BRITISH MEDICAL JOURNAL

19 MARCH 1977

771

CORRESPOND ENCE American ban on saccharin R Marian Hicks, MRCPATH, and J Chowaniec, BSC .........

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Burst abdomen-a preventable condition? T P N Jenkins, FRCS; H G Sturzaker, FRCS; P F Boreham, FRCS .. .................. 771 Training the trainers I M Richardson, FRCPED ................ 772 Metabolic and cardiotoxic effects of salbutamol A J Johnson, MRCP, and others .......... 772 Obstetric flying squads and mobile resuscitation units J S M Zorab, FFARCS, and P 1 F Baskett, FFARCS; I L C Fergusson, FRCS, and Margaret Watson, SRN .................. 773 Allergy to diazepam-or vehicle? O von Dardel, MD, and others .......... 773 Growth in renal failure C Chantler, MD, and others; P R Betts, MRCP, and others

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Timing of cervical smears J Elizabeth Macgregor, MD ............ 774

Vital follow-up of atypical cervical smears Lotte T Newman, MB .................. Voluntary Service Overseas A Ross, MD .......................... Methadone: evidence of accumulation D M Rutherford, MSC, and K Raymond, PHD Carbenoxolone, diuretic treatment, and body potassium C J Edmonds, FRCP; C Descamps, MD, and others ............................ Geriatricians to the gas chamber? J C Brocklehurst, FRCPED .............. Ophthalmic services for the elderly M J Goldacre, MFCM, and A Gatherer, FFCM Insurance companies' attitude to psychiatric illness J T Hutchinson, FRCPSYCH .............. Ascaris infection A Franklin, FRCS, and J A P Marston, FRCS. Breast size and cancer B N Catchpole, FRCS ....................

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American ban on saccharin effects, including diarrhoea, in both animals and man. This, coupled with the lack of retrospective epidemiological evidence for cyclamate, which was on the market for too short a time for it to be properly assessed,5 in our opinion is sufficient reason to continue to regard cyclamate with caution and not to advocate its reintroduction for general consumption. The situation in the USA is unfortunate because, as a result of the Delaney amendment which was enacted in 1964, "any food additive must be removed from the market if it has been shown to cause cancer when fed to humans or animals." There is no let-out clause which takes into consideration relative dose levels or risk/benefit assessment, and thus there is no option open to the Food and Drug Administration but -to ban saccharin and cyclamate, both of which can undoubtedly produce

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R T Austin, FRCSED .................... 778 Plight of young consultants A F M S Rahman, MRCPATH; J C Cameron,

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Correspondents are urged to write briefly so that readers may be offered as wide a selection of letters as possible. So many are being received that the omission of some is inevitable. Letters should be signed personally by all their authors.

SIR,-The United States ban on the use of saccharin, announced in the British press recently, will undoubtedly cause concern in this country both in medical circles and among the general public. We have tested both saccharin and cyclamate for their carcinogenic potential by feeding to laboratory rats and would like to express our opinion that it would be unfortunate if saccharin were to be withdrawn from the market here following the United States action. There are two ways of assessing the carcinogenic hazard to man of compounds such as saccharin-namely, retrospective epidemiology and testing in laboratory animals. The former approach was adopted by Sir Richard Doll and his colleagues, who found no positive correlation between the increase in bladder cancer and saccharin consumption in Britain; their studies suggest that saccharin is not carcinogenic for man in the amounts commonly consumed even by diabetics. ' Some years ago we demonstrated that either saccharin or cyclamate used on their own, when fed to rats at very high concentrations, could produce a low incidence of bladder cancer and could also have a synergistic effect with another known bladder carcinogen.: However, we also pointed out that with saccharin a dose level at least 300 times greater than the maximum daily consumption by diabetics was used to produce a carcinogenic effect.:' I Cyclamate on the other hand is less sweet than saccharin and approximately 10 times the quantity has to be eaten to achieve the same sweetening effect. We found that with cyclamate a weak carcinogenic effect in rats could be obtained with about 40 times the maximum likely consumption for man.: 4 Unlike saccharin, cyclamate is actively metabolised and can produce other toxicological

Underweight breast-fed babies I Elsbeth M F Grey, MB ................ Suicidal behaviour syndrome with low CSF 5-HIAA B Cronholm, MD, and others ............ Oxprenolol overdose with survival P C Mattingly, MRCP .................. Limulus test and meningitis N Clumeck, MD, and others ............ Effect of thyrotrophin-releasing factor on lactation D M B Hall and G Kay ................ IgA deficiency during penicillamine treatment R Forrest, MB, and others .............. Lingual polyp as cause of birth asphyxia O G Brooke, MD, and others ............ Lumbar disc surgery

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tumours in animals when used at very high dose levels. No such restrictive legislation exists in Britain. At the levels currently consumed saccharin does not appear to be a measurable hazard to health. It is, however, a valuable dietary substitute for sugar, not only for diabetics but also for the control of obesity and associated cardiovascular disease. To withdraw saccharin as well as cyclamate from the market in this country could well create more health problems than it could conceivably prevent. R MARIAN HICKS J CHOWANIEC School of Pathology, Middlesex Hospital Medical School, London Wl

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Armstrong, B, and Doll, R, British J7ournal of Preventive and Social Medicine, 1974, 28, 233. Armstrong, B, and Doll, R, British Journal of Preventive and Social Medicine, 1975, 29, 73. Hicks, R M, Wakefield, J St J, and Chowaniec, J, Chemico-Biological Interactions, 1975, 11, 225. Hicks, R M, and Chowaniec, J, Cancer Research. In press. National Cancer Institute, Division of Cancer Cause and Prevention. Report of the Temporary Committee for the Review of Data on Carcinogenicity of Cyclamate, pp 9-10. Bethesda, Maryland, National Institutes of Health, 1976.

Burst abdomen-a preventable condition?

SIR,-Surely the art of journalism lies in accurate reporting and in detecting quickly a breakthrough to new understanding. Your leading article on burst abdomen (26 February, p 534) achieved a wide survey of this complex problem, but I fail to understand why, in referring to my paper' the application of measurement to the distending abdomen and to wound closure was ignored completely, this being the point of the paper. Scientific advance follows measurement. Insulin had no clinical use until blood sugar could be measured. Curare came into anaesthetic use only when a standard preparation could be calibrated by biological assay. The mathematical facts which have been present

in every fascial wound closure have been ignored in the past 100 years of abdominal surgery. The many reported random trials testing suture materials shared the same technical faults in terms of length of sutures relative to the length of the wound and hence achieved the same results. By applying measurement I have shown that postoperative abdominal distension may lengthen the abdominal wound by 30"() or more; by the use of very simple mathematics, using the length of the wound fascial layer, the length of suture used to close it, and the number of stitches the effect of this distension on the tissue held by the sutures can be predicted. From theoretical and clinical

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evidence evisceration is associated with too low a ratio of suture length (SL) to wound length (WL). The risk of evisceration (and ventral hernia) rises increasingly rapidly as the ratio SL: WL falls from 2 : 1 to 1: 1 (or lower). On theoretical grounds closure with a simple continuous stitch using a stitch interval of 1 cm and a ratio SL: WL between 4: 1 and 6: 1 gives conditions in the wound so that the effect of 300, wound lengthening leads to a rise in tension of less than 2(O between the sutures and the tissues. Further, I have shown clinically that if the sutures are unabsorbable and monofilament, then sepsis in the wound or deep in the abdomen causes minimal risk of evisceration or ventral hernia. It is not difficult and very little time is required to include with the operation notes the ratio SL WL used in each fascial layer. Some surgeons fear that a large amount of non-absorbable sutures in the wound will lead to foreign body complications. I have a paper ready for publication showing that in the repair of ventral (incisional) hernia, having excised all scar tissue, closure of the fascial layers anatomically, using loop nylon, metric 3, at a ratio SL : WL of as much as 25 : 1 leads to sound wound healing without foreign body reaction and without recurrence of ventral hernia. It now remains for other surgeons to apply measurement to the other methods of fascial closure in the interrupted stitch pattern, the continuous mattress stitch, and the Smead Jones (massive suture) stitch techniques. As a result of this scientific check on the art of wound closure our profession should be able to ensure that virtually every wound includes a margin of safety adequate to withstand all predictable postoperative stresses, including that of deep abdominal sepsis. T P N JENKINS

BRITISH MEDICAL JOURNAL

they appear more comfortable for the patient; pus can drain freely; the incidence of incisional herniae appears very low; and tension sutures with their many disadvantages are unnecessary. I recommend this technique of closing wounds to all surgeons. H G STURZAKER Guy's Hospital, London

Jenkins, T P N, British J'ournal of Surgery, 1976, 63, 873.

19 MARCH 1977

application of which to general practice training has been inadequately tested is both discreditable and dangerous. Overdosage with such teaching leads either to a false misunderstood mystique or to near-total rejection of the need to learn to train. As a medical teacher I am just as dismayed by the wrong but sometimes understandable resort to nostalgic empiricism (you can only learn by apprenticetype experience like we did) as I am by the evasive resort to reflected questions (why did you respond to my question about how you felt about this patient by asking me why I asked you that question?) or by the arid insistence on excessive or unevaluatable objectives (the trainee shall be able to keep records -records of what, in what form, and how much ?). To perpetuate these opposing standpoints by intransigent statements serves neither trainee nor trainer well. Until accurate, valid, credible, and useful tests of training skills are available-and in my view we are a long way from such consummation-surely the best way forward is a continued reliance mainly on traditional on-thejob learning by trainees, with day release courses for some theoretical teaching but accompanied by a programme of evaluation of different techniques under more controlled conditions than has obtained hitherto. The diversity of training policies and practices must now be quite sufficient to allow measurement of trainee learning to tell us how effective various patterns are. Such experiments of opportunity are badly needed if the way ahead is to become respectable and acceptable.

SIR,-I think you could have omitted the question mark from the title of your otherwise admirable leading article on burst abdomen (26 February, p 534). There are as many ways of closing the abdomen as there are surgeons doing it, but the incidence of such a calamity as you mention and the related complication, incisional hernia, can be reduced below the alarming levels you quote. Unabsorbable material, even monofilament polyethylene, is liable to leave a foreign body sinus in a percentage of infected cases. Any suture material should, as you say, retain its tensile strength a bit more than long enough for the relatively avascular linea alba or rectus sheath to heal strongly and should then entirely disappear. In the 10 years since polyglycolic acid sutures have been available, allowing easy and accurate apposition of the layers of the abdominal wall (the relatively avascular layer being protected with a lattice stitch for added security) the incidence of burst abdomen, incisional hernia, and wound sinus has, if not I M RICHARDSON "virtually disappeared," at least been considerably reduced in this unit. I)epartment of General Practice, It is these iatrogenic complications which University of Aberdeen increase morbidity and mortality and consume time and money. With your encouragement we shall continue to strive to make them all Metabolic and cardiotoxic effects of Guildford salbutamol real rarities. PETER BOREHAM Jenkins, T P N, British Journal of Surgery, 1976, 63, SIR,-We have read with interest the recent 873. Cheltenham General Hospital, Cheltenham, Glos article relating to the metabolic effects of salbutamol by Mr A Neville and others (12 February, p 413) and the comparison of SIR,-Burst abdominal wounds are presalbutamol with aminophylline in severe ventable. They are the result of poor surgical Training the trainers asthma by Professor D Femi-Pearse and others technique. I was pleased that your leading article (26 February, p 534) referred to the SIR,-Recent BMJ articles and correspond- (19 February, p 491). Studies in stable asthmatics and in normal paper by Mr Terry Jenkins,' which should be ence show the deep divisions between those read by all practitioners of surgery. He has who enthusiastically espouse quite sophisti- subjects have demonstrated metabolic changes, now brought science to the art he has been cated courses and methods designed to develop including a rise in plasma nonesterified fatty practising and teaching for so many years- training skills in general practitioners and those acid (NEFA) concentration following salbutanamely, taking big bites and suturing loosely. who are sincerely sceptical-usually as a mol infusion. However, in a study of 63 I was fortunate to be his registrar and have result of some personal experience. Between asthmatic patients admitted with an acute used his technique of abdominal closure for the holders of these polar beliefs and attitudes attack pretreatment NEFA concentration was the past eight years, during which time only lie many trainers whose discriminatory skill greatly elevated, and no further rise was one of my wounds has dehisced. This occurred has enabled them not just to sift the educa- measured during a subsequent salbutamol in 1971, nine hours after resection of a tional wheat from the chaff but also to recog- infusion.' The infusion (10 ug/min) was carcinoma of the duodenojejunal flexure nise that learning to become a general prac- associated with an increase in plasma glucose through an upper midline incision. Exploration titioner depends on a judicious blend of and insulin and a fall in plasma potassium of the wound showed that the nylon knot had different techniques-some very old, some concentrations similar to those in stable undone-a technical fault of my knotting, not recent. Direct instruction (you should see the asthmatics and normal subjects.2 3 Thus the secretary about these forms), apprenticeship stress of acute asthma may in itself cause an of the suturing technique. During the past three years I have (you've watched me, now try it yourself), self- increase in NEFA concentration and the periodically measured the length of wounds teaching (you'll learn that best by seeing response to salbutamol may not necessarily be and of the nylon used and, like Mr Jenkins, patients, or reading, or listening to cassettes), as hazardous as claimed. Professor Femi-Pearse and his colleagues have found that the nylon length has a mean shared problem-solving (what is your own of four times that of the incision length. opinion about this problem ?), sensitivity state that aminophylline may be cardiotoxic Further evidence of the validity of this concept training (making contact in a group with your and responsible for sudden death if comes from three burst wounds I have repaired own feelings and relationships), and other administered rapidly. Intravenous salbutamol recently for other people. In each case the instruments can all contribute to trainee (200 ,ug) given in one minute caused a rise in nylon had torn out of the tissue, and in two learning provided the trainer feels at ease with pulse rate of 13-4 beats/min when measured cases the length of nylon was less than the them and is conscious of when he should use five minutes later. They do not report the pulse rate before administration, nor did they them. length of the wound. But to deluge potential or actual trainers measure the pulse rate at a shorter interval Other advantages of suturing wounds according to the Jenkins's principles are that with jargon-loaded educational theory the after administration. Fitchett et a14 have

Burst abdomen--a preventable condition.

BRITISH MEDICAL JOURNAL 19 MARCH 1977 771 CORRESPOND ENCE American ban on saccharin R Marian Hicks, MRCPATH, and J Chowaniec, BSC ......... ...
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