Frequently Asked Questions about your Anaesthetic


Do I need to attend a Pre-operative Assessment Clinic?

The purpose of the Pre-operative Assessment Clinic is to make absolutely certain that you are fit to undergo anaesthesia and surgery. If you are entirely fit there may be no need for you to attend but depending on your age and general condition it is quite useful to have a check up before operation. The clinic is run by a nurse practitioner who will complete a questionnaire with you. Appropriate blood tests and other investigations, such as a heart ECG or a chest X-ray will be arranged. The Pre-Operative Assessment is passed on to your Consultant Anaesthetist, who if may arrange for further tests or see another specialist, such as a Cardiologist, prior to your admission. 


What medical conditions might affect my anaesthetic?

Many types of medical conditions can affect your fitness for anaesthesia and the method of anaesthesia used. It is important for you to tell us about all medical conditions currently affecting you and any serious illnesses or operations you have had in the past. The types of problem that commonly cause difficulties are listed below. All information is treated in the strictest confidence.


Asthma should be as well controlled as possible before surgery. You are advised to see your GP about two weeks prior to surgery to have your treatment reviewed letting your GP know you are about to have surgery.


Chronic Bronchitis/Emphysema
You are advised to see your GP about two weeks prior to surgery to have your treatment reviewed letting your GP know you are about to have surgery. Your anaesthetist may also need to see you to evaluate fitness for anaesthesia and to decide on the best type of anaesthetic. In some cases  local or regional anaesthesia such as epidural or a spinal anaesthetic may be applicable.


Patients with diabetes generally need to attend the Pre-operative Assessment Clinic to discuss the management of their diabetes before surgery. It is important to get your blood sugar as well controlled as possible during the pre- and post- operative periods. Your anaesthetist will also need to monitor your blood sugar carefully during surgery. We generally try to do our diabetic patients first on the operating list as long periods of fasting are more difficult to manage in diabetes.


Ischaemic heart disease
Ischaemic heart disease can cause episodes of angina or heart failure, and there is an increased risk of a heart attack or myocardial infarct during or after surgery. This risk can be reduced by ensuring you have the right medication. In most cases we will ask for an assessment by a Cardiologist prior to elective knee surgery.


Stroke or transient ischaemic attacks (TIAs)
If you have had a stroke you can be at an increased risk of a further stroke during and after surgery. This will also influence the types of anesthesia used. This will need to be carefully assessed and discussed with you.


What about smoking, alcohol and recreational drugs?

Stopping smoking for a couple of months prior to surgery is an ideal opportunity to give up the habit and significantly reduces your risk of lung problems under anaesthesia. Smoking also impairs wound healing and increases your risk of heart attack and stroke. 

Even stopping for 16-24 hours before an operation helps reduce the carbon monoxide and nicotine levels in your blood, which will make it safer for you to have an anaesthetic. 
It is essential not to have any circulating alcohol in your blood stream on the day of an operation. Please let us know how many alcohol units you normally consume as this affects the amount of anaesthetic you will need.


Recreational drugs are a fact of life these days and it’s not uncommon for our patients let us know that they use them. It is important to realise that all drugs are important and can lead to problems and complications under anaesthesia including interactions with the anaesthetic agents. Please let us know what you are taking. All information will be treated in the strictest confidence.


Why do I need to fast before undergoing a general anaesthetic?

When anaesthetised or sedated we lose our protective could reflex which prevents food or drink being regurgitated from our stomach and being inhaled into the lungs. The problem is that stomach acid is also inhaled and this can be a serious or life-threatening problem. To reduce this risk you need to fast. Your last light meal should be a minimum of six hours before operation. Your last fluids including water, fizzy drinks, tea, coffee or clear fruit juices should be a minimum of two hours before operation. Do not take milk in your tea or coffee and no alcohol for a minimum of 12 hours before surgery.


What happens on the day of admission?

Please arrive in plenty of time which means arrival by around 7:00 am for a morning operating list. If you arrive late there is a good chance your case will have to be cancelled. When you arrive you need to go through the registration process with the hospital before being admitted to the ward.

After arrival at the ward one of the nurses will take your details and you will need to change into a threatre gown. Usually there will be several people having operations on the same operating list. Many factors determine the order of the list and some of these can only be clarified on the day, such as the availability of instruments or staff and problems individual to the other patients on the list. We cannot therefore guarantee the order of the list until the day. Because of that you should count the period of fasting for a morning list backwards from 8:00 am or from 1:30 pm for an afternoon list.

A nurse will take you to the operating theatre. You have the choice of walking the short distance to the lift and going down to the operating theatre on foot or if there are problems walking you may need to be taken down by trolley. On arrival at the anaesthetic room you will be checked in by the Operating Department Practitioner (ODP), the trained assistant who works with the anaesthetist. You will be attached to monitoring equipment to ensure your safety throughout the procedure and once your anaesthetic has commenced you will be transferred to the operating theatre, usually after you have gone to sleep.
The anaesthetist remains with you throughout the operation monitoring your condition, controlling your blood pressure and ensuring any fluid loss is replaced though an intravenous drip. After surgery you are taken to the recovery room, where you will stay until you are more awake and have recovered sufficiently to be transferred to the ward. 


Are modern anaesthetics safe?

Anaesthetics have never been safer. London Knee Clinic partners with Consultant Anaesthetists who are specialists with extensive experience in anaesthesia and in dealing with any complications that might arise. See separate section entitled “Anaesthetists”. The Consultant Anaesthetists are assisted by a trained Operating Department Assistants (ODAs). Our operating theatres and anaesthetic rooms are all equipped with the latest monitoring and anaesthetic equipment which is fully maintained and checked on a daily basis.


Will it be painful when I wake up?

You will be carefully checked in the recovery room and pain-killers given as necessary by the recovery room nursing staff who are specially trained in monitoring and treatment in the immediate post-operative period. They also liaise closely with the surgeon and anaesthetist.

In day-cases we prescribe a variety of medium strength pain killing drugs such as Paracetamol /Codeine combinations, non-steroidal anti-inflammatory drugs (unless contra-indicated) and for moderate to severe pain we use morphine related drugs such as Tramadol, Oxycodone or sometimes Morphine itself. Local anaesthetics injected directly into the knee while you are still under the general anaesthetic are also frequently used.

In more serious cases nerve blocks are often used in which a local anaesthetic is injected around the nerves in the thigh. In addition Patient Controlled Analgesia (PCA) is used in which the patient can self-administer small amounts of intravenous Morphine or other agent using a special pump every five minutes or whenever necessary. This is extremely safe and puts pain control in your own hands.


How long will it take to recover from the anaesthetic?

In most cases we use rapidly reversible anaesthetic drugs that have few hangover effects and which are rapidly cleared from the body. If you have a relatively minor day-case procedure you will likely be awake and conversing within about 30 minutes of the end of surgery. However, short term memory of events immediately after surgery may be impaired. You should be sitting up and able to have something to eat and drink within a couple of hours of surgery and shortly afterwards will be helped out of bed and taken for a walk around by the physiotherapist.

If you go home the same day it is a normal requirement that someone comes in to collect you. You should not drive a car or operate any dangerous machinery for 24 hours. This restriction may continue for a couple of days longer if you experience drowsiness as a side effect of the pain-killers.

If you are having a longer procedure as an in-patient such as a total knee replacement, there is a longer period of post anaesthetic drowsiness. You will have a rest for most of the remainder of the day. You are likely to be on strong pain-killers that tend to make you drowsy. Physiotherapy will start in earnest the following morning.

Full recovery will depend on precisely what you have had done. Please ask your surgeon.