All About Anaesthesia…

The literal translation of anaesthesia is ‘loss of sensation‘.

anaesthesia

Anaesthetics are the medications used that cause anaesthesia which are used during tests and surgical procedures. Anaesthetics block the signals that pass along your nerves to your brain; after the anaesthetic has worn off, the nerve signals will be able to reach your brain and your feelings will return.

Types of Anaesthesia

There are a number of different types of anaesthetic and only general anaesthetic makes you unconscious.

  • Regional anaesthetic:- used for larger/deeper operations where nerves are more difficult to reach (this is commonly used for Caesarean sections). Only ever conducted in an environment where a team is able to easily provide general anaesthesia if necessary.
  • Epidural anaesthetic:- a type of local anaesthetic usually used to numb the lower half of the body. A needle is used to locate an area of the spine known as the ‘epidural space’ and can numb areas such as the thoracic area (chest), abdomen, pelvic area and legs
  • Spinal anaesthetic:- type of regional anaesthetic that is used to numb the nerves of your spine so that surgery can be performed in this area.
  • Sedation:- sometimes used for minor procedures- a sedative relaxes you physically and mentally.
  • Local anaesthetic:- used to induce the absence of sensation in part of the body ( local insensitivity to pain). Anaesthetics sometimes combine both local and general anaesthesia techniques.
  • General anaesthetic:- a drug that has the ability to induce a reversible loss of consciousness. These are given to a patient in order to facilitate surgery so that they don’t feel any pain

There are a number of theories about how general anaesthetics work, however, the precise mechanisms remain unknown.

Side Effects

Anaesthetics consist of a number of medications that can cause side effects in some people.
These are some of the side effects of general or regional anaesthetics:

  • Nausea or vomiting (1 in 3 people feel sick after an operation)
  • Sore throat
  • Aches and pains
  • Dizziness
  • Blurred vision
  • Headache
  • Itchiness
  • Bruising and soreness

These side effects do not last very long and can be treated with further medication if necessary.

Risks

Anaesthesia has become much safer over the years and advances have meant that serious problems are uncommon.
However, there are always potential complications:

  • Permanent nerve damage (cause numbness or paralysis)
  • Anaphylaxis (serious allergic reaction)
  • Death (approx. 5 deaths for every million anaesthetics given in the UK).

History of Anaesthesia

Thankfully, anaesthetics have been developed and so now they are used commonly under safe situations. However, it has not always been like this.
The concept of anaesthesia has been around since they have been performing surgery.

Early anaesthetics such as soporifics (which dull the senses and induce sleep) and narcotics (including opium, mandrake, jimson weed, marijuana, alcohol and belladonna) were all used as substitutes of today’s drugs. Although all of these can provide some pain relief, sedation or amnesia, there were no guarantees.
In mid 1840s, opium and alcohol were the only two substances used regularly as anaesthesia in industrial countries. There were many negative side effects to using these:

  • Patients could easily become addicted
  • The doses needed to provide the amount of pain relief/ sedation could easily result in death.
  • Surgery usually resulted in the tortured screams of patients because the anaesthesia wasn’t good enough.

1845– Dr Horace Wells was the first person to use nitrous oxide to pull teeth out

Dr Horace Wells

Dr Horace Wells

1846– Dr William Morton removed a tumour for the jaw of a patient. He used a sponge soaked in ether and the patient claimed he had no memory of the surgery or any pain.

Dr William Morton

Dr William Morton

Chloroform was first used as an anaesthetic in the mid 1840s by Dr James Simpson. It is highly toxic and so ether was used instead in the early 1900s.
Using a sponge made it hard to control the dosage and therefore, nitrous oxide is now used as an inhalable gas. Anaesthesiologists administer the drugs via machines that measure the specific amount necessary for each individual patient.

Because the drugs interfere with breathing, patients are often intubated- a plastic/ rubber tube is inserted in the trachea to keep the airway open- and then, during surgery, the patient is kept on a mechanical ventilator.

general-anesthesia-coma_1

Gamma Saves Lives

Today in Physics we were learning about radiation and one thing in particular was mentioned that I found particularly interesting.

Because cancer cells are the most vulnerable to radiation, radiotherapy is used as a way to get rid of certain tumours. We learned about the ‘Gamma Knife’ which is a non-invasive procedure that can be used as an alternative to open surgery; especially if the tumour is very hard to operate on due to its size or positioning (especially if it is in the brain).

This treatment fires 200 rays of gamma radiation from different angles to the tumour which destroys it, leaving a very low risk of ionising surrounding healthy tissue. Such a high dose is needed as gamma radiation is not very ionising, however, due to the fact that the rays are fired from different angles, it results in a very low dose of radiation around the tumour.

rays gamma

Gamma knife can treat a number of different conditions including:

  • benign, malignant or metastatic brain tumours
  • vascular malformations – this is when some of your arteries and veins in your brain are connected in ways they would not usually be
  • other disorders such as trigeminal neuralgia and Parkinson’s disease

The procedure isn’t suitable for tumours larger than 4 to 5cm and it is a very accurate procedure as it has precision of less than a millimetre.

Steps in preparing for Gamma Knife Treatment:

  • A light-weight frame is fitted to your head and local anaesthetic is injected into four sites on your head where it will be fitted with pins.
  • An MRI (magnetic resonance imaging) will be taken to identify the exact place that needs to be treated. You may also have a cerebral angiogram (an X-ray image of the blood vessels in your head and neck) if the treatment is for a vascular malformation. Occasionally, your doctor will recommend a CT (computerised tomography) scan. A CT scan uses X-rays to make a three-dimensional image of part of the body.
  • The images taken by CT, MRI or angiography will be fed into a computer that calculates the exact treatment time and dose of radiation needed.
  • The radiographers will leave the room after you are fitted into the machine and the whole process can take up to several hours.
Gamma Knife

Gamma Knife

Advantages of Gamma Knife:

  • There are very few side effects as it only targets the affected areas
  • There are less risks than open surgery
  • No general anaesthetic is needed (no risks from that)
  • No infection after surgery

This procedure has a 90% success rate which I would consider very good 🙂

Results Of Gamma Kife

Results Of Gamma Kife