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Aviation Medicine 100 years ago

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  • Aviation Medicine 100 years ago

    Aviation Medicine 100 years ago

    I have had a little quiet time recently so have been trying to catch-up on some journal back issues. There’s quite a pile unread on my study floor.

    In that pursuit I stumbled across this article authored by a Dr G A Sutherland. He’d recently left the Royal Flying Corps and wrote a lengthy (approx.10k words) monograph which was accepted for edition 4972 of The Lancet. The article was titled “Observations on the medical examination of aviation candidates”. Checking the front page I note that it was the 14 December 1918 edition of The Lancet … just over 100 years ago now.

    In the second paragraph, discussing the aviation medical standards Dr Sutherland tells us:
    “Too often these were cast iron standards, with a fine halo of antiquity about them, but quite unsuited for present day purposes.”

    Now, as a regulatory practitioner, I am often assailed by such statements … rarely as delightfully phrased as Dr Sutherland’s halo of antiquity … in efforts to argue that a particular medical situation should be accommodated or allowed by the medical standards. This was not the argument that Dr Sutherland was making, however, as his following sentence was “The employment of the same standards led to the admission of many unfit men into the flying service. These results are more serious in this service than in the case of the older services, because a flying man’s training is a particularly expensive one, and when he fails or breaks down it usually means that his flying days are over for ever.”

    Some of my other favourites are:
    “In order to arrive at correct decisions fitness for his work is also necessary in the examiner.”
    “It is not the case that flying duties require special qualifications other than those called for in many branches of sport and mountaineering and in many country occupations.” Followed by “If, for instance, we take the public-school boy who has been captain of his football team and has held his own in the class-room we require no elaborate examination with special tests to estimate his physical fitness for flying.”
    “Instead of endeavouring to standardise the tests I think that an attempt might be made to standardise the examiners.”
    “The youth who stammered as a boy, but has been free from the habit for some years, resumes it when he has been in the flying service for a time. The youth who never stammered before, but whose father had a stammer, develops the condition under the stress of flying work. The subject of a previous nervous breakdown at school will probably have another similar attack after a slight crash. In this part of the examination the history of any previous nervous disability, personal or familial, plays an important part.”
    “Be to his faults a little blind and to his virtues ever kind.”

    Anyway, I have tried to accurately transpose the article into digital text, and have pasted it below for your education and entertainment.
    _____

    Observations on
    THE MEDICAL EXAMINATION OF AVIATION CANDIDATES.

    BY G. A. SUTHERLAND, M.D. EDIN., F.R.C.P.LOND.,
    LATE MEMBER OF THE SPECIAL MEDICAL BOARD, ROYAL FLYING CORPS.

    INTRODUCTORY.

    THE aim of the special medical examination is to select from amongst civilians, cadets, and officers those who are constitutionally fit, or who appear to be fit, for flying duties. In order to arrive at correct decisions fitness for his work is also necessary in the examiner. Unfitness on his part may lead to two undesirable results: first, candidates who are physically fit may be rejected; and, secondly, candidates who are physically unfit may be passed. There is no doubt that in the past the flying services suffered from both of these results.
    It has been assumed too readily, and not by the lay public only, that it was an easy enough thing to decide as to a man’s fitness for any duty. Experience in the flying service has shown that it is by no means easy to do so as regards flying work. It is impossible to estimate how many physically fit men have been rejected for the flying service. The decision depended on the examiner’s skill and experience, and on the standards he had been taught or had had laid down for him. Too often these were cast-iron standards, with a fine halo of antiquity about them, but quite unsuited for present-day purposes. The employment of the same standards led to the admission of many unfit men into the flying service. These results are more serious in this service than in the case of the older services, because a flying man’s training is a particularly expensive one, and when he fails or breaks down it usually means that his flying days are over for ever.

    The Scope of the Examination.

    There are certain things that the examiner must bear in mind. It is not the case that flying duties require special qualifications other than those called for in many branches of sport and mountaineering and in many country occupations.
    If, for instance, we take the public-school boy who has been captain of his football team and has held his own in the class-room we require no elaborate examination with special tests to estimate his physical fitness for flying.
    At the other extreme we have the civilian lad who is townborn and town-bred, whose practical experience of athletics has consisted in looking on at football matches, whose working hours have been passed in an office, and his leisure hours in the streets or a music-hall. Merely by inspection one can decide at once that he is quite unfitted for flying work. Between these two extremes there is a large intermediary class requiring careful medical examination.
    The examiner should also know that the diseases and disorders of flying men are not different from those met with in the civilian population. The contrast between the two lies in this, that the causes of flying disabilities are not present in ordinary life. The results are the same in both cases. Thus air-sickness bears a very close resemblance to sea-sickness. The man who gets sea-sick when the vessel leaves port on a calm day gets very much worse when the ship is storm-tossed. The pilot who gets sick at straightforward flying gets very much worse when the plane is buffeted about by pockets of wind or when stunting is indulged in.
    While it is extremely desirable that the examiner should know how the causes of flying disorders will affect the candidate before him that knowledge is not yet forthcoming.
    It is asking too much of the examiner at the present stage of flying to expect him to recognise the proper flying temperament or any inherent tendency to develop disabilities in the air. What he should concentrate on is the selection of those only who are physically and mentally fit. The rest is guess-work.

    Special Tests.

    Attempts have been made both in this country and in America to standardise the examination by means of fixed tests. Some would allow the tests, or even a single test, to dominate and decide the examination. So far, however, no tests have been found which can be accepted as reliable, and most of them require much more testing, especially by experience, before they can be accepted as definite standards.
    One must remember how fallacious tests have proved in the past. A systolic murmur heard at the apex was for long considered an infallible test of heart disease and disability. Its presence has led to the rejection of countless fit men for army and navy service. It was only after long experience and bitter controversy that this test was recognised to be of no value in deciding as to the condition of a man’s heart. It was useful in calling for a careful examination of the heart, of the significance of the murmur, and of the presence or absence of any associated cardiac lesion or functional disability. This is the value of all special tests, that they direct one’s attention to certain organs or functions which require specially careful examination. For this purpose they are to be welcomed and used as finger-posts, but not to be regarded as impassable barriers
    .
    Guiding Principles.

    Instead of endeavouring to standardise the tests I think that an attempt might be made to standardise the examiners.
    If certain guiding principles were drawn up and accepted the carrying out of these principles would bring all the examiners into line. If the examiners viewed the medical problems involved from the same standpoint the results of the examination would tend to be uniform.
    In the following pages certain broad principles are suggested, as the result of my experience, which may serve as a guide to the medical examiner who is beginning this work. The examiner does not start with an aptitude for assessing the fitness of a candidate for air duties. It has been my experience and that of most trained examiners I have talked to, that a somewhat long and arduous apprenticeship has been necessary before a decision can be given with confidence. That has been partly due to the fact that we had no guiding principles and that the problems set were entirely new. This period of apprenticeship will be considerably shortened if the examiners are agreed about the principles of examination and the standards to be adopted, and can convey them to those who are beginners.
    It is not advisable for the examiner to bring too many preconceived ideas with him on commencing this work. He may in the course of his professional work have acquired certain views which have not been submitted to the criticism and judgment of his compeers. He may feel inclined to reject or to pass a candidate on grounds which would not commend themselves to other examiners. Such views and such decisions may usefully form a subject for discussion at the Examiners’ Board, but should not be carried out in practice at an early stage of the work. On the other hand, the new examiner is perfectly justified in declining to allow his judgment to be over-ruled because of some test, with an authoritative name attached, or because of some scientific toy which is stated to be an automatic pilot-finder. He is perfectly entitled to demand some definite proof of the validity of all such tests, and some more evidence of their value than that of the name behind them, or the fact that they are said to be amongst the latest scientific discoveries.

    Essential Qualifications for Air Service.

    The examiner must consider what are the special duties and dangers which will be experienced in a flying career. A pilot will have to carry out his duties in a new element, or at least in one which varies much in its composition from the stable atmosphere he has been accustomed to live and work in. He will have to acquire the complete control of a car moving through space in such a way that all his controlling movements become as automatic and unconscious as those of an expert bicycle-rider. He has, further, to be prepared for active fighting in the air, the attacking of enemy air-craft, and the protection of his own aeroplane and of his own life. No small requirements these.
    From the medical standpoint I consider that there are certain necessary qualifications to meet these conditions successfully, or at least with the prospect of success. The first is a good physique; then comes a sound cardio-vascular system; and, lastly, a strong and stable nervous system.
    These are the essential qualifications required to meet the special conditions of the air service, on the principle that where the strain falls the resisting power must be strong.
    The necessity for these qualifications is not based on theoretical considerations only. Practical experience at the Invaliding Board of pupils under instruction who have-failed, and of officers who have broken down from accidents, or stress of service, or inability to continue flying, has supplied strong confirmatory evidence. The symptoms complained of are numerous and various, such as fainting, giddiness, loss of consciousness, loss of control, exhaustion, headache, sleeplessness, loss of confidence, &c. An examination of those who present such symptoms and who are not suffering from active illness or gross injury shows that there has been usually an exhaustion or a giving out of the cardio-vascular or the nervous system. This is the outstanding fact in the vast majority of cases, and it is an indication to the examiner that he will do well to concentrate on these two systems in determining the fitness of a candidate for the flying service.
    The examiner should bear in mind that while he has to exclude candidates with gross disease of a disqualifying kind it is not from gross disease that the flying men break down and become useless. Apart from the direct injuries or wounds of the service and the effects of previous or recent illness, it is functional disabilities which bring flying men before invaliding boards and which swell the numbers of the "permanently unfit for further flying." Some organ or some system has given out and the flying power has gone, although the officer may be perfectly fit for general service on the ground. It is this tendency to functional disability and the importance it assumes in flying work that the examiner must remember. His duty is to seek out and discover, if possible, any such tendency. Sufficient evidence of its presence may be obtained in the previous history of the candidate or in the medical examination carried out on the above lines.

    Limitations of the Examination.

    The examiner will also bear in mind the limitations of his examination. It is primarily and essentially a medical examination to determine physical fitness. It is not expected that the examiner will be able to pick out the future cream of airmen at this early stage, any more than at an entrance examination at the university the future I leaders of the medical profession are to be recognised. The examiner passes all those who come up to his standard of physical fitness and leaves to the future training and experience the development of the individual’s flying ability.
    As already stated, the examiner must not be expected to decide as to which candidates have “the flying temperament” and which have not. It may be apparent at once, but. on the other hand, it is an elusive qualification and may be entirely latent until developed under actual flying experiences. Attempts to determine at the examination as to what heights the candidates should fly and what line of flying work he is best suited for are, to say the least, premature. These questions can be settled only with knowledge and precision as the result of training and experience.
    The mentality of the candidate must be considered, but a low grade does not disqualify unless the examiner considers that it is so low as to amount to mental defect or deficiency. The quick, alert examiner must not mistake the slow cautious youth for an imbecile. The mental calibre, if not up to flying duties, will be sufficiently tested at the examinations which the candidate has yet to pass as a cadet before entering on actual flying, and to that test the medical examiner may safely leave the doubtful cases.

    Points to be Determined.

    A careful examination must be made to determine the presence of any gross or disqualifying disease. That applies in every medical examination, and the candidates must be found “fit for general service.”
    Over and above this the examiner has to try to determine how the important vital organs and tissues are doing their work and how they are likely to respond to conditions of stress and strain. From his examination of the human machine at rest and under ordinary conditions he has to attempt to gauge how the mechanism will work under entirely different and much more strenuous conditions. It is not a question merely as to the sounds and size of the heart, but how the whole cardio-vascular system is to stand strain and what are its reserve powers. It is not a question of percussion resonance, or breath sounds about the lungs, but how efficiently the respiratory functions will be carried out in the flying sphere. Above all, has the candidate a nervous system which is strong and stable in itself and over which he can exercise control under novel and trying experiences
    This determination of the functional powers and of the reserve powers of the vital organs is difficult, but it is the chief problem which the examiner must try to settle. He must find out wherein the candidate is weak and wherein he is strong. It is in this connexion that single and standard tests fail, because their significance as regards the candidate’s functional powers has not yet been ascertained.
    The examiner has to form his decision on purely medical grounds. While appreciating a candidate’s keenness to become a flying officer, which may tend to cloud his memory as to some points in his medical history, the examiner must not allow such keenness to counterbalance any evidence of physical disability. While dealing courteously with any special influences from the powers that be in favour of a particular candidate, he must not allow any such influence to affect his judgment or decision. An examiner recognising his professional responsibility in deciding on the fitness of a candidate for the arduous duties of the air service should give his decision without fear and without favour.

    PREVIOUS HEALTH AND ILLNESSES.

    The importance of a careful investigation into the previous health and illnesses of a candidate cannot be overestimated.
    No examiner, however experienced, can deal successfully with his work if he omits this, and bases his opinion solely on tests and physical examination. It may be said that the candidate will conceal important facts in his eagerness to be passed, and many do. But with the examiner noting down his replies and cross-examining him the truth will be elicited in the majority of cases: In this inquiry also stress is to be laid on a history of special symptoms, which may be of importance in directing attention to particular organs in the physical examination which is to follow, or may be of such importance as to render the candidate unfit for flying.
    The examiner, for his own guidance, might lay down some such rule as the following: Any form of constitutional or acquired disability which has rendered, or which may render, the candidate liable to attacks of loss of consciousness, lapses of memory (mind a blank), fainting, loss of vision (hemianopia, temporary amblyopia), or prostrating headache should be a definite cause of rejection.
    As regards special diseases the following list comprises those about which particular inquiry should be made: Asthma, malaria, syphilis, rheumatic fever and chorea, digestive disturbances, migraine, petit mal, epilepsy, nervous debility, neurasthenia, shell shock, concussion with unconsciousness, chronic joint disease (especially of the knee), and the diseases of active foreign service. Several of these form an absolute bar to acceptance, while others must be considered from the point of view as to whether recovery has been complete or not.
    The complete examination of the flying candidate requires an investigation as to his fitness from a general surgical standpoint. A special examination must also be made as to the condition of the eyes, nose, ear, and throat. The candidate’s vision must be tested, and this is the only part of the examination where definite standards have to be employed. It is to be hoped that the standard of normal binocular vision will soon be established. The examination of the ear, including the labyrinth, brings up the question of vertigo and balancing. On this subject my colleague, Mr. Arthur Cheatle, has introduced various testing exercises.
    which are useful not only as bearing on labyrinthine efficiency but also as indications as to the nervous tone and stability generally.
    The internal organs must be examined in order to exclude organic disease and to test their functional activity. We shall consider more particularly the two most important systems-namely, the cardio-vascular and the nervous.

    THE CARDIO-VASCULAR SYSTEM.

    Our system of examination here proceeds on .somewhat different lines from those of the naval and army services.
    Under the term cardio-vascular system are included the heart, the arteries, the veins, and the capillaries. Two entirely separate abnormalities are recognised-namely, organic disease and cardio-vascular debility.

    I - ORGANIC DISEASE OF THE HEART AND BLOOD-VESSELS.

    Cardiac Murmurs.

    Organic disease of the heart is not common amongst candidates, but none the less it must be carefully examined for. The definitely disqualifying lesions, which are generally accepted in all the services, are mitral stenosis, as shown by a presystolic murmur at the apex, and aortic regurgitation, as shown by a diastolic murmur at the base Expressing I this in another way, one may say that a definite murmur occurring during the period of diastole is a cause for rejection. It is not necessary to discuss why these lesions should be viewed so gravely, because medical opinion seems for ’, once to be unanimous on the subject. As regards our own experience amongst candidates previously examined we have found a tendency to diagnose a mitral presystolic murmur when it was not there and to overlook an aortic diastolic murmur when it was present.
    Apart from these two conditions, little attention is paid to murmurs, systolic in time, which are heard about the praecordia, unless they are the result of rheumatic fever or are accompanied by definite pathological changes in the heart. A healthy youth who has never had rheumatic fever and who has never had any cardiac symptoms is not to be rejected because a systolic whiff or murmur is heard about the apex or the base. In the majority of the young candidates a careful examiner will detect a systolic murmur, with its maximum intensity over the pulmonic area; this is regarded as physiological and not pathological. A basal systolic murmur due to aortic stenosis is very rare-no case has occurred in my experience-and this lesion should not be diagnosed in the absence of clear evidence of hypertrophy of the left ventricle.
    If a systolic murmur is present at the apex and is regarded as due to mitral regurgitation, and if there is a history of rheumatic fever, it will probably be advisable to reject the candidate. This decision would not be based solely on the mitral lesion, but also on the tendency to recurrence of the rheumatic disease. If a systolic murmur at the apex is regarded as due to mitral regurgitation, in the absence of a history of rheumatism we base our verdict on the presence or absence of any changes in the heart as the result of the mitral lesion. If the heart is not enlarged, or hypertrophied, as regards the right or the left ventricle, and if the sounds there are clear, and if the candidate has had no symptoms of cardiac disability, he may be regarded as possessing a functionally sound heart. In other words, a mitral lesion is weighed according to the effect it has produced on the musculature of the heart and the heart’s efficiency, and if no effect can be detected the cardiac lesion may be ignored.

    Cardiac Irregularity.

    Cardiac irregularity is not to be regarded as an indication of cardiac disease. The most of the irregularities met with amongst candidates are not associated with any form of heart disease.
    The most common form is the “youthful type of irregularity”, a sinus irregularity which manifests itself by a quickening of the cardiac rate during inspiration, and a slowing during expiration. Every examiner should make himself familiar with this type of irregularity, which is extremely common amongst candidates, and has in the past been a common cause of rejection for the public services.
    This irregularity is of no significance or importance.
    The occurrence of extrasystoles or premature contractions is another not uncommon form of heart irregularity, and is usually manifested by an occasional missed beat" discovered while one is auscultating the heart or feeling the pulse. This form of irregularity is of no importance taken by itself. If the candidate is conscious of the " missed beat" and says he can feel his heart stop and go on again, he probably has that sensitive type of nervous system which is potentially neurasthenic.
    In practice no candidate is rejected for any form of sinus irregularity or because of the presence of occasional extrasystoles.
    The more important forms of cardiac irregularity usually associated with an abnormal rhythm of the heart, such as auricular fibrillation or auricular flutter, heartblock, &c., are very rarely met with, but are to be regarded as evidence of disqualifying heart disease. Any form of paroxysmal tachycardia is a cause for rejection.

    Area of Cardiac Dullness.

    If there is marked dilatation of the heart with a persistently rapid rate there is probably serious myocardial disease or infection, and the candidate should be rejected.
    A slight alteration in size or shape from what is usually described as “the normal heart” must not be unduly emphasised. Candidates are not to be rejected because the apex beat is on or a little outside the nipple line, or because the normal area of cardiac dullness is slightly enlarged. At the age the candidates present themselves such variations in the size of the heart are common and are not of themselves of any special importance. On the other hand, cardiac hypertrophy, usually associated with dilatation, is always pathological.
    If there is a definitely heaving action of the right or left ventricle, a cause for this must be looked for, and full consideration given to the underlying cause and its probable effects. Dilatation of the heart must not be confused with displacement of the heart. In many cases the apex beat may be found outside the nipple line when the candidate is standing, and drops back within that line when he lies down.

    The Arteries.

    Organic disease of the arteries in the form of arteriosclerosis is not often met with; it is sometimes present in the older candidates. Arterial thickening, with or without tortuosity of the vessels, is probably always the result of some form of toxaemia. If associated with renal disease or retinal changes, or cardiac changes, or definite symptoms, it is clearly a cause for rejection. If it is present without any other evidence of disease, and the candidate is physically sound, he may be accepted.
    A high systolic blood pressure - namely, 130 to 150, as estimated by the sphygmometer - is often found amongst candidates, and is not of itself a cause for rejection. If the examiner considers the blood pressure too high at systole or too low during diastole, or that the pulse pressure " is unsatisfactory he must not reject the candidate on any one of these grounds unless he finds symptoms or signs of organic disease of the heart or blood-vessels. Striking variations in the sphygmomanometric reading are met with in connexion with cardio-vascular debility and in the absence of any organic disease.

    II - CARDIO-VASCULAR DEBILITY (C.V.D.).

    This is a condition which has come to occupy a position of great importance in the examination of flying candidates.
    As a clinical entity it may be said to have established itself owing to the war, but there is no agreement as to the underlying cause or causes of the condition. We shall therefore deal with it from a clinical point of view.
    In determining the symptoms and signs and their importance we have derived evidence from two sources-namely, (1) the condition as it is met with in civil life; and (2) the condition as it is met with in the case of flying officers who have broken down with similar signs and symptoms. A study of these two conditions will help one in determining the presence of cardio-vascular debility in candidates.

    Clinical Experience in Civil Life.

    In civilian practice clinical experience has marked out a type of individual characterised by certain cardio-vascular phenomena, present more especially during youth, but persisting in many cases through life. There is a tendency to breathlessness, to praecordial pain, to faintness or fainting, and to a rapid and thumping action of the heart under slight provocation. The faintness is often induced by a change of posture from the horizontal to the vertical, as on rising in the morning. The subject of this condition is in a chronic state of tiredness, and slight exertion soon brings on a feeling of exhaustion. Active games or heated rooms bring giddiness, fainting, or vomiting. He will state that he suffers from a weak circulation," that his hands and feet are usually cold, that he has chilblains in winter, and that he stands cold weather badly.
    On examination we find no evidence of organic heart disease. There may be an exaggerated sinus (respiratory) irregularity, or a rapid action of the heart, or some dilatation, or systolic murmurs heard over the praecordia. The pulse is a poor one in the sense that the tension is badly sustained. There may be exaggerated pulsation in the large vessels of the neck and in the abdominal aorta. The peripheral circulation is defective, as shown by the dusky and cold hands and lobes of the ear. There is a tendency to venous plethora, which is present also in the large abdominal veins. Functional albuminuria of the postural type that is to say, due to a change from the recumbent to the erect position-is often present.
    These are some of the chief features of cardio-vascular debility as we have recognised it in civilian life.

    Cardio-vascular Debility in the Flying Man.

    Let us turn now to the symptoms and signs presented by flying men who have broken down under instruction, or as the result of a minor crash, or during active service.
    Amongst the common symptoms are tiredness and a sense of exhaustion easily induced by any exercise, faintness, giddiness, blurring of the vision, headache, rapid action of the heart and palpitation, praeordial pain, and breathlessness on exertion. In a large number of these cases we shall find the evidences of a defective circulation which we have described in our civilian type.
    It is not necessary to assume that all these conditions are the result of a flying career, or that they denote any special aerial malign influence on a healthy individual. Rather should we infer that the new surroundings and stress had acted on an individual already possessed of cardio-vascular debility, in a more or less latent form, so as to bring out the symptoms in a striking and disqualifying way. Those who have been engaged in the study of a similar (if not identical) condition known as "soldiers’ heart" (D.A.H.) have been struck by the same fact. Hume and Parkinson have found that in a large number of cases of D.A.H. symptoms of a similar kind had existed during civilian life, and had only been intensified by army service, or intercurrent illness.

    Significance of the Symptom- Complex.

    It may be said that we are not dealing here with any known disease. This may be admitted, but a symptom complex such as we are dealing with has its value. If in civil life men who have this symptom-complex are found to be limited in their activities according to the degree of its manifestations we are entitled to lay some stress on it.
    If in the flying service many men who break down more or less easily are found to show this symptom-complex in a marked degree, we are justified in considering it of some importance. If civilian experience and that of medical i invaliding boards are to be made of practical value in the flying service it is of the greatest importance to apply them at the examination of candidates. Bearing these facts in mind the examiner will seek to determine the functional power of the cardio-vascular system in a candidate. Does it show any evidence of weakness? Will it probably be strong enough to stand the causes of disturbance associated with air work, or will it probably break down under the strain ? The results of the inquiry into the candidate’s previous health as to such symptoms as fainting and faintness, shortness of breath, &c., must be considered in connexion with the cardio-vascular system. The information supplied may or may not be correct, but if there has been any evidence of former cardio-vascular debility, it will usually be possible to obtain it by cross-examination. For various reasons boys who suffer from cardio-vascular debility are often sent to school with the statement that they are ‘delicate’, or have ‘a weak heart’, or ‘must not overdo games’.

    Examination of the Heart.

    From an examination of the heart itself we learn little of its efficiency from the cardio-vascular point of view. The sounds may ring clear and true, but the cardiac action may be weak. The sounds may be blurred or reduplicated, but no evidence of a defective circulation is revealed. The apex beat may not be felt, and yet the ventricular contraction may be a powerful one. On the other hand, cardiac pulsation may strike (apparently) strongly over a considerable area of the chest wall, simply as the result of nervous excitability. The cardiac efficiency is to be tested by its response to effort, and more especially by the degree of breathlessness induced by physical exercises. As a matter of practical experience, it may be pointed out that at the age under consideration the cardiac action is seldom inefficient, and a breakdown of myocardial contractility is not to be anticipated.
    The disturbances which may arise in the heart are not primarily myocardial in origin, but are most commonly nervous.
    Along with other organs the muscular tissues of the heart seem to suffer secondarily under stress from a loss of tone or power, but the ordinary physical examination of the heart does not supply any definite information as to the presence or absence of this condition. While evidences of organic heart disease are absent, this type of individual shows in great variety and with great frequency systolic murmurs about the praecordia.

    The Heart Rate.

    A difficulty which presents itself in the case of these young candidates is that the excitement and anxiety of a medical examination leads to a rapid cardiac action. We find not uncommonly a rate of 110, 120, or 130. If this were the usual rate of the candidate’s heart he would probably be rejected. As his anxiety may persist through the whole examination the increase in cardiac rate may be maintained.
    As very few individuals possess any control over the cardiac rate we cannot always succeed in checking the rate by calming words to the candidates.
    If the increased cardiac rate is due to nervous excitement there will usually be a diminution if the candidate is placed at rest on a couch and is asked to breathe slowly and deeply.
    Another test employed is as follows. The candidate, lying comfortably on a couch, is asked to breathe very slowly and very deeply. The apex is then carefully auscultated for any change in rate during inspiration and expiration. If the heart rate shows a respiratory variation, more especially a definite slowing during expiration, then in all probability the excited action is not cardiac in origin, but arises from some influence outside the heart, usually nervous and temporary. The reason for this conclusion is that the slowing of the heart is vagal in origin, elicited by respiration, and such slowing does not occur in hearts quickened by myocardial disease. If, on the other hand, the cardiac rate shows no change under rest or deep respiration there is probably some permanent disturbing factor at work, such as toxaemia or latent infection. In such a case the candidate cannot be accepted and must be refused or deferred for a time.
    If the heart rate is found to be moderately increased on examination, up to 100 or 110 beats per minute, and if after exercise this rate is not increased or is definitely lowered; one may conclude that the disturbance is of nervous origin and no real importance.
    The quickening of the heart rate is usually of nervous origin, and as such must be taken into consideration with the other signs of nervous instability which may be found.
    Amongst candidates it is a very common condition, and as a medical examination has often a similar effect on seasoned warriors, too much stress must not be laid on this condition when it is nervous in origin and temporary. On the other hand, a slow pulse-namely, a rate of 60 to 70-is usually a good sign. Its presence at once excludes the numerous causes of disturbance or disease leading to a rapid cardiac action. It is also helpful in enabling one to judge more accurately as to the state of the circulation generally than when an excited and rapid heart action is present.

    The Pulse.

    Passing from the heart to the larger blood-vessels, we find valuable information supplied by the pulse. In a good type of candidate the pulse at the wrist is of good volume, of well sustained tension between the beats, and does not show any sudden rise or fall during the beats. Elevation of the hand while the pulse is being felt may show a brief falling off in strength, but this soon passes off and the pulse quickly steadies itself whatever position the. candidate assumes and whether the hand is lowered or raised.
    In another type of candidate (C.V.D.) we find a pulse of a different kind. The volume may be good but the tension is badly sustained. The beat may be strong, may appear stronger than usual, but it is quick and snappy, and the tension falls abruptly. We seem to have a sudden filling and a sudden emptying of the vessel, which in well-marked cases is strongly suggestive of the collapsing pulse of Graves’s disease or aortic regurgitation.
    Suppose this condition is present when the candidate is lying on a couch with the arm at his side. If the arm is raised vertically so that the radial artery at the wrist is some 2 feet above the shoulder we find the above conditions are intensified to a marked extent. If the tension of the pulse (horizontal) seemed rather poorly sustained there is no doubt about it when the arm is raised, and, further, there is no recovery of tension while the arm is raised. It is found useful to make this test by feeling both pulses (radial) at the same time, the candidate’s one arm being raised and the other horizontal or pendant. One can then feel clearly the differences in the two pulses which has just been described.
    In extreme cases of C.V.D. we often find that the pulse falls away so markedly with the arm elevated as to become almost imperceptible. The beat itself is so weak and feeble that one cannot make out a diminution in tension between the beats. Whatever the cardiac driving power may be, its force seems to have been largely dissipated before it reaches the wrist. The healthy type of candidate seems to have circulatory organs always “on duty”, as it were, ready to respond to any change in the circulatory conditions, and able to maintain a steady circulation under altered conditions.
    The C.V.D. type, on the other hand, seems to have a circulation always “off duty”, as it were, never ready to respond to a sudden change in the circulatory conditions, and unable to main a steady circulation under altered conditions.
    Readings taken by the sphygmomanometer in a number of C.V.D. cases vary much, but they seem to show that the systolic pressure is normal or raised while the diastolic pressure is normal or lowered. In other words, the "pulse pressure" is usually above 50, and may be considerably increased.

    The Peripheral Circulation.

    As regards the. peripheral circulation, we expect a good type of candidate to present signs of a healthy circulation in the hands and lobes of the ear. The colour should be light red or ruddy, and after pressure the superficial circulation should quickly restore the normal colour, while the extremities should be warm under the ordinary conditions of examination.
    In a C.V.D. subject we find that the hands are dusky and cold, and that on pressure the pale patch fades away very slowly to be replaced by the same blue colour. When the limb is elevated above the head the force of gravity slowly removes the cyanotic hue from the extremity, which may become quite pale in colour. One is not surprised to find that chilblains are common in these subjects or that they suffer much from cold hands and feet.
    A few candidates have shown or given a history of white and cold hands instead of blue. This points to a condition of vaso-motor spasm in the arterioles rather than relaxation.
    It is a more crippling condition as regards the use of the hands, and a history of “white fingers” or evidences of the condition should disqualify, as it would probably be intensified under flying conditions. We have met with some flying officers permanently disabled for air work by this condition.

    Venous Plethora.

    A tendency to venous plethora undoubtedly exists in these C.V.D. subjects, but is difficult to determine by physical signs at an examination. It is probable that the symptoms in these cases are elicited under exertion or excitement by overfilling of the abdominal veins, the so-called "splanchnic needling " and fainting. The venous plethora in the abdomen is probably associated with the lack of tone in the abdominal muscles, to which reference will be made later. It may be shown in some cases, if the examiner presses both hands on the abdomen, by a swelling up and pulsation in the veins of the neck.

    Conclusions Reached from the Physical Signs.

    The above may be termed the physical signs by which we seek to determine the presence or absence of C. V. D. In themselves they do not indicate inability to perform the physical duties of ordinary life, nor do they imply ill health, although they may follow an illness. But the examiner’s task is in a sense a prophetic one, and the question to be decided is as to whether a candidate showing the above condition of the heart and blood-vessels has a strong and stable cardio-vascular system, fitted for the duties of a flying officer. To this the answer is that he has not, so far as we can judge from civilian practice, from army experience, and from experience of flying officers who have broken down.

    Practical Tests.

    It must be admitted that practical tests as regards the efficiency of the cardio-vascular system leave much to be desired. A candidate labouring under the excitement of a medical examination is not in a condition to show his best or his usual form at testing exercises. Before he has been asked to do anything we may notice the quickened pulse-rate and the quickened breathing, of nervous origin. The tests which we should like to apply are not available in the limited accommodation of the examination room. The tests we do employ tend to be of an artificial character, and such as the candidate has not been accustomed to do, and such as he would often do after a little practice. Hence the late comers in the day may have had time to practise successfully the tests which the. early comers have described to them’.
    One tests the effect on the heart rate and respiration of a definite amount of physical exertion such as that of swinging the raised arms down to the toes four times, or rising from the floor on one foot on to a chair and back again four times. The pulse-rate and respiration-rate are then counted, and the time taken until these rates return to normal (or to the candidate’s rate at rest) is noted. A quick return to normal, say under 30 seconds, is regarded as a healthy sign, while a delay of over two minutes is suggestive of C.V.D. Perhaps more valuable than the heart rate is the quickened and even laboured breathing which follows this moderate exercise in many cases of C.V.D.
    A greater amount of physical exertion may be employed by making the candidate march quickly up and down the room, or up and down a stair, and noting the effect on the pulse and respiration. No absolute standards can be given, but the examiner notes whether the result appears to be normal or excessive.
    Another test employed has been that of breath-holding.
    The candidate, when seated, is directed to expire as deeply as possible, to inspire fully, and then to hold his breath as long as possible while the nose is clipped or closed with the fingers. A minimum of 45 seconds has been suggested as the pass standard. There is a scientific preciseness as well as plausibility. about this test which has rendered it popular with some examiners. A failure to attain to the pass standard has been ascribed to an inability to obtain sufficient oxygen owing to a low "vital capacity," or to hypersensitivity, or to diminished oxygen pressure, or to the fact that the candidate uses up his available oxygen more rapidly than a normal man. There is evidently room for more scientific inquiry to determine what the test really does imply and mean, and its value as a test for aviation purposes. A high standard in breath-holding would seem to be more called for in sub-aqueous than in aerial pursuits.

    A Difficulty in Exercise Tests.

    One great difficulty in establishing any satisfactory exercise tests for the efficiency of the cardio-vascular system lies in this-that other systems are necessarily brought into action. If the exercise test is unsatisfactory the question arises as to how far the result was due to the cardio-vascular system and how far to some other system.
    For instance, if after a brisk walk the candidate’s pulse rate remains unduly high, and his breathing is unduly laboured, we shall have to distinguish between the effects of exercise on (1) the cardio-vascular system, (2) the respiratory muscles, (3) the muscles involved in locomotion, (4) the pulmonary organs, and (5) the nervous controlling and coordinating centres. We have not been testing the cardiovascular system alone, but have also of necessity brought in those other complicating factors.
    When we come to discuss the method of summing up the results of the candidate’s examination we shall find that this difficulty is often solved by the fact that, as a rule, evidences (symptoms and physical signs) of C.V.D. do not stand alone, but are accompanied by signs of debility in other tissues and organs. A very common cause of rejection is a combination of cardio-vascular and nervous debility.

    THE NERVOUS SYSTEM.

    Gross organic disease of the brain or spinal cord is not often met with amongst candidates. An old lesion like infantile paralysis, which may render a man unfit for general service, is no bar to flying work, provided that the functional efficiency of the affected limb or limbs meets the requirements of the flying service.
    Disturbances of nervous function, either masked, as in the form of petit mal or asthma, or open in the form of overexcitability or instability, are very common amongst candidates. Any pre-existing nervous weakness is apt to be intensified by the conditions of a flying officer’s life. The youth who stammered as a boy, but has been free from the habit for some years, resumes it when he has been in the flying service for a time. The youth who never stammered before, but whose father had a stammer, develops the condition under the stress of flying work. The subject of a previous nervous breakdown at school will probably have another similar attack after a slight crash. In this part of the examination the history of any previous nervous disability, personal or familial, plays an important part.

    Points Considered in Examination of the Nervous System.

    As the nervous system is exposed to considerable strain in the flying service, we wish to have some tests to determine the nervous tone and staying power. The task, however, is not easy owing to the absence of any recognised standards.
    We have to recognise amongst the candidates a great variety of temperaments. We meet with the level-headed and calm, the keen and excitable, the somewhat dull and irresponsive, the youthful Hercules with sluggish mentality, and the absolutely stolid type. Each and all of these types may do good flying service in different departments of the work.
    Some of the excitable may become notable flying men; some of the phlegmatic may carry out routine duties for months without achieving anything brilliant, or, on the other hand, may become exceedingly good pilots.
    The point to which we have directed attention in the selection is not whether a man is nervous and excitable, or I dull and phlegmatic, but what control can he exercise.
    Before making a speech a public speaker may be intensely nervous, but, when he begins, calm and clear owing to the control which he has learned to maintain over himself. So in the case of nervous and excitable young men, the question is as to how much control they already possess, or are capable of developing, in view of the strain that lies ahead.
    It is impossible to pass a complete and final judgment on this question at one medical examination. Those who have been accepted and passed should also be carefully observed as to the above points at the flying schools by the C.O.’s and instructors, who see them at work under the actual conditions of service.
    Another point which seems to have been brought out by experience is this, that the nervous type of individual, the man without much self-control, is apt to crack up readily under the stress of the minor accidents of training - e.g., a bad landing or a slight crash. There may be no physical injury, but the nervous control, such as it was, seems to be quickly and irretrievably lost. It is clear that a very large number of flying officers who have broken down never possessed a nervous system of even ordinary stability.
    One must allow for the effects of excitement on the nervous system under a medical examination. This can usually be estimated at its proper value by putting the candidate at his ease. It may be considerably increased if the candidate has been kept waiting for some hours, or has been travelling all night, or is convalescing from acute illness.
    These points must be inquired into and taken into consideration.

    Signs of Nervous Instability.

    The condition of the deep reflexes is tested. As a rule, they are fairly active in healthy candidates. An overexcitability and exaggeration of the knee-jerks and elbow-jerks has come to be regarded as an indication of nervous debility. When a brisk muscular response follows on tapping anywhere in the extremities there is positive evidence of an over-excitable nervous system. We do not find that these conditions stand alone. bub that the candidate shows other signs of nervous instability. We have also found them present in flying men who have broken down in the service from nervous causes.
    A persistent dilatation of the pupils with an excitable manner is regarded as suspicious of undue nervous excitability.
    General tremulousness is not to be reckoned as a good sign, although it may be present merely as the result of excitement at the medical examination. A candidate is asked to hold out his hands and to close his eyes. The presence of tremor in the fingers and eyelids is looked for, and if this is constant and pronounced it is regarded as indicative of nervous instability.
    Considerable emphasis is laid on the results of the balancing test, because healthy young men have no difficulty in balancing themselves steadily first on one foot and then on the other with the eyes closed and the hands at the sides.
    Many break down hopelessly from the start, and seem quite unable to maintain any stability on one foot. A man of this type will show other signs of nervous or neuro-muscular instability sufficient to cause his rejection. The pass standard requires that a candidate should be able to stand quietly and steadily on one foot for 15 seconds.
    A candidate who sleeps soundly is usually healthy. On the other hand, a man who sleeps badly and who wakes unrefreshed and tired will usually have associated (as cause or effect) a weakened nervous system.

    SUMMING-UP AND ASSESSING.

    A certain number of candidates are eliminated because of some definite medical or surgical disease, or of their previous medical history, or of other clearly disqualifying condition.
    Another group fall out, not from actual disease, but because the physique or cardio-vascular system or nervous system is so much below par as to show clearly that failure in the flying service would certainly follow.

    Borderland Cases.

    These two classes do not, as a rule, present much difficulty, but there is a third group of what may be termed borderland cases, in which the assessing of the candidate’s fitness is no easy task. There may be no reasonable objection to his undertaking ground duties, but what we have to do is to form an estimate as to his stability or staying power for airwork.
    Is the candidate suited for the special work during the training period and for the stress and strain of active service which will follow? As already stated, we are unwilling to base our decision on rigid single tests, first because it is easy to overestimate their importance, and, secondly, because we have not sufficient knowledge as to what they portend. The path of prognostic medicine is strewn with their discarded and dishonoured remains. In these borderland cases we lay most stress on the summing-up of the conditions found in connexion with the physique, the cardio-vascular system, and the nervous system.
    The result of experience has been to show that if one of these systems is weak as a whole, functionally considered, there are several or many evidences to be found on testing.
    For example, if we find a weak flabby pulse we shall also usually find other evidences that a steady, strong, and effective circulation is not being maintained. If we find that a candidate is very unsteady and tremulous, we shall probably obtain other evidences of an unstable and imperfectly controlled nervous system. Further, as a matter of experience we find that when there are signs of cardio-vascular debility in a candidate the examination also reveals signs of nervous debility, and vice versa. It would appear that the two systems are often functionally weak in the same individual, so that in weighing the evidence we have to combine the results of the examination. A candidate may have certain signs of nervous weakness, not sufficiently pronounced to lead to his rejection, but when signs of a defective circulation are also present the combined weaknesses are sufficient to condemn him.
    Not infrequently when the general physique of the cases which appear to be unsuitable from some systemic weakness is considered we shall find that it is definitely below the high standards and often distinctly poor.

    Some Exceptions: Deferring Decision.

    While the above experiences are common there are, naturally, exceptions met with. The candidate may have some weak points as regards the cardio-vascular system but be quite satisfactory as regards physique and nervous stability. He may be apparently weak in some points as to nervous control, but he may show a most satisfactory physique and cardio-vascular system. In such cases we should regard the weak points as being counterbalanced and compensated for by the strong ones, so far as the assessing is concerned.
    “Be to his faults a little blind and to his virtues ever kind.”
    It is to be recognised that at the age we are dealing with the full development of the candidate has often not yet been reached, and that while functional development in some parts of the body may be complete, it may be incomplete in others. It is also to be recognised that the effects of recent illness, of night travelling, or of the excitement of a medical examination, may cause temporary and local effects which must not be too much emphasised. For these reasons we do not reject candidates because of some evidences of defective functional powers, provided that they are counterbalanced by the presence of healthy functions generally, or can be explained by some temporary disturbance.
    In some cases a final decision has to be deferred. A candidate suffering from active illness (for example, tonsillitis), or from recent acute illness, is not at his best, and if there is any doubt as to his suitability a final decision should be deferred until a further examination after his recovery. The case of the undeveloped boy presents some difficulty. He may be all right as far as he goes-but he has not gone far enough. It would be courting disaster to put him to work and strain for which he is not yet physically fitted. The examiner should state definitely about such a candidate that he is too undeveloped for flying work, and defer a final decision for 6 or 12 months.
    This period ought to be spent in physical training.
    In the course of examination certain remedial defects or diseases may be discovered in otherwise eligible candidates which render them unsuited for air duties. In such cases the necessary treatment is to be ordered and the final decision deferred until a later examination, when the result of treatment can be estimated.

    Suitability of Candidates for Various Kinds of Work.

    It is not advisable to ear-mark the candidates who pass the medical examination for the special line of flying work they are fitted for. In the past we have made a distinction between those who were passed as pilots and those who were passed as observers. The latter were not quite up to the standard of the former, medically considered, and it was held that in the air the pilot had the more responsible post as, in addition to the control of his plane, his own life and that of the observer depended on his skill and judgment and self-control. On the other hand, if the observer broke down in the air the results would not probably be very serious.
    With the great intensification of aerial fighting that has taken place, and with the great nervous strain now imposed on both pilot and observer I am inclined to think that only first-class men should be passed as observers. Their individual responsibility may not be so great as in the case of pilots, but their duties call for physical and mental fitness of the highest order.
    As regards the question of nervous strain there is no doubt that an observer, flying with a pilot he does not know or in whom he has lost confidence, may be much more strained, in a passive way, than the pilot whose mind is occupied with the immediate duties of flying his machine. He is so strained, in fact, in many cases that he is anxious to qualify as a pilot himself, in order to get relief at duties which he believes to be less onerous. Experience has confirmed this view, and many observers by becoming pilots - often very good ones - have probably been saved from a nervous breakdown.
    For these reasons, at the medical examination we are disposed to establish the same pass standard for pilots and for observers.
    There are many types of work and many types of machine in the air force, but at the examination stage it is necessary to pass only first-class men. After qualifying they will be classified according to the type of work they show special aptitude for, and for which their physical powers and skill are best suited. Some will remain as home instructors, others will go in for scouting machines, bombing machines, low-flying machines, high-flying machines, &c. So far as their aptitudes, medically considered, are concerned, we think that there should not be an attempt at the examination to define them, or to impose any limitations as to the height at which a candidate should fly, or to specify the exact nature of his future work - e.g., artillery pilot, ferry pilot, &c. These matters can only be satisfactorily settled after the pilot has finished his regular course of training, when the commanding officer, the instructor, and the medical officer will have evidence before them of what actual experience has shown regarding each individual pilot. The examiner will do well to refrain from attempting to guess on limited knowledge what this actual experience will be.
    Last edited by Dougal; 25-December-2018, 20:57.

  • #2
    A lovely bit of history, particularly when I walk past the Neuiport 12 in our museum and think that I started practicing closer to when it was flying than the present.

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