Acute Ischemic Stroke - Prehospital Management

Introduction:

An acute ischemic stroke is also called a cerebrovascular accident. A stroke causes impairment of the brain. A stroke is an episode of brain dysfunction for more than 24 hours. It can be of two types, ischemic, which occurs due to low blood supply, and hemorrhagic, which occurs due to leaked blood vessels. An ischemic stroke is due to aggregation of platelets (blood clots)blood clot and a hemorrhagic stroke occurs due to a crack or leak in the blood vessels in the brain. Males are more affected than females. Any treatment for stroke should be started as early as possible because brain cells die quickly after a stroke. A concept called ‘time is brain’ is based on the quick diagnosis and treatment of stroke.

What Is an Acute Ischemic Stroke?

An acute ischemic stroke occurs when the blood vessels which supply blood and nutrients to the brain get hindered (blocked) by aggregation of platelets (blood clots). It starts with less flow of blood to a single area of the brain, and the core part is called an area of infarction where the death of tissues occurs. Surrounding tissues are called penumbra, which can be treated with early reperfusion. Energy is lost due to the increased use of adenosine triphosphate (ATP), causing ionic imbalance, therefore causing cell death due to necrosis.

What Conditions Can Give Rise to Acute Ischemic Stroke?

The causes of acute ischemic stroke are:

Defects in large vessels (intracranial arteries such as the circle of Willis along with its branches and extracranial arteries such as internal carotid, common carotid, and vertebral):

• Atherosclerosis (a condition that occurs due to increased build-up of plaque in the walls of blood vessels).

• Artery-to-artery embolism (a clot that comes from other parts of the body).

• Arterial dissection (tear in the artery).

Defects in small vessels include:

• Lipohyalinosis (thickening of hyaline in the blood vessels).

• Microatheromas (blood vessel lesions in the brain tissue).

Cardioembolism such as:

• Valvular heart disease (defect in the valve of the heart)

• Cardiomyopathy (defect in the muscle of the heart).

• Arrhythmia (irregular heartbeat).

• Bioprosthetic and mechanical heart valves.

What Are the Risk Factors for Acute Ischemic Stroke?

The risk factors for acute ischemic stroke are:

• Advancing age.

• Diabetes (a metabolic disorder in which blood sugar levels are increased).

• Hypertension (increased blood pressure).

• Hyperlipidemia (increased fat content in the blood).

• Arrhythmia.

• COVID-19 infection.

• Heart diseases such as heart infections or irregular heart rates.

• Smoking cigarette.

• Secondhand smoke exposure.

• Obstructive sleep apnea (sleep-related breathing disorder).

• Physical inactivity.

• Heavy intake of alcohol.

• Intake of illegal drugs such as Methamphetamine and Cocaine.

• Family history of stroke.

• Use of birth control pills.

What Are the Symptoms of Stroke?

The symptoms of stroke include:

• Trouble speaking.

• Unable to concentrate.

• Paralysis of the face, leg, or arm mostly affects one side of the body.

• Problems in vision such as blurry, double vision, or blackened vision.

• Severe headache.

• Dizziness.

• Altered consciousness.

• Vomiting.

• Trouble walking.

• Unable to balance the body.

• Loss of coordination.

What Is the Prehospital Management of Acute Ischemic Stroke?

The prehospital phase is the time from the onset of the stroke up to admission to the hospital. During this phase, the instructions should be short and should document the patient’s history, time of onset of stroke, history of medication, associated diseases, and surgical interventions. The prehospital management includes:

The ambulance staff, along with the primary care staff, should recognize stroke patients as early as possible by identifying symptoms such as paralysis, dizziness, loss of alertness, visual, speech, balance, and sensory impairments. The patient’s members should be asked for the onset of the symptoms because less time of onset has a high benefit from therapy and requires an urgent need for the treatment.

The emergency staff should identify the onset of signs and symptoms along with the development, which should look for improvement, stable or worsening of symptoms.

The emergency care includes:

• Stabilizing the vital functions and also securing them, which includes airway, breathing, and circulation (ABC). In addition to these, capillary oxygen saturation and blood sugar should be tested.

• History of the onset of the symptoms, along with its development and previous diseases, should be documented.

• The upper body should be elevated.

Standard stroke screening is available, which can be used by non-medical staff but has a false-negative rate of about five percent. A screening test called the FAST test (face–arm–speech–test) is used, which has 95 percent of sensitivity. The FAST test includes:

• Facial - whether both sides are symmetrical or not? And Is it paralyzed?

• Arm Drift - whether both arms drift symmetrical or not?

• Speech - speech is slurred or not?

• Talking - using wrong words or being silent?

If any of these are pathological, then the patient is likely having a stroke.

1. A thrombolysis (removal of the clot) procedure should be initiated. Early management includes within six hours of the onset of symptoms. But the contraindications of this procedure should be evaluated, which include:

• Any known coagulation disorders.

• Previous hemorrhagic events.

• Currently on any anticoagulant therapy.

• Invasive procedures in the last month.

• Any Surgeries in the previous last three months.

• Malignant disorders.

2. A peripheral venous catheter (a flexible tube inserted in a vein) is given to all patients to provide intravenous fluids, drugs, or blood transfusion. The catheter should not be inserted in the paralyzed arm.

3. In case of hypoxemia (decreased oxygen levels in the blood and less than 95 percent of peripheral oxygen saturation), four-liter per minute of nasal oxygen should be given.

4. In case of blood pressure of more than 220 mm Hg (millimeters of mercury) systolic blood pressure or 120 mm Hg diastolic blood pressure, should receive Urapidil 10 to 12.5 mg IV (intravenously) , or Metoprolol in 5 to 10 mg steps IV.

5. In case of hypoglycemia (decreased blood sugar levels) of less than 60 mg/dL (milligrams per deciliter), 30 mL (milliliter) 20 to 40 percent glucose IV is given.

6. In case of hyperglycemia (increased blood sugar levels) of more than 200 mg/dl, adequate intake of liquid is recommended.

7. In the case of arterial hypertension less than 120 mm Hg and no signs of heart failure, NaCl 0.9 percent IV or 500 mL electrolyte solution is given.

8. Unless the diagnosis is made, whether it is an ischemic or hemorrhagic stroke through cerebral imaging, antithrombotic or platelet aggregation inhibitors such as aspirin lysine IV and heparin should not be given.

9. In case of associated illnesses such as heart failure, aspiration, or respiratory insufficiency, individual treatment based on severity should be given.

10. The emergency team should hand over the information gathered about the prehospital management to the hospital team.

Conclusion:

Acute ischemic stroke is a serious condition that requires immediate care. A successful outcome is possible if the prehospital phase is well-managed and well-structured. The main goal should involve minimizing the time between the stroke and admission to the hospital.