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Laboratories and Post-Mortem Rooms.2 This report hasbeen accepted by the Department of Health, and theHealth and Safety Executive will adopt it as a Code ofPractice within the 1974 Act. The Executive’s inspector-ate will work to its standards, both within and outsidethe N.H.S. (in other words, academic departmentsshould not think themselves immune from its implica-tions).An advisory code of practice, produced by experts to

improve the safety of clinical laboratory practice,deserves a warm welcome. Not everyone, however, is

happy about the tone of the report, in which the word"must" is always used. Obviously Sir James Howie andhis working-party believe that the recommendationswere essential and that softer alternatives would haveemasculated their report. However, a code of practiceshould try to incorporate standards which can beattained in the foreseeable future; directives on essen-tials should of course be unambiguous but, for moreremote or more theoretical hazards, common-sense guide-lines are more appropriate. No doubt the mandatorytone of the report will help heads of departments to

secure financial priority for their laboratories. Neverthe-less, many departments will have great difficulty in im-plementing the entire code without additional space andstaff. Failure of the laboratory to comply would be ahandy weapon for any worker with a grievance.The Howie Report states that the responsibility for

safety within the laboratory remains with the head ofdepartment. He may delegate particular functions andthe authority to carry them out, but the ultimate

responsibility for safety is his. Within timescaleslaid down by the D.H.S.S., the head of departmentmust make critical decisions as to whether his own

department can handle safely certain category Bl patho-gens-e.g., sputum and other material which may con-tain tubercle bacilli, and material and reagents known tocontain hepatitis-B virus. Clearly he needs advice. How-ever, no central authority has been designated by theD.H.S.S. to advise. Furthermore, to handle category Blpathogens, a laboratory must have a safety cabinetwhich, according to the Howie Report, must be of adesign approved by the D.H.S.S. and supplied by anapproved manufacturer. Since a British Standard speci-fication has not yet been published, it may well be someconsiderable time before cabinets meeting these stan-dards are commercially available in the numbers thatwill be required; the D.H.S.S. intends them to be in useby the end of the financial year 1980/81. These particu-lar safety cabinets must be ducted to the exterior. Havehospital architects and engineers the resources to planthe necessary modifications? To which official body canthey turn for advice?A rigid code of practice, together with efficient safety

cabinets and other mechanical devices, is no substitutefor good laboratory technique. Once again it is the ulti-mate responsibility of the head of department to ensurethat the practical aspects of the training of his depart-mental staff are not neglected. Technical training inlaboratory bench work has always been supervised bychief medical laboratory scientific officers and thisshould continue. But administrative demands on theseworkers are large, and increasing. In addition to

organising staff duty rosters which allow for day-releasetraining courses and making provision for staff holidays,2. Code of Practice for the Prevention of Infection in Clinical Laboratories and

Post-Mortem Rooms. H.M. Stationery Office, 1978.

they are conscious that in many departments the techni-cal establishment is already stretched to its limits. Theyhave themselves numerous commitments which takethem outside the laboratory. Yet supervision of juniorstaff remains of foremost importance.What if the head of department finds that, within the

time-scale laid down by the D.H.S.S., he cannot securethe facilities demanded by the code? The D.H.S.S. saysthat specimens may have to be transferred to otherlaboratories. The head willl have to decide for himselfwhether this can be done without lessening the qualityand quantity of diagnostic services. Maybe there isanother way. The Health and Safety at Work, &c., Act,1974, obliges an employer to ensure, so far as is reason-ably practicable, the health, safety, and welfare at workof all his employees. Could the head of department claimthat he had done all that was reasonably practicable inhis own particular circumstances? The D.H.S.S. isbound by the Act, but as Crown bodies the health auth-orities are immune to the punitive clauses. Health Ser-vice workers will not be prosecuted instead of theiremployer, but they may be prosecuted if they do nottake reasonable care.3 So far no guidance on this is

forthcoming from either the D.H.S.S. or the Health andSafety Executive.

W.H.O. ON ESSENTIAL DRUGS

THE 31st World Health Assembly passed a compre-hensive resolution aimed at improving the supply of use-ful and essential pharmaceuticals in developing coun-tries. Discontent focused on the cost in relation to

capacity to pay, the lack of quality control by someinternational suppliers, and the lack of guidance hithertoover what constitutes necessary drugs in developingcountries so that an adequate range can be imported.The multinational pharmaceutical industry was criti-cised for its diminishing interest in research on drugsrelevant to the endemic diseases of tropical developingcountries. W.H.O. hopes to correct some of these ten-dencies with its list of essential (perhaps basic would bea better word) drugs, and hopes also to foster a clocerdialogue between industry and third-world consumers.Some members of the pharmaceutical industry have

been less than enthusiastic at these developments, butthe technical discussions in May this year, attended bydelegations from developing countries, did much formutual understanding: most people now accept that theneeds of the poorer communities must be met. How canthis be done? For a start, drug manufacturers couldoffer drugs on the W.H.O. essential-drugs list in the sim-plest possible formulation and presentation, at priceswhich cover costs and afford only small profits. Largeproduction runs, especially of the patent-expired pr-ducts, seem an attractive way of securing drugs at aprice developing countries can afford. Donor agenciescould on request of the governments of poorer countries

supply pharmaceutical packages as part of their aid pro-gramme : in the U.K. they could take advantage of thestrict quality control and keen pricing exacted by theNational Health Service. There is also the possibility oftransferring some manufacturing technology to the de-veloping world. An adequate supply of basic drugs isvital to the success of the hard-pressed but slowly3. See Br. med. J. 1978, ii, 1240.1. See Lancet, 1978, i, 423.

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extending health services in poor countries. Let us hopethat pharmaceutical companies, governments, and aidorganisations will take the point.

HIGH-TENSION ELECTRICAL INJURY

HIGH-TENSION shocks cause only a small proportion ofelectrical injuries but the results are serious (the voltageis usually 11 000 or more, though high tension meansanything higher than the domestic supply). Depressinglyoften the outcome is amputation of a limb. Luce andothers’ have lately reported the loss of 11 upper limbsin 18 patients, most of whom were young men. The tis-sue damage is largely due to the conversion of electricalenergy to thermal energy.2 According to Joule’s law,when a current passes through a conductor the power(heat) is proportional to the amperage squared timesresistance; thus bone and skin, which are poor conduc-tors of high resistance, will very efficiently convert elec-trical energy to thermal energy.

This accounts for the severe damage to periosseousmuscles beneath viable tissue. When the current in a

high-tension accident arcs, commonly from the palm tothe volar aspect of the wrist, there is a voltage dropabsorbing much of the electrical energy as the air parti-cles become ionised. The temperature in such an arc canreach 4000 °C, with burning of tissue and ignition ofclothing3. Thus tissue damage can result from both theheat of the electric arc and the flow of current.The patient with a high-tension injury needs careful

initial examination. The shock may have thrown himand caused other injuries;3 and extensive flame burnsmay obscure the lesions at the site of contact. Whenfluid requirements are calculated the percentage areaburned may not be a good criterion, since the death oftissue simulates a crush injury in which additional fluidis needed to prevent renal failure.4 Particular attentionmust be paid to the tissue damage at the site of contact.Immediate decompression by escharotomy and fascio-tomy must be followed by debridement of dead tissue.There has been much argument about the timing andextent of the debridement. The usual policy with burnsis to watch for progressive necrosis of muscle and todebride periodically. In high-tension injuries this policyis inappropriate because excision tends to be inadequateor delayed, and skin cover is not achieved early enoughto preserve the function of nerves and tendons.

Clearly, any progressive necrosis of muscle cannot bedue to the high-tension injury; it results from infectionand hypoxia and is prevented by thorough debridementof all dead muscle-especially around bone. Nerves andtendons, even if apparently not viable, should be sparedsince some regeneration is possible if good cover is pro-vided early with a skin flap; this is especially so in

children, who have remarkable powers of recovery. Afterthe excision, early application of a skin flap is essentialto provide a good blood-supply and cover, and it can beraised at the first operation. The wound can thereafterbe inspected by lifting the flap from the wound and resu-turing. Alternatively, xenograft can be used as tempor-

1. Luce, E. A., Dowden, W. L., Hoopes, J. E. Surgery, Gynec. Obstet. 1978,147, 38.

2. Hunt, J. L., Mason, A. D., Masterson, T. S., Pruitt, B. A. J. Trauma, 1976,16, 335.

3. Skoof, T. ibid, 1970, 10, 816.4. Hartford, C. E., Ziffren, S. E. ibid. 1971, 4, 331.

ary cover for the vital structures, a flap being con-structed later. Microscopy of doubtful tissue has beenrecommended as a guide to excision5 but even with thisguide another look is probably still necessary.

THE ANOMALY THAT WOULDN’T GO AWAY

CORRELATIONS can be treacherous. Textbooks warnthat a correlation coefficient must be interpreted withcaution-that its statistical significance need not meancause. An aura of implicit cause and effect may hangover a good correlation, nonetheless. Perhaps it isbecause of this aura that the problems inherent in corre-lation analysis do little to deter their use. Give a man aweapon-and he’ll use it. Multiple regression is moretreacherous still. So impressive. So elegant in its multi-dimensional space. So easy to do on a computer. And,some say, the logistic function can now rescue it from thefallacy of linearity. Thus, despite the difficulties in sortingout the meaning of partial regression coefficients whenpredictor variables are inter-related, it is used. Give aman a weapon ... Correlation and regression analysisof international differences in mortality against a widevariety of dietary, social, and economic variables has adepressing history. It began with, and repeatedly returnsto, the enthusiastic interpretation of a few points pur-porting to represent the diets and coronary disease of mil-lions of people of diverse backgrounds.l The assertionsof causality on the basis of such evidence have been attimes extreme. But give a man three weapons-correla-tion, regression, and a pen-and he will use all three.

Against this background we must set a display byCochrane and his colleagues,2 who have taken up the oldarms in yet another assault on international differencesin mortality. And their results are indeed as they des-cribe them-"both interesting and amusing". One

might add sobering, as well, like so many displays ofweaponry. For though high levels of educational stan-dards and a high percentage of health expenditurecovered by public funds both correlate satisfyingly withlow levels of mortality in 18 developed countries, not allthe results are so comforting. Oddly enough, highernumbers of paediatricians per birth are correlated withhigher infant death rates. This is but a taste of the ulti-mate paradox: the more doctors per person, the higherthe death-rates in general. Such anomalies may well in-terest or amuse. On the other hand, the authors tell usthat, despite extensive juggling of the figures, the ano-malies would not go away.

These associations are eloquent in questioning theexpanding use of multivariate analysis in the medicalsciences. But the reasons for the sobering results areonly partly statistical. There are the problems of distribu-tions all around: of variables which are not normallydistributed, as the statistician would have them; ofcauses of death which are not uniformly distributed, as

. the inter-country comparisons would have them; and ofdoctors and health services which are not equably distri-buted, as justice would have them. Indeed, much in thisworld is attributable to anomalous distributions.

5. Quinby, W. C., Burke, J. F., Trelstad, R. L., Caulfield, J., ibid.1978, 18,423.

1. Keys, A. Atherosclerosis, 1971, 14, 193.2. Cochrane, A. L., St. Leger, A. S., Moore, F. J. Epidem. Comm. Hlth, 1978,

32, 200.