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Title: The scientific revolution in design for medical care

Pages: 50 - 57

                        

Author: S.M.Davies

Text: The scientific revolution in design for medical care
The laser that threatened James Bond is now a delicate tool of healing. Medical equipment draws its technical aids from space research, from industrial processes, from engineering science. Somehow, this complex new equipment, with all its great potential, must be harnessed to the needs - and the capabilities - of its users, to the demands of world markets.
by S. M. Davies
A hospital requires for its efficient functioning all the items found in a normal household, all the equipment and fittings of a large hotel and a wide range of technical supplies not found anywhere else. Without descending too far into sub-species, there are at least 30,000 items of equipment and supply in a modern hospital. To maintain this vast inventory, the hospital service in England and Wales alone spends over 90 million annually, and in addition over the next decade will spend about 100 million on the equipping of new hospitals. About half the cost goes on what may be called domestic supplies -furniture, textiles, kitchen ware, etc - but it is to the specialised equipment, its design, function and general suitability in use, that more (though belated) attention is now being given.
'The medical supplies industry' is merely a convenient expression for the hundreds of firms who produce all the technical supplies continued on page 52
which hospitals need. There are no less than 17 trade associations in the medical field: their membership totals more than 1,000, and ranges from tiny craftsman concerns to great international organisations with marginal medical interests. In addition, there are many hundreds of suppliers outside the trade associations who are active in medical trading - in all, the Ministry of Health's list of authorised suppliers contains about 2,000 names.
Lasers and ultrasonics
Given this diversity of size and product, it is extremely difficult even dangerous - to make firm statements about the medical supplies industry as though it were a cohesive organism operating a standard supply policy and having a common design motivation. In the technical sector, developments are appearing at a frantic rate and, more difficult, they are increasingly originating outside the range of classical medical science.
Ultrasonics - now used widely for both diagnosis and treatment was developed from industrial flaw-detecting techniques; one of the most successful anaesthetic gases came from research
into refrigerants; the laser now used in operations on the eye originated in non-medical science; and the impact of miniaturisation on the design of medical instrumentation stimulated by space and telecommunications research has been spectacular. There are many more examples of the profound effect which the general advance of science and technology is having on medical equipment. The medical world is alive with new ideas, many of them involving equipment of increasing sophistication.
Nor is this technological surge limited to individual products; increasingly, the hospital service is becoming aware that the need is for a system made up of co-ordinated modules rather than of the old haphazard assembly of individual items. Automated laboratory equipment has to be thought of, for example, as an analytical system receiving and processing information and perhaps linked, on-line, to a computer. Each component in such a system must be designed and selected not only for its intrinsic functional efficiency but also for its compatibility with the other elements in the process.
The importance of design is easy to demonstrate although it is, perhaps, not universally well understood. This may be because 'design' in a hospital sense has in the past been thought to concern chiefly the aesthetics of interior decoration, the choice of furniture and furnishings, the clarity and siting of indicator notices, and many
other conventional design features. These are, of course, of great importance in hospitals, perhaps much more so than in a hotel or home. For example, the choice of colours in a psychiatric unit may have an effect which borders on the therapeutic - as Goethe asserted in Der Farbenlehrer, "Colours act on the soul, exciting sensations, awaking emotions and thoughts which can quieten or disturb us and which provoke happiness or sadness". These considerations are touched on elsewhere in this issue; it is design in medical hardware which is to be considered here.
Vital role of ergonomics
Until recent years not much has been done to link the production of medical products with modern industrial design thinking. Such a basic matter as the handle shapes of surgical instruments has received little scientific attention apart from the pioneer work of Kovar in Czechoslovakia and one or two enthusiasts in the West. And yet the cumulative strain on clinical operators caused by poorly designed hand held instruments must be very great. Equally, bed heights,chair shapes and the positioning of teed head call systems too
An electrocardiograph for the GP
An electrocardiograph is as essential a diagnostic tool for the doctor doing heart examination today as the stethoscope was to his predecessor; yet size and price have traditionally kept this instrument outside the range of the general practitioner. A physician at a leading London hospital has now designed a truly portable electrocardiograph which can be expected, when it is readily available, to be very popular with the individual doctor.
The whole concept of the machine has been reconsidered to meet the particular needs of examination in the patient's home. The traditional electrocardiograph as used in hospital is bulky and complicated, although there are semi-portable models which weigh about 8 lb. This machine weighs only 4 lb, measures 3 x 2' x 8, inches, and can fit inside the average doctor's bag. When it is fully charged and fitted with a new roll of paper, the doctor can make at least 12 full examinations - many more than are likely to be conducted by one man, outside hospital, in one day. Its controls have been rationalised, but provide the full facilities frequently demonstrate almost total disregard of anthropometric and ergonomic principles. The result: unnecessary labour for nurses and discomfort for patients. Happily, there are real signs of improvement, and real reasons to believe that in the current widespread rationalisation of hospital equipment design is not being neglected.
Like piloting a jet
When one turns to the more sophisticated technical equipment, the need for good design is particularly acute. The control unit of a super voltage therapy apparatus, for instance, involves problems of control and information display which are analogous to - and as critical as -the arrangement of the control panel of a jet aircraft.
It is not sufficient to select any available digital display or any type of fail-safe control; these and all other control features must be designed with the operator and the operational environment in mind. In situations as critical as this and their number is rapidly multiplying in medicine - attention must be paid to the fundamental work
commonly needed in routine examination (the more complex procedures would in any case be done in hospital). Even so, the instrument is accurate to international standards, though it runs at one paper speed and provides only a standard or half standard deflection to 1 millivolt input.
A long period of experimentation went into the production of the prototype. A major problem in achieving the size reduction related to the spool of recording paper and the mechanism to unroll it. This was finally overcome by putting the unwinding motor into the spindle itself and supplying paper on an especially large roll to go over it. The paper unwinds straight down over a knife edge, where it is marked by the stylus, and is drawn out of the machine. The instrument casing is sufficiently cut back over the knife edge for the stylus to be seen while writing. The paper is 4 5 cm wide.
The controls have been reduced to a pen centering control, a lead switch, and a combined on/off and function switch. This has five positions: machine off; machine on stand-by (pen heating up and pre-amplifier switched on); power amplifier switched on and pen responding to incoming signals; motor running and machine recording; and gain of amplifier cut by half while recording continues. A small button provides the
standard deflection of 1 millivolt/cm shift of the pen, or half standard deflection if the machine is running at the last position. There is also a small light to show when the machine is switched on and when the accumulators need recharging. The instrument's powerful accumulators are sealed, and can be recharged from the mains electricity supply or a car battery. A very brief charging will provide sufficient power for one examination. The input socket for the charger is also the connection for the patient leads.
The instrument is shaped to be comfortably gripped in the hand. Its clean, uncluttered appearance and attractive metal finish make it a very acceptable machine for the nervous patient; and the intended retail price - anything up to 100 less than a standard machine - should make it very acceptable to the doctor too. (The device shown in our photographs is a prototype model: there will be some small alterations of detail in the production version.)
The technical challenge
which has been done in the industrial and military fields (for example, on the design of instrumental displays).
Should information, for instance, be given by counters or by graduated scale ? It has been shown by a number of workers that counters are far superior to dial displays provided that values are not likely to change rapidly; but if a dial is preferred, there are optimum design characteristics for the graduation of intervals land for pointer design, founts, colour combination and the design of numbers. There may even be reason to consider aural, in place of visual, warnings. Controls and switches, too, are far too important to be satisfied by the nearest trade pattern of knob or handle. And when the individual control and information items have been appraised in this fashion, their assembly in a logically interrelated presentation is essential if the operator is to work with maximum safety and effectiveness, and minimum effort and strain.
Reducing unnecessary effort
I may appear to have taken an extreme case where medicine is using great and potentially dangerous power - but the same requirements for scientific design thinking exist in many other medical situations. Anyone who has visited a modern recovery ward or intensive care unit (or watched any of the popular tv medical series) will have observed how the condition of seriously ill patients is now commonly monitored by electronic instruments; he will have been impressed by the oscilloscopes, rate meters and other devices used to measure perhaps four or five physiological quantities.
The information they provide has to be read and interpreted by doctors and nurses who, however highly skilled in their profession, are not engineers. It is therefore essential to display the information with the utmost clarity and thus to enable corrective action to be taken in the shortest time.
Perhaps less spectacularly, the dental chair and dental operating unit provide particularly good examples of the scope for modern design principles. Chairs idedentistry is an arduous and exacting occupation, and it is most desirable that all the equipment which the dental surgeon may wish to use should be continuously available to him without the exercise of unnecessary effort. This involves anthropometric considerations of the space envelopes in which the operator's hands and feet must and can move, the ergonomic considerations of the angle of presentation of powered instruments, their design in relation to physical effort expended, the least tiring design of foot-control, and so on. It must be admitted that not all the equipment used by British dental surgeons exhibits these desirable design features.
Cornering a valuable market
These few examples briefly suggest why design in medical equipment is - and indeed always has been - important. What now adds urgency and even more importance is its increasing complexity and sophistication. To use the language of the systems engineer, it is slowly becoming apparent that doctors, nurses, medical scientists and many other professional medical operatives are often best
Diagnosis by tv
Television can of course be a source of entertainment in hospitals; but the familiarity of this use of the medium has tended to obscure the vital role it is now playing in x-ray diagnosis. British researchers have pioneered developments in this field, and the introduction some 12 years ago of the image intensifier - an entirely British invention revolutionised x-ray diagnosis.
Before image intensifiers (electronic devices which increase the brightness of the x-ray image), conventional x-ray examinations had to be conducted in total darkness. Subsequent developmentsinvolving the use of optical systems to magnify and intensify the image - to a certain extent eliminated the need for darkness, but the number of viewers was restricted and the image tended to be difficult to watch for long periods. Obviously television was the answer to these viewing problems, but considerable research had to be carried out to find a tube that would successfully scan a fluorescent screen and transfer a clear image on to a television monitor. The first image intensifiers scanned a field of only some 5, 6 or 7 inches.
In 1958, however, the x-ray division of Marconi Instruments increased the field size to 12 inches. This enabled radiologists to undertake general screening (the field of view can cover the adult heart, both kidneys, etc). Moreover, the duration of the examination is not as restricted as with
conventional x-ray work, since the x-ray energy required is not so intense. With this system, investigations can be carried out under normal viewing conditions; the radiologist need no longer crouch over his patient to see the x-ray image, and students and other medical staff can also watch the monitors in comfort. Further refinements available with the system include automatic control, cine recording or video tape units; Polaroid prints can also be produced without interrupting the screening.
However, because of the complicated equipment it houses, the 12 inch apparatus tends to be bulky when used with a conventional x-ray table, and in order to overcome this difficulty Marconi Instruments is now about to introduce a new design, the Marionette, which will incorporate several new developments. This is a 10 inch image amplifier: it is fully automatic, and needs no manual adjustment to light, etc. It uses the same system as the 12 inch version, but the camera has been redesigned so that it is more compact. The fluorescent screen and aperture lens are housed in a small camera head, and this alone projects over the table, so that the rest of the camera does not impede the radiologist. The monitor unit has also been redesigned, and is now standard equipment with all Marconi image intensifiers. It has a 17 inch circular screen which is virtually flat, and which can be viewed in normal daylight conditions. Designer Marconi x-ray division. Maker Marconi Instruments Ltd.
The technical challenge
regarded as the control elements in closed loop servo-systems with the output directed at the patients. If this is so, then it follows that there is a need for the scientific design both of the system and its individual components.
There is another practical reason why the design of medical equipment is now closely engaging the attention of industry and of Government. Our national economic situation demands the maximum possible export performance, and this applies to the medical supplies industry as it does to any other productive sector.
There is a great - and unsatisfied - demand for all types of medical supplies in many parts of the world, and the sophisticated countries are already competing strongly for this valuable trade. If we are to maintain and progressively increase our share of the world market, it is essential for our products to be equal in design to those of the best of our competitors - many of whom are now producing apparatus which looks good, works well and has had the benefit of design thinking throughout its development.
In selling abroad, it is no longer sufficient offer devices which function satisfactorily; the perceptive customer now looks for a product which has been consciously designed with full regard to environmental, operating and many other factors additional to functional efficiency.. It is no longer sensible, even economically, to enclose an assembly of components in a pretty case in the belief that this is a design contribution.
Fortunately, there is already a wide range of British medical items in the production of which well known industrial designers have co-operated. It is perhaps no accident that some of these items sell heavily overseas. Sometimes one hears grumbles from firms that they 'cannot afford good design'; but most forward looking producers now see that they cannot afford bad - or totally absent design, and this understanding is being sharpened by overseas competition. It seems certain that in the future there will be an increasing liberalisation of trade in medical products, and in consequence the home market will be exposed to more foreign products. Conversely, more markets will be available to our industries. The extent to which the British medical supplies industries will succeed in increasing their exports and coping with overseas competitors at home will be significantly affected by the quality of
their product design. And this means design in depth from the locating of a control to packing and presentation - and even to the production of clear, well printed promotional and instructional literature.
Spreading the 'esoteric mysteries'
The main stimuli are likely to come from doctors adopting technological innovations which will increasingly involve critical design considerations; and from the general spread through the specialised sectors of industry of a better understanding of design, ergonomics and anthropometry so that hey are recognised notes esoteric mysteries but as intensely practical skills which cannot be disregarded in the creation of a medical product of any sophistication.
At Government level, the Ministry of Health -through its own
research and development programme in selected areas of medical equipment - will continue to assist in the promotion of better design. The ministry is also responsible for sponsoring, both nationally and internationally, the British medical supply industries; and in discharging this function there are considerable opportunities for influencing the quality of design, particularly by bringing to notice the design performance of overseas competitors.
It would be unrealistic to think that in the design of medical products things are not too bad now and will be much better soon. There are many difficulties; the fragmentation of the industry and the disparate size of producers (and of their ranges of products) are just the main ones. Better communications are needed between industry and Government, better communications between industry or research institutions and the professional end users. There must be more money for design projects and more co-operative effort among firms at home and overseas. The list could be extended much further, but on all of these problems a start has been made. The future for the design of British medical products is at least modestly encouraging.
Oxygen therapy
It is only during the last decade that hyperbaric therapy - treatment by gases at pressures above atmosphere- has been perfected, and as well as large 'walk-in' pressure chambers, smaller systems for individual patients are now available. The bed illustrated here is a new development. The designers' main concern was to produce a design that would be comfortable and not look too formidable from the patients' point of view; at the same time, the structure had to be light and easily handled by nursing staff. The system has therefore been made to look as much like a bed as possible. The patient may be treated in a sitting position, and a foam rubber mattress and adjustable back rest are provided. The bed head is covered with two Perspex domes, the outer protecting the inner from scratches, etc. The top half of the bed is counterpoised and balanced with specially developed springs so that it is easy to lift, and the whole bed can easily be tilted to a 'feet-up' or 'head-up' position. It is made from two thin skins of aluminium filled with plastics foam, giving a light structure while avoiding any problems of heat loss or gain. The lower half of the bed is in steel. Designer Vickers research establishment. Maker Vickers Ltd. Medical Division.
S. M. Davies has spent 30 years in the Civil Service in several departments, but for the past 20 years has been mostly engaged in medical supply buying and administration. He was appointed assistant director of supplies to the Ministry of Health in 1961, and director of equipment in 1962. In addition to this responsibility for medical and nonmedical supplies for the hospital service, he has a keen interest in the promotion of medical exports. He is an assessor to the ColD.
1 and 2 Properly planned hospitals need proper furnishings. The idea of cramming patients into any odd area of the hospital where there is a bit of spare space has given way to the neatly demarcated waiting and reception area.
1 The Royal Eye and Ear Hospital, Bradford.
2 Its replacement, the Ear, Nose, Throat and Eye Unit of the Bradford Royal Infirmary (architects Watkins, Gray and Partners).

 

 

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