What is a Stroke?

A stroke or cerebrovascular accident (CVA) is caused by a disruption to the circulation (blood supply) to the brain. The onset and persistence of the resulting injury to the brain and nervous system (neurologic system) depends on where the disruption of circulation has occurred. It is important to understand that the disruption of blood supply to the brain can alter different areas of brain function, even though there is no direct damage.

When the circulation to a part of the brain stops, the brain tissue is permanently damaged, and the brain cells die. If the blood supply has been blocked by a blood clot in a blood vessel it is called an ‘Ischaemic stroke’ (often more than 70% of people have this type of stroke), and when there has been bleeding from an artery or vein it is called a ‘Haemorrhagic stroke’ (associated with a greater likelihood of a patient dying).

The Brain

The brain is located between the skull and face bones and is attached to the spinal cord via the brainstem. The brain has many complex functions and is central to the functioning of body organs, nervous system and hormones. The brain has 4 main arteries that supply it, the right and left carotid arteries and right and left vertebral arteries. The brain is surrounded by layers or membranes that support the brain and moves blood and cerebrospinal fluid (the fluid produced in the spinal column to help with lubrication and suspending the brain to diminish any shocks from movement). All parts of the brain are at risk of being affected by a stroke. .

When someone has a ‘Stroke’ or CVA, it can mean there has been a blood clot in one of the arteries preventing blood supply to the brain, or a bleed into the brain from a damaged artery or vein. The cause of a CVA will determine the treatment. The cause is also important when looking at the possible outcomes and prognosis of the patient. The brain is a very complex organ and it is not always possible for medical and nursing staff to give a definite answer to your questions of what the outcome will be at the time of an injury.

What are the symptoms of a Stroke?

There are many possible symptoms following a stroke and it depends which area has been affected by the stroke. Some of the symptoms include:

• Loss of consciousness or change to how a person responds
• Changes to speech, vision, movement and sensation
• Aphasia – not being able to talk because there are problems recognising what others are saying or problems expressing what they want to say
• Dysphasia – problems talking and pronouncing words
• Problems may appear in recognising people, reading words, common sounds, or a familiar touch. Ability to write, gesture, and express emotions can also be affected

What tests are done?

• Computerised tomography scan (CT scan) – An x-ray which is taken in a machine which moves around the head /body to scan the tissues. The scan assists in identifying abnormal tissue changes
• Angiogram – A procedure where a catheter is inserted into an artery and guided into a blood vessel which supplies the brain and an x ray sensitive liquid is injected into the brain to review the blood vessels.
• Magnetic Resonance Imaging (MRI) – A MRI is a test which provides pictures of tissues by recognising different water density in body structures, and can identify specific changes in the brain from detailed images.
• Intracranial Pressure (ICP) monitoring – A catheter which is inserted into the brain to measure the pressure in the brain

What are the treatment options?

When there is a blood clot, there may be little or no blood supply to the brain beyond the blockage and this means the brain cells are starved of oxygen and nutrients and waste products build up in the brain cells. The initial reduction in blood supply causes the cells to stop functioning adequately and is called ischaemia of the brain. After a time of no blood supply, the cells die, and this is called infarction of the brain. The larger the area affected, the greater the number of brain areas involved. There are different medications which may be effective in treating a blood clot but this is individual to each patient.

When there is bleeding, the wall of the blood vessel is damaged and so blood leaks into the surrounding brain tissue where there is normally no blood. This blood forms a clot and begins to compress and destroy local brain tissue.
This places pressure on the surrounding cells and the blood supply to these areas are also affected because the blood supply is prevented from getting to the cells and they start to die. Sometimes surgery is indicated when a blood vessel is bleeding into the brain if it is likely to be stopped. Other times, the bleeding is too extensive to operate.

What happens in ICU?

• Monitoring of the heart rate, blood pressure, oxygen saturation and temperature. This will be seen on a bedside monitor
• If the patient has a head injury they may have monitoring of the pressure in their brain (ICP monitoring)
• An arterial line may be inserted to monitor blood pressure and to take blood samples
• Medication and intravenous fluids may be given via an intravenous cannula or a central venous catheter
• If a patient is unconscious, or cannot breathe or swallow properly, an endotracheal tube will be inserted and they will be mechanically ventilated. Some patients who need to be ventilated for more than a week or two will have a tracheostomy tube inserted. The ventilated patient will require suctioning to remove secretions from the lungs and airways
• If a patient is unable to eat, nutrition will be given via a nasogastric tube. This is a tube that is placed in the nose and goes down the throat into the stomach. Fluid can also be removed from the stomach via the nasogastric tube.
• Insertion of an indwelling catheter to drain and measure urine output.
• Chest x rays and other tests such as blood tests, CT scan, MRI, echocardiogram, electrocardiogram (ECG), and urine tests
• Warming /cooling blankets may be needed
• Sequential compression devices may be put on the legs to prevent deep vein thrombosis
• An air mattress may be used to prevent pressure areas developing

The patient will remain in intensive care while they have investigations and treatment. If they continue to require an endotracheal tube and ventilator, they will continue to be managed in the ICU. Each patient’s condition is very unique and it is important to speak with the medical team caring for the patient to discuss the potential outcome and prognosis.

Internet Links

• Stroke Foundation

The information contained on this page is general in nature and therefore cannot reflect individual patient variation. In addition it reflects Australian intensive care practice which may differ from other countries. It is meant as a back up to specific information which will be discussed with you by the Doctors and Nurses caring for your loved one. ICCMU attests to the accuracy of the information contained here BUT takes no responsibility for how it may apply to an individual patient. Please refer to the full disclaimer.

Stroke Version 1 Author Janet Berry CNC First published August 2008