The Development of Anaesthesia

  by Siha H

Most of the surgery we hear about today is a successful, painless procedure, thanks to anaesthetics. Anaesthetics are substances, often a carefully calculated combination of gases and drugs used to control one’s sensation to avoid discomfort and pain during medical procedures. The effects of anaesthetics can range between partially numbing one area of the body (which is done by injecting that part with a local anaesthetic), or making someone unconscious by administering a general anaesthetic, typically as a gas. Before the 1840s, when they started being used more frequently, operations were emotionally distressing and traumatising for both the patient and the doctor, where the patient could be knocked unconscious beforehand or simply held down by other doctors.

The earliest forms of pain relief were crude forms of sedation - this would make a patient relaxed or less conscious - such as giving them alcohol or opium. Opium would be extracted from the opioid poppy, and it is a depressant drug, therefore it would slow down the messages travelling from the pain receptors to the brain. Other drugs such as cannabis (‘weed’) were often used too. Sedative potions like these can be traced back to approximately 200 AD, where Chinese surgeon Hua Tuo mixed and administered herbal extracts before complex operations, and he successfully performed numerous complex surgeries. 

In the Middle Ages a sedative potion known as ‘Dwale’ emerged, and it was a combination of bile, opium, hemlock, vinegar, lettuce and other ingredients, all given to the patient with alcohol. Opium and hemlock are poisons which our bodies are very sensitive to, and it would not take much for an overdose, yet it is likely that when dwale was used the plants they came from would have been less potent, and even less so after the process of boiling. Dwale would result in drowsiness in the patients which was effective, yet sometimes caused hallucinations too.

One of the most influential early medical texts was The Canon of Medicine, five books forming an encyclopaedia, and it was written by Ibn Sina, also known as Avicenna, an Islamic philosopher and physician from Uzbekistan. Within The Canon, the use of a sponge soaked in herbal potions was described. This sponge or cloth would be placed under the nose of a patient during surgery to keep them sedated, and inhaling sedatives made from herbs was more effective than ingesting the potions, and likely far safer too.

One of the most well known forms of pain relief was laughing gas, or nitrous oxide gas, discovered as effective pain relief by Humphrey Davy in 1798, who inhaled it and found his toothache less painful. It was not immediately accepted when he proposed its use as an anaesthetic but was often used in parties due to the state of euphoria it caused in those who inhaled it. The gas would displace oxygen from the blood and cause an increase in the stimulation in the brain necessary for making dopamine - the hormone that makes you feel good. In the nineteenth century Henry Hill Hickman experimented on animals by administering carbon dioxide to them before amputating; seeing if they felt pain or not. His discoveries were dismissed by a president of the royal society, but despite that carbon dioxide is still used in anaesthetics today.

The first general anaesthetic to become popular in surgery was ether. Ether however was first discovered by a Prussian botanist called Valerius Cordus and it was used as medication for spasms. It then became popular as a drug used in parties, similar to laughing gas, ‘ether frolics’ became a trend in America, and it was taken by inhaling the smell of the drug from towels. Dr Crawford Long, a pharmacist and physician, went to an ether frolic and noticed how after taking ether some people who got into fights did not seem to experience pain and so he decided to use this in his surgeries. The results were successful when he started in 1842 - a patient having a tumour removed from their neck said they felt little pain, yet he wanted to keep testing - and when he did publish his results seven years later, someone else had already done so. This was Willian T.G. Morton, a dentist. He used a combination of sulfuric ether, fragrance and colourings and called it ‘Letheon’ (the name of a river in Greek mythology that caused forgetfulness). He performed a surgical demonstration at Harvard Medical School using Letheon and after its success, Morton was seen as the person who discovered the potential anaesthetic purpose of ether. Morton had placed a sponge soaked in ether in a glass globe with two spouts, one of which the patient would breathe in through. Ether was officially used by the US Army from 1849.

Chloroform was discovered as an anaesthetic and used in obstetrics by Professor of Midwifery James Simpson. It had been invented in 1831 however it was not studied thoroughly, though in 1842 it had shown to be a good though risky anaesthetic in animals by Dr Robert Glover. Simpson first tried using chloroform on humans in 1847, where he and his two assistants took it. The three of them often sampled different chemicals, experimenting with the effects of them. After taking the chloroform in the evening, they felt emotional changes before collapsing and regaining consciousness hours later in the morning. Simpson had been an advocate for using anaesthesia in obstetrics, and after he found chloroform to be a suitable substance for it, Dr John Snow administered it to Queen Victoria when she gave birth to her children. This gave it the royal seal of approval and surgeons in England began using it more and more. 

Modern anaesthetics typically use the following substances: halothane, enflurane, isoflurane, nitrous oxide and methoxyflurane. Less dangerous and more pleasant for the patient to take than some of the previously discovered anaesthetics, these substances can be controlled better too. There are a few ways for these substances to work: some directly affect cells which results in a loss of sensation in specific areas, others pause brain function in specific areas. Overall, anaesthesiology is an area of medicine that has evolved significantly over centuries and developments within it have revolutionised surgery.