Anaesthetic

Written by Dr Gordon FN Smith, consultant anaesthetist

What is an anaesthetic?
An anaesthetic is used to temporarily reduce or take away sensation, usually so that otherwise painful procedures or surgery can be performed.

There are two types of anaesthetics:

• general, which make the patient unconscious.
• local, which numb the part of the body that would otherwise feel pain.

Anaesthesia-induced sleep is not the same as ordinary sleep but a form of temporary unconsciousness that is carefully controlled by the anaesthetist. This involves administering the right quantity of anaesthesia for each kind of operation. Throughout the procedure, different types of medicines are added or removed to relieve the pain and maintain the right level of unconsciousness.

For some operations, the best option is to combine a local anaesthetic such as spinal or epidural anaesthesia with medicines to make the patient sleepy. The anaesthetist can explain these details in advance.

Who is the anaesthetist?
A consultant anaesthetist is a specialist doctor who, after qualifying in medicine, spends about six years training in the specialty of anaesthesia. Anaesthetists see patients while being trained, but a consultant supervises them during all procedures.

What does the anaesthetist do?
The anaesthetist takes a careful look at the history of the patient's general health and uses this information to decide how best to offer care. The various options will be discussed with the patient before the operation; patients are encouraged to ask questions and speak about any worries they may have. During the operation, the anaesthetist stays with the patient at all times to make sure they are comfortable and safe. This includes controlling pain, replacing body fluids and measuring and controlling all the vital functions of the the body such as the heart beat, blood pressure and brain and kidney function. This process continues after the operation, when the anaesthetist will organise the control of any pain or sickness and advise on when it is safe to eat and drink again.

Why is eating and drinking not allowed before an operation?
If there is food and drink in the stomach, the patient may be sick while under the anaesthetic. The vomit can pass into the lungs but the body, which is depressed by the medicine, loses its ability to cough it up. This can cause serious lung damage. Eating is usually not allowed from six hours before surgery but in some cases clear fluid may be taken up to two hours beforehand.

What about crowns and loose teeth?
During the operation, it is often necessary to pass a tube into the throat to permit normal breathing. The instrument used to pass this tube into the gullet can easily damage loose teeth and crowns, so the anaesthetist will ask if you have any so that extra care can be taken to avoid them.

The same problem applies to dentures, which are removed to prevent them interfering with breathing.

Are anaesthetics safe?
Anaesthetics are almost entirely safe, but every operation carries a very slight risk. A recent survey in the UK showed that death due to anaesthesia occurred in about five in every million anaesthetics given. People who are in poor health run a higher risk than those who are fit and well. This can be discussed with the anaesthetist.

What is a 'premed'?
While waiting for their operation, patients are given a medicine known as a 'premed' to make them them feel slightly drowsy and stop them becoming anxious. They might not even remember going to the operating theatre or being put to sleep.

Where and how does the patient go to sleep?
Patients are given a small injection in the hand to make them go to sleep. This usually takes place in a room next to the operating theatre. Some patients - especially children - have an anaesthetic cream rubbed onto the skin beforehand so that they won't even feel the injection. Others are given a mixture of gases to put them to sleep very quickly.

Day-case patients are usually taken straight to the operating theatre. Parents are encouraged to stay with their children until they are asleep.

How and where does the patient wake up?
After the operation, the anaesthetist stops giving the medicines that were keeping the patient unconscious and he or she is taken to a recovery room where there are specially trained staff. The longer the operation, the longer it takes to wake up. When the patient has woken up completely, they are taken back to the ward. Occasionally, people recover consciousness in the operating theatre once their operation is over. This is quite safe.

How do people feel when they wake up?
Patients often feel cold and slightly confused. They may have pain or feel a bit sick, but these symptoms can be treated when the anaesthetist visits the patients to check that they are alright.

What is it like after the operation?
How people feel after the operation depends on the kind of surgery they have had. They will be encouraged to get out of bed as soon as possible and will be usually be allowed to eat and drink in the first few hours after a minor operation.

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