BRITISH MEDICAL JOURNAL

VOLUME 286

14 MAY 1983

have affected his father.4 Presumably Delius system, though he will no doubt realise that his was aware of this and it may have been an comments on the safety of the system have been important factor in his choice of an amanuensis. answered.' An over pressure or safety release valve can be included in the expiratory limb (if such a There must be many other examples. valve does not already exist as an integral part of the anaesthetic machine). The paper also reviews ALAN EMERY the so called errors of lever position.
University Department of Human Genetics, Western General Hospital, Edinburgh EH4 2XU
L'Etang H. The pathology of leadership. London: Heinemann Medical, 1969. Heston LL, Heston R. The medical casebook of Adolf Hitler. London: William Kimber, 1979. 3Porphyria-a royal malady: London: BMA, 1968. 4 Heron JR. The Times 1983;13 April:8.

Cost of anaesthesia

SIR,-I note with some concern that Dr D Humphrey and others (5 March, p 800) advocate the use of the "ADE" anaesthetic circuit, because I believe that this circuit is not designed to fail safe. A change from spontaneous to controlled ventilation is achieved by turning two sleeve valves in opposite directions through 90. An inexperienced anaesthetist may fail to turn one of the valves, thus creating a circuit without an exhaust valve or disconnected from the ventilator. Barotrauma or apnoea would then occur, which could be rapidly fatal if unrecognised. I believe that anaesthetic equipment should be kept as simple as possible if we are to minimise risks of operator errors, and I would suggest that the ADE circuit be redesigned to make the valves rotate in the same direction, preferably crosslinked so that only one movement is required, and that an overpressure valve be incorporated into the circuit. As Dr Humphrey and others well know the major cost of anaesthetic practice is the salaries of the staff, and more efficient use of staff will always outweigh savings made on drugs. Any change in use of equipment which might increase the risks of errors causing harm to the patient should not be made.
We would be alarmed if the inexperienced anaesthetist were to be left solely in charge of patients if he was unable to recognise apnoea immediately after connecting a patient to a ventilator, since this is part of the accepted cockpit drill. Unsupervised anaesthetists should have an adequate knowledge of the equipment they use every day, including individual Mapleson A, D, and E systems. We did consider and design a system in which the two valves rotated in the same direction and were crosslinked. This appeared simpler, but we then found that the versatility of the system was rather limited. With two levers controlled independently the more experienced anaesthetist will appreciate the use of a dummy lung during controlled ventilation in children since adult ventilators can then be used. Some paediatric anaesthetists may prefer to use the ADE for spontaneous respiration as a Mapleson A system without a valve, the latter resulting in a system with an expiratory resistance almost half that of the T-piece yet being twice as efficient. Detachable positive and expiratory pressure valves can be used for both spontaneous and controlled ventilation, both being attached to the expiratory bypass outlet. These and other advantages offer much to those who appreciate these more subtle applications of the ADE, while the simplicity of the basic use is retained. Hence the independently controlled levers remain part of the commercially available model, and we invite Dr Cundy (and others) to test the system for himself. We reject the suggestion that a change to
significance of the presence or absence of a bruit in such patients has been described by us previously.2 An audible bruit early after a transplant in our patients was often associated with good renal function, and the disappearance of the bruit was associated with an increase in serum creatinine concentration. In the series of Mr Khoury and others patients 3, 4, 5, and 6 had increased serum creatinine concentration and no bruit was audible. Digital vascular imaging is certainly a useful method of screening for anomalies after transplantation. Intra-arterial attenuation, described by Mr Khoury and others, was also reported by me and my colleagues in 1979.2 Similar changes were seen in a quarter of our patients with allograft renal artery stenosis. The pattern of hypertension in the patient with attenuation of small vessels was similar to that in patients without this anomaly. The hypertension responded to antihypertensive, anticoagulant, and antirejection treatment, either individually or in combination. In one patient the transplanted kidney was excised, after which the blood pressure returned to normal. Control of blood pressure in these patients was associated with high serum creatinine concentration. The authors rightly presumed that the attenuation of small vessels could be considered a form of chronic vascular rejection. Renal biopsy in two of our patients with similar changes showed fibrin deposition and fibroplastic proliferation in the arcuate and interlobular arteries, suggesting vascular rejection.

S J JACHUCK

Medical Research Centre, Newcastle upon Tyne NE5 2LH
'Jachuck SJ, Wilkinson R. Abdominal bruit after renal transplantation. Br MedJf 1973;iii:202-3. 2 Jachuck SJ, Wilkinson R, Uldall PR, Elliott RW, Taylor RMR, Hacking PM. The medical management of renal artery stenosis in transplant recipients. Br J Surg 1979;66:19-22.
new equipment or techniques should not be made simply because initially one may not know exactly what to do. Inevitable unfamiliarity with complicated equipment may increase the risk of error. Our nurse anaesthetists, however, understood the principles and became confident and competent in the use of the system after only one morning. The scientific principles and techniques involved in the use of the ADE system are merely a combination of those with which all competent practising J M CUNDY anaesthetists are already familiar. With the ADE system not only will the hazard of Lewisham Hospital, London SE13 6LH theatre pollution to all theatre personnel be much reduced owing to lower fresh gas flows ***We sent a copy of this letter to Dr and facilitated scavenging but also the Humphrey and others, who reply below. patient will immediately benefit from a better ED, BM7. safer anaesthetic. D HUMPHREY J W DOWNING SIR,-While Dr Cundy seems to accept the J G BROCK-UTNE concept of the "ADE" system he comments on Departments of Physiology the design, which was not, in fact, discussed in and Anaesthetics, our letter (5 March, p 800). Some of the University of Natal, Congella 4013, Natal, answers to Dr Cundy's theoretical questions South Africa have been appropriately answered in a paper Humphrey D. A new anaesthetic breathing system describing the function and practical use of the combining Mapleson A, D and E principles: a system.' simple apparatus for low flow universal use without
The ADE system can be used for adults and children, whether for spontaneous or for controlled ventilation, and was designed with simplicity and safety as some of the main objectives. Despite its unique versatility we believe that we have achieved these objectives even in the hands of the inexperienced anaesthetist, who has to remember only two points: both levers vertical for spontaneous respiration, both levers horizontal for controlled ventilation. Nothing else is altered. As a reminder the system is clearly labelled. A simple spring loaded self locking device prevents accidental displacement of either lever from the selected
carbon dioxide absorption. Anaesthesia 1983;38: 361-72.
Plight of ophthalmic medical practitioners
SIR,-Comparison of the value of medical work carried out by doctors with that of other paramedical professions is rather a difficult task. I would like to draw your readers' attention to the discrimination by the National Health Service against ophthalmic medical practitioners as compared with ophthalmic opticians. Fees payable for the prescription of glasses are for doctors and 800 for opticians. This unbelievable situation is unique to the United Kingdom, and the reason given for the difference is that the opticians' expenses are greater. In fact the reverse is true in many cases. When the NHS was formed the remuneration for doctors for refraction was twice that of ophthalmic opticians, which is not surprising since medical examination of the eye was invariably a part of the service given to patients by doctors. The total reversal of rewards for this service is inexplicable. Is it too much to ask for parity ? I do hope that all ophthalmic medical practitioners will recognise the absurdity of this discrimination and will individually protest. I for one will ask the Secretary of State for Health to remedy this untenable situation, sending a copy of my letter to the chairman of the Ophthalmic Group Committee for information. J L REIS

Western Ophthalmic Hospital, london NWI
Digital vascular imaging in renal transplant recipients
SIR,-The report of Mr G A Khoury and others (26 March, p 1003) will be useful to those screening for anomalies of the allograft renal vessels after renal transplant. I wish to draw their attention to two earlier reportson the subject which support their assumptions in position. Despite its simplicity we believe that the new interpreting digital vascular imaging. Only one of their patients with stenosis of an system is as fail safe as is necessary. We are grateful for Dr Cundy's suggestions for improving the allograft renal artery had an audible bruit. The