Your Anaesthetic

Why do I have to go to Pre-operative Assessment Clinic?

Some patients are asked to attend a Pre-operative Assessment Clinic in advance of their operation. Here they are seen by a nurse with training in pre-operative assessment. The nurse will assist you in the completion of a health questionnaire and will arrange blood tests and other investigations, such as a heart ECG or a chest X-ray where these are appropriate. The pre-operative assessment nurses liaise closely with yourConsultant Anaesthetist, who will where necessary arrange that you have more sophisticated tests or see another specialist in advance of the operation, for example a cardiologist. This process is intended to ensure that we are fully informed of all medical conditions which you might have and satisfied that you are fit to undergo anaesthesia and surgery.

Can medical conditions affect my anaesthetic?

There are numerous medical conditions which affect the choice of anaesthetic techniques and anaesthetic drugs, as well as the level of monitoring required to make the surgery and post-operative care as safe as possible. Some of the commoner conditions we encounter are mentioned below, but there are many others of importance so full disclosure of your entire previous medical history is essential. All information is treated in the strictest confidence.

Ischaemic heart disease:

If you have had a previous heart attack or suffer from angina or heart failure, you may be at increased risk of suffering further heart damage. This risk can be minimised by optimising your cardiac medications, or in some cases by having a cardiologist assess you to exclude any need for coronary artery angioplasty or coronary artery bypass grafts.

Previous stroke or transient ischaemic attacks (TIAs):

Depending on the cause of your stroke, and whether you have been put on preventive medication or had corrective surgery, you may be at an increased risk of further stroke during your operation and recovery period. Your anaesthetist will assess your individual risk and make a decision on the most suitable anaesthetic based on your history and the medications you are taking.


It is important that your asthma is as well controlled as possible prior to surgery. If you feel you could be better, you should visit your GP or respiratory physician at least two weeks prior to surgery to have your treatment optimised.

Chronic Bronchitis/Emphysema:

Your medications need to be optimised so that you are as well as possible prior to surgery. Your anaesthetist will assess you carefully and decide on the best anaesthetic management. For more severe cases this might involve giving you a regional anaesthetic such as an epidural injection or spinal injection.


It is important that your blood sugar is well controlled during the peri-operative period. Patients with diabetes maybe asked to attend the Pre-operative Assessment Clinic to discuss the management of their diabetes prior to surgery. Your anaesthetist will ensure that your blood sugar is well controlled during your operation and recovery.

What about smoking and alcohol?

Smoking increases your risk of post-operative chest infection, increases airway irritability (coughing and wheezing more likely), impairs wound healing, and increases your risk of heart attack and stroke. Carbon monoxide is a by-product of tobacco smoke which contaminates the blood and reduces the ability of the blood to carry oxygen. Nicotine is also present in the blood of smokers and increases the requirement for oxygen in body tissues, while also reducing the flow of blood through the coronary arteries.

Smoking cessation for 6-8 weeks before an operation will significantly reduce the extra risk of lung problems after an anaesthetic. Stopping for just 16-24 hours before an operation is enough to reduce the carbon monoxide and nicotine levels to near normal in your blood, and this simple act will make it safer for you to have an anaesthetic.

With regard to alcohol, it is important not to have any alcohol in the circulation on the day of an operation as this may accentuate the effects of the anaesthetic. We also need to know how many units of alcohol you usually consume as alcohol affects the amount of anaesthetic you will need, and an excessive intake can be associated with other complications such as increased bleeding.

Why must I go without food and drink before an anaesthetic?

When you are anaesthetised or undergo intravenous sedation, the normal protective cough reflex is lost. This means that any stomach contents can potentially be regurgitated and get into the lungs, causing pulmonary aspiration – a potentially life-threatening condition. To negate this risk, it is vital that you abstain from food and drink for a period before the operation. After a great deal of research into how long is required to guarantee stomach emptying, the current expert recommendations are:

1) Clear fluids – allowed up to 2 hours before the anaesthetic or sedation.

Clear fluids include water, clear fruit juices, carbonated drinks and black tea/coffee. Avoid juices with particles in, milky tea or coffee, and alcohol.

2) Light meal – allowed up to 6 hours before the anaesthetic or sedation.

Examples of a light meal include toast, boiled or poached eggs, breakfast cereals (all right to have with milk) and fruits. You should avoid any fried foods as these can take much longer to digest.

Often there are several people having operations by the same surgeon on an operating ‘list’. Many factors determine the actual order of an operating list and some of these can only be clarified on the day, eg the availability of certain operating instruments or additional staff such as operating theatre radiographers. Because of these factors the timing of 2 hours or 6 hours referred to above should be calculated backwards from the beginning of the operating list – 7.30am for a morning operation, 1.30pm if you are being operated on in the afternoon and 5.00pm for the evening operating list.

What happens when I go for my operation?

You will be escorted to the operating theatres by a nurse from your ward. On arrival in theatres you are “checked in” by the Operating Department Practitioner (ODP) who is a trained assistant for the anaesthetist. You will then be taken into the anaesthetic room, where you continue to be looked after by both the ODP and the anaesthetist. Intensive monitoring equipment is used to ensure your safety throughout the operation, and we begin this monitoring in the anaesthetic room. Once the anaesthetic has been started you are moved through connecting doors into the actual operating theatre.

Here your anaesthetist will stay with you continuously throughout the operation. With the help of the monitors we make continual adjustments to the levels of anaesthetic and analgesia (pain control) you are receiving. Several other kinds of medicines may be required as well, such as anti-emetics (anti-nausea drugs), antibiotics, muscle relaxants, and drugs to stop your blood pressure from getting too high or too low. The anaesthetist controls and balances all of these. We also make sure that any fluid lost from your body, such as blood loss and dehydration, is replaced through an intravenous drip. After completion of your surgery you will be transferred to the recovery room, where you will stay until you are more awake and we know that you are comfortable. Your anaesthetist hands over your care to a trained recovery room nurse, but we continue to be directly responsible for you until you are well enough for a ward nurse to accompany you back to the ward.

How safe are anaesthetics?

Having an anaesthetic these days is safer than ever. Your Consultant Anaesthetist is a highly trained specialist doctor with extensive experience in assessing patients and dealing with any complications that might arise. In addition, over the last 10 to 20 years anaesthetic drugs and anaesthetic monitoring equipment have undergone significant developments which further contribute to improved safety. As a speciality, anaesthesia is one of the leaders in adverse incident reporting and clinical governance and in this regard our Consultant Anaesthetists are dedicated to maintaining the very highest of standards.

What will I get for pain relief after my operation?

Your anaesthetist will routinely discuss post-operative pain relief (analgesia) with you. For joint replacement surgery, this might include the use of an epidural or spinal anaesthetic or nerve blocks. These are often performed by the anaesthetist in addition to the use of general anaesthesia or intravenous sedation.

We usually prescribe paracetamol or a paracetamol-codeine combination (co-codamol) to be taken regularly after surgery. This provides a good basic level of pain relief with minimal side effects. Where there are no contra-indications we then add in a non-steroidal anti-inflammatory drug (NSAID) such as diclofenac (Voltarol ) or ibuprofen (Nurofen ). For moderate to severe pain we might need to give a morphine-based or morphine-related analgesic drug such as tramadol, oxycodone or morphine itself. Morphine is extremely useful and when correctly used for relatively short periods to treat operative pain there is no risk of addiction. It can be taken orally or injected intramuscularly, or you may be given a Patient Controlled Analgesia (PCA) machine. This consists of a special pump containing morphine, which injects a small amount into your intravenous cannula when you press a hand-controlled button. The pump will only allow an injection every 5 minutes, which has been shown to be both safe and effective; this allows you to have optimum control over exactly how much pain relief you receive.

How long does it take to recover from anaesthesia?

Modern anaesthetic drugs have far fewer hangover effects than those used in the past. Most people are awake and conversing within 30 minutes of the end of surgery. However, if you are going home the same day it is important to remember that you should under no circumstances drive a car or operate dangerous machinery for 24 hours after a general anaesthetic or intravenous sedation. Exactly how long you take to recover depends on the extent of surgery and also on the amount of analgesia you require. Stronger painkillers tend to make you drowsy; however this is not always a bad thing as it allows you to rest and recover.