The Central Nervous System (the Brain and Spinal Cord)
What does it do?
The central nervous system is made up of the brain, the spinal cord and the nerves. It is one of the most complex systems in the body: controlling movement, feeling, emotions, breathing, blood pressure, temperature and even our personalities. The brain is housed within the skull.
In the brain can be divided into 8 different areas:
- The lobes of the brain
- The meninges
- The motor and sensory cortex
- The blood supply
- The cranial nerves
- The brain stem
- The pituitary gland
- The ventricles
These work together to make the body move and feel, to breathe, maintain a normal temperature and blood pressure (basic functions of life) and allows us to process information and respond appropriately. However, when an outside force such as a blow to the head causes injury to the brain, one or more of these control centres may stop working. In many cases there is swelling of the brain with less oxygen reaching the affected area.
- Traumatic brain injury
“A traumatic brain injury occurs when an outside force impacts the head hard enough to cause the brain to move within the skull or if the force causes the skull to break and directly hurts the brain” (Brain Injury Association of America)This force may cause a single problem (eg a bleed) or a combination of problems. This is referred to as the ‘primary’ injury. Without appropriate treatment, further or ‘secondary’ injuries may occur due to a combination of swelling or bruising to the brain, inadequate breathing and low blood pressure. There are a number of different primary injuries and these are explained further on Brain Injury pages.
Traumatic brain injuries can be mild, moderate or severe depending on the damage to the brain. A mild injury or concussion is diagnosed when a person experiences a brief change in their mental status (such as memory loss or headache) at the time of the injury. Often there is no sign of damage on a brain scan. A person suffering moderate injury can lose consciousness for several minutes and be confused, sleepy and agitated in the following days to weeks. When brain injury is severe the person is described as being in a 'coma’. Many terms are used and sometimes you may have read these in magazines - they are difficult to explain and may have been described incorrectly. Coma is a word used to describe a person who is unconscious - or a state where the person is unable to respond to the spoken word or to a stimulus (such as a pinch to the shoulder area or on the chest). There are varying levels of coma/unconsciousness. Sometimes the person may be able to move and open their eyes, but they are unable to obey commands (semi-conscious or semi-comatose).
When the brain injury is so severe the person may be so deeply comatose that they can no longer cough or swallow properly and they could inhale their own saliva. To protect the airway and lungs the patient will need a tube placed into throat and be attached to a breathing machine (ventilator) to help breathe properly. As the hours go by after a severe brain injury, the brain may start to swell and the patient's condition may deteriorate.
What happens in the Intensive Care Unit?
Patients admitted to hospital with a severe brain injury will need specialised care in an Intensive Care Unit Specialist neurosurgical services. People injured away from a major trauma centre will need to be transferred.
Initially if the injury can be repaired with an operation, this will happen as soon as possible. Other treatment may include:
- Monitoring of the heart rate, blood pressure, oxygen saturation and temperature. This will be seen on a bedside monitor.
- An arterial line may be inserted to monitor blood pressure and to take blood samples.
- The patient may require monitoring of the pressure in the brain (ICP monitoring), and an external ventricular drain (EVD) to help reduce the pressure inside the brain.
- Medication and intravenous fluids may be given via a central venous catheter including sedatives (to minimise the activity of the brain), analgesics (pain killers) and antibiotics (for infections). These medications will be given via infusion pumps.
- Oxygen may be delivered via a face mask, and artificial ventilation via an endotracheal tube or tracheostomy may be required to assist with breathing. The ventilated patient will require suctioning to remove secretions from the lungs and airways.
- Nutrition may 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 urinary catheter to drain and measure urine output.
- Chest x rays and other tests such as blood tests.
- Sequential compression devices may be put on the legs to prevent deep vein thrombosis.
- Cooling blankets may be needed to keep the temperature normal.
- An air mattress may be used to prevent pressure areas developing.
How long will the patient remain in ICU?
The length of time the patient remains in intensive care depends on how badly injured the brain is and how quickly the person begins to recover. One of the most frustrating things for families is that it is very difficult to predict how the person will be after a brain injury. It is a struggle in the first few days to keep the person alive and it is only after this that the extent of the damage may be known. If the patient wakes up (regains consciousness) they may behave differently to how they would have before their injury. This may be very uncomfortable and confronting for the patient and for their relatives and friends. Regaining control of the body and being able to live in society are challenges for the person who survives a major brain injury. There are many organisations available to help both patients and their families.
References & Internet Links
Brain Injury NSW – advocacy group for people with acquired brain injury, their family and carers and service providers. Website includes multicultural communication
Brain Foundation Australia
Brain Injury USA
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.
Traumatic Brain Injury Version 1
Maureen Edgetton-Win CNC Liverpool Hospital ICU
First published August 2008