Sometimes the whole is greater than the sum of its parts
This quote perfectly describes anaesthesia in the 21st century
For the past two hundred years brilliant human beings working in the fields of pharmacology, medical equipment, and academia developed anaesthetic gasses, drugs and devices to manage airways and delivery systems. The result is the medical speciality of anaesthesia and its development ranks among the greatest advances in modern medicine.
Pain has been overcome and the surgical techniques used today are only possible because of modern anaesthesia. Every human on the planet has and will be grateful for modern anaesthesia. This article touches on some of the key moments and people responsible for that development.
In the U.K. Joseph Priestly discovered Nitrous Oxide in 1792 and in 1799 Humphrey Davy described the properties of euphoria and analgesia when the gas was inhaled. Michael Faraday was studying Ether and published his findings in 1818 describing how the gas induced drowsiness and sleep together with an analgesic effect.
We move to the U.S.A where a young Boston Dentist William Morton induced anaesthesia in a patient using ether and Dr. John Warren, a surgeon at Massachusetts General Hospital removed a tumour from a patient’s neck performing the first successful surgical procedure with anaesthesia. When Morton administered the ether, the process didn’t have a name. Later that year, Oliver W. Holmes, a writer, and professor of anatomy, named the process which Morton demonstrated as anaesthesia, derived from the Greek for ‘without sensation.’
Once ether was used then further inhalational agents were introduced. Chloroform was introduced by the Professor of Obstetrics in Edinburgh, James Simpson, in 1847. This was a more potent agent, but it had more severe side effects. It could precipitate sudden death, particularly in very anxious patients and it also had the potential to cause late-onset and very severe liver damage. However, it worked well and was easier to use than ether and so, despite its drawbacks, became very popular.
In the 20th century, significant advances were made in developing better inhaled agents
The use of ether and chloroform fell away as newer and much safer products were developed. Halothane was introduced in the 1950’s and is still used today. Isoflurane, desflurane and sevoflurane were developed later, and this group are the most commonly used agents in practice today.
Anaesthesia produced by nerve block, or regional anaesthesia, became possible after cocaine was isolated from the coca plant in 1860. Dr Karl Koller first produced anaesthesia of the skin and mucous membranes in 1884 in Vienna. In New York in 1885, Dr J.L. Corning, an American neurologist gave the first spinal anaesthetic. The German surgeon August Bier developed Corning’s work and he conducted the first operation under spinal anaesthesia in 1898. Bier pioneered the use of intravenous regional anaesthesia, a technique which is commonly referred to as a "Bier block".
Intravenous anaesthetics were developed to put a patient to sleep before an operation (induction)
The first intravenous anaesthetic, sodium thiopental (thiopentone), was not synthesised until 1934. Sodium thiopental is a short-acting, rapid-onset barbiturate sometimes used for anaesthetic induction. Its earliest documented use in humans was later in 1934 by Ralph Waters, an American anaesthetist. Intravenous anaesthesia allowed more precise dosing and Sodium thiopental was commonly used. Although it remained popular for many years sodium thiopental was gradually replaced by propofol which was introduced in the 1980’s and became the preferred induction agent. Other intravenous anaesthetics in use today are Etomidate and Ketamine.
Alongside the development of induction agents, muscle relaxants were also introduced. Although known by this title they are neuromuscular blocking drugs that enable light anaesthesia to be used with adequate relaxation of the muscles of the abdomen and diaphragm. They also relax the vocal cords and allow the passage of a tracheal tube. Curare was the first muscle relaxant used in the 1950’s. Much later other intravenous muscle relaxants were developed including vecuronium, atracurium, rocuronium and suxamethonium.
Fundamental to modern anaesthesia is the establishment of a safe, secure airway
This allows the patient to be ventilated and the delivery of anaesthetic gasses to the patient. The laryngeal tube had existed since the late 16th century. A tracheostomy was carried out and the tube was inserted through an incision in the windpipe. The first successful delivery of endotracheal general anaesthesia was performed through tracheotomy by German surgeon Friedrich Trendelenburg in 1871. This procedure became well established but there was a need to develop a non-surgical solution to airway management. Early attempts were made to place a metal catheter into the larynx blindly and use bellows to ventilate the patient.
Intubation developed further in 1895 when the German physician Alfred Kirstein conducted the first laryngoscopy that allowed the physician to see the vocal cords. This paved the way, allowing physicians to visually insert catheters and tubes deep into the patient’s airway. By the early 20th century direct laryngoscopy and endotracheal intubation(ETT) became very common. A further development took place when, in 1943 Sir Robert McIntosh introduced his curved blade. Today, the McIntosh laryngoscope blade is the most widely used laryngoscope blade.
The Guedel airway was introduced in 1933. It is an oropharyngeal airway and is made up of a rigid plastic tube which sits along top of mouth and ends at base of tongue, preventing it from obstructing the airway.
The laryngeal mask airway (LMA) was developed in the 1980’s by a British anaesthetist Dr. Archie Brain. It was first used in 1988. It provided a clear airway and sat just behind the larynx as opposed to the ETT which sits deep in the trachea. Advantages of the include producing less stress to the patient’s body and causing less coughing and throat discomfort. Also, patients need less anaesthetic when an LMA is used.
One further development took place in the early 20th century which significantly helped in the development of anaesthesia
In the late 19th century when nitrous oxide, ether and oxygen were combined as the anaesthetic gas. Around the same time the ability to compress gasses into a liquid form in metal cylinders was developed allowing anaesthesia to become more portable. Some sort of machine was needed to mix and transport the gasses.
The American anaesthetist James Gwathmey developed and introduced the first continuous flow anaesthetic machine in 1912. This machine was further developed by the British anaesthetist HEG Boyle, and he introduced his machine in 1918. It became known as the Boyles Apparatus.
The original design was a wooden box, which contained cylinders of compressed oxygen and nitrous oxide, an ether vaporiser, and a water flow meter. Additionally, the machine had a manometer to measure the pressure in the cylinders, sensitive pressure-reducing valves, and an alcohol lamp (to prevent the nitrous oxide from freezing and thus obstructing the cylinder).
Although Gwathmey and others were the first to develop these machines, all the credit has gone to Boyle. His design became the standard for all anaesthesia machines going forward. Many improvements have been made to Boyle’s design and with the addition of mechanical ventilators in the 1950’s, the modern anaesthesia machine was born.
To chart the game changing people and events in the development of modern anaesthesia in a short blog has not been easy. I hope I have done it justice and made it interesting for you. The medical speciality of anaesthesia truly is greater than the sum of its parts.
Anaesthesia continues to develop and who knows where we will be in the 22nd century
Brilliant and dedicated people working in the fields of pharmacology, medical equipment, and academia are focused on that development with patient safety and experience at its heart.
One such individual is Dr. Andrew Wallis, a practising anaesthetist and medical director at Innovgas. He has developed our current product range of EyePro, NoPress and BiteMe with patient safety and experience in the operating theatre front and centre of everything we do at Innovgas. Why not view our Innovgas range and see for yourself how our products help keep patients safe during surgery and you too can play your part in the developing world of anaesthesia.
Author: Niall Shannon, European Business Manager, Innovgas
This article is based on research and opinion available in the public domain.
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