Safety in anaesthesiaback to top 

 

Anaesthesia has made much of today’s surgery possible, and has brought great benefits. Today, joints can be replaced, organs can be transplanted, and diseased tissue can be removed with a high degree of comfort and safety.

 

The benefit of anaesthesia is that it will remove pain and sensation. This benefit needs to be weighed against the risks of the anaesthetic procedure and the drugs used.

 

It is difficult to separate the risks of the anaesthetic from those of your operation and your general health.

 

 

The risk to you as an individual will depend on:

 

       Any underlying health problems you may have

 

       Personal factors, such as whether you smoke or are overweight

 

       The type of surgery that is planned

 

       The urgency of the situation

 

 

Everyone varies in the risks they are willing to take. Anaesthetists and patients may also hold different views about the importance of risk.

 

 

Safety of anaesthetic drugsback to top 

 

Many of the drugs used by anaesthetists have been successfully used for a long time. In Australia, all drugs must be tested and licensed by the Therapeutic Goods Administration before they can be generally prescribed. This involves examining the risks, safety, effectiveness and side effects of each drug before it is given a licence.

 

 

Side effects and complications of anaesthesiaback to top 

 

Anaesthetic risks are thought of in terms of side effects and complications.

 

Side effects are secondary effects of drugs or treatment. They can often be anticipated but are sometimes unavoidable. Almost all treatments (including drugs) have side effects of some kind. Unpleasant side effects do not usually last long. Some are best left to wear off and others can be treated. Examples would be a sore throat or sickness after a general anaesthetic.

 

Complications are unexpected and unwanted events due to a treatment. Examples would be an unexpected allergy to a drug or damage to your teeth caused by difficulty in placing a breathing tube.

 

 

Very common and commonback to top 

 

Nausea and vomiting after surgery

 

Some anaesthetic and pain-relieving drugs are more likely to cause nausea or vomiting than others. Vomiting can be treated with medication (anti-emetics), but it may last from a few hours to several days. Some operations also are more likely to cause vomiting.

 

 

Sore throat

 

If you have had a tube in your airway to help you breathe, it may give you a sore throat. The discomfort or pain lasts from a few hours to days and can be treated with pain-relieving lozenges.

 

 

Dizziness, blurred vision

 

Your anaesthetic or loss of fluids may lower your blood pressure and make you feel faint. Fluids or drugs (or both) may be given into your drip to treat this.

 

 

Shivering

 

This may be due to you getting cold during the surgery, to some drugs, or to stress. You may often be kept warm during the surgery using a hot-air blanket.

 

 

Headache

 

This may be due to the effects of the anaesthetic, to the surgery, to lack of fluids, or to anxiety. More severe headaches may occur after a spinal or epidural anaesthetic. The headache usually gets better in a few hours and can be treated with pain relievers.

 

 

Itching

 

This is a common side effect of opiates (such as morphine) but can also happen as an allergic reaction to drugs, dressings or skin preparations. If you have itchiness, it can be treated with other drugs.

 

 

Aches, pains and backache

 

During your operation you may lie in the same position on a firm operating table for a long time. Great care is taken to position you, but some people still feel uncomfortable afterwards.

 

 

Pain during injection of drugs

 

Drugs may cause some pain or discomfort when they are injected, this is especially common when the drug is injected to put you to sleep.

 

 

Bruising and soreness

 

This can happen around injection and drip sites. It may be caused by a thin vein bursting, movement of a nearby joint, or infection. It normally settles without treatment, but if the area becomes uncomfortable, the position of the drip can be changed.

 

 

Confusion or memory loss

 

This is common among older people who have had an operation under general anaesthetic. It may be due to several causes. It is usually temporary, but may last a few days or weeks.

 

 

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Uncommon side effects and complicationsback to top 

 

Chest infection

 

A chest infection is more likely to happen to people who smoke, and may lead to breathing difficulties. This is why it is very important to give up smoking for as long as possible before your anaesthetic.

 

 

Bladder problems

 

After certain types of operation and regional anaesthesia (particularly with a spinal or epidural), men may find it difficult to pass urine, and women tend to leak. To prevent problems, a urinary catheter may be inserted at a suitable time.

 

 

Muscle pains

 

These sometimes happen if you have received a drug called suxamethonium. This is a muscle relaxant which is given for emergency surgery when your stomach may not be empty.

 

 

Slow breathing (depressed respiration)

 

Some pain-relieving drugs can cause slow breathing or drowsiness after the surgery. If muscle relaxants are still having an effect, the breathing muscles may be weak. These effects can treated with other drugs.

 

 

Damage to teeth, lips or tongue

 

Damage can be caused to your teeth by clenching them as you recover from the anaesthetic. If your anaesthetist finds it difficult to get the breathing tube in the right place, your teeth may also be damaged. This is more likely if you have limited mouth opening, a small jaw or a stiff neck.

 

 

An existing medical condition getting worse

 

Your anaesthetist will always make sure that you are as fit as possible before your surgery. However, if you have had a heart attack or stroke, it is possible that it may happen again – as it might even without the surgery. Other conditions such as diabetes or high blood pressure will also need to be closely monitored and treated.

 

 

Awareness

 

Your risk of becoming conscious during your operation will depend on your general health and the type of operation you are having. For example, if you are very ill, the anaesthetist may use a combination of muscle relaxants and a lighter general anaesthetic to reduce the risks to you. However, the risk of your being aware of what is going on is increased.

Monitors are used during the operation to record how much anaesthetic is in your body and how your body is responding to it. Some more recent monitors also allow monitoring of brain wave patterns. These normally allow your anaesthetist to prevent your anaesthetic from becoming too light.

If you think you may have been conscious during your operation, your anaesthetist should be told about it as soon as possible. He or she will want to know, to help both you and future patients. Further information is available from the Australian Society of Anaesthetists.

Awareness pamphlet (.pdf)

 

 

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Rare or very rare complicationsback to top 

 

Damage to the eyes

 

Anaesthetists take great care to protect your eyes. Your eyelids are held closed with adhesive tape, which is removed before you wake up. However, sterilising fluids could leak past the tapes or you could brush your eyes as you wake up after the tapes have been removed. These could cause damage to the surface of your eye, which is usually temporary and responds to drops.

 

 

Serious allergy to drugs

 

Allergic reactions will be noticed and treated very quickly. Very rarely, these reactions lead to death even in healthy people. Your anaesthetist will want to know about any allergies in yourself or your family.

 

 

Nerve damage

 

Nerve damage (paralysis or numbness) may be due to damage by the needle when performing a regional block, or it can be caused by pressure on a nerve during an operation. Most nerve damage is temporary and recovers within two to three months.

 

 

Death

 

Deaths caused by anaesthesia are very rare, and are usually caused by a combination of four or five complications arising together. There are probably about five deaths for every million anaesthetics given in Australia.

 

 

Equipment failure

 

Vital equipment that could fail includes the anaesthetic gas supply or the ventilator. Monitors are now used which give an immediate warning of problems, and these failures rarely have serious effects.