RELIEF OF PAIN

Evening Star, Issue 22326, 30 April 1936, Page 12

RELIEF OF PAIN

WIDE RANGE OF NEW DRUGS The arguments for euthanasia, for the legitimacy of self-destruction in certain circumstances, _ depend on various facts, one of which is the existence of continuous pain, writes the scientific correspondent of the ' Manchester Guardian.’ Before forming an opinion on this subject it is necessary to discuss the prospects of relieving pain. If the progress of medical science should reveal how pain could be eliminated, the plea for the legalisation of self-destruction would be less relevant. Pain may be eliminated by two methods. If it is due to disease it may be eliminated by curing the dis-. ease, or if the cure is unknown _by interfering with the mechanism through which it is felt. The first method depends on the general advance of medical science and the prevention and cure of disease. The second depends largely on the progress of one branch of the science of drugs. As the approach of the first method is the more fundamental, vastly more is to be expected from it, and has actually been accomplished through it, than from the second. The increased knowledge of drugs has been of far greater use in treatments for the cure or alleviation of disease causing pain than in the direct and continuous suppression of pain. Gunn, opium, and its components, such as morphine, remain the best drugs for relieving continuous severe pain. .The great achievements of th» modern science of drugs have consisted mainly in increasing the scope and effectiveness of surgery and in alleviating diseases that in 'turn led to relief from pain. The drugs of special importance in surgery are anaesthetics, which suspend sensation completely or locally. They are not required to act for more than the few minutes or hours of the operation, but during that short period their effects on the patient should be under sensitive control. The operators should be able to vary the depth of the unconsciousness rapidly, in order to adapt its degree to the condition of the patient during the operation. The surgeon requires rapid and easily controllable anmsthetics. It is to be expected that these will be found among gases and vapours, for these may be easily controlled and introduced into the blood stream very rapidly. The whole of the blood in the body passes through the lungs once in 30sec, so breathing may be a remarkably rapid method of absorbing a drug. The effects of liquid drugs injected or passed into the blood may be much slower and more difficult to control, because liquids diffuse much less quickly than gases. , Gases may be introduced through the patient’s breathing in infinitely variable mixtures and concentrations; but liquids cannot easily be run into his veins in infinitely variable mixtures. This is one of the fundamental reasons why gaseous anaesthetics are so important. FIRST OBSERVATIONS.

The first observations of the anaesthetic properties of gases were due to Thomas Beddoes. He believed that the discovery of the nature of gases by the eighteenth century chemists, such as Priestly, must have important medical applications. He founded a Pneumatic Institute at Bristol to investigate the medical properties of gases, and engaged Humphrey Davy, then 20 years old, ns his assistant.

Beddoes used to take cows into his patients’ bedrooms because be believed their breadth might be of medical value. In 1800 he noticed the anesthetic properties of ether vapour, and in 1799 he and Davy noticed those of nitrous oxide. In 1800 Davy suggested the use of nitrous oxide for minor operations. The medical profession ignored these observations for 42 years, until American dentists began to use ether and nitrous oxide as anaesthetics. Some years later Simpson introduced chloroform. For many decades ether was much used in the_ United States and chloroform in Britain. Chloroform is about four times as strong an anaesthetic as ether, and partly for this reason three times as dangerous, though the rapidity of its action may be convenient for the surgeon. Mixtures of nitrous oxide, oxygen, and ether are now considered generally to be the best. In 1912 the American Medical Association advised against the use of chloroform.

COMPARATIVE DEATH RATES. According to statistics published by Bortone in 1932, . the death rate per thousand cases treated with nitrous oxide and oxygen mixtures 0.44, and for nitrous oxide-oxygen-ether mixtures. 0.35. The skill of the anaesthetist is ot great importance.' The death rate_ in cases treated by untrained anaesthetists is three and a-half times that in cases treated by experienced anaesthetists. In recent years important advances in premedication, the preparation of the patient for the operation, have been made. The patient is given a drug which relieves his apprehension, of the removal to the operating theatre and the application of the anesthetic. . , ~ , The anaesthesia is then completed with nitrous oxide : oxygen-ether mixtures, or with a spinal or local ansesthetic. . . The new premedication drugs that have given so much psychological relief to patients are tri-brom-ethyl-alco-bol or overtin, introduced by Eichholtz in 1927, and various derivatives of barbituric acid. _ Nebelthau discovered the first barbituric acid drugs in 1898, and chemists have synthesised about 60 of them. Their chemical structure indicates that this number is only a small fraction of the possible barbiturates, and more are being discovered rapidly. Two out of the long list of barbiturates are di-ethyl barbituric _ acid, variously named baritone, barbital, or veronal; and sodium ethyl methyl butyl barbiturate, known as nembutal. Barbituric acid derivatives are proving valuable in the treatment of mental disorders and epilepsy, for calming excitement. But they are not as effective as opiates for relieving pain. Professor A. J. Clark writes that it is very difficult to assess the relative merits of hypnotic drugs, such as the barbiturates and others. The newer are generally overvalued, and the older undervalued, because the dangers of the first are not as familiar as those of the second. The recent progress in the science of drugs has much reduced the _ unpleasantness of surgical operations, but has not contributed very much to the relief of constant severe pain due to incurable disease. It is much easier to improve unpleasant but short techniques such as operations than to discover drugs that null relieve a patient from pain for periods of months or years. The steady control for years of the state of a living organism is technically far more difficult than complicated control for a short period of three hours or so.