HYDROXYDIONE IN CARDIOPULMONARY BYPASS

637 comments. I took a locum s.H.M.O. post at a definite announcement had been made, but there was a possibility of a substantive grading; later, when it became apparent that the post would be replaced by a medical assistant grade, I remained hoping vainly (as it turned out) that I could continue broadly on the same basis as before, although now a medical assistant. The new grade is meant to provide a career in the hospital service for those who cannot, or do not, aspire to consultant status ; it specifically denies responsibility for the patient, and so, logically, the remuneration is much lower. Where the S.H.M.O. grade commenced at E2280, the medical assistant commences at E1650-this alone must have been a great source of satisfaction to a Government bent on economy at all costs. For myselfI find the lack of responsibility dreary and the pay prospects unattractive. I have had my pay protected at its former rate as a locum s.H.M.o., but it will take five years before my medical-assistant pay overtakes it, and I shall not receive the maximum pay of E2900 until I am 53. What sort of reward is this for experience and a higher qualification ? Because my mobility has been limited by family obligations, I have had to work within travelling distance of my home, so I cannot easily apply for another post. As an S.H.M.O. I was doing work I liked on a pay scale that was tolerable, and I would have been content to remain in my post until I reached retiring age. This no longer applies. Ulcombe, FREDA REED. near Maidstone, Kent. m

make a few

time when no

SANDS OF PLANNING Sir,-I am sure all can agree that the schemes outlined in Bw leading article last week (p. 578) that might speed up projects are important. In view of the lack of finance it appears that the Ministry has difficulties, perhaps by promising too many eggs in too many baskets. It is a fact that plans already Mised for some hospitals will not come to full fruition in many cases for periods of seven to ten years or even longer. It is impossible to forecast accurately requirements so far ahead, so that at least many departments of our new hospitals will be outdated when they are eventually functioning. Many modern large buildings of the size of hospitals are now completed within about two years. Would it not be wiser to concentrate on fewer projects for short-term completion in tum? It would be better to select those for immediate building out of a hat, rather than wait for a large number of delayed outmoded hospitals in the distant uncertain future. SIDNEY SHAW. Edgware, Middlesex.

HALOTHANE AND AORTIC COARCTATION Sir,-The increased incidence of paradoxical hypertension after correction of aortic coarctation when halothane anaesthesia had been used has been reported by Davis et al.l In their series of 24 patients, 7 developed hypertension. Of these 7 patients, 5 had been given halothane anaesthesia and 2 had received Mtous-oxide/thiopentone anaesthesia. All the remaining 17 patients had received nitrous-oxide/thiopentone anaesthesia. In continuation of that series a review was made of records of all patients who underwent surgical correction of aortic coarctation at this centre over the 71/2-year period 1959-66. Of the total of 41 patients, 20 received halothane anaesthesia, while 21 :eceived balanced anaesthesia (nitrous oxide, supplemented by muscle relaxants, barbiturates, and narcotics). Of the 21 pabents in the balanced-angesthesia group 9 developed hyper:"’1lSlon postoperatively. 14 patients in the halothane group heloped hypertension. Thus, in this series, the incidence of :’hypertension was 70% after halothane anaesthesia and 43% after balanced anaesthesia. The difference between these two values is not statistically significant (x2=2’06, 0.2> P > 0,1). Davis, T. B., Morrow, D. H., Herbert, C. L., Cooper, T. Anesthesiology, 1961, 22, 135.

The cause of paradoxical hypertension after correction of coarctation of the aorta is not known. Srouji and Trusler,2 in their study of 16 patients, found that the incidence of postoperative hypertension was related to the severity of coarctation and the completeness of operative repair. Similarly, the reason for the increased incidence after halothane anaesthesia is unknown. Davis and Morrow1 postulated that the hypertension was " an expression of adaptation of the peripheral vascular bed to increased arterial pressure in a situation of autonomic imbalance following halothane". In laboratory canine preparations they demonstrated greater autonomic imbalance and vascular resistance after relief of aortic occlusion under nitrous-oxide/halothane than under nitrous-oxide/thiopentone anaesthesia. In the light of these tentative reports on halothane and paradoxical hypertension it might be advisable to avoid halothane anaesthesia in aortic-coarctation repair until more definitive studies can be carried out. Department of Anesthesiology, Clinical Center, National Institutes of Health, United States Public Health Service Department of Health, Education, and Welfare,

Bethesda, Maryland, U.S.A.

L. H. COOPERMAN P. E. G. MANN.

HYDROXYDIONE IN CARDIOPULMONARY BYPASS SIR,-During cardiopulmonary bypass it is important to maintain a high proportion of oxygen in the oxygenator. In addition, at normal body temperatures any technique used must be capable of maintaining unconsciousness. Although nitrous oxide is usually the agent of choice for this purpose in normal cases, it cannot be used in effective concentrations in an oxygenator without dangerously reducing the oxygen tension. Therefore at normal body temperatures it becomes necessary to use either potent volatile or intravenous agents. Halothane is used in many centres,3 but has the disadvantages that it causes cardiovascular depression and that its use may be associated with postoperative jaundice, and has accordingly been abandoned by some workers.4 Pethidine has been used for the purpose by Brown,5 but it too may cause cardiovascular depression, which is especially to be avoided during open heart surgery. A significant advance

seems to have been made by the use of phenoperidene (R.1406, ’Operidene ’, Janssen Pharmaceuticals) which is fairly free from the risk of causing cardiovascular depression. Phenoperidene has been used in conjunction with haloperidol6 and methohexitone,4both of which, however, have been associated with some degree of hypotension. Hydroxydione sodium succinate is a steroid anaesthetic agent which was introduced some years ago, and the early claims of excellent cardiovascular stability have been substantiated in clinical practice.’ Nevertheless it has been largely abandoned because of two big disadvantages-venous thrombosis, and delayed onset of anaesthesia. These disadvantages are largely

eliminated when it is used as an agent to maintain unconsciouswith a pump oxygenator-a certain amount of forethought can allow for the slow onset of anaesthesia, and the problem of venous thrombosis does not apply when the drug is given directly into an oxygenator. We have used hydroxydione in calves undergoing cardiopulmonary bypass, and have been impressed with the absence of cardiac effects, despite very large doses (30 mg. per kg.), which were used to gain some indication of the therapeutic ratio. Our experience of the use of hydroxydione in cardiopulmonary bypass in man is limited to four patients, in all of whom extracorporeal cooling was used. Dosage has ranged

ness

2. 3. 4. 5. 6. 7.

Srouji, M. N., Trusler, G. A. Can. med. Ass. J. 1965, 92, 412. Hutton, A. M., Vale, R. J. Anœsthesia, 1964, 19, 239. Vale, R. J., Hellewell, J. ibid. 1966, 21, 357. Brown, W. M. Personal communication. Prys Roberts, C. The Application of Neuroleptanalgesia in Anaesthetic and Other Practice (edited by N. W. Shepherd); p. 81. Oxford, 1965. Bryce-Smith, R. Br. J. Anœth. 1959, 31, 262.

638 from 25

to 100 mg., and the cardiovascular stability has been confirmed. We suggest that hydroxydione, possibly in association with phenoperidene for those patients in whom hypothermia is not being induced, is worthy of further trial for this

purpose.

JOHN CLUTTON-BROCK of

Anæsthetics,

Department University of Bristol.

GEOFFREY W. BURTON PETER J. F. BASKETT.

ANÆSTHESIA FOR ELECTROPLEXY SIR,-It is a little concerning that Dr. Blatchley (July 2) should suggest the routine use of large doses of suxamethonium in cases where these are not particularly indicated. I have now administered over 30,000 anaesthetics for electroplexy. My routine dose has been 20-25 mg. of suxamethonium for females and about 30 mg. for males, and there have been no untoward complications. Patients with broken necks or severe cardiorespiratory problems have been given more, but I contend that the modification of the convulsion by this or similar drugs need be only such as will prevent the patient from being injured in any way, and that larger doses are unnecessary. In this series the complaints of muscular pain after electroplexy have been very few and quite sporadic, and I believe that muscle pains are more frequent after large doses. One has been lulled into a false sense of security by the knowledge that the metabolites of suxamethonium are nontoxic ; but we have no proof that suxamethonium is an entirely harmless drug, and the dose suggested by Dr. Blatchley, particularly if given over a long period, may well give rise to some muscular damage. The appearance of haem pigments and myoglobin in the urine after large doses of suxamethonium1 suggests that caution should be exercised and that the necessary

aluminium container with a hinged lid. The system evolved at Kingston-on-Thames which I have described1 has many other merits-such as procedure-packs within these containers, and ease of packing and transport. Two further years of experience have confirmed the bacteriological and economic advantages of the svstem. Twickenham, Middlesex

D. STARK MURRAY

PROPER USE OF OCCLUSIVE CAROTID CLAMPS SIR,-With the advance of techniques, carotid ligation can no longer be condoned in the first few weeks after subarachnoid haemorrhage, because of the danger of permanent hemiplegia; and I hope that Dr. Lowe and his colleagues (Aug. 27, p. 495) may find some way of achieving the obvious alternativegradual carotid occlusion. But they will not achieve it with screw clamps, which are much too clumsy and unpredictable. Even if it were possible to devise a machine which would automatically open or close the carotid from minute to minute according to the carotid pressure above the level of occlusion, patients would still get hemiplegia. Measurement of the cerebral capillary pressure would be a different matter. If, as seems likely, gradual carotid occlusion is impossible, the best we can do is to make sudden occlusion easily reversible. The incidence of permanent hemiplegia after torsion2 is less than a third of that after occlusion with screw clamps. Brook General Hospital, Shooters Hill Road, London S.E.18.

J. R. GIBBS.

DIAZOXIDE IN HYPERTENSIVE CRISIS SIR,-We wish to call attention to the use of intravenous dose should not he exceeded. diazoxide (’ Hyperstat ’) in patients in hypertensive crisis who General Hospital, F. F. WADDY. are refractory to other agents. In the past year we have treated Northampton. with diazoxide ten patients who had severe hypertension and renal disease. All had responded poorly or not at all to other parenteral agents, and four had had convulsions. The technique CATHETER FOR CONTINUOUS INTRAVENOUS of rapid intravenous injection within 30 seconds of 300 mg. of SAMPLING the drug (one ampoule) has been adequately described by device Dr. and described his Finnerty.14 There was an immediate decrease in bloodSIR,-The by Spathis co-workers (July 30) is remarkably similar to the cannula pressure (B.P.) to normotensive levels in nine of the ten patients. The maximum effect occurred at 2-5 minutes, and the duration which my co-workers and I developed in 1959. This work was reported at a meeting in New York in 1959, and was published of action varied from 2 to 24 hours. Some patients required up in 1960.2 Subsequent articles dealt with various applications of to four injections per day. In view of the lack of response to large doses of other hypotensive agents, the immediate response this technique. was impressive even in the patients whose B.P. rose within MORTON LINDER. 2 hours. We give here 2 illustrative case-reports. Case 1.-A 16-year-old boy with severe glomerulonephritis * *This letter has been shown to Dr. Spathis and his and the nephrotic syndrome had an acute hypertensive crisis as " We who write follows: are to Dr. colleagues, grateful with convulsions. He failed to respond to large doses of Linder for drawing our attention to the catheter described by him, which antedated ours by 6 years, and clearly uses the same guanethidine, hydrallazine, and parenteral reserpine, and required a constant intravenous infusion of sodium nitroconcept (for which we claimed no originality). The dimensions of our catheter are advantageous (outside diameter reduced prusside to control his B.P. After 13 days the nitroprusside was from 1.22 to 0 94 mm., inside diameter increased from 0.28 to discontinued, but he remained severely hypertensive; an infusion of trimetaphan (’ Arfonad ’) was ineffective. A single 0-50 mm.), owing largely to availability of better tubing. Coupled with the use of the Seldinger technique this enables intravenous dose of 300 mg. of diazoxide produced a normal B.P. and increased urinary flow. The effect persisted for 24 the diameter of the introducing needle to be reduced from 1-63 to 0-91 mm.-a great advantage when entering arteries or hours, and he was maintained for the next 14 days by daily small veins. We offer our apologies to Dr. Linder."-ED. L. injections of 300 mg. of the drug without adverse effects. Case 2.-A 10-month-old male, weight 7-7 kg. (17 lb.), with the hsmolytic uraemic syndrome, who had failed to respond to large doses of methyldopa, hydrallazine, and pentolinium, DOUBLE-WRAPPED STERILE PACKS received 26 injections of 30-60 mg. (usually 45 mg.) of diazoxide SIR, There is a very simple solution to the problem of over a period of 2 months with excellent control of his B.P. possible contamination by dust when opening a sterile pack of We have noted no side-effects from this therapy. Hyperwhich the outer wrap is paper. A paper bag should be used, so was not observed, and urine volume was not reduced. glycaemia that opening is simple, and there are no folds to be shaken out; 1. Stark Murray, D. Lancet, 1964, i, 1207. and the instruments and dressings should be put inside an 1. 2.

Tammisto, T., Airaksinen, M. Br. J. Anœsth. 1966, 38, 510. Weller, C., Linder, M., Macaulay, A., Ferrari, A., Kessler, G. Ann. N.Y. Acad. Sci. 1960, 87, 658.

2. 3.

4.

Gibbs, J. R. Br. J. Surg. 1965, 52, 947. Finnerty, F. A., Jr., Kakaviatos, N., Tuckman, J., Magill, I Circulation, 1963, 28, 203. Finnerty, F. A., Jr. Am. J. Cardiol. 1966, 17, 652.