Anesthesia means “loss of sensation”. Medications that cause anesthesia are called anesthetics. Anesthetics are used during tests and surgical operations to numb sensation in certain areas of the body or induce sleep. This prevents pain and discomfort, and enables a wide range of medical procedures to be carried out.
Anesthetics work by stopping the nerve signals that keep you awake and aware from reaching your brain. During this state of induced sleep, procedures can be carried out without you feeling anything. After the anesthetic has worn off, the nerve signals will be able to reach your brain, and consciousness and feeling will return.
Types of anesthesia
Local anesthetics and general anesthetics are two commonly used types of anesthetics.
A local anesthetic is often used during minor procedures where a small area of the body is numbed and you remain fully conscious. A general anesthetic is often used for more serious operations where you’re totally unconscious and unaware of the procedure.
Aside from local and general anesthetics, there are a number of other types of anesthesia. Unlike general anesthetic, these don’t make you unconscious; they stop you feeling pain in a particular area of your body.
The different types of anesthetic are described below.
- Regional anesthetic – this is a local anesthetic given to a specific region of your body, giving numbness or pain relief for deeper operations where more extensive numbness is needed
- Epidural anesthesia – a type of regional anesthetic usually used to numb the lower half of the body; for example, as pain relief during labour and childbirth
- Spinal anesthesia – a type of regional anesthetic used to give total numbness lasting about three hours to the lower parts of the body so surgery can be safely carried out in this area
- Sedative – medication that makes you feel sleepy and relaxes you both physically and mentally; it’s sometimes used to keep you calm during minor, painful or unpleasant procedures
Different types of anesthesia can be used in combination. For example, a regional anesthetic can be used with a general anesthetic to relieve pain after an operation.
A sedative is also sometimes used with a regional anesthetic to help you feel relaxed and calm during an operation, as well as pain-free.
How anesthetics are given
An anesthetic can be given in a number of ways:
- as an ointment, spray or drops
- as an injection into a vein
- as a gas you breathe in
Anesthesiologists are doctors who have received specialist training in anesthesia. They’ll give you your anaesthetic and be responsible for your safety and wellbeing during your procedure.
Before the procedure, your anesthesiologist will discuss a number of things with you, including:
- the types of anesthetic appropriate for the procedure you’re having
- any risks or side effects associated with different types of anesthetic
They’ll plan your anesthetic and pain control with you, taking into account any preferences you have for a particular type of anaesthetic. You should ask your anesthetist to clarify anything you’re unsure about.
Your anesthesiologist will carefully monitor you throughout your operation and make sure you wake up comfortably afterwards. They may also help with any pain relief you might need after the procedure.
Anasthetics consist of a number of medications that can cause side effects in some people. Your anesthesiologist will tell you about any side effects you may experience after having a specific type of anesthetic, and measures that will be taken to reduce these.
Some common side effects that can occur after having a general anesthetic and some regional anesthetics include:
- feeling sick or vomiting
- dizziness and feeling faint
- feeling cold or shivering
- bruising and soreness
- difficulty passing urine
- aches and pains
Side effects don’t usually last very long and, if necessary, some of them can be treated.
Tell the healthcare professionals treating you if you experience any of the above side effects or if you’re in pain after your procedure.
Risks and complications
In recent years, having anesthesia has become very safe. Advances in equipment, medication and training mean serious problems are rare.
However, as with any type of surgery or medical procedure, there’s a potential risk of complications. The benefits and risks of surgery and anaesthesia will be carefully weighed up and explained to you before you have any operation.
Very rare possible complications include:
- Permanent nerve damage – this can cause numbness or paralysis (inability to move a part of the body), although this may be a result of the surgery itself; peripheral nerve damage occurs in less than 1 in 1,000 anesthetics (the peripheral nerves run between the spinal cord and the rest of the body)
- An allergic reaction to an anesthetic medication (anaphylaxis) – although this can be severe, appropriate treatment is on hand to enable the best chance of dealing with this effectively and immediately; it’s not clear exactly how often anaesthetics cause anaphylaxis, but the best estimate is that a life-threatening allergic reaction occurs during 1 in 10,000 to 1 in 20,000 anesthetics
- Death – there are approximately 10 deaths for every million anesthetics given in the UK.
Your risk of developing complications will depend on a number of factors, including:
- Your medical history – for example, whether you have any other serious medical conditions or illnesses
- Personal factors – for example, whether you smoke or are overweight; if you smoke, stopping several weeks before your operation will reduce your risk of having breathing problems, and losing weight will also help reduce your risk
- The type of procedure – for example, whether it’s a planned or an emergency procedure, or whether it’s a major or minor procedure
- The type of anesthetic – local anesthesia can have advantages over general anaesthetics in the right circumstances
Before your procedure, your anesthesiologist will explain if there are any particular risks of developing possible complications.
In most cases, the benefits outweigh the risks. Any concerns you have should be discussed with your anaesthesiologist before surgery.