212
stronger if their follow-up had been longer and their coverage greater. A.D.N.’s remarks at a workshop sponsored by the Program for Applied Research on Fertility Regulation were misrepresented by McCann and Kessel. He stated that it has always been the practice of this hospital for women to be sterilised by hysterectomy if they have complained of heavy periods. This does not mean that we are more liberal than other surgeons in our indications for hysterectomy. We were pleased that McCann and Kessel drew attention to the other disadvantages of sterilisation by diathermy and that they believe that sterilisation by this method should be discontinued. A. T. LETCHWORTH Royal Hampshire County Hospital, A. D. NOBLE Winchester
CLIOQUINOL TOXICITY SIR,-A Round the World commentary on clioquinoll states that experiments from Ciba-Geigy’s research department are at variance with those done in Japan and by us. We have done joint studies with the Basle workers.2 Beagle dogs were given 250 or 400 mg clioquinol/kg bodyweight daily for 25 weeks, earlier studies having failed to demonstrate any adverse effects at 100 mg.3 The diets were supplemented with 200 ml fresh cow’s milk daily. In some animals at both dose levels there was lack of appetite, abnormal hind-limb gait and proprioceptive reflexes, and yellow staining of the fur (due to the urinary excretion of unchanged clioquinol). One female on the higher dose had pale optic papillae and a sluggish pupillary light reflex. Over most of the study dogs on clioquinol had lower erythrocyte-counts and higher urinary creatine/creatinine ratios than controls. In one of six dogs at 250 mg, and in four of six at 400 mg, changes were identified in the posterior columns of the spinal cord, mainly in the cervical region and close to the medullary nucleus gracilis. The lesions were dystrophic, the morphological features including axonal swelling and degeneration, myelin degeneration with slight myelinophagia, and occasional astrocyte activation. They thus resembled those recorded in beagles as a result of nutritional deficiency,4 the gastrectomy syndrome, overdose with vitamin B6,6or ageing.7 Similar changes were seen in the optic nerve of one animal, but there was no evidence of any adverse effect upon peripheral nerves or spinal and autonomic ganglia. The lack of effect upon peripheral nerves accords with the findings of Tateishi et al.8 and not with reports of neuropathy of the "dying back" type9 included in the criteria for subacute myelo-optic neuropathy (S.M.O.N.).lO Dietary factors, especially fat, are important in the development of clioquinol toxicity in the dog:" in earlier studies in Basle12 the diets were not supplemented with milk, as in our study, and Tateishi et al. 8 administered clioquinol in milk. Epidemiological studies on S.M.O.N. have been reviewed by Meade.13 Extrapolation of experimental data to man is notoriously difficult, but in the animal model C.N.s. damage is seen only at very high dosages of clioquinol in suitable dietary cir1. Lancet, 1977, ii, 1219. 2. Worden, A. N., Heywood, R., Prentice, D. E., Chesterman, H., Skerrett, K., Thomann, P. E. Toxicology (in the press). 3. Heywood, R., Chesterman, H., Worden, A. N. ibid. 1976, 6, 41. 4. Zimmermann, H. M. Res. Publ. Ass. nerv. ment. Dis. 1943, 22, 51. 5. Nørgaard, F. Histological changes in the Central Nervous System in Experimental Endogenous Gastroprival Pellagra. Copenhagen, 1942. 6. Antopol, W., Tarlov, I. M. J. Neuropath. exp. Neurol. 1942, 1, 330. 7. Newberne, J. W., Robinson, V. B., Estill, L., Brinkman, D. C. Am. J. vet. Res. 1960, 21, 782. 8. Tateishi, J., Kuroda, S., Ikeda, H. Seishin Shinkeigaku Zasshi, 1975, 77, 5. 9. Cavanagh, J. B. Crit. Rev. Toxicol. 1973, 2, 365. 10. Kono, R. Japan J. med. Sci. Biol. 1971, 24, 195. 11. Lannek, B., Lindberg, P. Acta vet. scand. 1974, 15, 398. 12. Hess, R., Koella, W. P., Krinke, G., Petermann, H., Thomann, P., Zak, F. Arzneim-Forsch. 1973, 23, 1566. 13. Meade, T. W. Br. J. prev. soc. Med. 1975, 29, 157.
cumstances, and not all the s.M.o.N. are found.
signs
Huntingdon Research Centre, Huntingdon, Cambridgeshire PE18 6ES
and lesions attributed
to
ALASTAIR N. WORDEN RALPH HEYWOOD
HERPES-SIMPLEX INFECTION PRESENTING AS BRAINSTEM ENCEPHALITIS
SIR,-Fenton et al.1 described a case of herpes-simplex infection presenting as a brainstem encephalitis. We report here a further case which poses some unusual questions. A 20-month-old girl did not wake as usual. She had been seen well 1 h before her mother found her cyanosed. At the local hospital she was unconscious with fixed pupils, cyanosed, hypotonic, and hypotensive. There were no signs of aspiration of vomit. After initial resuscitation she was transferred to our intensive care unit where we noted minimal respiratory effort and papilloedema. An electroencephalogram (E.E.G.) showed marked suppression of all cortical rhythms and was almost flat. Before she was admitted, her development had been normal and there was no significant medical history. Chest X-ray, routine blood-chemistry, cerebrospinal fluid examination (repeated), and liver function tests including blood ammonia were normal. Complement-fixation titres to herpes simplex rose from < 10 on day 2 and day 13 to 1280 on day 28. During this period there was no clinical evidence of any local herpetic infection. The child was managed by intermittent positive pressure ventilation, initially via a Jackson Rees endotracheal tube and subsequently through a tracheostomy. The cerebral oedema responded to fluid restriction and dexamethasone and the seizures which characterised the first 48 h were controlled by diazepam and then phenobarbitone, monitored by serum levels. On day 4 pupillary action returned and by day 7 she showed random movement with a withdrawal response to pain on day 11. An E.E.G. on day 14 showed generalised slow-wave activity. By the 24th day she sucked a bottle and on the 30th day was able to breathe on her own for an hour. By the 45th day her developmental age was assessed as 6 months and by the 56th day 14-16 months. By day 72 her parents felt that she was functioning much as before the illness. Using an Alder Hey tracheostomy tube she is now able to vocalise but hypotonia and sleep hypoventilation have retarded further progress and she requires ventilation during sleep. The first point raised by this case is the degree of recovery from an apparently hopeless situation. In this unit2 an electrocuted child with a similar E.E.G. completely recovered in 180 days. One should thus not be too pessimistic about a flat E.E.G. in young children. Further prospective studies in similar cases might determine whether the latent period between the onset of the illness and the phase of rapid recovery is of value in predicting the ultimate extent of recovery. The second point concerns the sleep hypoventilation. This has been well described.3-5 One patient progressed to coma after an influenza-like illness and 7 months later was mentally normal but required ventilation at night. Herpes simplex encephalitis produces temporal lobe, basal ganglia, and brainstem lesions6·’ so that focal signs are considered to be a feature of this condition. Sleep hypoventilation has not been reported. Our patient still requires a tracheostomy and a raised F(02 at night. Might herpes simplex encephalitis be a more frequent Fenton, T. R. and others. Lancet, 1977, ii, 977. Horsfield, J., Williams, A. J. Dev. Med. Child Neurol. 1977, 19, 224. Swift, P. G. F. Lancet, 1976, ii, 588. Swift, P. G. F. ibid. p. 695. Guilleminault, C., Eldridge, F. L., Simmons, F. B., Dement, W. C. Pediatrics, 1976, 58, 23. 6. Illis, L. S., Gostling, J. V. T. Herpes Simplex Encephalitis; Bristol, 1972. 7. Illis, L. S. Br. J. hosp. Med. 1977, 18, 412.
1. 2. 3. 4. 5.
213
cause
of
sleep hypoventilation
than the
parting
curse
of
Ondine? Department of Child Health and Intensive Care Unit, Alder Hey Children’s Hospital,
A. D. KINDLEY F. HARRIS
G. H. BUSH
Liverpool L12 2AP
IF I WERE A DEAN
SIR,-Dr Bennet (Jan. 14, p. 86) is right to be uneasy about the personal qualities of convergers-authoritarian, uncritical, at ease with hard scientific facts, and uncomfortable with paradox and ambiguity. Liam Hudson noted in addition that they are cautious about expressing their feelings, careful to limit their emotional involvement with other people, resistant to unsettling thoughts and feelings, and all too ready to take refuge from people in things. Hardly characteristics calculated to make a happy doctor. Most sixth-formers who can get three grade A’s in science at A level are convergers. So are many of the unhappy presentday doctors. It was not, as Bennet implies, the elaborate medical training which left them so disaffected. They loved that. Absorbing hard facts about dead bodies and diseases from converger anatomists and consultants was right up their street. It is the patients-those demanding, unpredictable, emotional individuals, unable even to describe their own symptoms logically-who drive them to drink and drugs. To produce doctors whose jobs satisfy them you need students of a contrary stamp: divergers. They do not take beliefs on trust or accept conventional wisdom, are not hooked on certainty, but enjoy argument and controversy. They prefer arts to sciences and get their A levels in history, English, and languages, and can be identified, as Byrne and Freeman showed in their studies of vocational trainees for general practice and established G.P.s, by fairly simple tests. Convergers are still needed in medicine to become surgeons, anoesthetists, medical scientists, and the like, and it would not be difficult to estimate how many. But at least half the medical-school intake, the future general practitioners and psychiatrists, should be divergers. They might not understand the biological complexities of endocrinology but that need not impair their diagnostic acumen. If you are intrigued by your patients as people you are not slow to guess that their changed behaviour might be due to, say, hyperthyroidism or myxredema madness. A few simple tests and a tube of blood to the laboratory will quickly confirm or refute your guess. But I am afraid nothing will change so long as deans are recruited from the more convergent convergers. I suppose it is better than appointing anatomists. Why not appoint a satisfied general practitioner for a change? Good gracious, what a thought. He would soon be cutting down the basic-science courses to positively dangerous levels, involving students with patients and their problems as soon as they got into medical school. Very threatening for them. They are not mature enough, you know, to cope with such unsettling emotions. Before you know where you are you will have the whole profession filled with artistic types who cannot tell a benzene ring from a rotavirus. Not really scientists at all, which is what Medicine is about-isn’t it? Department of Family and Community Medicine, University of Newcastle upon Tyne Medical School, Newcastle upon Tyne NE1 7RU
ANDREW SMITH
SIR,-J. P. Mackintosh4 asks how professional people, par-
ticularly doctors,
are to
be controlled. He goes
Jenson, K., and others. Lancet, 1975, ii, 926. Rao, B., Broadhurst, A. D. Brit. Med. J. 1976,i, 460. Herrington, R. N., and others. Psychol. med. 1976, 6, 673. 4. Mackintosh, J. P. Br. J Hosp. Med. 1978, 19, 72. 1. 2. 3.
on to
give
an
authentic example of the inadequacy of N.H.S. reorganisation, which does not ensure that environmental and psychological factors affecting sick individuals are taken into sufficient account, as compared with provision for care of "the biophysical workings of the skin-contained individual". This last phrase comes from Mr Horobin’s contribution (Jan. 7, p. 30) to your series "If I Were a Dean", the first three of which have emphasised much the same point that Mackintosh is making. Thus these contributors stress that medical education is failing to provide guidance in the importance of and management of personal relationships and the emotional, social, and cultural aspects of the practice of medicine, as opposed to giving instruction in McKeown’s "engineering model" of man as a machine. Doctors are controlled by the General Medical Council which is responsible to the nation for maintaining the standards and defining the content of their training. If the human aspects of medical practice referred to by your decanal aspirants were insisted upon more forcefully by this august governing body, the general public might be better advised, with more confidence, to leave leadership of the N.H.S. unequivocally in medical hands, as discussed in an editorials and in associated contributions in the British Medical Journal. District medical committees might then be safely given more than their present advisory function—e.g., one more comparable with the decision-taking say of district councils, area and/or regional medical committees becoming equated with the proposed devolution of power from Westminster, and D.H.S.S. medical committees with a medical parliament. It follows that N.H.S. administrators would have a relationship to doctors similar to the time-honoured one between the permanent Civil Service and members of the Government. Although "selected" by a rigorous and long process of training and apprenticeship, rather than "elected", as are most members of local or national government, practising doctors are similarly answerable daily to members of the public who seek their aid. This continuing exchange between affected individuals and doctors with an especially broad education should make medical leadership of a patient-oriented National Health (or ? Medical) Service indispensable. In view of the "notorious individuality" of doctors, Mackintosh need have no fear that there will be a dearth of different opinions or "counterexperts" available, any more than is the case in politics. Newhouse, Ide Hill, Kent
JOHN P. CRAWFORD
NUTRITION AND OPEN HEART SURGERY
SIR,-Although Mr Walesby and his colleagues (Jan. 14, p. 76) have rediscovered and extended to patients who look clinically normal observations made as long ago as 1954,1 their numerical inferences
are at
fault. To
use a
statistical
test to
dis-
tinguish an individual reading (total body potassium) from a predicted value as if the predicted value was an absolute figure, as
distinct from
a mean
with confidence limits of unknown
extent, is false. The way to make such comparison would be to calculate the regression of total body potassium on some other variable and show that the depleted patients lay off the line; even techniques of this kind depend on the data being normally distributed, and it is usually unwise to assume this. To assume that duration of hospital stay is also normally distributed, and thus calculate means and standard deviations for use in statistical testing, is wrong. Hospital stays are hardly ever normally distributed, nor would one expect them to be. The correct technique is a rank test such as the Wilcoxon. This does give p
stronger if their follow-up had been longer and their coverage greater. A.D.N.’s remarks at a workshop sponsored by the Program for Applied Research on Fertility Regulation were misrepresented by McCann and Kessel. He stated that it has always been the practice of this hospital for women to be sterilised by hysterectomy if they have complained of heavy periods. This does not mean that we are more liberal than other surgeons in our indications for hysterectomy. We were pleased that McCann and Kessel drew attention to the other disadvantages of sterilisation by diathermy and that they believe that sterilisation by this method should be discontinued. A. T. LETCHWORTH Royal Hampshire County Hospital, A. D. NOBLE Winchester
CLIOQUINOL TOXICITY SIR,-A Round the World commentary on clioquinoll states that experiments from Ciba-Geigy’s research department are at variance with those done in Japan and by us. We have done joint studies with the Basle workers.2 Beagle dogs were given 250 or 400 mg clioquinol/kg bodyweight daily for 25 weeks, earlier studies having failed to demonstrate any adverse effects at 100 mg.3 The diets were supplemented with 200 ml fresh cow’s milk daily. In some animals at both dose levels there was lack of appetite, abnormal hind-limb gait and proprioceptive reflexes, and yellow staining of the fur (due to the urinary excretion of unchanged clioquinol). One female on the higher dose had pale optic papillae and a sluggish pupillary light reflex. Over most of the study dogs on clioquinol had lower erythrocyte-counts and higher urinary creatine/creatinine ratios than controls. In one of six dogs at 250 mg, and in four of six at 400 mg, changes were identified in the posterior columns of the spinal cord, mainly in the cervical region and close to the medullary nucleus gracilis. The lesions were dystrophic, the morphological features including axonal swelling and degeneration, myelin degeneration with slight myelinophagia, and occasional astrocyte activation. They thus resembled those recorded in beagles as a result of nutritional deficiency,4 the gastrectomy syndrome, overdose with vitamin B6,6or ageing.7 Similar changes were seen in the optic nerve of one animal, but there was no evidence of any adverse effect upon peripheral nerves or spinal and autonomic ganglia. The lack of effect upon peripheral nerves accords with the findings of Tateishi et al.8 and not with reports of neuropathy of the "dying back" type9 included in the criteria for subacute myelo-optic neuropathy (S.M.O.N.).lO Dietary factors, especially fat, are important in the development of clioquinol toxicity in the dog:" in earlier studies in Basle12 the diets were not supplemented with milk, as in our study, and Tateishi et al. 8 administered clioquinol in milk. Epidemiological studies on S.M.O.N. have been reviewed by Meade.13 Extrapolation of experimental data to man is notoriously difficult, but in the animal model C.N.s. damage is seen only at very high dosages of clioquinol in suitable dietary cir1. Lancet, 1977, ii, 1219. 2. Worden, A. N., Heywood, R., Prentice, D. E., Chesterman, H., Skerrett, K., Thomann, P. E. Toxicology (in the press). 3. Heywood, R., Chesterman, H., Worden, A. N. ibid. 1976, 6, 41. 4. Zimmermann, H. M. Res. Publ. Ass. nerv. ment. Dis. 1943, 22, 51. 5. Nørgaard, F. Histological changes in the Central Nervous System in Experimental Endogenous Gastroprival Pellagra. Copenhagen, 1942. 6. Antopol, W., Tarlov, I. M. J. Neuropath. exp. Neurol. 1942, 1, 330. 7. Newberne, J. W., Robinson, V. B., Estill, L., Brinkman, D. C. Am. J. vet. Res. 1960, 21, 782. 8. Tateishi, J., Kuroda, S., Ikeda, H. Seishin Shinkeigaku Zasshi, 1975, 77, 5. 9. Cavanagh, J. B. Crit. Rev. Toxicol. 1973, 2, 365. 10. Kono, R. Japan J. med. Sci. Biol. 1971, 24, 195. 11. Lannek, B., Lindberg, P. Acta vet. scand. 1974, 15, 398. 12. Hess, R., Koella, W. P., Krinke, G., Petermann, H., Thomann, P., Zak, F. Arzneim-Forsch. 1973, 23, 1566. 13. Meade, T. W. Br. J. prev. soc. Med. 1975, 29, 157.
cumstances, and not all the s.M.o.N. are found.
signs
Huntingdon Research Centre, Huntingdon, Cambridgeshire PE18 6ES
and lesions attributed
to
ALASTAIR N. WORDEN RALPH HEYWOOD
HERPES-SIMPLEX INFECTION PRESENTING AS BRAINSTEM ENCEPHALITIS
SIR,-Fenton et al.1 described a case of herpes-simplex infection presenting as a brainstem encephalitis. We report here a further case which poses some unusual questions. A 20-month-old girl did not wake as usual. She had been seen well 1 h before her mother found her cyanosed. At the local hospital she was unconscious with fixed pupils, cyanosed, hypotonic, and hypotensive. There were no signs of aspiration of vomit. After initial resuscitation she was transferred to our intensive care unit where we noted minimal respiratory effort and papilloedema. An electroencephalogram (E.E.G.) showed marked suppression of all cortical rhythms and was almost flat. Before she was admitted, her development had been normal and there was no significant medical history. Chest X-ray, routine blood-chemistry, cerebrospinal fluid examination (repeated), and liver function tests including blood ammonia were normal. Complement-fixation titres to herpes simplex rose from < 10 on day 2 and day 13 to 1280 on day 28. During this period there was no clinical evidence of any local herpetic infection. The child was managed by intermittent positive pressure ventilation, initially via a Jackson Rees endotracheal tube and subsequently through a tracheostomy. The cerebral oedema responded to fluid restriction and dexamethasone and the seizures which characterised the first 48 h were controlled by diazepam and then phenobarbitone, monitored by serum levels. On day 4 pupillary action returned and by day 7 she showed random movement with a withdrawal response to pain on day 11. An E.E.G. on day 14 showed generalised slow-wave activity. By the 24th day she sucked a bottle and on the 30th day was able to breathe on her own for an hour. By the 45th day her developmental age was assessed as 6 months and by the 56th day 14-16 months. By day 72 her parents felt that she was functioning much as before the illness. Using an Alder Hey tracheostomy tube she is now able to vocalise but hypotonia and sleep hypoventilation have retarded further progress and she requires ventilation during sleep. The first point raised by this case is the degree of recovery from an apparently hopeless situation. In this unit2 an electrocuted child with a similar E.E.G. completely recovered in 180 days. One should thus not be too pessimistic about a flat E.E.G. in young children. Further prospective studies in similar cases might determine whether the latent period between the onset of the illness and the phase of rapid recovery is of value in predicting the ultimate extent of recovery. The second point concerns the sleep hypoventilation. This has been well described.3-5 One patient progressed to coma after an influenza-like illness and 7 months later was mentally normal but required ventilation at night. Herpes simplex encephalitis produces temporal lobe, basal ganglia, and brainstem lesions6·’ so that focal signs are considered to be a feature of this condition. Sleep hypoventilation has not been reported. Our patient still requires a tracheostomy and a raised F(02 at night. Might herpes simplex encephalitis be a more frequent Fenton, T. R. and others. Lancet, 1977, ii, 977. Horsfield, J., Williams, A. J. Dev. Med. Child Neurol. 1977, 19, 224. Swift, P. G. F. Lancet, 1976, ii, 588. Swift, P. G. F. ibid. p. 695. Guilleminault, C., Eldridge, F. L., Simmons, F. B., Dement, W. C. Pediatrics, 1976, 58, 23. 6. Illis, L. S., Gostling, J. V. T. Herpes Simplex Encephalitis; Bristol, 1972. 7. Illis, L. S. Br. J. hosp. Med. 1977, 18, 412.
1. 2. 3. 4. 5.
213
cause
of
sleep hypoventilation
than the
parting
curse
of
Ondine? Department of Child Health and Intensive Care Unit, Alder Hey Children’s Hospital,
A. D. KINDLEY F. HARRIS
G. H. BUSH
Liverpool L12 2AP
IF I WERE A DEAN
SIR,-Dr Bennet (Jan. 14, p. 86) is right to be uneasy about the personal qualities of convergers-authoritarian, uncritical, at ease with hard scientific facts, and uncomfortable with paradox and ambiguity. Liam Hudson noted in addition that they are cautious about expressing their feelings, careful to limit their emotional involvement with other people, resistant to unsettling thoughts and feelings, and all too ready to take refuge from people in things. Hardly characteristics calculated to make a happy doctor. Most sixth-formers who can get three grade A’s in science at A level are convergers. So are many of the unhappy presentday doctors. It was not, as Bennet implies, the elaborate medical training which left them so disaffected. They loved that. Absorbing hard facts about dead bodies and diseases from converger anatomists and consultants was right up their street. It is the patients-those demanding, unpredictable, emotional individuals, unable even to describe their own symptoms logically-who drive them to drink and drugs. To produce doctors whose jobs satisfy them you need students of a contrary stamp: divergers. They do not take beliefs on trust or accept conventional wisdom, are not hooked on certainty, but enjoy argument and controversy. They prefer arts to sciences and get their A levels in history, English, and languages, and can be identified, as Byrne and Freeman showed in their studies of vocational trainees for general practice and established G.P.s, by fairly simple tests. Convergers are still needed in medicine to become surgeons, anoesthetists, medical scientists, and the like, and it would not be difficult to estimate how many. But at least half the medical-school intake, the future general practitioners and psychiatrists, should be divergers. They might not understand the biological complexities of endocrinology but that need not impair their diagnostic acumen. If you are intrigued by your patients as people you are not slow to guess that their changed behaviour might be due to, say, hyperthyroidism or myxredema madness. A few simple tests and a tube of blood to the laboratory will quickly confirm or refute your guess. But I am afraid nothing will change so long as deans are recruited from the more convergent convergers. I suppose it is better than appointing anatomists. Why not appoint a satisfied general practitioner for a change? Good gracious, what a thought. He would soon be cutting down the basic-science courses to positively dangerous levels, involving students with patients and their problems as soon as they got into medical school. Very threatening for them. They are not mature enough, you know, to cope with such unsettling emotions. Before you know where you are you will have the whole profession filled with artistic types who cannot tell a benzene ring from a rotavirus. Not really scientists at all, which is what Medicine is about-isn’t it? Department of Family and Community Medicine, University of Newcastle upon Tyne Medical School, Newcastle upon Tyne NE1 7RU
ANDREW SMITH
SIR,-J. P. Mackintosh4 asks how professional people, par-
ticularly doctors,
are to
be controlled. He goes
Jenson, K., and others. Lancet, 1975, ii, 926. Rao, B., Broadhurst, A. D. Brit. Med. J. 1976,i, 460. Herrington, R. N., and others. Psychol. med. 1976, 6, 673. 4. Mackintosh, J. P. Br. J Hosp. Med. 1978, 19, 72. 1. 2. 3.
on to
give
an
authentic example of the inadequacy of N.H.S. reorganisation, which does not ensure that environmental and psychological factors affecting sick individuals are taken into sufficient account, as compared with provision for care of "the biophysical workings of the skin-contained individual". This last phrase comes from Mr Horobin’s contribution (Jan. 7, p. 30) to your series "If I Were a Dean", the first three of which have emphasised much the same point that Mackintosh is making. Thus these contributors stress that medical education is failing to provide guidance in the importance of and management of personal relationships and the emotional, social, and cultural aspects of the practice of medicine, as opposed to giving instruction in McKeown’s "engineering model" of man as a machine. Doctors are controlled by the General Medical Council which is responsible to the nation for maintaining the standards and defining the content of their training. If the human aspects of medical practice referred to by your decanal aspirants were insisted upon more forcefully by this august governing body, the general public might be better advised, with more confidence, to leave leadership of the N.H.S. unequivocally in medical hands, as discussed in an editorials and in associated contributions in the British Medical Journal. District medical committees might then be safely given more than their present advisory function—e.g., one more comparable with the decision-taking say of district councils, area and/or regional medical committees becoming equated with the proposed devolution of power from Westminster, and D.H.S.S. medical committees with a medical parliament. It follows that N.H.S. administrators would have a relationship to doctors similar to the time-honoured one between the permanent Civil Service and members of the Government. Although "selected" by a rigorous and long process of training and apprenticeship, rather than "elected", as are most members of local or national government, practising doctors are similarly answerable daily to members of the public who seek their aid. This continuing exchange between affected individuals and doctors with an especially broad education should make medical leadership of a patient-oriented National Health (or ? Medical) Service indispensable. In view of the "notorious individuality" of doctors, Mackintosh need have no fear that there will be a dearth of different opinions or "counterexperts" available, any more than is the case in politics. Newhouse, Ide Hill, Kent
JOHN P. CRAWFORD
NUTRITION AND OPEN HEART SURGERY
SIR,-Although Mr Walesby and his colleagues (Jan. 14, p. 76) have rediscovered and extended to patients who look clinically normal observations made as long ago as 1954,1 their numerical inferences
are at
fault. To
use a
statistical
test to
dis-
tinguish an individual reading (total body potassium) from a predicted value as if the predicted value was an absolute figure, as
distinct from
a mean
with confidence limits of unknown
extent, is false. The way to make such comparison would be to calculate the regression of total body potassium on some other variable and show that the depleted patients lay off the line; even techniques of this kind depend on the data being normally distributed, and it is usually unwise to assume this. To assume that duration of hospital stay is also normally distributed, and thus calculate means and standard deviations for use in statistical testing, is wrong. Hospital stays are hardly ever normally distributed, nor would one expect them to be. The correct technique is a rank test such as the Wilcoxon. This does give p
