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is usually appointed. I should be grateful if any of your readers with such qualifications would inform me, adding a note of their present occupation. T D WHITTET

BRITISH MEDICAL JOURNAL

muscle for increased pharmacological sensitivity to caffeine, succinylcholine, and potassium chloride as well as halothane. Halothaneinduced muscle contracture alone is a less reliable index of susceptibility to malignant hyperpyrexia than is the serum CPK.

15 NOVEMBER 1975

also refused admission at the other designated intensive care unit in our region. Could Dr Reynolds and his colleagues publish details of the numbers of cases they have had to refuse over the period reviewed, so that the DHSS may begin to realise that Department of Health and Social Security, No 127 of their Reports on Public Health Alexander Fleming House, Elephant and Castle, M A DENBOROUGH and Medical Subjects remlains a hollow London SEI 6BY mockery and that no provision is yet made Departnent of Clinical Science, for many of these babies either in the hosJohn Curtin School of Medical Research, pital where they are born or at designated Australian National University, Canberra centres? Arsine toxicity aboard the Asiafreighter SHEILA LEWIS Moulds, R F W, and Denborough, M A, British MARY ROSSITER Medical Yournal, 1974, 2, 245. SIR,- We are the managing agents to the North Middlesex Hospital, owners of the above vessel, on whose behalf London N18 I now write, and have read with interest the article by Dr S P Wilkinson and others (6 Oral contraceptives and premenstrual *** We showed this letter to Miss Blake and September, p 559). In relation to the section tension Dr Reynolds, whose reply is printed below. symptoms" initial and headed "The incident the following should be pointed out in order SIR,-I am writing to protest at the advice given in "Any Questions" (27 September, p SIR,-We agree to keep the record straight. Dr Lewis and Dr (1) It might be understood from the word- 761) for the most suitable oral contraceptive Rossiter that it is with a matter great regret bottom for a woman suffering from premenstrual that insufficient facilities are for ing of the article that the double available in the tanks were examined as a result of heavy tension and irritability. UK for the care of sick newborn The general advice given by your expert infants. Our intensive weather. The examination was in fact of a own unit always runs at more nature. over assessing the routine woman's own hormone than 100 %' bed occupancy and we have to in stowed were balance/imbalance and dhoosing a suitable (2) The cylinders of arsine on a first-come first-served basis. the second tier from the top and not in the combination pill to alter it as required is operate the number of babies refused sound, although, as the writer of the article Our data for second from the bottom. in 1972-4 are incomplete. During (3) Tihe cause of the escape of the gas from referred to, my advice would be the opposite admission the past 12 months, however, more were the cylinder is open to some doubt and to in such a case-that is, to give a pill which refused than admitted, as implied in Dr little is on balance progestational rather than attribute it to a previous storm can be oestrogenic. However, there is a more major Lewis and Dr Rossiter's letter. more than supposition. P J F HENDERSON error. The articles to which the reader is ANTHEA M BLAKE Manager-Insurance, referred classified all available oral contraDenholm Ship Management Ltd ceptives according to hormone balance, but E 0 R REYNOLDS your expert, quoting products from this list, Paediatric Unit, Glasgow University College Hospital, has taken no account of the important find- London WC1 ings and guidance since then over the amount of oestrogen in the pill-and all those Serum creatine phosphokinase and named by your expert except one contain malignant hyperpyrexia more than the recommended amount of Clonidine overdose some of them are rightly dis- SIR,-We read with interest the report by SIR,-I was interested in the paper by Dr oestrogen and This is quite unnecessary. The Dr N Hunyor and others (4 October, p F Richard Ellis and others (30 August, p continued. hormone balance of the pill does not depend 23) Sdescribing two cases of clonidine over511) in which they concluded that serum on the dose of or oestrogen but progestogen creatine phosphokinase (CPK) estimations on the balance of both. It is perfectly possible dose associated with severe hypertension. The mechanism which they propose for were of no value in screening for suscepti- using newer low-dose oral contraceptives the observed paradoxical hypertension in bility to malignant hyperpyrexia. This con- containing not more than 50 of mestranol ,ug clusion was based on the assumption that or ethinyl oestradiol to attain the same effect these cases is a dominance of the peripheral action of the drug over its halothane-induced muscle contracture in hormone balance without the added risks alpha-agonist central hypotensive in the presence of vitro was a specific test for susceptibility to on with the use of more than this high serum levels of effect the drug. In preliminary malignant hyperpyrexia. Unfortunately this associated amount of oestrogen. studies of clonidine pharmacokinetics and assumption is invalid, as we have already ELEANOR MEARS concentration-effect relationships in man, pointed out that halothane-induced contracture can occur in normal individuals.' More Grimsby, South Humberside using a specific and sensitive mass fragmentographic assay for clonidine developed in our recently we have found that among 54 laboratory,' we have demonstrated an unusual normal persons 30% had muscle fibres that relationship between plasma clonidine conresponded to halothane treatment with contracture. centration and the effect on blood pressure. Transport of infants for intensive care At low plasma concentrations the fall in Individuals susceptible to malignant hyperpyrexia have muscle with heightened SIR,-In table I of their paper Miss A M arterial pressure is related to the plasma sensitivity not only to halothane but also to Blake and her colleagues (4 October, p 13) level. With high plasma concentrations, caffeine, succinylcholine, potassium chloride, seemed to show that the best chance is however, there is considerable reduction and temperature change. Increased sensi- offered to seriously ill babies if they are born in the expected hypotensive effect. We tivity to all these pharmacological agents in a hospital with an intensive care baby think that this represents a predominance must be shown in order to be certain that unit. Much as we have appreciated the help of the peripheral alpha-agonist effect of the a patient is affected by the myopathy that Dr Reynolds and his colleagues have drug at higher plasma concentrations and is given us on many occasions, their figures are probably seen only clinically immediately predisposing to malignant hyperpyrexia. Using this more detailed in-vitro muscle incomplete unless they include the number following intravenous bolus injection, when test we have found that serum CPK levels of babies they have had to refuse from our transient hypertension occurs. Our finding are usually reliable in screening relatives of and other district general hospitals. We have would support the proposed mechanism for patients who have suffered from malignant no foreknowledge on any one occasion when the hypertension observed in Dr Hunyor and hyperpyrexia for the presence of the pre- -with our inadequate staff-we will have to his colleagues' cases. It was surprising to read that diazoxide disposing myopathy. In particular, we have provide the only intensive care available to yet to find a relative with a normal serum a particular infant. Up to the time of writing, and not alpha-adrenoceptor blocking agents CPK level who gave an abnormal muscle since 1 January this year, University College had been used to lower blood pressure in contracture response in vitro. If the serum Hospital has been able to accept only three these patients, as alpha-adrenoceptor blockCPK result is equivocal affected individuals of the 12 infants we have thought justified ing agents block the peripheral hypertensive must be identified by testing their skeletal referral; seven of the remaining nine were action of clonidine.2 We would suggest that

Letter: Transport of infants for intensive care.

408 is usually appointed. I should be grateful if any of your readers with such qualifications would inform me, adding a note of their present occupa...
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