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Section 3.2

EMS Management Of Acute Stroke

NOTES on this recommendation

  • This recommendation covers management of potential stroke patients between the time of first contact with the local emergency medical services 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 emergency medical services.
  • This recommendation is directed to paramedics and those individuals who support emergency medical services, 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

* local variations need to be taken into consideration for pre-hospital time

Patients who show signs and symptoms of hyperacute stroke must be treated as a time-sensitive emergency and should be transported without delay to the closest institution that provides emergency stroke care [Evidence Level C].

  1. Immediate contact with emergency medical services (e.g., 911) by patients or other members of the public is strongly recommended because it reduces time to treatment for acute stroke [Evidence Level B].
  2. The emergency medical services system must be set up to categorize patients exhibiting signs and symptoms of a hyperacute stroke as a high priority [Evidence Level C].206
  3. Paramedics should use a standardized acute stroke out-of-hospital diagnostic screening tool [Evidence Level B].
  4. Out-of-hospital patient management should be optimized to meet the needs of suspected acute stroke patients [Evidence Level A].
  5. Direct Transport Protocols must be in place to facilitate the transfer of eligible patients to the closest and most appropriate facility providing acute stroke care [Evidence Level C].
  6. Direct Transport Protocol criteria must be based on (1) the local emergency department performance which is recommended as being 60 minutes or less; (2) the pre-hospital phase, including symptom duration and anticipated transport time, being 3.5 hours or less; and (3) other acute care needs of the patient [Evidence Level B].
  7. Paramedics should obtain a history of the stroke event, including time of onset, signs and symptoms, and previous medical and drug history from the patient if able or informant when available [Evidence Level C].
  8. Paramedics must notify the receiving facility of a suspected acute stroke patient so the facility may prepare for patient arrival [Evidence Level C].
  9. Transfer of care from paramedics to receiving facility personnel must occur without delay [Evidence Level C].
  10. Patients who are considered ineligible for time-sensitive thrombolytic therapy should be transported to the closest emergency department which provides access to neuroimaging and stroke expertise for assessment and initiation of secondary prevention management [Evidence Level C].
    Rationale

    Acute 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 (pre-hospital) assessment and management of suspected stroke patients. Acute interventions such as thrombolytic therapy are time-sensitive and therefore strategies such as re-directing

    System Implications
    • Programs to train all emergency medical services personnel regarding stroke 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 and the need to provide appropriate out-of-hospital treatment.
    • Paramedic education on the use of validated and rapid 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 Strategy has developed assessment tools in collaboration with emergency medical service leaders for implementation across Canada.
    • Direct transport agreements (bypass or redirect) between emergency medical service providers and regional health authorities and/or receiving facilities.
    • Emergency medical service providers who are 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.
    Performance Measures
    1. Time from initial call received by emergency dispatch centre to patient arrival at an emergency department that provides stroke services.
    2. Percentage of (suspected) stroke patients arriving in the emergency department who were transported by emergency medical services.
    3. Time from initial call received by emergency dispatch centre to emergency medical services arrival on scene.
    4. Time from emergency medical services arrival on scene to appropriate emergency department arrival.
    5. Percentage of cases where out-of-hospital time is less than 3.5 hours from symptom onset to arrival at the emergency department (performance target is ³ 75 percent).
    6. Percentage of potential stroke patients transported by emergency medical services who received a final diagnosis of stroke or transient ischemic attack in the emergency department or as an inpatient.

    Measurement Notes

    Implementation Resources and Knowledge Transfer Tools
    Summary of the Evidence

    The evidence available to support training and appropriate processes for emergency medical services in the transport of stroke patients is underdeveloped at this time. However, several other recommendations presented in the Canadian Best Practices Recommendations for Stroke Care (2010) are dependent on and/or emphasize the need for rapid transport of potential stroke patients to an appropriate acute care facility. For example, interventions such as acute thrombolysis are time-sensitive and require a coordinated system of care in order to maximize access and eligibility to these therapies.207

    Prehospital delays in the treatment of stroke patients, including identification of stroke as a medical emergency, represent a significant and preventable obstacle to optimal stroke care.208 Patient delays in seeking care are the greatest barrier to expedient treatment following a stroke event; however, delays often also exist in the identification, transport, and triage of stroke patients. Emergency health services and service providers are a critical participant in systems of care for stroke.209 Crocco cites the appropriate training of emergency medical service personnel as an essential component of community-wide, coordinated stroke care.208 In addition, emergency physicians must be engaged in the effort to limit delays if the rates of patients eligible for thrombolytic therapy are to improve.

    The Emergency Medical Services Chiefs of Canada recommended 11 key policy points that can be enacted by EMS to improve services in Canada.210 The areas addressed in their report include: Clear Core Identity; Stable Funding; Systematic Improvement; emergency medical services systems should demonstrate high accountability and transparency for quality emergency medical services; Personnel Development; National Occupational Competency Profile, Leadership Support; Mobilized Health Care; emergency medical services leaders should pursue opportunities to provide enhanced types and levels of healthcare including public health and safety education, emergency response preparedness, disaster management, and pandemic response capability in order to respond to community-defined scopes of practice. All aspects of these policy issues are relevant to stroke care and will require strong advocacy to be fully implemented.

    The American Stroke Association/ American Heart Association expert panel on Emergency Medical Services Systems and the Stroke Council issued a policy statement in 2007 regarding implementation strategies for emergency medical services within stroke systems of care). 206,211 Prehospital delays in the treatment of stroke patients, including identification of stroke as a medical emergency, represent a significant and preventable obstacle to optimal stroke care. Although patient delay in seeking care represents the greatest barrier to expedient care, delays often exist in the identification, transport, and triage of stroke patients. Public education in recognizing stroke symptoms as warranting immediate care and appropriate training of emergency medical service personnel are essential parts of community-wide, coordinated stroke care. In addition, emergency physicians must be engaged in the effort to limit delays if the rates of patients eligible for thrombolytic therapy are to improve.

    The use of a standardized stroke diagnostic screening tool by emergency medical service responders has been recommended to increase sensitivity of identifying potential stroke patients on scene, especially those who may be candidates for time-sensitive interventions. The Cincinnati Prehospital Stroke Scale (CPSS) is a three-item scale based on a simplification of the National Institutes of Health (NIH) Stroke Scale.212 It uses the mnemonic, FAST (“Face”, “Arm”, “Speech”, “Time”), for rapid identification of stroke and transient ischemic attacks. When performed by a physician, it has a high sensitivity and specificity in identifying patients with stroke who are candidates for thrombolysis. In a validation study of this tool with emergency medical service responders, a total of 860 scales were completed on a convenience sample of 171 patients from the emergency department and neurology inpatient service. Of these patients, 49 had a diagnosis of stroke or transient ischemic attack. High reproducibility was observed among prehospital providers for total score (intraclass correlation coefficient [rI], .89; 95% confidence interval [CI], .87 to.92) and for each scale item: arm weakness, speech, and facial droop (.91, .84, and.75, respectively). There was excellent intraclass correlation between the physician and the prehospital providers for total score (rI, .92; 95% CI, .89 to.93) and for the specific items of the scale (.91, .87, and.78, respectively). This scale was found to have good validity in identifying patients with stroke who are candidates for thrombolytic therapy, especially those with anterior circulation stroke.

    The Los Angeles Prehospital Stroke Screen (LAPSS) is a one-page instrument designed to allow prehospital personnel to rapidly identify acute stroke patients in the field.213 A prospective, in-the-field validation study

    of the LAPSS was conducted by assigning Paramedics to three University of California at Los Angeles-based advanced life support units were trained and certified in use of the LAPSS. Over seven months, paramedics completed the LAPSS on noncomatose, nontrauma patients with complaints suggestive of neurological disease. LAPSS form stroke identification results were compared with emergency department and final hospital discharge diagnoses. LAPSS forms were completed on 206 patients. Paramedic performance when completing the LAPSS demonstrated sensitivity of 91 percent (95% CI, 76% to 98%), specificity of 97 percent (95% CI, 93% to 99%), positive predictive value of 86% (95% CI, 70% to 95%), and negative predictive value of 98 percent (95% CI, 95% to 99%). With correction for the four documentation errors, positive predictive value increased to 97 percent (95% CI, 84% to 99%). 213

    The predictive value of the Ontario Pre-Hospital Stroke Screening Tool was determined in a retrospective study at a large Canadian regional stroke centre.214 Consecutive patient charts were reviewed over a 12-month period following implementation of the tool and were compared with those for the 12-month period prior to implementation. Final diagnoses, treatments, and outcomes were abstracted from a provincial registry, including rates of thrombolysis. Three hundred twenty-five patients were triaged under the emergency medical services (EMS) acute stroke protocol over the study period. The PPV of the screening tool was 89.5 percent (95% confidence interval [CI]: 85.7–92.7%) for acute stroke. Thirty-four patients (11%) had nonstroke conditions, with the most common being seizure (four percent). The rate of administration of tissue plasminogen activator (tPA) for all patients with suspected stroke increased from 5.9 percent to 10.1 percent (p = 0.04) compared with the rate in the 12-month period prior to implementation of the acute stroke protocol. The tPA rate for patients arriving under the stroke protocol was 17.2 percent. Most patients (75%) receiving tPA arrived from outside the hospital catchment area. In this preliminary study, the Ontario Prehospital Stroke Screening Tool had a high PPV for acute stroke and appeared to be effective for identifying patients who required triage to a single regional stroke center.