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The practice of modern medicine

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psychi¬atric breakdowns, and malingering is more prevalent.

The medical branch may provide advice about disease prevention, but the actual execution of this advice is through the ordinary chains of command. It is the duty of the military, not of the medical, officer to ensure that the troops obey orders not to drink infected water and to take tablets to suppress malaria.

Army medical organisation. The medical doctor of first contact to the soldier in the armies of developed countries is usually an officer in the medical corps. In ðåàãåíòå the doctor sees the sick and has functions similar to those of the general practitioner, prescribing drugs and dressings and there may be a sick bay where slightly sick soldiers can remain for a few days. The doctor is usually assisted by trained nurses and corpsmen. If a further medical opinion is required, the patient can be referred to a specialist at a military or civilian hospital.

In a war zone, medical officers have an aid post where, with the help of corpsmen, they apply first aid to the walking wounded and to the more seriously wounded who are brought in. The casualties are evacuated as quickly as possible by field ambulances or helicopters. At a com¬pany station, medical officers and medical corpsmen may provide further treatment before patients are evacuated to the main dressing station at the field ambulance head¬quarters, where a surgeon may perform emergency oper¬ations. Thereafter, evacuation may be to casualty clearing stations, to advanced hospitals, or to base hospitals. Air evacuation is widely used.

In peacetime most of the intermediate medical units exist only in skeleton form; the active units are at the battalion and hospital level. When physicians join the medical corps, they may join with specialist qualifications, or they may obtain such qualifications while in the army. A feature of army medicine is promotion to administra¬tive positions. The commanding officer of a hospital and the medical officer at headquarters may have no contacts with actual patients.

Although medical officers in peacetime have some choice of the kind of work they will do, they are in a chain of command and are subject to military discipline. When dealing with patients, however, they are in a special po¬sition; they cannot be ordered by a superior officer to give some treatment or take other action that they believe is wrong. Medical officers also do not bear or use arms unless their patients are being attacked.

Naval and air force medicine. Naval medical services are run on lines similar to those of the army. Junior medical officers are attached to ships or to shore stations and deal with most cases of sickness in their units. When at sea. medical officers have an exceptional degree of re¬sponsibility in that they work alone, unless they are on a very large ship. In peacetime, only the larger ships carry a medical officer; in wartime, destroyers and other small craft may also carry medical officers. Serious cases go to either a shore-based hospital or a hospital ship.

Flying has many medical repercussions. Cold, lack of oxygen, and changes of direction at high speed all have important effects on bodily and mental functions. Armies and air forces may share the same medical services.

A developing field is aerospace medicine. This involves medical problems that were not experienced before space-flight, for the main reason that humans in space are not under the influence of gravity, a condition that has pro¬found physiological effects.

CLINICAL RESEARCH

The remarkable developments in medicine that have been brought about in the 20th century, especially since World War II, have been based on research either in the basic sci¬ences related to medicine or in the clinical field. Advances in the use of radiation, nuclear energy, and space research have played an important part in this progress. Some laypersons often think of research as taking place only in sophisticated laboratories or highly specialized institutions where work is devoted to scientific advances that may or may not be applicable to medical practice. This notion, however, ignores the clinical research that takes place on a day-to-day basis in hospitals and doctors' offices.

Historical notes. Although the most spectacular changes in the medical scene during the 20lh century, and the most widely heralded, have been the development of potent drugs and elaborate operations, another striking change has been the abandonment of most of the remedies of the past. In the mid-19th century, persons ill with numer¬ous maladies were starved (partially or completely), bled, purged, cupped (by applying a tight-fitting vessel filled with steam to some part and then cooling the vessel), and rested, perhaps for months or even years. Much more recently they were prescribed various restricted diets and were routinely kept in bed for weeks after abdominal oper¬ations, for many weeks or months when their hearts were thought to be affected, and for many months or years with tuberculosis. The abandonment of these measures may not be though of as involving research, but the physician who first encouraged persons who had peptic ulcers to eat normally (rather than to live on the customary bland foods) and the physician who first got his patients out of bed a week or two after they had had minor coronary thrombosis (rather than insisting on a minimum of six weeks of strict bed rest) were as much doing research as is the physician who first tries out a new drug on a patient. This research, by observing what happens when remedies are abandoned, has been of inestimable value, and the need for it has not passed.

Clinical observation. Much of the investigative clinical field work undertaken in the present day requires only relatively simple laboratory facilities because it is observa¬tional rather than experimental in character. A feature of much contemporary medical research is that it requires the collaboration of a number of persons, perhaps not all of them doctors. Despite the advancing technology, there is much to be learned simply from the observation and analysis of the natural history of disease processes as they begin to affect patients, pursue their course, and end, either in their resolution or by the death of the patient. Such studies may be suitably undertaken by physicians working in their offices who are in a better position than doctors working only in hospitals to observe the whole course of an illness. Disease rarely begins in a hospital and usually does not end there. It is notable, however, that observational research is subject to many limitations and pitfalls of interpretation, even when it is carefully planned and meticulously carried out.

Drug research. The administration of any medicament, especially a new drug, to a patient is fundamentally an experiment: so is a surgical operation, particularly if it involves a modification to an established technique or a completely new procedure. Concern for the patient, care¬ful observation, accurate recording, and a detached mind are the keys to this kind of investigation, as indeed to all forms of clinical study. Because patients are individuals reacting to a situation in their own different ways, the data obtained in groups of patients may well require statistical analysis for their evaluation and validation.

One of the striking characteristics in the medical field in the 20th century has been the development of new drugs, usually by pharmaceutical companies. Until the end of the 19th century, the discovery of new drugs was largely a matter of chance. It was in that period that Paul Ehrlich, the German scientist, began to lay down the principles for modern pharmaceutical research that made possible the development of a vast array of safe and effective drugs. Such benefits, however, bring with them their own disadvantages: it is estimated that as many as 30 percent of patients in, or admitted to, hospitals suffer from the adverse effect of drugs prescribed by a physician for their treatment. Sometimes it is extremely difficult to determine whether a drug has been responsible for some disorder. An example of the difficulty is provided-by the thalidomide disaster between 1959 and 1962. Only after numerous deformed babies had been born through¬out the world did it become clear that thalidomide taken by the mother as a sedative had been responsible.

In hospitals where clinical research is carried out, ethical committees often consider each research project. If the committee believes that the risks are not justified, the project is rejected.

After a potentially useful chemical compound has been identified in the laboratory, it is extensively tested in an¬imals, usually for a period of months or even years. Few drugs make it beyond this point. If the tests are satisfactory, the decision may be made for testing the drug in humans. It is this activity that forms the basis of much clinical research. In most countries the first step is the study of its effects in a small number of health volunteers. The response, effect on metabolism, and possible toxicity are carefully monitored and have to be completely satisfactory before the drug can be passed for further studies, namely with patients who have the disorder for which the drug is to be used. Tests are administered at first to a limited number of these patients to determine effectiveness, proper dosage, and possible adverse reactions. These searching studies are scrupulously controlled under stringent condi¬tions. Larger groups of patients are subsequently involved to gain a wider sampling of the information. Finally, a full-scale clinical trial is set up. If the regulatory authority is satisfied about the drug's quality, safely, and

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