Preparing for a general anaesthetic

When a patient has an operation, particularly if it is not an emergency, it is important that they are in the best condition for that surgery.

Prior to surgery, an anaesthetist will visit the patient and make a formal, concise assessment which will include detailed questions about previous operations, their medical history, what medication they may be taking, and any allergies.

It will also give the anaesthetist an opportunity to examine the patient. For example, to make sure the patient does not have another illness at the time, such as a cough or a cold.

This is required for safety reasons to ensure the risks of undergoing general anaesthetic are minimised.

What happens at a pre-assessment clinic?

The patient will be invited to attend a pre-assessment clinic. This is an important part of preparing for surgery as it allows routine tests to be performed, such as blood tests and an ECG (an electrocardiogram) if necessary.

This ensures that the patient is in the optimum condition for their surgery and general anaesthetic.

During this appointment, it is common for the nurses to advise patients on further things they can do to reduce the risks of surgery and undergoing a general anaesthetic. For example, to stop or reduce smoking.

Any patient who has a general anaesthetic is more at risk of having a chest infection after their operation. This is particularly true of smokers. It takes six weeks for lung function to recover completely once an individual stops smoking, so to reduce the risks of retaining sputum and having a chest infection it is important to stop or reduce smoking prior to general anaesthetic.

If a patient feels unable to stop smoking for six weeks they are advised to try to stop for the 24 to 48 hours before surgery, because this will improve the amount of oxygen their blood will be able to carry whilst under general anaesthetic.

Another important thing the patient needs to do is to starve themselves before surgery, often from the night before the operation is scheduled. This is because it takes a certain number hours for the stomach to empty. If the stomach is not empty then there is a small chance that at the time the patient undergoes general anaesthetic they may aspirate, drawing the contents of the stomach into the lungs. This can cause serious problems with lung infections afterward surgery.

What happens on the day of surgery?

On the day of surgery, the anaesthetist will visit the patient and take a comprehensive history to ensure that they are aware of all of any medical conditions or allergies and any drugs the patient may be taking.

It is also an opportunity for the patient to ask the anaesthetist any questions they may have about undergoing general anaesthetic, pain relief, or any other concerns they may have.

Before surgery, it may seem to the patient that each doctor that visits them is asking the same questions. This is important as the answers are interpreted by each doctor with their specialism in mind. It also acts as a safety mechanism to ensure that the correct patient is having the correct operation on the correct side.

It can be frustrating for the patient, but it is a necessary and very important component in preparing for surgery.

Is it possible to wake up during surgery?

An anaesthetist is present throughout the operation. Part of their role during the surgery is to ensure that the patient is receiving the correct dose of anaesthetic.

It is extremely unlikely that a patient would be aware of anything happening during their operation. There are numerous machines which monitor the patient’s heart rate and blood pressure. These would alert the anaesthetist and the surgeon to any change in the depth of the patient’s anaesthetic.

Waking up from general anaesthetic during surgery may create interesting tabloid stories but the reality is that it is extremely unlikely to happen.

What happens after surgery?

A patient will be woken up as soon as surgery is completed. The patient is then sent to a recovery area. In the recovery area a specialist nurse will monitor them and ensure that they are pain-free, not feeling nauseous, and are safe to be transferred back to the hospital ward.

The patient will then be kept on the ward and monitored again until they are in a fit condition either to be discharged, if it is a day case, or to be kept on the ward.

It is the responsibility of the anaesthetist to make sure the patient is comfortable when the patient wakes up from their surgery and that any side effects are minimised.

The majority of surgery in the UK is now done on a day case basis. However, before a patient is booked for a day case the nurses will check at the pre-assessment clinic that the patient has the right support network. This will involve having a responsible adult at home and having access to a telephone to call if they are having any problems.

It is important not to drive or operate heavy machinery in the first 24 hours, and preferably 48 hours, after surgery.

All of these factors are for the patient’s own safety.

Dr Daman Mulhi, Anaesthetic Consultant, NHS
Specialist in anaesthesia, diabetes, obesity, metabolic syndrome, and public health awareness.