PREHOSPITAL MANAGEMENT OF ACUTE STROKE

Because fast recognition and treatment of a stroke can reduce the possibility of death and long-term disabilities, the American Heart Association developed the “Stroke Chain of Survival.” This chain involves eight links or steps that should be taken by patients, family members, and prehospital and emergency room personnel in caring for stroke patients. This approach can be an effective way to make certain that appropriate care is delivered as rapidly as possible, increasing the odds for a full recovery. The eight links include:

1. Detection: Rapid recognition of stroke symptoms
2. Dispatch: Early activation and dispatch of EMS
3. Delivery: Rapid EMS identification, management, and transport
4. Door: Transport to stroke center within three hours of symptom onset
5. Data: Rapid triage, evaluation, and management in emergency department (ED)
6. Decision: Stroke expertise and therapy selection
7. Drug/device: Fibrinolytic therapy, intra-arterial strategies
8. Disposition: Rapid admission to the stroke unit or critical care unit

Prehospital management of acute stroke involves the first three links of the chain: detection, dispatch, and delivery (NHCPS, 2022).

The Role of Patients and Bystanders

The role of patients and bystanders involves the first two links in the stroke chain of survival:

1. Detection: Recognizing a stroke
2. Dispatch: Responding by calling 911

RECOGNIZING A POTENTIAL STROKE

Recognizing that a stroke may be taking place is the first step in caring for the patient, so public education and information is required in order to increase recognition of potential strokes. This information should include the following symptoms:

• Sudden numbness or weakness of face, arm, or leg, especially on one side of the body
• Sudden confusion or trouble speaking or understanding
• Sudden trouble seeing in one or both eyes
• Sudden trouble walking, dizziness, loss of balance or coordination
• Sudden severe headache with no known cause
  (NINDS, 2022a)

RESPONDING BY CALLING 911

People often wonder what first aid to give to a stroke victim. The best first aid is professional transport to a hospital, and bringing an emergency medical service (EMS) team to the patient is the most important action to take for a stroke victim.

In an emergency, people often believe that time is being lost by waiting for an EMS team to arrive, and so family members or bystanders often hurriedly drive patients to the hospital. In fact, patients usually get to the appropriate hospital more quickly if they use the EMS system by calling 911. EMS teams are trained to choose the most appropriate hospital in the region, which may not be the closest hospital. In addition, the care and assessment that an EMS team provides a stroke victim shortens the time lag between the onset of stroke symptoms and the evaluation and treatment of the stroke.

When calling 911, it is important to:

• Provide the emergency dispatch operator with the location of the emergency.
• If calling from a cell phone, provide the operator with the wireless phone number so the emergency operator can call back in case the call gets disconnected.
• Remember that many emergency operators currently lack the technical capability to receive texts, photos, and videos.
• Learn and use the state’s designated number for highway accidents or other non-life-threatening incidents.

The Role of Emergency Response

EMS DISPATCHERS (PUBLIC SAFETY TELECOMMUNICATORS)

The role of EMS dispatchers (911 operators) also involves the first two links in the stroke chain of survival:

1. Detection: Identifying a possible stroke
2. Dispatch: Responding with speed to bring EMS to the patient

Dispatchers play a key role in the diagnosis of stroke. EMS dispatchers are the first medical contact the patient has. Their job is to interrogate the caller about the presence or absence of priority symptoms. EMS dispatchers have these responsibilities:

• Identifying the presenting problem
• Choosing, notifying, and sending the team of responders that is appropriate for each emergency
• Advising the callers on possible first aid for the patient
• Getting critical background information about the patient
  (Everitt & Raczek, 2020)

Identifying the Problem

Without ever seeing the patient, dispatchers are tasked with identifying the complaint, triaging the patient’s severity, and providing prearrival instructions to callers.

Once the nature and location of the emergency has been confirmed, the dispatcher’s responsibility turns to identifying the chief complaint, age, level of consciousness, and breathing status of the patient.

Stroke is difficult to identify over the phone, as callers often use vague terms to describe symptoms. Despite the challenges, however, EMS dispatchers are able to correctly identify strokes with surprising accuracy. The dispatcher will interrogate callers for time of symptom onset, rule out common stroke mimics (e.g., hypoglycemia), gather important previous medical history (e.g., prior strokes), and discover pertinent medications (e.g., antiplatelet agents or anticoagulants), thereby helping responders make improved triage and transport decisions.

With a few key questions, EMS dispatchers can respond by alerting an EMS team and shorten time-critical response. Using a stroke diagnostic tool, such as BE FAST (see below), the dispatcher will ask the patient (or ask the caller to ask the patient) to:

• Smile to check for facial drooping
• Raise both arms to check for weakness or paralysis on either side
• Repeat a simple phrase such as “the early bird catches the worm” to hear if speech is unusual

Patients are scored based on their response. If the score is high, it is more likely the person is having a stroke (Everitt & Raczek, 2020).

The time “last known normal” (LKN) must be established, with the goal of determining time of symptom onset. This information becomes critical due to time constraints around treatment. It is best obtained from the patient, if possible, but family, friends, and bystanders may have information to contribute. LKN is the time when the person was last known to be at baseline. It should not be interpreted as the time the patient was found with symptoms, as the onset of brain ischemia may have started before symptoms were recognized (AHA, 2021c).

Prehospital Triage Factors

EMS dispatchers decide what type of response is appropriate for each emergency. They choose:

• The skill level and equipment of the EMS response team: basic life support (BLS) or advanced life support (ALS)
• The type of vehicle to send
• The initial speed requirement (e.g., sirens, flashing lights, etc.)

Prehospital triage factors for acute stroke includes:

• Symptom onset
• Patient stability
• Distance to stroke-capable facility
• Run times
• Stroke designation tiers
• Comprehensive Stroke Centers (CSC)
• Thrombectomy-capable Stroke Center (TCS)
• Primary Stroke Center (PSC)
• Acute Stroke Ready Hospital (ASRH)
• Availability of services
• Mobile Stroke Unit (MSU)
• Ground transport
• Air transport
• Public versus private EMS
• Patient preference

Acute strokes are given a priority dispatch requiring the same level of emergency treatment as heart attacks and trauma. When patients having a stroke are more than one hour’s travel time by ambulance from a hospital that is equipped to treat acute strokes, then air transport should be considered (AHA, 2021c).

Advising on Possible First Aid

From the time the call is dispatched to the time the first unit arrives on scene, the EMS dispatcher plays an important role in providing prearrival instructions (PAI). These are a set of medically approved, standardized, and protocolized instructions given to a layperson by the dispatcher.

The dispatcher offers prearrival instructions, which can include:

• If the caller is the patient, instruct them to lie down.
• If the person is unconscious, provide instructions on airway control.
• Keep the person calm and reassure them that help is on the way.
• Do not allow the person to move around.
• If the person is having difficulty breathing, keep the neck straight and remove pillows.
• Do not give the person anything to eat or drink.
• Gather the person’s medications (if any).
• Unlock the doors to allow EMS quick entry.
• If anything changes or the person’s condition worsens, call back immediately.
  (ADH, n.d.)

Collecting Critical Information

When an EMS operator suspects that a call concerns an individual experiencing a stroke, the operator also begins collecting critical background information. Dispatchers make a special effort to get an estimate of the elapsed time since any potential stroke symptoms first appeared and to collect as much relevant data as possible, including:

• Past medical or surgical history
• Past history of a stroke
• Recent trauma or injury
• History of diabetes
• Recent seizure activity
• Recent severe headache
• Time the person was last known to be without any symptoms of stroke (LKW)
• Medications the person is currently taking
  (ADH, n.d.)

EMS RESPONDERS

The links in the stroke chain of survival that EMS responders are concerned with include:

• 1. Detection: Rapid EMS confirmation of a possible stroke
• 3. Delivery: Rapid management and transport
• 4. Door: Appropriate triage to a stroke center or high-acuity area facility

EMS best practice states that “time loss is brain loss,” and most patients who call EMS with symptoms of stroke are those who are within three hours of symptom onset. Stroke should be a priority dispatch with prompt EMS response (Jauch, 2022).

Confirming a Possible Stroke

A prehospital stroke assessment is completed using an assessment tool. The tool most commonly used is the Cincinnati Prehospital Stroke Scale (CPSS) (see below), a simple three-item scale based on the National Institutes of Health Stroke Scale and designed specifically for use by EMS. Another tool, the Los Angeles Prehospital Stroke Screen (LAPSS), comprises multiple elements, including the history, blood glucose, and specific physical findings (ASA, 2022e).

Determining Stroke Severity

When a potential stroke has been confirmed, a stroke severity tool is utilized to differentiate a patient with large vessel occlusion from one without. This distinction is critical for EMS when determining the best destination hospital. Such assessment tools include:

• RACE (Rapid Arterial Occlusion Evaluation Scale)
• FAST-ED (Field Assessment Stroke Triage for Emergency Destination)

First responders and emergency personnel can also access a mobile application (app) to assess the severity of the stroke using one of several stroke scales. These scales measure certain physical indicators, which may include the ability to squeeze and release a hand, control eye movement, make facial expressions, feel a pin prick, and more. Based on results from the stroke scale, the app recommends the type of facility where a stroke patient can receive appropriate treatment (SNIS, 2022).

Collecting Critical Background Information

Regardless of the information provided to the responders that has been collected by the dispatcher, EMS responders attempt to collect other essential information about the patient. The history is direct and focused to prevent delaying transport. A baseline neurologic assessment and a medication list with a focus on anticoagulation is obtained, and it is determined if the patient has significant prestroke disability or any comorbid conditions that may impact treatment decision (e.g., recent surgery).

It is critically important to determine when the patient was last known well (LKW), since time is important in determining treatment. A patient who woke up with new symptoms should be considered LKW at the last time he or she was seen awake, even if that was the evening prior.

Because time is of the essence, responders also gather telephone numbers of relatives and witnesses. If knowledgeable acquaintances are available, they are asked to meet responders at the receiving hospital, or if necessary, to travel with responders. For emergency treatments, it is helpful if next of kin are immediately available for consent (ASA, 2022e).

Transport and Delivery

One of the most important components of stroke care, advance notification to the receiving hospital is provided by EMS as soon as possible in the case of a potential stroke patient. This prenotification allows the receiving institution to activate local protocols, ready necessary medications, prepare and hold the brain imaging facilities, and prepare to assess the patient upon arrival (ASA, 2022e).

Additional Care En Route

Instructions for care en route can include:

• Assess and reassess ABCs. Do not treat hypertension unless directed by medical command.
• Perform cardiac monitoring. Do not delay transport to obtain a 12-lead ECG.
• Provide oxygen at 4 liters/min per nasal cannula to maintain oxygen saturation of 94%–99%. Routine oxygen administration is not indicated.
• Perform blood glucose assessment. Treat if less than 60 mg/dL. Do not treat with oral medication. Maintain strict NPO.
• Establish IV access, at least one in each antecubital fossa. Do not administer excess fluid or glucose.
  (ASA, 2022e; HCPS, 2021)