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Chapter 14 - First Aid and Emergency Medical Services

FIRST AID

Antonio J. Dajer

First aid is the immediate care given to victims of accidents before trained medical workers arrive. Its goal is to stop and, if possible, reverse harm. It involves rapid and simple measures such as clearing the air passageway, applying pressure to bleeding wounds or dousing chemical burns to eyes or skin.

The critical factors which shape first aid facilities in a workplace are work-specific risk and availability of definitive medical care. The care of a high-powered saw injury is obviously radically different from that of a chemical inhalation.

From a first aid perspective, a severe thigh wound occurring near a surgical hospital requires little more than proper transport; for the same injury in a rural area eight hours from the nearest medical facility, first aid would include-among other things-debridement, tying off bleeding vessels and administration of tetanus immunoglobulin and antibiotics.

First aid is a fluid concept not only in what (how long, how complex) must be done, but in who can do it. Though a very careful attitude is required, every worker can be trained in the top five or ten do's and don'ts of first aid. In some situations, immediate action can save life, limb or eyesight. Co-workers of victims should not remain paralyzed while waiting for trained personnel to arrive. Moreover, the "top-ten" list will vary with each workplace and must be taught accordingly.

Importance of First Aid

In cases of cardiac arrest, defibrillation administered within four minutes yields survival rates of 40 to 50%, versus less than 5% if given later. Five hundred thousand people die of cardiac arrest every year in the United States alone. For chemical eye injuries, immediate flushing with water can save eyesight. For spinal cord injuries, correct immobilization can make the difference between full recovery and paralysis. For haemorrhages, the simple application of a fingertip to a bleeding vessel can stop life-threatening blood loss.

Even the most sophisticated medical care in the world often cannot undo the effects of poor first aid.

First Aid in the Context of the General Organization of Health and Safety

The provision of first aid should always have a direct relationship to general health and safety organization, because first aid itself will not handle more than a small part of workers' total care. First aid is a part of the total health care for workers. In practice, its application will depend to a large extent on persons present at the time of an accident, whether co-workers or formally trained medical personnel. This immediate intervention must be followed by specialized medical care whenever needed.

First aid and emergency treatment in cases of accident and indisposition of workers at the workplace are listed as an important part of the functions of the occupational health services in the ILO Occupational Health Services Convention (No. 161), Article 5, and the Recommendation of the same name. Both adopted in 1985, they provide for the progressive development of occupational health services for all workers.

Any comprehensive occupational safety and health programme should include first aid, which contributes to minimizing the consequences of accidents and is therefore one of the components of tertiary prevention. There is a continuum leading from the knowledge of the occupational hazards, their prevention, first aid, emergency treatment, further medical care and specialized treatment for reintegration into and readaptation to work. There are important roles that occupational health professionals can play along this continuum.

It is not infrequent that several small incidents or minor accidents take place before a severe accident occurs. Accidents requiring only first aid represent a signal which should be heard and used by the occupational health and safety professionals to guide and promote preventive action.

Relation to Other Health-Related Services

The institutions which may be involved in the organization of first aid and provide assistance following an accident or illness at work include the following:

·     the occupational health service of the enterprise itself or other occupational health entities

·     other institutions which may provide services, such as: ambulance services; public emergency and rescue services; hospitals, clinics and health centres, both public and private; private physicians; poison centres; civil defence; fire departments; and police.

Each of these institutions has a variety of functions and capabilities, but it must be understood that what applies to one type of institution-say a poison centre-in one country, may not necessarily apply to a poison centre in another country. The employer, in consultation with, for example, the factory physician or outside medical advisers, must ensure that the capabilities and facilities of neighbouring medical institutions are adequate to deal with the injuries expected in the event of serious accidents. This assessment is the basis for deciding which institutions will be entered into the referral plan.

The cooperation of these related services is very important in providing proper first aid, particularly for small enterprises. Many of them may provide advice on the organization of first aid and on planning for emergencies. There are good practices which are very simple and effective; for example, even a shop or a small enterprise may invite the fire brigade to visit its premises. The employer or owner will receive advice on fire prevention, fire control, emergency planning, extinguishers, the first aid box and so on. Conversely, the fire brigade will know the enterprise and will be ready to intervene more rapidly and efficiently.

There are many other institutions which may play a role, such as industrial and trade associations, safety associations, insurance companies, standards organizations, trade unions and other non-governmental organizations. Some of these organizations may be knowledgeable about occupational health and safety and can be a valuable resource in the planning and organization of first aid.

An Organized Approach to First Aid

Organization and planning

First aid cannot be planned in isolation. First aid requires an organized approach involving people, equipment and supplies, facilities, support and arrangements for the removal of victims and non-victims from the site of an accident. Organizing first aid should be a cooperative effort, involving employers, occupational health and public health services, the labour inspectorate, plant managers and relevant non-governmental organizations. Involving workers themselves is essential: they are often the best source on the likelihood of accidents in specific situations.

Whatever the degree of sophistication or the absence of facilities, the sequence of actions to be taken in the case of an unforeseen event must be determined in advance. This must be done taking due account of existing and potential occupational and non-occupational hazards or occurrences, as well as ways of obtaining immediate and appropriate assistance. Situations vary not only with the size of the enterprise but also with its location (in a town or a rural area) and with the development of the health system and of labour legislation at the national level.

As regards the organization of first aid, there are several key variables to be considered:

·     type of work and associated level of risk

·     potential hazards

·     size and layout of the enterprise

·     other enterprise characteristics (e.g., configuration)

·     availability of other health services.

Type of work and associated level of risk

The risks of injury vary greatly from one enterprise and from one occupation to another. Even within a single enterprise, such as a metalworking firm, different risks exist depending on whether the worker is engaged in the handling and cutting of metal sheets (where cuts are frequent), welding (with the risk of burns and electrocution), the assembly of parts, or metal plating (which has the potential of poisoning and skin injury). The risks associated with one type of work vary according to many other factors, such as the design and age of the machinery used, the maintenance of the equipment, the safety measures applied and their regular control.

The ways in which the type of work or the associated risks influence the organization of first aid have been fully recognized in most legislation concerning first aid. The equipment and supplies required for first aid, or the number of first aid personnel and their training, may vary in accordance with the type of work and the associated risks. Countries use different models for classifying them for the purpose of planning first aid and deciding whether higher or lower requirements are to be set. A distinction is sometimes made between the type of work and the specific potential risks:

·     low risk-for example, in offices or shops

·     higher risk-for example, in warehouses, farms and in some factories and yards

·     specific or unusual risks-for example, in steelmaking (especially when working on furnaces), coking, non-ferrous smelting and processing, forging, foundries; shipbuilding; quarrying, mining or other underground work; work in compressed air and diving operations; construction, lumbering and woodworking; abattoirs and rendering plants; transportation and shipping; most industries involving harmful or dangerous substances.

Potential hazards

Even in enterprises which seem clean and safe, many types of injury can occur. Serious injuries may result from falling, striking against objects or contact with sharp edges or moving vehicles. The specific requirements for first aid will vary depending on whether the following occur:

·     falls

·     serious cuts, severed limbs

·     crushing injuries and entanglements

·     high risks of spreading fire and explosions

·     intoxication by chemicals at work

·     other chemical exposure

·     electrocution

·     exposure to excessive heat or cold

·     lack of oxygen

·     exposure to infectious agents, animal bites and stings.

The above is only a general guide. The detailed assessment of the potential risks in the working environment helps greatly to identify the need for first aid.

Size and layout of the enterprise

First aid must be available in every enterprise, regardless of size, taking into account that the frequency rate of accidents is often inversely related to the size of the enterprise.

In larger enterprises, the planning and organization of first aid can be more systematic. This is because individual workshops have distinct functions and the workforce is more specifically deployed than in smaller enterprises. Therefore the equipment, supplies and facilities for first aid, and first aid personnel and their training, can normally be organized more precisely in response to the potential hazards in a large enterprise than in a smaller one. Nevertheless, first aid can also be effectively organized in smaller enterprises.

Countries use different criteria for the planning of first aid in accordance with the size and other characteristics of the enterprise. No general rule can be set. In the United Kingdom, enterprises with fewer than 150 workers and involving low risks, or enterprises with fewer than 50 workers with higher risks, are considered small, and different criteria for the planning of first aid are applied in comparison with enterprises where the number of workers present at work exceeds these limits. In Germany, the approach is different: whenever there are fewer than 20 workers expected at work one set of criteria would apply; if the number of workers exceeds 20, other criteria will be used. In Belgium, one set of criteria applies to industrial enterprises with 20 or fewer workers at work, a second to those with between 20 and 500 workers, and a third to those with 1,000 workers and more.

Other enterprise characteristics

The configuration of the enterprise (i.e., the site or sites where the workers are at work) is important to the planning and organization of first aid. An enterprise might be located at one site or spread over several sites either within a town or region, or even a country. Workers may be assigned to areas away from the enterprise's central establishment, such as in agriculture, lumbering, construction or other trades. This will influence the provision of equipment and supplies, the number and distribution of first aid personnel, and the means for the rescue of injured workers and their transportation to more specialized medical care.

Some enterprises are temporary or seasonal in nature. This implies that some workplaces exist only temporarily or that in one and the same place of work some functions will be performed only at certain periods of time and may therefore involve different risks. First aid must be available whenever needed, irrespective of the changing situation, and planned accordingly.

In some situations employees of more than one employer work together in joint ventures or in an ad hoc manner such as in building and construction. In such cases the employers may make arrangements to pool their provision of first aid. A clear allocation of responsibilities is necessary, as well as a clear understanding by the workers of each employer as to how first aid is provided. The employers must ensure that the first aid organized for this particular situation is as simple as possible.

Availability of other health services

The level of training and the extent of organization for first aid is, in essence, dictated by the proximity of the enterprise to, and its integration with, readily available health services. With close, good backup, avoiding delay in transport or calling for help can be more crucial to a good outcome than is skilful application of medical manoeuvres. Each workplace's first aid programme must mold itself to-and become an extension of-the medical facility which provides the definitive care for its injured workers.

Basic Requirements of a First Aid Programme

First aid must be considered part of sound management and making work safe. Experience in countries where first aid is strongly established suggests that the best way to ensure effective first aid provision is to make it mandatory by legislation. In countries which have chosen this approach, the main requirements are set out in specific legislation or, more commonly, in national labour codes or similar regulations. In these cases, subsidiary regulations contain more detailed provisions. In most cases, the overall responsibility of the employer for providing and organizing first aid is laid down in the basic enabling legislation. The basic elements of a first aid programme include the following:

Equipment, supplies and facilities

·     equipment to rescue the victim at the site of the accident so as to prevent further harm (e.g., in the case of fire, gassing, electrocution)

·     first aid boxes, first aid kits or similar containers, with a sufficient quantity of the materials and appliances required for the delivery of basic first aid

·     specialized equipment and supplies which may be required in enterprises involving specific or unusual risks at work

·     an adequately identified first aid room or a similar facility where first aid can be administered

·     provision of means of evacuation and emergency transportation of the injured persons to the first aid facility or the sites where further medical care is available

·     means of giving the alarm and communicating the alert

Human resources

·     selection, training and retraining of suitable persons for administering first aid, their appointment and location at critical sites throughout the enterprise, and the assurance that they are permanently available and accessible

·     retraining, including practical exercises simulating emergency situations, with due account given to specific occupational hazards in the enterprise

Other

·     establishment of a plan, including links between the relevant health or public health services, with a view to the delivery of medical care following first aid

·     education and information of all workers concerning the prevention of accidents and injuries, and the actions workers must themselves take following an injury (e.g., a shower immediately after a chemical burn)

·     information on the arrangements for first aid, and the periodic updating of this information

·     posting of information, visual guides (e.g., posters) and instruction about first aid, and plans with a view to the delivery of medical care after first aid

·     record keeping (the first aid treatment record is an internal report which will provide information concerning the health of the victim, as well as contributing to safety at work; it should include information on: the accident (time, location, occurrence), the type and severity of the injury, the first aid delivered, the additional medical care requested, the name of the casualty and the names of witnesses and other workers involved, especially those transporting the casualty)

Although basic responsibility for implementing a first aid programme lies with the employer, without full participation of the workers, first aid cannot be effective. For example, workers may need to cooperate in rescue and first aid operations; they should thus be informed of first aid arrangements and should make suggestions, based on their knowledge of the workplace. Written instructions about first aid, preferably in the form of posters, should be displayed by the employer at strategic places within the enterprise. In addition, the employer should organize briefings for all workers. The following are essential parts of the briefing:

·     the organization of first aid in the enterprise, including the procedure for access to additional care

·     colleagues who have been appointed as first aid personnel

·     ways in which information about an accident should be communicated, and to whom

·     location of the first aid box

·     location of the first aid room

·     location of the rescue equipment

·     what the workers must do in case of an accident

·     location of the escape routes

·     workers' actions following an accident

·     ways of supporting first aid personnel in their task.

First Aid Personnel

First aid personnel are persons on the spot, generally workers who are familiar with the specific conditions of work, and who might not be medically qualified but must be trained and prepared to perform very specific tasks. Not every worker is suitable to be trained for providing first aid. First aid personnel should be selected carefully, taking into account attributes such as reliability, motivation and the ability to cope with people in a crisis situation.

Type and number

National regulations for first aid vary with respect to both the type and number of first aid personnel required. In some countries the emphasis is on the number of persons employed in the workplace. In other countries, the overriding criteria are the potential risks at work. In yet others, both of these factors are taken into account. In countries with a long tradition of occupational safety and health practices and where the frequency of accidents is lower, more attention is usually given to the type of first aid personnel. In countries where first aid is not regulated, emphasis is normally placed on numbers of first aid personnel.

A distinction may be made in practice between two types of first aid personnel:

·     the basic-level first-aider, who receives basic training as outlined below and who qualifies for appointment where the potential risk at work is low

·     the advanced-level first-aider, who will receive the basic and advanced training and will qualify for appointment where the potential risk is higher, special or unusual.

The following four examples are indicative of the differences in approach used in determining the type and number of first aid personnel in different countries:

United Kingdom

·     If the work involves relatively low hazards only, no first aid personnel are required unless there are 150 or more workers present at work; in this case a ratio of one first-aider per 150 workers is considered adequate. Even if fewer than 150 workers are at work, the employer should nevertheless designate an "appointed person" at all times when workers are present.

·     Should the work involve higher risk, one first-aider will normally be required when the number of workers at work is between 50 and 150. If more than 150 workers are at work, one additional first-aider for every 150 will be required and, if the number of workers at work is less than 50, an "appointed person" should be designated.

·     If the potential risk is unusual or special, there will be a need, in addition to the number of first aid personnel already required under the criteria set out above, for an additional person who will be trained specifically in first aid in case of accidents arising from these unusual or special hazards (the occupational first-aider).

Belgium

·     One first-aider is usually required for every 20 workers present at work. However, a full-time occupational health staff member is required if there are special hazards and if the number of workers exceeds 500, or in the case of any enterprise where the number of workers on site is 1,000 or more.

·     Some degree of flexibility is possible in accordance with particular situations.

Germany

·     One first-aider is required if there are 20 or fewer workers present at work.

·     If more than 20 workers are present, the number of first-aiders should be 5% of those at work in offices or general trade, or 10% in all other enterprises. Depending on other measures which may have been taken by the enterprise to deal with emergencies and accidents, these numbers may be revised.

·     If work involves unusual or specific risks (for instance, if hazardous substances are involved), a special type of first aid personnel needs to be provided and trained; no specific number is stipulated for such personnel (i.e., the above-mentioned numbers apply).

·     If more than 500 workers are present and if unusual or special hazards exist (burns, poisonings, electrocutions, impairment of vital functions such as respiratory or cardiac arrest), specially trained full-time personnel must be made available to deal with cases where a delay in arrival of no more than 10 minutes may be allowable. This provision will apply in most larger construction sites where a number of enterprises often employ a workforce of several hundred workers.

New Zealand

·     If more than five workers are present, an employee is appointed and put in charge of the equipment, supplies and facilities for first aid.

·     If more than 50 persons are present, the person appointed must be either a registered nurse or hold a certificate (issued by the St. John's Ambulance Association or the New Zealand Red Cross Society).

Training

The training of first aid personnel is the single most important factor determining the effectiveness of organized first aid. Training programmes will depend on the circumstances within the enterprise, especially the type of work and the risks involved.

Basic Training

Basic training programmes are usually on the order of 10 hours. This is a minimum. Programmes can be divided into two parts, dealing with the general tasks to be performed and the actual delivery of first aid. They will cover the areas listed below.

General tasks

·     how first aid is organized

·     how to assess the situation, the magnitude and severity of the injuries and the need for additional medical help

·     how to protect the casualty against further injury without creating a risk for oneself; the location and use of the rescue equipment

·     how to observe and interpret the victim's general condition (e.g., unconsciousness, respiratory and cardiovascular distress, bleeding)

·     the location, use and maintenance of first aid equipment and facilities

·     the plan for access to additional care.

Delivery of first aid

The objective is to provide basic knowledge and delivery of first aid. At the basic level, this includes, for example:

·     wounds

·     bleeding

·     fractured bones or joints

·     crushing injuries (e.g., to the thorax or abdomen)

·     unconsciousness, especially if accompanied by respiratory difficulties or arrest

·     eye injuries

·     burns

·     low blood pressure, or shock

·     personal hygiene in dealing with wounds

·     care of amputated digits.

Advanced Training

The aim of advanced training is specialization rather than comprehensiveness. It is of particular importance in relation to the following types of situation (though specific programmes normally deal only with some of these, in accordance with needs, and their duration varies considerably):

·     cardiopulmonary resuscitation

·     poisoning (intoxication)

·     injuries caused by electric current

·     severe burns

·     severe eye injuries

·     skin injuries

·     contamination by radioactive material (internal, and skin or wound contamination)

·     other hazard-specific procedures (e.g., heat and cold stress, diving emergencies).

Training Materials and Institutions

A wealth of literature is available on training programmes for first aid. The national Red Cross and Red Crescent Societies and various organizations in many countries have issued material which covers much of the basic training programme. This material should be consulted in the design of actual training programmes, though it may need adaptation to the specific requirements of first aid at work (in contrast with first aid after traffic accidents, for instance).

Training programmes should be approved by the competent authority or a technical body authorized to do so. In many cases, this may be the national Red Cross or Red Crescent Society or related institutions. Sometimes safety associations, industrial or trade associations, health institutions, certain non-governmental organizations and the labour inspectorate (or their subsidiary bodies) may contribute to the design and provision of the training programme to suit specific situations.

This authority should also be responsible for testing first aid personnel upon completion of their training. Examiners independent of the training programmes should be designated. Upon successfully completing the examination, the candidates should be awarded a certificate upon which the employer or enterprise will base their appointment. Certification should be made obligatory and should also follow refresher training, other instruction or participation in field work or demonstrations.

First Aid Equipment, Supplies and Facilities

The employer is responsible for providing first aid personnel with adequate equipment, supplies and facilities.

First aid boxes, first aid kits and similar containers

In some countries, only the principal requirements are set out in regulations (e.g., that adequate amounts of suitable materials and appliances are included, and that the employer must determine what precisely may be required, depending on the type of work, the associated risks and the configuration of the enterprise). In most countries, however, more specific requirements have been set out, with some distinction made as to the size of the enterprise and the type of work and potential risks involved.

Basic content

The contents of these containers must obviously match the skills of the first aid personnel, the availability of a factory physician or other health personnel and the proximity of an ambulance or emergency service. The more elaborate the tasks of the first aid personnel, the more complete must be the contents of the containers. A relatively simple first aid box will usually include the following items:

·     individually wrapped sterile adhesive dressing

·     bandages (and pressure dressings, where appropriate)

·     a variety of dressings

·     sterile sheets for burns

·     sterile eye pads

·     triangular bandages

·     safety pins

·     a pair of scissors

·     antiseptic solution

·     cotton wool balls

·     a card with first aid instructions

·     sterile plastic bags

·     access to ice.

Location

First aid boxes should always be easily accessible, near areas where accidents could occur. They should be able to be reached within one to two minutes. They should be made of suitable materials, and should protect the contents from heat, humidity, dust and abuse. They need to be identified clearly as first aid material; in most countries, they are marked with a white cross or a white crescent, as applicable, on a green background with white borders.

If the enterprise is subdivided into departments or shops, at least one first aid box should be available in each unit. However, the actual number of boxes required will be determined on the basis of the needs assessment made by the employer. In some countries the number of containers required, as well as their contents, has been established by law.

Auxiliary kits

Small first aid kits should always be available where workers are away from the establishment in such sectors as lumbering, agricultural work or construction; where they work alone, in small groups or in isolated locations; where work involves travelling to remote areas; or where very dangerous tools or pieces of machinery are used. The contents of such kits, which should also be readily available to self-employed persons, will vary according to circumstances, but they should always include:

·     a few medium-sized dressings

·     a bandage

·     a triangular bandage

·     safety pins.

Specialized equipment and supplies

Further equipment may be needed for the provision of first aid where there are unusual or specific risks. For example, if poisonings are a possibility, antidotes must be immediately available in a separate container, though it must be made clear that their administration is subject to medical instruction. Long lists of antidotes exist, many for specific situations. Potential risks will determine which antidotes are needed.

Specialized equipment and material should always be located near the sites of potential accidents and in the first aid room. Transporting the equipment from a central location such as an occupational health service facility to the site of the accident may take too long.

Rescue equipment

In some emergency situations, specialized rescue equipment to remove or disentangle an accident victim may be necessary. Although it may not be easy to predict, certain work situations (such as working in confined spaces, at heights or above water) may have a high potential for this type of incident. Rescue equipment may include items such as protective clothing, blankets for fire-fighting, fire extinguishers, respirators, self-contained breathing apparatus, cutting devices and mechanical or hydraulic jacks, as well as equipment such as ropes, harnesses and specialized stretchers to move the victim. It must also include any other equipment required to protect the first aid personnel against becoming casualties themselves in the course of delivering first aid. Although initial first aid should be given before moving the patient, simple means should also be provided for transporting an injured or sick person from the scene of the accident to the first aid facility. Stretchers should always be accessible.

The first aid room

A room or a corner, prepared for administering first aid, should be available. Such facilities are required by regulations in many countries. Normally, first aid rooms are mandatory when there are more than 500 workers at work or when there is a potentially high or specific risk at work. In other cases, some facility must be available, even though this may not be a separate room-for example, a prepared corner with at least the minimum furnishings of a full-scale first aid room, or even a corner of an office with a seat, washing facilities and a first aid box in the case of a small enterprise. Ideally, a first aid room should:

·     be accessible to stretchers and must have access to an ambulance or other means of transportation to a hospital

·     be large enough to hold a couch, with space for people to work around it

·     be kept clean, well ventilated, well lit and maintained in good order

·     be reserved for the administration of first aid

·     be clearly identified as a first aid facility, be appropriately marked and be under the responsibility of first aid personnel

·     have clean running water, preferably both hot and cold, soap and a nail brush. If running water is not available, water should be kept in disposable containers near the first aid box for eye washing and irrigation

·     include towels, pillows and blankets, clean clothing for use by the first aid personnel, and a refuse container.

Communication and Referral Systems

Means for communicating the alert

Following an accident or sudden illness, it is important that immediate contact be made with first aid personnel. This requires means of communication between work areas, the first aid personnel and the first aid room. Communications by telephone may be preferable, especially if distances are more than 200 metres, but this will not be possible in all establishments. Acoustic means of communication, such as a hooter or buzzer, may serve as a substitute as long as it can be assured that the first aid personnel arrive at the scene of the accident rapidly. Lines of communication should be pre-established. Requests for advanced or specialized medical care, or an ambulance or emergency service, are normally made by telephone. The employer should ensure that all relevant addresses, names and telephone numbers are clearly posted throughout the enterprise and in the first aid room, and that they are always available to the first aid personnel.

Access to additional care

The need for a referral of the victim to more advanced or specialized medical care must always be foreseen. The employer should have plans for such a referral, so that when the case arises everybody involved will know exactly what to do. In some cases the referral systems will be rather simple, but in others they may be elaborate, especially where unusual or special risks are involved at work. In the construction industry, for instance, referral may be required after serious falls or crushings, and the end point of referral will most probably be a general hospital, with adequate orthopaedic or surgical facilities. In the case of a chemical works, the end point of referral will be a poison centre or a hospital with adequate facilities for the treatment of poisoning. No uniform pattern exists. Each referral plan will be tailored to the needs of the enterprise under consideration, especially if higher, specific or unusual risks are involved. This referral plan is an important part of the enterprise's emergency plan.

The referral plan must be supported by a system of communication and means for transporting the casualty. In some cases, this may involve communication and transport systems organized by the enterprise itself, especially in the case of larger or more complex enterprises. In smaller enterprises, transport of the casualty may need to rely on outside capacity such as public transport systems, public ambulance services, taxis and so on. Stand-by or alternative systems should be set up.

The procedures for emergency conditions must be communicated to everyone: workers (as part of their overall briefing on health and safety), first-aiders, safety officers, occupational health services, health facilities to which a casualty may be referred, and institutions which play a role in communications and the transport of the casualty (e.g., telephone services, ambulance services, taxi companies and so on).

TRAUMATIC HEAD INJURIES

Fengsheng He

Aetiological Factors

Head trauma consists of skull injury, focal brain injury and diffuse brain tissue injury (Gennarelli and Kotapa 1992). In work-related head trauma falls account for the majority of the causes (Kraus and Fife 1985). Other job-related causes include being struck by equipment, machinery or related items, and by on-road motor vehicles. The rates of work-related brain injury are markedly higher among young workers than older ones (Kraus and Fife 1985).

Occupations at Risk

Workers involved in mining, construction, driving motor vehicles and agriculture are at higher risk. Head trauma is common in sportsmen such as boxers and soccer players.

Neuropathophysiology

Skull fracture can occur with or without damage to the brain. All forms of brain injury, whether resulting from penetrating or closed head trauma, can lead to the development of swelling of the cerebral tissue. Vasogenic and cytogenic pathophysiologic processes active at the cellular level result in cerebral oedema, increased intracranial pressure and cerebral ischaemia.

Focal brain injuries (epidural, subdural or intracranial haematomas) may cause not only local brain damage, but a mass effect within the cranium, leading to midline shift, herniation and ultimately brain stem (mid-brain, pons and medulla oblongata) compression, causing, first a declining level of consciousness, then respiratory arrest and death (Gennarelli and Kotapa 1992).

Diffuse brain injuries represent shearing trauma to innumerable axons of the brain, and may be manifested as anything from subtle cognitive dysfunction to severe disability.

Epidemiological Data

There are few reliable statistics on the incidence of head injury from work-related activities.

In the United States, estimates of the incidence of head injury indicate that at least 2 million people incur such injuries each year, with nearly 500,000 resultant hospital admissions (Gennarelli and Kotapa 1992). Approximately half of these patients were involved in motor accidents.

A study of brain injury in residents of San Diego County, California in 1981 showed that the overall work-related injury rate for males was 19.8 per 100,000 workers (45.9 per 100 million work hours). The incidence rates of work-related brain injuries for male civilian and military personnel were 15.2 and 37.0 per 100,000 workers, respectively. In addition, the annual incidence of such injuries was 9.9 per 100 million work hours for males in the work force (18.5 per 100 million hours for military personnel and 7.6 per 100 million hours for civilians) (Kraus and Fife 1985). In the same study, about 54% of the civilian work-related brain injuries resulted from falls, and 8% involved on-road motor vehicle accidents (Kraus and Fife 1985).

Signs and Symptoms

The signs and symptoms vary among different forms of head trauma (table 14.1) (Gennarelli and Kotapa 1992) and different locations of traumatic brain lesion (Gennarelli and Kotapa 1992; Gorden 1991). On some occasions, multiple forms of head trauma may occur in the same patient.

Table 14.1 Classification of traumatic head injuries

Skull injuries

Brain tissue injuries

 

Focal

Diffuse

Vault fracture

Haematoma

Concussion

Linear

Epidural

Mild

Depressed

Subdural

Classical

 

Intracranial

 

Basilar fracture

Contusion

Prolonged coma, (diffuse axonal injury)

Skull injuries

Fractures of cerebral vault, either linear or depressed, can be detected by radiological examinations, in which the location and depth of the fracture are clinically most important.

Fractures of the skull base, in which the fractures are usually not visible on conventional skull radiographs, can best be found by computed tomography (CT scan). It can also be diagnosed by clinical findings such as the leakage of cerebropinal fluid from the nose (CSF rhinorrhea) or ear (CSF otorrhea), or subcutaneous bleeding at the periorbital or mastoid areas, though these may take 24 hours to appear.

Focal brain tissue injuries (Gennarelli and Kotapa 1992; Gorden 1991)

Haematoma:

Epidural haematoma is usually due to arterial bleeding and may be associated with a skull fracture. The bleeding is seen distinctly as a biconvex density on the CT scan. It is characterized clinically by transient loss of consciousness immediately after injury, followed by a lucid period. Consciousness may deteriorate rapidly due to increasing intracranial pressure.

Subdural haematoma is the result of venous bleeding beneath the dura. Subdural haemorrhage may be classified as acute, subacute or chronic, based on the time course of the development of symptoms. Symptoms result from direct pressure to the cortex under the bleed. The CT scan of the head often shows a crescent-shaped deficit.

Intracerebral haematoma results from bleeding within the parenchyma of the cerebral hemispheres. It may occur at the time of trauma or may appear a few days later (Cooper 1992). Symptoms are usually dramatic and include an acutely depressed level of consciousness and signs of increased intracranial pressure, such as headache, vomiting, convulsions and coma. Subarachnoid haemorrhage may occur spontaneously as the result of a ruptured berry aneurysm, or it may be caused by head trauma.

In patients with any form of haematoma, deterioration of consciousness, ipsilateral dilated pupil and contralateral haemiparesis suggests an expanding haematoma and the need for immediate neurosurgical evaluation. Brain stem compression accounts for approximately 66% of deaths from head injuries (Gennarelli and Kotapa 1992).

Cerebral contusion:

This presents as temporary loss of consciousness or neurologic deficits. Memory loss may be retrograde-loss of memory a time period before the injury, or antegrade-loss of current memory. CT scans shows multiple small isolated haemorrhages in the cerebral cortex. Patients are at higher risk of subsequent intracranial bleeding.

Diffuse brain tissue injuries (Gennarelli and Kotapa 1992; Gorden 1991)

Concussion:

Mild concussion is defined as a rapidly resolving (less than 24 hours) interruption of function (such as memory), secondary to trauma. This includes symptoms as subtle as memory loss and as obvious as unconsciousness.

Classic cerebral concussion manifests as slowly resolving, temporary, reversible neurologic dysfunction such as memory loss, often accompanied by a significant loss of consciousness (more than 5 minutes, less than 6 hours). The CT scan is normal.

Diffuse axonal injury:

This results in a prolonged comatose state (more than 6 hours). In the milder form, the coma is of 6 to 24 hours duration, and may be associated with long-standing or permanent neurologic or cognitive deficits. A coma of moderate form lasts for more than 24 hours and is associated with a mortality of 20%. The severe form shows brain stem dysfunction with the coma lasting for more than 24 hours or even months, because of the involvement of the reticular activating system.

Diagnosis and Differential Diagnosis

Apart from the history and serial neurologic examinations and a standard assessment tool such as the Glasgow Coma Scale (table 14.2), the radiological examinations are helpful in making a definitive diagnosis. A CT scan of the head is the most important diagnostic test to be performed in patients with neurologic findings after head trauma (Gennarelli and Kotapa 1992; Gorden 1991; Johnson and Lee 1992), and allows rapid and accurate assessment of surgical and nonsurgical lesions in the critically injured patients (Johnson and Lee 1992). Magnetic resonance (MR) imaging is complementary to the evaluation of cerebral head trauma. Many lesions are identified by MR imaging such as cortical contusions, small subdural haematomas and diffuse axonal injuries that may not be seen on CT examinations (Sklar et al. 1992).

Table 14.2 Glasgow Coma Scale

Eyes

Verbal

Motor

Does not open eyes

Makes no noise

(1) No motor response to pain

Opens eyes to painful stimuli 

Moans, makes unintelligible noises 

(2) Extensor response (decerebrate)  

Opens eyes upon loud verbal command 

Talks but nonsensical  

(3) Flexor response (decorticate)  

Opens eyes spontaneously

Seems confused and disoriented 

(4) Moves parts of body but does not remove noxious stimuli 

 

Alert and oriented

(5) Moves away from noxious stimuli 

   

(6) Follows simple motor commands

Treatment and Prognosis

Patients with head trauma need to be referred to an emergency department, and a neurosurgical consultation is important. All patients known to be unconscious for more than 10 to 15 minutes, or with a skull fracture or a neurologic abnormality, require hospital admission and observation, because the possibility exists of delayed deterioration from expanding mass lesions (Gennarelli and Kotapa 1992).

Depending on the type and severity of head trauma, provision of supplemental oxygen, adequate ventilation, decrease of brain water by intravenous administration of faster-acting hyperosmolar agents (e.g., mannitol), corticosteroids or diuretics, and surgical decompression may be necessary. Appropriate rehabilitation is advisable at a later stage.

A multicentre study revealed that 26% of patients with severe head injury had good recovery, 16% were moderately disabled, and 17% were either severely disabled or vegetative (Gennarelli and Kotapa 1992). A follow-up study also found persistent headache in 79% of the milder cases of head injury, and memory difficulties in 59% (Gennarelli and Kotapa 1992).

Prevention

Safety and health education programmes for the prevention of work-related accidents should be instituted at the enterprise level for workers and management. Preventive measures should be applied to mitigate the occurrence and severity of head injuries due to work-related causes such as falls and transport accidents.

REFERENCES

Cooper, PR. 1992. Delayed traumatic intracerebral haemorrhage. Neurosurg Clin N Am 3(3): 659-665.

Gennarelli, TA and MJ Kotapa. 1992. Trauma to the head-general considerations. In Principles and Practice of Emergency Medicine, 3rd edition, Vol. 1., edited by GR Schwartz, CG Cayten, MA Mangelsen, TA Mayer and BK Hanke. Philadelphia/London: Lea and Febiger.

Gorden, K. 1991. Head and neck trauma. In Emergency Medicine. An Approach to Clinical Problem-solving, edited by GC Hamilton, AB Sanders, GR Strange and AT Trott. Philadelphia: WB Saunders Company.

Jennett, B. 1992. Head trauma. In Diseases of the Nervous System-Clinical Neurobiology, 2nd edition, Vol. 2, edited by AK Asbury, GM Mckhann and WI McDonald. Philadelphia: WB Saunders Company.

Johnson, MH and SH Lee. 1992. Computed tomography of acute cerebral trauma. Radiol Clin N Am 30(2): 325-352.

Kraus, JF and D Fife. 1985. Incidence, external causes, and outcomes of work-related brain injuries in males. J Occup Med 27(10):757-760.

Sklar, EM, RM Quencer, BC Bowen, N Altman, PA Villanueva. 1992. Magnetic resonance applications in cerebral injury. Radiol Clin N Am. 30(2): 353-366.