Beds, wheelchairs, etc.

    These unexciting pieces of equipment are much more important to their users than the general public might suppose. At present a bewildering variety of hospital beds is made and used in Britain, and not all of them are equally good for their various purposes. What would, in some types of society, be a straightforward mechanical and economic design problem (to design the number of types or bed, or of adaptations, which would satisfy all the users' needs at minimum cost) is complicated almost to the point of insolubilityby the large measure of local autonomy which British hospitals have in the purchasing of equipment. whether this autonomy is on balance a good or a bad thing is a matter for separate discussion; the present point is that in this context it prevents the community from receiving as much advantage as it might from the application of good engineering

    Wheelchairs are anither class of device in which engineering design cannot be performed in isolation from the social or economic system in which its productswill be used. It is not impossibly difficult to list the types of person who need wheelchairs, and the purposes for which they need them, and thence to produce a numberof standard wheelchairs for various needs. One might, for example, have one design intended for inside use, occupant-propelled; one for outside use, occupant-propelled; one for outside use, attendant-propelled; one for outside use.powered, one to be occupied while working and therefore adapted to carry certain equipment; one fir transfer from home to car and easily stowable in the car; or some of these types might be combined in one design. The aim of any design programme of this kind would be to obtain the cheapness consequent on the quantity production of a range which would meet the needs of the largest possible number of users, leaving some to be dealt with by special designs or, preferably, adaptations to one of the standard designs. Yet all this is unrealistic in a country in which most wheelchairs are supplied through the National Health Service, which obtains them from manufacturers who hold contracts which do not appear to encourage the rational use of the total resources available to produce improved designs. Certainly many wheelchair users who can afford to do so change from the standard issue to a proprietary design, and this in the interest not of appearance, as with proprietary spectacle frames, but of function.

  It has always been the business of engineering to take account of all the conditions, including economic and organizational, imposed on the intended product; but the economic and organizational conditions can be such as to make the effective application of engineering impossible.

Scale of resources

  Estimates of the ratio of annual sales to expenditure on research and development are difficult to make in respect of the undertakings active in the field covered by this chapter, partly because of the large number and variety of those undertakings, and partly because much of the research and development expenditure is not known to those outside the firms concerned.

  Estimates of annual sales can be made from publicly available figures in some better-established parts of the field.

  Total hip replacements are now performed in Great Britain at the rate of tens of thousands per year; the prostheses themselves cost between about ￡25 and ￡80 (those containing polyethylene being cheaper than the all-metal designs); so the cost (borne largely by the taxpayer) of the prostheses alone is not less than half a million pounds a year, and probably more. The number used seems certain to increase during the next few years, as does the export market; in the U.S.A.. there are roughly ten times more orthopaedic surgeons than in the U.K., which gives an idea of the potential market there, of which British exports ought to take a share.

  About 4000new patients are fitted with artificial legs each year in England and Wales; if each patient is provided with two legs, at a charge to the National Health Service which can be assumed to be in the region of￡100 each, that means an annual payment of  ￡800 000 to the leg manufacturers (who, with one exception, are owned by one industrial group). Of course, there are also established limb-wearers whose legs need replacing at intervals, and the total charge is thus considerably greater than the figure estimated above.