1 Access to Emergency Medical Services (EMS)
- Immediate contact with emergency medical systems (e.g. 911) by people experiencing the signs of stroke, a witness or other members of the public is strongly recommended [Evidence Level B]. Refer to Section 1 for additional information on Signs of Stroke.
- EMS Communications Centre: All regions should implement a dispatch process through the EMS communications centre to recognize the probable stroke signs (such as FAST – Face, Arms, Speech), potential stroke diagnosis, and need for priority response to the scene and transport to a hospital capable of providing acute services for the rapid diagnosis and time-sensitive treatment of stroke (such as neuroimaging, and acute thrombolysis) [Evidence Level C].
- After dispatching the ambulance, it is recommended that emergency medical system communications centre personnel provide pre-arrival instructions to the person reporting the stroke (such as unlock door, move pets, determine stroke symptom onset time, determine current medications), in order to expedite and optimize pre-hospital care [Evidence Level C]. Note, if the person experiencing the signs of stroke is the one to contact EMS, they may not be able to comply with these requests.
3.2 Paramedic On-Scene Management
Note: On-scene goal is to ‘recognize and mobilize’ – it is of the utmost importance to proceed rapidly and safely to transport suspected stroke patients, as on-scene management for stroke patients is limited.
- EMS personnel should use validated acute stroke out-of-hospital diagnostic screening tools as part of on-scene assessment [Evidence Level B]. [New for 2018]
- Patients should be screened for signs of stroke using a validated stroke assessment tool that includes the components of FAST (Face, Arm, Speech, and Time) [Evidence Level B].
- Patients who demonstrate any FAST signs should then undergo a second screen using a tool validated to assess stroke severity, which may be considered in decisions for transportation destination [Evidence Level B]. [New for 2018] Note: the purpose of this second screen is to look for possible EVT candidates, such as people exhibiting signs of cortical dysfunction (aphasia, visual changes, neglect).
Refer to Appendix 2, Table 2A Canadian Stroke Best Practices Table of Standardized Acute Stroke Out-of-Hospital Diagnostic Screening Tools; Table 2B Glasgow Coma Scale, and Table 2C Canadian Stroke Best Practices Table of Pre-Hospital Stroke Severity Scales.
- It is recommended that EMS personnel obtain information from the patient, family members or other witnesses about the suspected stroke event (presenting symptoms, time of onset or time of symptom recognition or time last known well, and sequence of events), co-morbid conditions, current medications (especially anticoagulants), and any formal or informal advance directives that may influence care by EMS and in the emergency department [Evidence Level C].
- On-scene time with suspected stroke patients should be as short as possible; ideally a median time of 20 minutes or less* for patients who present within the 4.5-hour treatment time window [Evidence level C]. (* Target median of 20 minutes based on median EMS on-scene time data from across provinces contained in HSF Stroke Report 2015).
- Initial assessment provided by paramedic’s on-scene should include capillary blood glucose measurement [Evidence Level B].
- Prior to transport, it is recommended that paramedics on-scene provide instructions to the patients’ family, including recommending that the family/decision-maker accompany the patient to hospital or be accessible by phone for decision-making, as well as confirming time last known well, and providing required information about existing health conditions, current medications and other information as needed [Evidence Level C].
3.3 Transport of Suspected Stroke Patents
- Direct transport protocols must be in place to facilitate the transfer of suspected acute stroke patients who are potentially eligible for thrombolytic and/or endovascular thrombectomy to the most appropriate acute care hospital capable of providing services for the diagnosis and treatment of acute stroke [Evidence Level C].
- It is recommended that direct transport protocol criteria be based on:
- an EMS system set up to categorize patients exhibiting signs and symptoms of an acute stroke as a high priority for evaluation, response and transport [Evidence Level C];
- the medical stability of the patient [Evidence Level B];
- the presenting signs and symptoms of stroke [Evidence Level B];
- the probability that the patient is acutely treatable with either intravenous alteplase and/or endovascular thrombectomy (EVT) [Evidence Level B];
- patients are eligible for medical thrombolysis (intravenous alteplase) within 4.5-hours of known or presumed symptom onset [Evidence Level B];
- some patients may be eligible for endovascular treatment when highly selected by neurovascular imaging up to 24-hour from known or presumed symptom onset. Transport time and receiving hospital projected treatment time must be considered when making transport and triage decisions [Evidence Level B];
- the Emergency Department ability to provide acute stroke services within a target 90th percentile for door-to-needle (i.e. arrival to treatment) time of 60 minutes (upper limit) and a target median door-to-needle time of 30 minutes or less [Evidence Level B],
- other acute care needs of the patient [Evidence Level B].
- Patients with suspected stroke should be triaged by EMS personnel as Canadian Triage Acuity Scale (CTAS) Level 2 in most cases and as a CTAS Level 1 for patients with compromised airway, breathing or cardiovascular function [Evidence Level B].
- For pediatric stroke cases, patients with suspected stroke should be triaged by EMS personnel as Pediatric Canadian Triage Acuity Scale (P-CTAS) Level 2 in most cases, and as a P-CTAS Level 1 for patients presenting with severe symptoms or compromised airway, breathing or cardiovascular function [Evidence Level C].
- Pre-notification: While enroute to the receiving hospital with acute stroke services, paramedics should notify the Emergency Department of the incoming suspected acute stroke patient, providing sufficient details such that a “Code Stroke” can be activated at that time [Evidence Level B].
- Information required includes: time of stroke onset or time of symptom recognition or time when last known well (as accurate as possible), total symptom duration at anticipated arrival in the Emergency Department, presenting signs and symptoms of stroke, Glasgow Coma Scale (GCS) score, CTAS triage score (or P-CTAS), patient age, current use of antithrombotic drugs, and expected time of arrival at the receiving hospital. Refer Box 3A for details of information required during pre-notification.
- Patients who are considered ineligible for thrombolytic therapy or endovascular thrombectomy should still be transported urgently (either directly or indirectly) to the closest hospital capable of providing services for the diagnosis and treatment of stroke (Emergency Department, access to neurovascular imaging, stroke unit, and stroke expertise on site or through Telestroke modalities) [Evidence Level C].
3.4 Hospital Arrival and EMS Handover to Emergency Department (ED) Staff
- Transfer of care from paramedics to receiving hospital personnel should occur with minimal delay; patients with suspected hyperacute stroke who are potentially eligible for thrombolytic therapy or endovascular thrombectomy should receive the highest priority in the ED triage queue [Evidence Level B]. Refer to Section 4.1 for more information.
- Paramedics should provide the receiving hospital with the following information on hospital arrival: time of stroke onset or time of symptom recognition or time when last known well (as accurate as possible), total symptom duration at arrival in the ED, Glasgow Coma Scale score (GCS), CTAS triage score (or P-CTAS), patient age, comorbidities, current medications including antithrombotic drugs and medication allergies, and vital signs (including capillary glucose) [Evidence Level C].
- Paramedics should ensure all information noted above is documented on the patient’s emergency medical system record, and provided to the receiving hospital, during pre-notification and upon arrival to the hospital [Evidence Level B].
Clinical Considerations: [New for 2018]
- Direct transport in many regions involves two considerations: (1) patients who may be eligible for intravenous alteplase may be directed to the closest centre (primary/advanced stroke centre or comprehensive stroke centre) and, (2) patients who are determined to be a likely candidate for endovascular thrombectomy may proceed directly to an EVT-enabled comprehensive stroke centre OR to the primary centre first to rapidly receive intravenous alteplase, and then be considered for transport to the EVT-enabled comprehensive stroke centre.
- Screening for potential stroke and likelihood of large vessel occlusion should be done early in the on-scene assessment. If the stroke screen is positive, all actions on-scene from that point should be directed at moving to the ambulance and beginning transport. All treatments not immediately required (IVs, etc.) could be undertaken while the patient is enroute to the hospital or after hospital arrival. Scene time (location of patient at time of stroke) is an important variable that EMS professionals can control and needs to be monitored very closely. Time lost due to inefficient scene care cannot be made up during subsequent transport to hospital, regardless of the use of lights and sirens.
- Pre-notification contact with the receiving Emergency Department should be as soon as possible; where possible, the paramedics and receiving Emergency Department physician or stroke team member should speak enroute.
- The term ‘eligible’ for acute stroke therapies is usually defined within regional jurisdictions. Generally it refers acute stroke patients within the 4.5 hour time window for medical thrombolytic therapy, however local definitions should be clarified during implementation of these recommendations.
- For endovascular thrombectomy, the strongest evidence for benefit exists for treatment received within 6 hours of stroke symptom onset (with or without concurrent medical thrombolytic therapy). However, randomized trial evidence exists to show that highly selected patients may be considered for endovascular thrombectomy based upon neurovascular imaging within a 24 hour window from symptom onset.
- In some stroke centres, the alteplase treatment time window may extend beyond 4.5 hours under the directive of a research or local protocols. These factors should be taken into consideration during transport and agreements should be in place between the provincial/regional EMS system and the receiving hospitals.
- In regions with a specialized pediatric hospital every attempt should be made to transport children with signs of stroke to that specialized pediatric hospital.
The recommendations from this module have been published in International Journal of Stroke by SAGE Publications Ltd. Copyright © 2018 World Stroke Organization.
Hyperacute stroke is a medical emergency and optimizing out-of-hospital care improves patient outcomes. Emergency medical services play a critical role in out-of-hospital (prehospital) assessment and management of suspected stroke patients. Acute interventions such as thrombolytic therapy are time-sensitive and therefore strategies such as re-directing ambulances to stroke centres to facilitate earlier assessment, diagnosis, and treatment may result in better outcomes.
Newer endovascular thrombectomy treatments have with very strong, high-quality evidence that demonstrates patients with disabling ischemic stroke who meet imaging criteria have significant benefits from receiving these therapies. The strongest evidence supports endovascular thrombectomy within 6 hours from stroke symptom onset as a highly beneficial treatment in combination with intravenous thrombolysis (given within 4.5 hours of symptom onset), with numbers needed to treat reported as low as 3 — 4. Endovascular thrombectomy is also beneficial as a sole treatment among those ineligible for intravenous thrombolysis. In addition, a small group of patients may still benefit from endovascular thrombectomy up to 24 hours from symptom onset when selected by neurovascular imaging in the context of a coordinated stroke system, including experts in stroke and neurointerventional care.
- Programs to train all emergency medical services personnel regarding stroke recognition, assessment, management, and transport requirements in the pre-hospital phase of care.
- Paramedic education that includes the recognition of the signs and symptoms of acute stroke, including knowledge of the FAST mnemonic, and the need to provide rapid and appropriate out-of-hospital assessment.
- Ongoing paramedic education on the use of validated pre-hospital stroke screening protocols and tools and the ability to incorporate such protocols and tools into all pre-hospital assessments of suspected stroke patients. The Canadian Stroke Best Practice Recommendations include assessment tools and educational materials in collaboration with emergency medical service leaders for implementation across Canada.
- Ambulance services in all parts of Canada with direct transport protocols and agreements (for bypass or redirect) between emergency medical service providers and regional health authorities and/or receiving hospitals.
- Emergency medical services able to provide coordinated seamless transport (land, water, and air) and care for acute stroke patients.
- Communication systems such as telemedicine to support access to specialized stroke services.
- Protocols and agreements in place to support the transfer of patients with disabling stroke to hospitals that provide advanced acute stroke treatments including endovascular thrombectomy, regardless of geographic location.
- Development of processes in each region that has both adult and pediatric acute services with criteria for transporting children with suspected stroke — based on symptoms and age — to pediatric versus adult stroke centres. These criteria should be agreed upon by both adult and pediatric centres, and EMS.
- Development of processes for EMS that can help support evaluation of whether suspected stroke patients could be transported directly to comprehensive stroke centres that have endovascular thrombectomy services or undergo initial imaging and care at primary stroke centres.
- Time from initial call received by emergency dispatch centre to patient arrival at an Emergency Department that provides stroke services.
- Percentage of (suspected) stroke patients arriving in the ED who were transported by EMS.
- Proportion of acute stroke patients transported by EMS to a stroke enabled hospital (i.e. designated hyperacute stroke treatment centre) as first hospital destination. Target greater than or equal to 90%.
- Proportion of acute stroke patients presenting to the ED as a result of EMS transport versus "walk in". Target greater or equal than 90%.
- Time from initial call received by emergency dispatch centre to EMS arrival on scene.
- Time from EMS arrival on scene to arrival at the receiving ED (ideally at a stroke centre providing acute stroke services).
- Percent of EMS transports of ischemic stroke patients with symptoms less than 4.5 hours, and less than 6 hours, for which the receiving hospital received notification enroute (pre-notification) of an incoming acute stroke patient.
- Percentage of EMS calls where out-of-hospital time is less than 3.5 hours from symptom onset time (or time last known well) to arrival at the ED (performance target is greater or equal to 75 percent).
- Percentage of potential stroke patients transported by EMS who received a final diagnosis of stroke or transient ischemic attack in the ED or at hospital discharge.
- For pediatric stroke patients, the time from initial presentation to any entry point in the healthcare system (such as primary care or pediatrician office, Emergency Department) with symptoms of stroke to a confirmed diagnosis of stroke is received.
- Emergency department records and administrative databases track stroke patients who arrive by ambulance (land, air, or water) as a standard data element.
- ”Appropriate” Emergency Department refers to an Emergency Department that has access to a CT scanner in the facility, provides access to acute thrombolysis, and has medical personnel with stroke expertise available for emergent consult.
- Appropriate” Emergency Department may also refer to Emergency Departments in stroke centres that have access to endovascular thrombectomy.
- An appropriate/acceptable ‘over-triage’ rate should be less than 15% - i.e., false positive stroke determinations. (Indicator 9).
- Refer to Section 3.1 for more information.
Health Care Provider Information
- Canadian Triage Acuity Scale for adults (CTAS) and Pediatric Scale (P-CTAS)
- Canadian Stroke Best Practice Recommendations Acute Stroke Management Module: Appendix Two: Standardized Acute Stroke Out-of-Hospital Diagnostic Screening Tools
- FAST Signs of Stroke
Patients arriving to hospital using EMS (emergency medical services) following a stroke experience fewer delays in receiving appropriate diagnostic tests (e.g. brain imaging) and are more likely to receive t-PA, if eligible. Patients are also more likely to receive timely transportation and care when pre-notification systems, including the use of trained EMS dispatchers, are adopted. Watkins et al. (2013) reported that the percentage of patients whose final diagnosis was stroke increased significantly (63% to 80%, p<0.01) after EMS dispatchers completed training, aimed at improving their ability to detect suspected stroke patients. In a study that included 27,566 patients who were identified as suspected stroke patients by dispatchers, the mean times associated with transportation, including time to scene, time at scene, time from scene to destination and total transportation time were all significantly reduced, compared to persons whose final diagnosis was stroke, but who were not identified by dispatchers (Caceres et al. 2013). Berglund et al. (2012) reported that patients in the Hyper Acute STroke Alarm (HASTA) Study assigned an upgraded priority level by dispatching personnel experienced fewer delays along the chain of stroke care from symptom onset to arrival at a stroke unit and were more likely to be treated with t-PA compared with patients who had been assigned to a standard-priority level by the emergency medical communications centre. Patients classified as Priority Level 1 received thrombolysis more often than those classified as priority level 2 (24% vs. 10%, p<0.001) and a greater number arrived at the stroke unit within 3 hours of symptom onset (61% vs. 46%, p=0.008).
Hospital pre-notification typically involves informing emergency department physicians and other relevant personnel (blood and EKG technicians, radiologists and pharmacologists) of the arrival of a potential stroke patient. The results from several studies indicate that the process indicator associated with thrombolysis treatment may be shortened for patients arriving to hospitals by EMS with prenotification protocols. Lin et al. (2012) included data from 371,988 acute ischemic stroke patients from the Get with the Guidelines database and reported that among patients transported to hospital using EMS pre-notification, they had significantly shorter door-to-imaging time (26 vs 31 mins, p<0.001), door-to-needle time (78 vs 81 mins, p<0.001), and stroke onset-to-needle time (141 vs 145 mins, p<0.001). Furthermore, of those who arrived at hospital within 2 hours of stroke onset, patients with a pre-notification were significantly more likely than those without to receive t-PA within 3 hours of stroke onset (73% vs 64%, p<0.001). In another US study based on registry data (Patel et al. 2011), of 13,894 patients who whose discharge diagnosis was stroke, patients arriving by EMS with hospital pre-notification were more likely to have brain imaging completed within 25 min (RR= 3.0, 95% CI 2.1-4.1) and to have the results interpreted within 45 min (RR= 2.7, 95% CI 2.3-3.3) compared to arriving by private transport. Patients eligible for t-PA were more likely to receive it if arriving by EMS with pre-notification (RR=1.5, 95% CI 1.1-1.9). Dalloz et al. (2012) included the results from 10 studies in a systematic review examining the use of pre-hospital stroke codes. A stroke code system was defined as efforts to improve the identification, transport and presentation of suspected stroke patients to the emergency department. The odds of treatment with thrombolysis were highest in settings that had a pre-hospital stroke code system in place compared with facilities with no stroke code (OR= 5.43, 95% CI: 3.84-7.73, p<0.001), and were lower in studies comparing pre-hospital stroke code with in-hospital stroke codes (OR=1.97, 95% CI: 1.53-2.54, p<0.001).
In the last several years, as endovascular techniques are becoming more widely available, several on-scene screening tools to identify patients with large vessel occlusions (LVO), designed for use by EMS technicians, have emerged. Examples of these scales include Field Assessment Stroke Triage for Emergency Destination (FAST-ED) (Lima et al. 2016), Vision, Aphasia, and Neglect (VAN) (Taleb et al. 2016), the Prehospital Acute Stroke Severity Scale (PASS) (Hastrup et al. 2016), Cincinnati Prehospital Stroke Severity Scale (CPSSS) (Katz et al. 2015), and The Los Angeles Motor Scale (LAMS) (Nazliel et al. 2008). Most of these scales are based on 3-6 selected items from the National Institutes of Health Stroke Scale. The sensitivities and specificities associated with these scales range from 61% to 100% and 40% to 92%, respectively. Smith et al. (2018) included the results from 36 studies evaluating the accuracy of LVO prediction scales in patients with suspected stroke or presumed acute ischemic stroke in pre-hospital or emergency department settings. The authors concluded that no scale had both high sensitivity and specificity to determine the presence vs. absence of LVO, and that in clinical practice that the probability of LVO given a negative test could still be ≥10%.
The use of mobile stroke units, ambulances which are equipped with specialized equipment, such as on-site laboratories and CT scanners, and are staffed with additional personnel with stroke expertise, are now appearing in some large, urban cities. Their feasible and effectiveness are the subjects of ongoing investigation. Kunz et al. (2016) compared the outcomes of patients who received thrombolysis therapy using the mobile stroke unit, STEMO from 2011-2015 with patients who received thrombolysis, but arrived at hospital via traditional emergency medical services. A significantly higher proportion of patients in the STEMO group were treated ≤ 90 minutes of stroke (62% vs. 35%, p<0.0005) and were living without severe disability at 3 months (83% vs. 74%, p=0.004). The 3-month mortality was also significantly lower in the STEMO group (6% vs. 10%, p=0.022). However, there was no significant difference in the primary outcome, the number of patients who achieved an excellent outcome (mRS 0-1) at 3 months (53% STEMO vs. 47% conventional, p=0.14). There were no significant differences in the safety outcomes between the 2 groups (sICH 3% vs. 5%, p=0.27 and 7-day mortality 2% vs. 4%, p=0.23). Adjusting for baseline characteristics, STEMO was an independent predictor of living without severe disability at 3 months (OR=1.86, 95% CI 1.20-2.88, p=0.006), but not for the primary outcome (OR=1.40, 95% CI 1.00-1.97, p=0.052). In an earlier study examining the use of STEMO, (Ebinger et al. 2014), among patients for whom STEMO was deployed, the mean alarm-to-treatment time for patients who received thrombolysis was reduced by 25 minutes, compared with control weeks. Of the eligible patients, t-PA was used in 32.6% of STEMO deployment cases, 29% during STEMO weeks, and 21.1% during control weeks.