What is a coma?

When someone is in a coma, they are unconscious and they cannot be woken up. Someone who is in a coma is alive but completely unresponsive to the world around them. There is very little activity in their brain.

A coma can result from a severe illness or injury. It is a medical emergency and the person in the coma will need immediate treatment in hospital.

In some cases, doctors may put a person into a coma using medicines. This is known as an 'induced coma'. They might do this if it will help the person heal from their illness or injury. This may also help their brain to keep functioning after an injury and saves the patient from feeling extreme pain.

Some people in a coma can breathe on their own but others will need help. They won't be able to cough or swallow and they won't respond to pain, light or sound. Their eyes will be closed and they won't be able to move or communicate.

There are different levels, or depths, of coma. Hospital staff will examine a person to measure the depth of their coma. They do this to work out how badly the brain has been damaged and to track the person's level of consciousness over time.

What are the causes of coma?

The causes of coma include:

• brain injuries caused by car accidents, falls and other types of trauma
• a stroke
• lack of oxygen to the brain — such as from drowning or a heart attack
• diabetes — if sugar levels get much too high or too low
• a brain infection such as meningitis or encephalitis
• a seizure
• overdosing on drugs or medicines, or being exposed to a toxic substance such as carbon monoxide

Sometimes doctors put a person into a medically induced coma with medicines. This helps their brain to keep functioning after an injury and saves the patient from feeling extreme pain.

What care does someone in a coma need?

Someone in a coma needs intensive care in hospital. They may need help with breathing. They will be fed through a tube and they will receive blood and fluids through a drip inserted into their vein.

The cause of their coma will also need to be treated to prevent further brain damage.

They will need medical support to stop their body deteriorating and to prevent complications such as pressure sores and ulcers, infections or deep vein thrombosis (DVT). Their arms and legs will need to be exercised gently to prevent the muscles from getting tight. They may also need medicine to calm them down if they get restless.

Although it has not been scientifically proven, families of people who have been in a coma say that talking to them, playing their favourite music and stimulating them can help them to wake up.

What is the expected outcome of a coma?

Comas usually don't last longer than 4 weeks, although cases have been recorded where people stay in a coma for several years.

Some people will come out of a coma, but others will continue to be unresponsive or may die. It depends on how severe the coma is, how long it lasts and what has caused it.

Recovery

When someone comes out of a coma, they become more aware and regain consciousness gradually. After they wake up, they might be very confused about the day and time, where they are and sometimes even who they are.

Their long-term expected outcome (prognosis) will depend on the brain injury that caused the coma. Some people, such as people who were in a diabetic coma, will make a full recovery. Others may have permanent brain damage and will need therapy and support for the rest of their lives.

Post-coma unresponsiveness

Some people may become more alert and wake up but show no signs of awareness. They might open their eyes, blink, smile or make sounds — but not in response to anything around them.

This is called post-coma unresponsiveness (previously called persistent vegetative state). Some people may improve, but others can be in this state for months or years. The longer it lasts, the less likely they are to recover. They may gradually pass into a minimally conscious state, where they are more aware and may be able to communicate.

End of life

Unfortunately, some people never recover from a coma. If the coma lasts more than a few weeks, their family may be asked to make decisions about whether to continue medical support. It's easier to make the decision if family members have discussed their wishes earlier.

Resources and support

You can find more information about brain injury and coma from the following organisations:

• Brain Foundation
• Synapse (Australia's brain injury organisation)
• Brain Injury Australia

If your relative or friend is in a coma, you can register their details on the Australian Register of Disorders of Consciousness (ARDoC). They also offer an online forum, helping families, carers and loved ones to contact each other for advice, help and support.