There are two principle types of anaesthetic –
The anaesthetist uses a combination of drugs to produce a state of controlled and monitored unconsciousness. Patients will not be awake or aware at any time during surgery.
Part of the body is rendered numb, comfortable and pain-free. Not all types of surgery are suitable, but in many cases regional anaesthesia provides specific advantages. Local anaesthetic agents can be injected in the skin or around nerves to make an area numb, such as a foot, toe or leg.
Spinals and epidurals involve an injection of local anaesthetic in the back to numb the spinal nerves, which supply sensation to larger areas of the body from the chest down. Spinal anaesthetics are slightly simpler to perform and are more commonly used than epidurals.
Often combinations of these techniques are used. For example, all patients that undergo a general anaesthetic will also have a local anaesthetic block, to make the patients foot numb and pain free after the operation.
For operations at the level of the ankle the nerve behind the knee (popliteal) is blocked by the anaesthetist. To help locate the nerve and increase the effectiveness of the block, the injection is carried out usually under ultrasound guidance. For operations below the ankle, an ankle block is performed. Your surgeon Mr Malik will numb the saphenous, tibial, superficial peroneal, deep peroneal and when necessary the sural nerve. The success rate for an ankle block is around 95%. This means 19/20 patients usually wake up with no pain.
Consultant Anaesthetist – Dr Matthew Size carrying out a popliteal block under ultrasound guidance
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.
Full disclosure of your entire previous medical history is essential. It is also important to let your anaesthetist know what drugs you are taking and any allergies or intolerances to drugs. All information is treated in the strictest confidence.
This should be discussed with you at your pre-assessment. As a guide blood-thinning medication should be stopped usually 5 days prior to surgery.
If you take warfarin you may need a blood test on the day of surgery to check the clotting has come back down to a safe level to proceed with surgery.
For a number of conditions, due to the risk of blood clots, you may need cover with a short-acting blood thinner that is injected (heparin or low-molecular weight heparin) until the operation. This is typical for patients with metallic heart valves, but you should discuss this at the pre-operative assessment.
Generally you should continue medications that are controlling a chronic condition such as asthma, high blood pressure, epilepsy etc. However there are a few exceptions that include medications for diabetes and medicines that ‘thin the blood’ such as aspirin and warfarin. These should be stopped before the operation.
We will inform you at your pre-assessment what medications should be stopped and which should be continued.
Smoking increases your risk of post-operative chest infection, increases airway irritability (coughing and wheezing more likely), impairs wound healing (wound infections more likely), 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.
Stopping smoking 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.
There may be some instances where your surgeon, Mr Malik, will not proceed with surgery until you have stopped smoking due to the increased risks, particularly for certain operations, such as fusions.
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. Over the last 10 to 20 years anaesthetic drugs and anaesthetic monitoring equipment have undergone significant improvements, which further contribute to improved safety.
Your consultant anaesthetist will discuss the risks that are specific to you at the pre-operative visit and also explain how they will try to reduce these.
If you have worries about specific risks you can discuss these with your anaesthetist. The Royal College of Anaesthetists publishes a large amount of information on risks of anaesthesia written specifically for patients, which you can read on their website.
Orthopaedic Outpatient Department
30 Devonshire Street, London, W1G 6PU
tel: +44 (0) 203 7956053
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