Side Effects and Complications

Is Anaesthesia Safe?

Your anaesthetist has spent many years of training to make sure that you are safe during surgery. They are constantly monitoring for changes in breathing, heart rate, blood pressure, depth of anaesthesia and unexpected events which although rare, may occur during surgery. It is this training and standards set by the Australian and New Zealand College of Anaesthetists that has made anaesthesia here in Australia as safe if not safer than anywhere in the world.

You can help by making some simple modifications to your lifestyle. For example, regular exercise and weight loss can reduce your anaesthetic risk and improve your long term health. If you smoke, try to stop smoking now. Stopping smoking several weeks before your operation may reduce your chances of getting complications and again, also improve your long term health.

What are the side effects of general anaesthesia?

Nausea and Vomiting

Nausea and vomiting affects some people more than others and it occurs more after certain types of surgical procedures. There are special types of medications that anaesthetists give to try to prevent vomiting however, there is always a risk that you mayl become sick after an anaesthetic. If you have been sick after previous anaesthetics or if you are prone to motion sickness, please discuss this with your anaesthetist.


Your anaesthetist will try to make sure that you wake after your operation as comfortable as possible. However, people vary greatly with their pain relief requirements for surgery and pain control techniques make need to be adjusted. If you wake with pain in recovery, you will be given extra pain relief quickly.

Sore Throat

While you are asleep, an airway or breathing tube is inserted into the throat to make sure that you can breath well. This may cause a small amount of discomfort which may last for a day or two.

Skin Bruising

The skin may bruise at the site of an intravenous drip or other injections.

Dental Damage

Occasionally teeth may get damaged during an anaesthetic. Let your anaesthetist know if you have loose teeth, crowns or bridgework.

Allergic Reaction

Although uncommon, there is a small chance that you may get a reaction from an anaesthetic drug. These reactions can vary from a rash to more serious breathing and blood pressure problems. Your anaesthetist is trained to manage these uncommon emergencies.

Breathing problems

Anaesthesia can cause breathing problems. These problems are more common in people with pre-existing asthma or other medical problems such as obstructive sleep apnoea. Another serious complication can occur if stomach contents get into the lungs and damage them. This is the reason that you have to be fasted before your operation.

Heart Attack

Heart attacks during anaesthesia is uncommon. However, patients especially at risk are those with pre-existing heart disease, diabetes or high blood pressure.


Strokes occur when there is an interruption of blood supply to the brain. It is uncommon in patients that are fit prior to surgery. At risk patients are those with a previous history of strokes, heart disease, diabetes and high blood pressure.

Side effects from nerve blocks and epidurals

Sometimes your anaesthetist may elect to do a nerve block or an epidural as part of the anaesthetic. While nerve blocks have proven to be very safe, some numbness and weakness can be associated with this. Rarely nerve damage can occur which could result in numbness or weakness lasting longer (months or even permanently). These complications are very rare.