The history of veterinary and human anaesthesia as practised today began in 1847; however, the word “anaesthesia”, first used by Plato (c.424-348 BC), was in a philosophical context describing an “impulse” transmitted to the brain not being received. One should also remember the Old Testament, Genesis 2:21-22, wherein God caused Adam to fall into “a deep sleep” before removing his rib to create Eve – words valued later in the story of anaesthesia.
The (very) early days
In ancient times, there was great interest in the relief of pain, which caused many methods to be explored.
Herodotus (c.484-425 BC) refers to the inhalation of hemp (Cannabis sativa), hashish or marijuana to produce “intoxication”. Pliny (24-79 AD) mentions the juices of certain leaves used to aid sleep or reduce pain, and Dioscorides (40-90 AD) described the opium poppy (Papaver somniferum) – the source of morphine, codeine and heroin – as a pain-easer and sleep-causer. He also observed that the liquid which results from boiling the root of the mandrake plant (Mandragora spp) in wine produces unconsciousness and narcosis to aid sleep and “abolish” pain. This was also said to have been used to aid surgery, but few details are given.
Over many generations, a variety of concoctions were used for pain relief and surgery. Mandrake, hemp, henbane, hemlock and opium have all been used in various combinations
Over many generations, a variety of concoctions were used for pain relief and surgery. Mandrake, hemp, henbane (Hyoscyamus niger), hemlock (Conium maculatum) and opium have all been used in various combinations to induce anaesthesia.
Other methods described to control pain in surgery were the compression of nerves and blood vessels close to the operation site or compression at the neck to produce unconsciousness. Alcohol consumption to induce drunkenness was used and sometimes simply a sharp hard blow to the head! However, all these methods were both dangerous and essentially uncontrollable.
The emergence of modern anaesthesia
A new definition
While there was no significant progress towards developing anaesthetics before the 1750s, the word “anaesthesia” was redefined as “a defect of sensation as in paralytic or blasted persons” in 1751.
Then in 1753, the German chemist Wilhelm Frober synthesised di-ethyl ether. This was just before Joseph Black discovered carbon dioxide gas in 1754, followed by Joseph Priestley’s discovery of oxygen (1771) and nitrous oxide (1772). The key elements of what would be called “pneumatic medicine” had been identified! The first use of ether was as a headache cure in 1773 by William Cullen of Edinburgh, but it was not until the 1790s that it was recognised as a “pneumatic” medicine.
Laughing gas, ether, carbon dioxide and more
Sir Humphry Davy (1778-1829), a brilliant chemist and inventor, discovered the properties of nitrous oxide in 1799. He was amazed that it made him laugh, so he called it “laughing gas” and wrote of its potential as an anaesthetic. The pleasurable effects of the drug were discovered in the 1830s, with parties held to enjoy the experience. During these, it was observed that injuries received as a result of falling over after taking the gas had not been felt. This began to develop the idea that the gas could be used for surgery, but it was poorly demonstrated publicly in 1844 and did not come into dental use until 1864.
In 1824, Henry Hill Hickman, an English surgeon, investigated the use of carbon dioxide (then called “fixed air”) on puppies and a mature dog. Hickman found they slowly went to sleep when placed in a carbon dioxide atmosphere; however, he did not realise he was asphyxiating them rather than demonstrating inhaled anaesthesia.
In 1831, chloroform was discovered simultaneously by workers in France, Germany and the USA, but it was not used as an anaesthetic until 1847.
William T G Morton, an American dentist and physician, experimented on dogs with ether before using it in his dental practice. He gave a successful public demonstration in October 1846, and two weeks later administered it for Dr John Collins Warren to painlessly remove a tumour from the neck of a patient. On 19 December 1846, London dentist James Robinson used ether for a painless tooth extraction. He was watched by London surgeons who immediately adopted the procedure. The age of modern anaesthesia was about to commence.
The birth of veterinary anaesthesia
On 29 January 1847, the first use of veterinary anaesthesia was reported in The Times of London: a horse had been successfully anaesthetised with ether at the Royal Veterinary College (RVC), probably by the then principal, William Sewell. Also that year, Edward Mayhew, MRCVS, a highly intelligent and innovative practitioner, published two papers in The Veterinarian titled “Inhalation of ether fumes” and “The vapour of ether”after testing the anaesthetic on himself and then dogs.
On 29 January 1847, the first use of veterinary anaesthesia was reported in The Times of London: a horse had been successfully anaesthetised with ether at the Royal Veterinary College
Curare
Sewell had also cooperated with medical researchers to investigate curare, the South American arrow poison discovered in 1516. In 1836, they explored its effect on a donkey, who survived a dose by receiving intra-tracheal artificial ventilation, and then lived for 25 years. Sewell wrote of its possible value in controlling muscle spasms in tetanus and rabies cases, and then, in 1838, he injected curare into two horses with tetanus as a trial. He stated that both survived following artificial ventilation but added they died later. This was the first use of curare medically, but it did not enter regular human practice until 1946.
Inhalant anaesthetics in veterinary practice
In the 1840s, Scottish physician James Young Simpson was looking for an anaesthetic to use in his obstetrical practice. He had tried ether but did not like its flammability; then, in 1847, he was given a sample of chloroform. He tried it on himself and, it is said, on two rabbits which was successful, but they were found dead the following morning! This seemingly did not trouble him – within a month, he had used it with good effect on 50 patients. He was the first person to use chloroform on humans but did not realise its potential risk and danger.
The religious faithful argued that the use of chloroform to relieve pain was unholy because, according to the scriptures, women were destined to be punished for Eve’s original sin of tempting Adam. Simpson, a deeply religious man who knew his Bible, retorted that anaesthesia was actually inspired by God who sent Adam into “a deep sleep”; he said God was the first anaesthetist! The argument ended in 1853 when Queen Victoria said she “was most gratified with the effect of chloroform” after two births.
Veterinary medicine now had two inhalant anaesthetics. Chloroform was initially the favourite, in particular for horses and large animals, and was administered by a facemask containing chloroform-soaked absorbent wool. However, it soon became obvious that this was a dangerous procedure (as was also recognised in humans). For small animals, chloroform was administered by air pumped over liquid chloroform. Sir Frederick Hobday used both these methods, but Professor J G Wright was critical, stating chloroform use should be avoided where possible. Mixtures with alcohol and ether (AC or ACE) were also used.
Chloroform was initially the favourite, in particular for horses and large animals, and was administered by a facemask containing chloroform-soaked absorbent wool
Eventually, ether became the most popular anaesthetic for small animals, particularly for cats, where a 2lb jam jar containing a wad of ether-soaked cotton wool provided excellent controllable anaesthesia.
Intravenous methods
Pierre-Cyperien Ore, a French surgeon, tested intravenous choral hydrate in animals, and used it to anaesthetise humans in 1872. In 1875, it was used in horses, and in 1958, Wright described 20 years of its successful veterinary use.
A developing field
The field of veterinary anaesthesia was well developed by Professor Wright, working at the RVC. Together with Madeleine Oyler, they trialled and tested pentobarbitone and thiopentone in animals, which would become the mainstay of dog and cat anaesthesia – revolutionising small animal surgery. At the RVC, Gordon Knight studied endotracheal intubation in small animals with a newly designed pump. He was followed by Leslie Hall and then Barbara Weaver, who developed “balanced anaesthesia”, introducing premedication and a choice of barbiturates, cyclopropane, oxygen, nitrous oxide and trichloroethylene in the 1950s and 1960s.
And so modern veterinary anaesthesia became a part of everyday practice – allowing time for careful surgery, controlled respiration and recovery, and enabling a significant advance in both surgical technique and procedures.
