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they learn faster and more effectively as a result. I!

Secondly, they help teachers to communicate withtheir colleagues. Thirdly, they facilitate educa-tional planning: they make it easier to select appro-priate learning activities and to ensure that thecontent of teaching is relevant. Finally, clear objec-tives, because they spell out the performancerequired from the student, make it simpler to assesswhether he has succeeded or to tell why he hasfailed. Evaluation will therefore be more valid andmore precise and feedback to the student will be ofgreater value in helping him to correct his deficien-cies.

Not surprisingly, many of the audience at theG.M.C. meeting were unfamiliar with the ideaspresented. Some did not grasp their importanceand were openly sceptical about the likely benefits.One member of the audience suggested that thespelling-out of goals and objectives was inimical tothe concept of university education: he expressed afear that it would result in a general lowering ofstandards. A student representative disagreed withhim, claiming that students benefited greatly whengoals and objectives were clearly stated. He saidthat many medical students struggle during theircourse because they are not sure what is expectedof them and he believed that standards would riseif this anomaly was corrected.The conference served to highlight an important

problem in medical education. Teachers have littleexpertise in educational methods. No pressure is

placed on them to acquire it and there are few in-centives offered to those who wish to improve theirteaching. It is assumed that enthusiasm, experi-ence, or knowledge of a subject can compensate forthis deficiency. But this is not the case. The bestteachers are those who help students to learn effec-tively ; they are not necessarily the most popular in-dividuals or the best lecturers. There is much moreto the promotion of learning than the transfer ofinformation. An educational programme involves

many teachers and should be properly planned andcoordinated if it is to be both effective and efficient.At present curricula are designed, time allocated,teaching methods chosen, and examinations pre-pared without anyone having a clear idea what stu-dents should be able to do at the end of the course.Some may believe that such a laissez-faire attitudeis a desirable characteristic of university educationbut it seems a curious way to handle anything asimportant and expensive as the training of doctors.

That the statement of goals and objectives wouldimprove educational planning seems self-evident.Clinical teachers asked to declare their goalsusually concentrate on important areas like history-taking and physical examination, on clinical prob-lem-solving, and on the principles, rather than onthe detail, of patient management. Yet these areasare poorly represented in day-to-day teaching.

They are also poorly represented in the qualifyingexaminations which are interpreted by students asthe outward and visible sign of what is expected ofthem; and it is the examinations which dominatewhat students learn and the ways in which theylearn. If the deficiencies of medical education are tobe corrected we must start with a definition of our

goals. We must be clear about our educational pri-orities. And we should communicate them to stu-dents in such a way that they know exactly whatthey must learn and what they must be able to do,Only when its students are seen to achieve its goalsshould a medical school claim to be producing"good doctors".

Who’s for Amniocentesis?

AMNIOCENTESIS fbt earJy prenatal diagnosis ofcertain abnormalities is. now an established part ofclinical-genetic practice and antenatal care. Apartfrom the experience of single units, several colla-borative studies front North America and Europehave been reported. The first of these was a reviewby POLANI and BENON,,1 who in 1973 were able tocollect, from the then published data and from per-sonal inquiry, the results of over 1700 amniocen-teses. MILUNSKY2 collected the results of about1500 prenatal diagnoses from 41 centres in NorthAmerica later the same year; and, more recently,over 1600 cases from six large centres in Europewere presented to.the European Medical ResearchCouncils.3 The latest review is by GALJAARD,4 whocollected information on over 6000 cases obtainedfrom no fewer than 46 of the major Western Euro-pean centres. From these studies the present indica-tions for diagnostic amniocentesis for cytogeneticreasons emerge quite clearly. The commonest areadvanced maternal age and a previous child withDown’s syndrome. The others are a family historyof Down’s syndrome or possibly other chromosomeanomalies, and repeated abortions. A small but im-portant group is that where one of the parents car-ries a balanced translocation, and a larger onewhere fetal sex is determined because of the likeli-hood of one of the X-linked disorders. The chanceof a fetus having either trisomy 21 or some otherchromosome anomaly seems to be rather greaterthan was suggested by earlier retrospective stu-

dies.5 The risk seems to be around 5% for mothersover the age of 38; and if one of the parents is acarrier the chance of an unbalanced translocationin the fetus is about 7%. GALJAARD suggests thatthese last two very high risk categories of mothers

1. Polani, P. E., Benson, P. F. Guy’s Hosp. Reps, 1973, 122, 65.2. Milunsky, A. Prenatal Diagnosis of Hereditary Disorders. Springfield,

Illinois, 1973.3. Lindsten, J., Zetterström, R., Ferguson-Smith, M. Acta pediat. scand. 1976,

Suppl. 259.4. Galjaard, H. Cytogenet. Cell Genet. 1976, 16, 453.5. Collmann, R. D., Stoller, A. Am. J. publ. Hlth, 1962, 52, 813

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should be encouraged to have their pregnanciesmonitored with a view to selective termination, butfeels that the other purely cytogenetic indicationsare less urgent-espccially. if there is pressure oncytogenetic services-since the risk is often lessthan 1.5%. This recommendation seems to ignorethe value of a diagnostic amniocentesis for reliev-ing parental anxiety, which is often severe.As to metabolic disorders, in Europe just over

200 amniocenteses have been carried out for thedetection of twenty-three such disorders4 where therisk to the fetus is 1 in 4: The largest single group(31 cases) was those investigated for possible Tay-Sachs disease. With so many centres, including 17in the United Kingdom alone, dealing with such alimited amount of clinical material, it is surprisingthat few mistaken diagnoses have so far been

reported. Reliable prenatal diagnosis of these meta-bolic disorders requires an’intimate knowledge ofthe particular enzymes and metabolic pathways,together with sufficierit control and mutant cellmaterial for the high enzyme levels in an affectedfetus to be distinguished om the lower levels in aheterozygous carrier. Since existing arrangementsrepresent uneconomic use of resources and staff,the time is ripe for European collaboration and forconcentration of the diagnostic work in fewercentres. A European cell bank (yet to be estab-lished) would enable other centres to use the clini-cal material for research..

"

More specific investigations into the techniqueand safety of amniocentesis have been commis-sioned by the National Institutes of Health in theUnited States,6 the Canadian Medical Research

Council,’ and the Medical Research Council in theUnited Kingdom, each investigation includingabout a thousand cases from several centres. TheCanadian and the United States studies have beenpublished, and the U.K. report is expected by theend of the year. The evidence so far suggests that,in practised hands, the procedute carried out in amajor health centre at about 16’weeks is safe, accu-rate, and reliable, when monitored by ultrasound.Under these circumstances the miscarriage-rateseems to be no greater than that in control preg-nancies. 6 7

This form of monitoring for pregnancies at highrisk for a limited number of fetal abnormalities hasa long way to go. In a five or’six year period in Eur-ope, only about 300 abnormal fetuses have beenprevented from reaching term, and a further 5000couples have been given the assurance withoutwhich they would probably not have risked a

further pregnancy-a very modest dent in theannual total of about 100 000 abnormal babiesborn in Western Europe. A vigorous publicity cam-

6. N.C.H.D. Study Group. J. Am. med. Ass. 1976, 236, 1471.7. Simpson, N. E., Dallaire, L., Miller, J. R., Siminovich, L., Hamerton, J. L.,

Miller, J., McKeen, C. Can. med. Ass. J. 1976, 23, 739.

paign, aimed for instance at pregnant women who,because of advanced age, are at high risk of havinga chromosomally abnormal child, might reduce thenumber of such infants to a third of the presentnumber born to that group. Additional clinical and

laboratory facilities would be needed to meet thisload, and maternity booking arrangements wouldhave to be changed. This would be expensive inmoney (in the short term, at least); but unless thiswork was confined to centres experienced with thetechniques, the greatest cost might be in fetal lossesand mistakes.

MANAGEMENT OF APNOEA OF PREMATURITY

Up to a quarter of all babies born under 2500 g have

spells of apnrea in the neonatal period.’ The incidenceincreases with shorter gestation, as many as 84% ofbabies under 1000 g being affected.2 These figures maybe too low, since perhaps half the attacks lasting over 20seconds are unnoticed by the nursing staff.3 Apncea is anon-specific symptom in the preterm baby, associatedwith many pathological states. In particular, it may bethe earliest feature of lung disease-especially in

asphyxiated or very immature babies who are too feebleto produce the usual signs-and of hypoglycsemia, sep-ticx-mia, convulsion, or cardiac failure; all these must belooked for in all cases. Trometamol (THAM) may alsocause apnoea,4 and is therefore best reserved for babiesalready on ventilators. A large percentage of attacks,however, occur in otherwise healthy preterm infants,and may continue for weeks. Some of these babies sus-tain permanent brain damage5 6 which should be largelypreventable if due to hypoxia during attacks, as seemslikely in most cases. The aetiology of idiopathic apnoea ismultifactorial, and the proposed mechanisms have beenreviewed by Kattwinkel. 7

Management consists of monitoring of respirationand heart-rate, and of manoeuvres to diminish the fre-quency of attacks. Various respiratory monitors are

available which trigger an alarm if no movement is

detected after a pre-set interval. Periodic respiration andshort pauses in breathing are common in pretermbabies, so the interval is usually set at 15 or 20 seconds.this may be too long for a few, usually very small,babies, who become bradycardic within 5-7 seconds, oreven before the onset of apnoea.3 A safe interval is onewhich the baby can tolerate without bradycardia orcyanosis, and needs to be determined for each individ-ual. Audible heart-rate monitoring is also useful in con-junction with a respiratory alarm. A quiet regular"beep" soon becomes subliminal for nurses workingnearby, but a change in rate is noticed immediately. Ithelps them to distinguish attacks requiring interventionfrom extremes of periodic breathing. Environmental

temperature is important. Apnoeic spells are more likely

1. Daily, W. J. R., Klaus, M., Meyer, H. B. P. Pediatrics, 1969, 43, 510.2. Alden, E. R., Mandelhorn, T., Woodrum, D. E., Wennberg, R. P., Parks,

C. R., Hodson, A. ibid. 1972, 50, 40.3. Stem,I. M., Shannon, D. C. ibid. 1975, 55, 599.4. Roberton, N. R. C. Archs Dis. Childh. 1970, 45, 206.5. Fitzhardinge, P. M., Ramsay, M. Devl. Med. Chld Neurol. 1973, 15, 447.6. Francis-Williams, J., Davies, P. A. ibid. 1974, 16, 709.7. Kattwinkel, J. J. Pediat. 1977, 90, 342.