anaesthesia, general

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anaesthesia, general The idea of deliberately inducing unconsciousness to avoid the pain of an operation must have been a strange one to our forebears: ether, one of the earliest anaesthetics, had been known and available for some 300 years before it was used, and Humphry Davy, in 1800, had suggested nitrous oxide (laughing gas) for this purpose. Following the not entirely satisfactory introduction of nitrous oxide by the American dentist Horace Wells (1815–48) in Hertford, Connecticut, in December 1844, the first successful public administration of ether anaesthesia for a surgical operation was demonstrated by his colleague W. T. G. Morton (1819–68), on 16 October 1846, at the Massachusetts General Hospital, Boston. The news was brought to England by steam ship, and the first ether anaesthetic for a surgical operation in London was administered at University College Hospital on 21 December.

In England the practice of anaesthesia was established on a firm foundation of basic science by John Snow (1813–58), who devised inhalers which allowed him to know and control the strength of the vapour that the patient was breathing. The psychological barrier having been broken, the unpleasant and irritating ether was replaced within a year by the pleasanter and more potent chloroform, introduced primarily to relieve the pains of labour by the Scottish obstetrician James Young Simpson (1811–70). Other vapours were soon tried, but with less success. Although the inception of general anaesthesia at this particular time is attributed by some historians to the development of a greater sense of empathy with one's fellows, citing in support of this thesis the many humanitarian reforms of the early Victorian period, it has to be pointed out that general anaesthesia originated not in Great Britain, but in the US, where the climate was quite different. Morton, who tried to patent the process, was motivated by the desire to emulate the entrepreneurial success of other Americans who had become extremely wealthy in a very short time. It is significant that both Wells and Morton were specifically looking for a means of rendering dental extractions pain free.

The spread of the practice of anaesthesia across the globe has been traced assiduously in recent years, but research has shown also that its availability tended to be restricted by financial considerations. The operation for club foot, without an anaesthetic, described vividly by Flaubert, son of a surgeon, in his novel Madame Bovary, was not a rarity in real life, and as late as 1893 some English Poor Law institutions were being criticized for not providing anaesthesia for surgical operations. But John Snow was called in 1853, and again in 1857, to administer chloroform to Queen Victoria in childbirth.

Snow introduced quantitative methods into anaesthesia. He recorded the amount used in each case, attempted to measure in animals the blood level of ether and chloroform required for surgical anaesthesia, and established that the potency of an anaesthetic agent is inversely related to its solubility in the blood. At his death his mantle fell on Joseph Clover (1825–82), who devoted his life to making anaesthesia safer. The photograph below, well known to anaesthetists, shows him demonstrating the induction of chloroform anaesthesia with a finger on the patient's pulse. He was involved in reintroducing nitrous oxide into anaesthetic practice during the late 1860s, and devised a number of apparatuses, one of which, the famous Clover inhaler, remained in use, in its various modifications, for many years.

Following Clover's death, British anaesthesia settled into a state of complacency and inertia, until stirred out of it towards the turn of the century by the physiologist A. D. Waller (1856–1922). Concerned by the steadily increasing number of deaths attributed to chloroform, Waller advocated limitation of the concentration being inhaled, and stimulated the design of several ‘dosimetric’ apparatuses. But the peripatetic anaesthetist, who generally gave his hospital services free, and travelled from one nursing home, or even private house, to another, to earn his living, had little enthusiasm for anything which could not be carried in his pocket or his top hat. Hence the popularity of the ‘rag and bottle’ widely used for chloroform.

In 1910 Frederick Hewitt, the leader of the specialty, pointed out that whereas it was illegal to sell alcohol without a licence, anyone, even a hospital porter or the surgeon's coachman, could, and did, administer anaesthetics. But his attempt to get the practice of anaesthesia restricted to the medically qualified received no support from the then Home Secretary, Winston Churchill, and to this day there is no specific legislation on the subject. In the 1890s Hewitt designed a nitrous oxide apparatus which remained in use in casualty departments and dental surgeries for the next 40 years. The gas flowed to the face mask via a large rubber reservoir bag and a three-way valve. The routine was to administer pure nitrous oxide until the patient was deep blue, then allow one breath of air via the valve, or two if the patient was twitching, then settle down to three breaths of gas to one of air.

The Great War brought with it the Boyle's machine, a name now generically applied to most anaesthetic apparatuses. Copied by H. E. G. Boyle (1875–1941) of St Bartholomew's Hospital from an American apparatus, this incorporated cylinders of nitrous oxide and oxygen, a flowmeter, and vaporizers for ether and chloroform, all mounted on a trolley. The vapour mixture flowed to the patient via a reservoir bag, delivery tube, expiratory valve (the breathing circuit), and a face mask.

The Great War also put many possible developments into abeyance, and during the 1920s the lead passed to the US. The 1930s saw the introduction of new inhalational agents, notably cyclopropane, so potent that it could be given with a high percentage of oxygen, and as a result valuable for the developing surgery for lung disease. The decade saw also the spread of ‘mechanization’, deplored by some, the increasing use of Boyle's-type machines to replace the ‘art’ of dripping ether or chloroform onto a gauze-covered wire mask. Also, rather tentatively at first, came the introduction of drugs which could be given by intravenous injection to induce unconsciousness rapidly and avoid the unpleasantness of an inhalational induction. This, together with the development of methods that involved passing a tube through the larynx into the trachea to prevent obstruction of the air passages during operations on the nose and throat, and to allow control of respiration during surgery of the lungs, required the anaesthetist to learn a range of new skills. This did not come easily to the older generation.

The 1930s also saw a drive, led by Lucy Baldwin, wife of the then Prime Minister, towards the improvement of pain relief in midwifery. The Minnitt apparatus, devised by R. J. Minnitt (1890–1974) of Liverpool in 1934, supplied a mixture of nitrous oxide and air, and was approved by the Central Midwives Board for use by midwives without medical supervision. Another important development, which stemmed from the generosity of Lord Nuffield, was the establishment in the University of Oxford of an academic research and teaching department with its own professor, the first in the UK.

Anaesthesia developed rapidly during the second half of the 1940s, both in techniques and standards. During World War II many doctors were trained as anaesthetists in the Forces, and found hospital appointments on demobilization, during the run-up to the establishment of the National Health Service in 1948, so expertise became much more widely spread. Until the late 1940s, outside the major teaching hospitals, the great majority of general anaesthetics were given by self-trained general practitioners who had learned the easy way, and by dentists usually working dangerously on their own.

The introduction in 1946 of the relaxant drugs — derived from curare, the South American arrow poison — dramatically changed the techniques of anaesthesia. One of the problems was always to secure relaxation of the muscles, particularly in abdominal surgery, where the sensitiveness of the viscera tended to produce spasm of the abdominal muscles, causing the intestines to be heaved out, and the surgeon to complain about the moving target. The older inhalational anaesthetics affected every cell in the body. Their safe use depended on the nervous system being more susceptible than the remainder. This could be relied on in a healthy person, but not, for example, where there was a diseased heart. But now, rather than soaking the whole body with ether, with the postoperative sequelae of prolonged nausea and vomiting, it was possible to aim at specific pharmacological targets, so the concept of the ‘anaesthetic triad’ was developed, using one drug to produce unconsciousness, another for analgesia, and a third for muscular relaxation. Paralyzing the muscles required that the anaesthetist take over the ventilation of the patient's lungs, and this resulted in the development of automatic ventilators, the forerunners of today's life support machines. The expertise so learned brought anaesthetists to the care of the seriously injured or ill, and thence to involvement in the development and staffing of intensive care units. Expertise in performing nerve blocks with local anaesthetics led to the treatment of severe and chronic pain, and the establishment of pain clinics, a movement which started during the 1960s. A third development during the same period was the growth of the obstetric epidural analgesia service.

The work of the anaesthetist has been greatly aided, and the safety of the patient greatly improved, by the introduction of sterile disposable equipment — at first, syringes and needles, which removed the need to keep in one's waistcoat pocket a small sharpening stone (an Arkansas slip), and a fine wire, for removing hooked points and blood clots from non-disposable needles which were repeatedly resterilized and reused. More and more items, even entire breathing circuits, and complete sterile packs for the induction of epidural anaesthesia, have become available in disposable versions, minimizing the risk of infection being transferred from one patient to another.

Another major development, commencing in the 1970s, has been the increasing availability of apparatus which allows the anaesthetist to monitor routinely not only the patient's pulse rate, blood pressure, and electrocardiogram, but also such physiological parameters as the oxygen and carbon dioxide levels in the blood. This, together with the measurement of blood loss during operations, provides an early warning of possible problems. The new generation of inhalational and intravenous agents, which are rapidly removed from the body leaving no hangover, has greatly improved patient comfort and safety.

From the earliest days the British pioneers set the trend for safety, and self audit has been a continuing feature of anaesthesia. Several commissions of enquiry were set up by the profession from the 1860s on, and the tradition has been continued by the Association of Anaesthetists, which participates very actively in the establishment of the fruitful and continuing confidential enquiry into perioperative deaths (NCEPOD).

The older anaesthetists regarded their technique as an art, learned by trial and error. Today it is still an art, but established on a firm foundation of science, and in the UK has its own academic body to establish standards, supervise training, and conduct examinations for its own higher qualification, the Fellowship of the Royal College of Anaesthetists (FRCA).

David Zuck


Duncum, B. (1994, 1947). The development of inhalation anaesthesia. Royal Society of Medicine Press, London (1994). Oxford University Press (1947).
Rushman, G. B., et al. (1996). A short history of anaesthesia. Butterworth-Heinemann, Oxford.
Thomas, K. B. (1975). The development of anaesthetic apparatus. Blackwell, Oxford.
Thorwald, J. (1961, 1957). The century of the surgeon. Thames and Hudson, London (1957). Pan Books (1961).

See also anaesthesia, local; anaesthetic mechanisms; surgery.