CHAPTER 15
The National Poisons Unit: the development of electronic databases and their proposed use for chemical disaster management
Introduction
The chemical and pharmaceutical industries have undergone massive expansion over the last four decades, and at least 70,000 chemicals are available in the United Kingdom alone. Accidents and poisonings by chemicals are increasing and an association between the exposure to certain chemicals and the incidence of certain diseases is now recognised.
Release of industrial chemicals into air, water or food may expose many thousands of individuals through ingestion, inhalation or skin contact. The chemicals may have the potential to cause a wide range of acute and long-term effects on health, some of which may not be readily distinguishable from those having natural causes, and only linked with chemical exposure though epidemiological studies (Baxter 1991).
The medical management of such chemical incidents has been given little attention in comparison to other aspects of the response planned by emergency and other non-medical services (Taylor et al 1990). Most emergency plans suggest that once a patient has reached a hospital and has been given medical advice, little more action needs to be taken.
However, a review of previous major chemical incidents found that in many cases medical management could be faulted in retrospect (Baxter 1990), the key deficiency being a delay in properly identifying the health hazard and obtaining adequate information. The review concluded that health-risk assessment must begin as soon as possible after an incident occurs or a health hazard is suspected, and that the assessment should be continually updated as the situation unfolds.
Information on the toxic hazard is crucial to:
- devising appropriate treatment for exposure victims;
- identifying the evacuation needs both in terms of the nature of such an evacuation and its likely duration;
- limitation of the incident's spread including avoidance of procedures which may unintentionally lead to exacerbation of an incident;
- allay public concern (Bridges 1990).
Such an assessment requires information on the nature of the chemical, its toxic effects and chemical and physical properties, the exposure conditions and site factors.
Information from past experience is essential for planning prevention and a more effective response to emergencies involving release of toxic chemicals. It is therefore important when incidents occur to ensure that detailed information is logged about the effects in man and other species and the measures taken to ameliorate these (Bridges 1990).
Information management is therefore a primary theme in disaster management (Kulling 1990), and information management systems are coming to rely increasingly on electronic data-processing technology. Indeed, in the United States, it is expected that centres engaged in hazardous materials response efforts should have their information on hazardous materials computerised (Tong 1990).
Poisons centres
Information management systems for toxicological data already exist in poisons centres in most industrialised countries and many developing countries. It is essential for poisons centres to compile and assess clinical toxicology data so that they can fulfil their two main functions. These are firstly, the provision of information and medical advice related to the diagnosis and management of poisoning and secondly the identification, investigation and evaluation of toxic risks in the community with a view to taking measures to reduce or eliminate these risks (International Programme on Chemical Safety IPCS, (WHO/ILO/UNEP) 1991).
Databases containing chemical hazard and toxicity data exist in many other organisations, but it is the emphasis on information about diagnosis and management of poisoning, based as far as possible on clinical experience, which makes poisons centre databases of particular relevance to the medical management of chemical disasters, and their value is increased by their accessibility. Poisons centres are organised to respond to medical emergencies and their information must be immediately available to enquirers on a 24-hour basis, usually by telephone.
In several countries poisons centres are already considered to be essential scientific resources for management of chemical incidents. Their services extend beyond the provision of information: clinicians with expertise in clinical toxicology are always available for consultation and most centres can arrange emergency laboratory investigations on a 24-hour basis. In the UK the role and responsibility of poisons information services in the medical management of chemical incidents was recognised at a meeting on ‘Major Chemical Disasters: Medical Aspects of Management’ organised by the National Poisons Unit (NPU) and the Section of Occupational Medicine, Royal Society of Medicine (Murray 1990).
The function of poisons centres in chemical disaster management
The principal functions of poisons centres in the event of an incident are:
- the assessment of the nature of the toxic hazard;
- the dissemination of information;
- the provision of advice on such issues as decontamination, treatment, case registration and follow-up (Kulling 1990).
In addition many centres maintain emergency stores of antidotes and could take responsibility for their distribution and provision, and many can provide laboratory services for analytical toxicology. The structure and organisation of a poisons centre should make it possible to continually monitor the development of an incident and changes in the situation as they occur (Murray 1991). It should also be possible to send members of staff to the site or to the hospital immediately responsible for managing cases (Tong 1990).
Poisons centres computerisation programmes
To discharge these functions poisons centres need information on the toxicity of a large number of chemical substances, commercial products, plants, and animals. The information is obtained from a number of published and unpublished sources, and may take the form of research reports, literature reviews, individual clinical case histories of patients exposed to toxic hazards, reviews of a series of case reports and hazard data sheets for chemical substances of manufactured products. All this information needs to be evaluated and used to prepare a clear concise summary suitable for use in an emergency situation, with first-aid advice, diagnosis and treatment. Both the summary and many of the original documents need to be rapidly accessible even though a substance may be commonly known by a number of chemical names, common or trivial names, proprietary names and functional descriptions.
Because speed of access and versatility of access to the information is important, poisons centres have for a long time been interested in the application of computers to store and retrieve information.
All poisons centres keep records of cases which are the subject of enquiries to the information service. The ability to monitor the incidence and severity of poisoning attributed to named agents is important as it provides information on the nature and incidence of chemical hazards and the effectiveness of measures to reduce or prevent these hazards. The ability to monitor incidence of cases attributed to a chemical incident is important for the medical management of such incidents. In some instances surveillance of reported cases has provided the first evidence of a chemical incident.
Many centres receive several thousand enquiries per year and so the ongoing surveillance or retrospective searching of their records is almost impossible without a computer. The improvement in methods of detecting abnormal clusters of cases is one of the potential advantages of computer databases.
The first large-scale database for case histories was established in Lyons, France in 1973. These were cases reported to all French Poisons Centres by users of the information services (Vincent 1983). In the UK at the NPU in London, records of all enquiries have been stored on computer since 1983 and by 1989 the database contained 350,000 records.
Other databases have been developed to store evaluated toxicity summaries. Some have been developed by individual centres for their own use, to give more rapid access to large volumes of information and make it more easily updatable. Others have realised that computerisation offers the possibility of making their databases accessible outside the poisons centre, either by telecommunications links, or by distribution of portable electronic media such as diskettes or CD-ROM. Very large databases which would have been difficult and costly to distribute in paper form and difficult to keep up-to-date, can thus be easily disseminated.
POISINDEX is a commercial database available on CD-ROM, which has been developed specifically for use in poisons information centres in the United States, although it is also used in poisons centres in many other countries.
The INTOX project coordinated by IPCS aims to distribute a database of Poisons Information monographs to newly established poisons centres in developing countries. This depends on the ability to compress a large volume of information onto a CD-ROM which can be easily and cheaply disseminated by post. The database is being compiled by an international group of poisons centres working together. This will reduce the duplication of work by different centres making their own evaluations of toxicity of chemical substances and give new centres the benefit of information compiled and evaluated by those with experience and expertise in particular areas of clinical toxicology.
Another application of computers is being developed in Europe by the EUROTOXNET project, sponsored by the Commission of the European Communities. This project aims to improve communications between poisons centres in Europe by establishing computer links between them (Volans 1990). The objectives of EUROTOXNET include:
- promotion of international compatibility of data by:
– use of compatible systems in European poisons centres;
– agreement of European standards for data recording and reporting;
- development of an international thesaurus for vocabulary control;
- provision of training in toxicology and information technology.
Improvements in communications between centres greatly improve their ability to alert each other in the event of a chemical incident and to cooperate in the medical management of such incidents. Use of compatible computer systems and compatible data formats makes it easier to exchange information and, in the event of an incident affecting areas crossed by national boundaries, it would be easier to carry out joint surveillance operations.
For some centres the aim of computerisation has been to make their database accessible to their users, rather than to share it with other poisons centres. To supplement, but never to replace, the conventional approach, whereby users obtain information indirectly by a telephone conversation with someone in a poisons centre with direct access to the database, the users are offered the possibility of reading the information themselves usually via an online telecommunications link to a host computer at the poisons centre.
For instance, the Scottish Regional Centre of the National Poisons Information Services established a viewdata system (Prestel), to make information on symptoms and treatment of acute poisoning directly available to clinicians in hospital or general practice, on a television screen linked to a telephone line (Proudfoot 1983). In Cape Town, South Africa, a database has been developed by the University of Cape Town Poisons Information Centre and has been distributed on diskette to district and regional hospitals. In Singapore, information on poisoning by plants or venomous creatures is being made available to the public via a television-based viewdata system.
There are advantages to this approach: the user may find it easier and quicker to obtain information by reading it rather than through a spoken dialogue, especially if complex chemical substance names are involved or drug treatment regimes have to be written down. There is less potential for misunderstanding than with the spoken word when the dialogue takes places over a noisy telephone line. However, there are also some disadvantages. For those concerned with the management of chemical disasters the greatest disadvantage must be that by allowing the user to obtain poisons information without making a telephone enquiry to a poisons information service, this usually means that the case cannot be trapped by the centre's surveillance mechanisms. The unique potential of the poisons centre to detect and monitor potential victims of a chemical incident is then lost.
Conclusion
Information technology is only a tool. The quality of information is fundamental to the effectiveness of the database. To maintain comprehensive, up-to-date information is no small task, requiring resources and manpower. Furthermore an information centre must have the resources and manpower to make effective use of the database, to organise a service which will be able to respond effectively to emergencies, disseminating information when it is needed, in an appropriate means. To maintain an effective incident log and monitor effects of chemical exposure requires not only a computer database but staff to carry out the follow-up operation, collate incoming information, assess and analyse it and produce an incident report.
The development of centres to provide medical and toxicological information, advice, and support, with responsibilities for training, monitoring exposed populations and environments, and evaluating the management of incidents, has become a matter of national and international concern.
In the UK the feasibility of developing a centre is one of the tasks given to a working group created under the aegis of the Royal Society of Medicine (Murray 1990). Internationally the IPCS has emphasised the need for Poisons Centres to expand their roles and responsibilities related to identification, investigation and evaluation of toxic hazards and to be active in alerting others when such risks are identified (IPCS, 1991). The development and/or strengthening of poisons centres facilities has been targeted as one of the principal activities of IPCS (Mercier 1990).
Many centres lack resources. For instance they are unable to purchase both the hardware and software that would enable them to make optimum use of the best available information technology. Some do not have sufficient staff to maintain a comprehensive database or provide an effective response to a major chemical disaster. Currently the challenge for poisons centres is to obtain the financial resources which would enable them to use their information resources and their expertise in diagnosis and management of poisoning to full advantage for the medical management of chemical disasters.
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