Anaesthesia explained

Published: 02/08/2019

The pre-assessment clinic

Before your anaesthetic we need to know about your general health. Some hospitals use a health questionnaire, or you may be invited to a pre-assessment clinic. If you are having an urgent operation, the health check will be done by your doctors and nurses on the ward. 

In most pre-assessment clinics you will see a pre-assessment nurse specialist. An anaesthetist may also see you, which is especially useful if you are having a major operation.

Tests that you need will be arranged. This may include blood tests, an ECG (electrocardiogram or heart tracing), an X-ray, or other tests. Some tests can be done in the clinic, but for others you will need to come back another day. 

This is a good time to ask questions and talk about worries that you may have. If the staff in the clinic cannot answer your questions, they will help you find someone who can.

Health-check information  

You may be asked about:

  • your general health and activity level
  • serious illnesses you have had
  • problems with previous anaesthetics
  • problems you know about when people in your family have had an anaesthetic
  • symptoms relating to the heart or lungs such as chest pain, shortness of breath, palpitations or dizzy spells
  • heartburn or indigestion pain
  • medicines that you take, including those you can buy over the counter  and vitamins or herbal remedies
  • allergies
  • smoking habits and the amount of alcohol you drink, and
  • if you use recreational drugs such as cocaine or marijuana, heroin or the so called ‘legal highs’.

Pills, medicines, inhalers, and herbal remedies

An accurate list of your medicines is very important. Please bring with you either the pills themselves, or a complete list from your GP. 

Delaying your operation 

If your operation is not urgent, the anaesthetist or nurse at the pre-assessment clinic may talk to you about taking some time to improve your health. More tests may be needed or some treatment may need to be started. They would do this working closely with your surgeon. 

It is also possible that the anaesthetist you see thinks there are very high risks if you have the operation. You may want time to think about whether to go ahead with the operation. 

Taking part in a clinical trial

Anaesthetists are always trying to improve the care that you receive. Clinical trials are studies of groups of patients which allow treatments to be compared. You may be asked to take part in a trial. A trial nurse or doctor would explain in detail what is involved, and you will receive full written information as well. You are free to decide whether to take part, and you can also withdraw at any time. If you can help, other patients in the future will benefit.

In the few days before your operation


You should continue to take your medicines up to and including the day of the operation unless you are told not to.

Please follow carefully the instructions you have been given in the pre-assessment clinic. Please look out for specific instructions if you take:

drugs to thin your blood (for example, warfarin, dabigatran, rivaroxaban, clopidogrel, aspirin)

  • drugs for diabetes
  • all herbal remedies, and
  • some blood-pressure pills. 
Taking a shower 

Some hospitals give patients a disinfecting shower gel to use for several days before the operation. It helps prevent serious infections such as MRSA. You should use this on your body and hair.