One of the most remarkable features of asthma epidemiology in recent years has been a widely documented rise in prevalence (Cookson & Moffat, 1998; Burr, 1993; Anderson, 1989) which is so consistent across national and world-wide studies that differences in definition and methodology in recording prevalence cannot account for the change (Anderson et al., 1994).
On a global level, over 100 million people have asthma, with highest prevalence in those countries which appear to enjoy a high standard of living including Great Britain, where there are an estimated 1.3 million children and 1.8 million adult sufferers (National Asthma Campaign, 1995; Asher, 1997). The proportion of wheeze labelled as asthma in this country has increased from 31 per cent in 1978 to 61 per cent in 1991 (Rona et al., 1995).
Data gathered by the Lung and Asthma Information Agency (1993) revealed the real impact of respiratory disease on the UK population, accounting for 10.8 per cent of all deaths, contrary to a figure of six per cent quoted in the Health of the Nation (Department of Health, 1992). Although asthma has a high mortality profile, Botting and Bunting (1996) state that death is an extreme measure and makes up only a small part of the total health experience, suggesting the real cost of asthma lies in morbidity, it being the most common chronic disease in childhood (Cookson & Moffat, 1998).
Predisposing factors
Atopy: Atopy is the inherited predisposition to produce an exaggerated Immunoglobulin E (IgE) immune response to specific allergens (e.g. animals and pollens). Allergy is an abnormal or hypersensitive response resulting in the expression of symptoms. In allergic asthma this would present as cough, breathlessness and wheeze. Allergy occurs at random in 1520 per cent of the population, however, the possibility of developing asthma depends upon both the genetic and environmental factors to which the individual is exposed.
The risk of developing asthma in childhood where one parent has asthma is doubled. If both parents have asthma the risk may be as high as 40 per cent (Hall, 1996).
Smoking: It is known that maternal smoking increases the likelihood of children developing wheezing illnesses and in children with established asthma, parental smoking is associated with more severe disease (Lewis et al., 1995; Strachan & Cook, 1998). Similarly, exposure to tobacco smoke worsens lung function and respiratory symptoms in adults with asthma and increases circulating IgE (Coultas, 1998). Nurses have an important role to play in helping asthmatic smokers and their relatives who smoke to stop. Fox Harding (1993) sympathises with individuals who cannot be expected to shoulder all the blame for indulging in a habit so heavily promoted by government advertising.
Hastings (1991) confirms that this advertising does influence behaviour in children, reinforcing and encouraging this habit from a young age. However, it should be born in mind that even very brief cessation advice has been shown to be effective (Fiore et al., 1996).
Asthma is known to be influenced by a variety of physical, psychological and social parameters, but their inter-relationship and impact on daily life has received little attention and still remains poorly understood (Barnes, 1994; Miles et al., 1997; Nocon, 1991). Lane (1996) suggests large surveys have often relied on voluntary self-reporting, rather than on systematic enquiry covering a complete population, resulting in an underestimation of disease impact. However, even these surveys show a significant number of asthmatics (42 per cent) have daily symptoms, time off school (71 per cent) and work (49 per cent) with 13 per cent suffering symptoms every night, reflecting a major impact on their quality of life (Gallop, 1996).
The socioeconomic environment has long been known to exert a powerful influence on health, and there is an undeniable correlation between social deprivation and the severity of asthma. Those in the lower social classes and those on low income, appear to be at higher risk of receiving inadequate treatment for asthma, both in terms of appropriate medication and lack of consultation with a health care professional (National Asthma Campaign, 1995; Burr, 1997). Such findings clearly have implications for the delivery of care to such groups e.g. availability of child care, times and accessibility of clinics.
Management
Table 1: Pet Allergen avoidance
· Best advice to any asthmatic is not to buy a pet
· If they have one get rid of it
If they find this impossible reduce exposure by:
· Keeping pet outdoors or in the kitchen
· Keep out of bedroom
· Wash weekly (ask vet for advice)
· Not replacing the animal
Remember if pet is removed allergen may take months to clear (especially cats)
Guidelines on Asthma Management produced by the British Thoracic Society (1997) advise on the current best practice and identify the avoidance of provoking factors, drug treatment and patient self-management as three important facets of good care, the implementation of which requires collaborative working at a local level.
Avoidance of trigger factors: Both allergens and irritants can affect asthmatic airways. Limiting exposure to substances that worsen symptoms is to be encouraged wherever possible. Common examples of irritants are cigarette smoke, aerosols, paint fumes and pollutants. Avoiding smoky atmospheres or staying indoors when air pollution levels are high may be necessary to prevent a deterioration in asthma control.
It should be remembered that people living in the UK are said, on average to spend 85 per cent of their time indoors (Wilson, 1998) suggesting that indoor pollution may have a far greater impact than the external environment whilst poor housing has been linked to the incidence and severity of asthma symptoms (Strachan, 1988).
The most common allergens to cause problems are house dust mite, pets (especially cats) and pollens. Although many asthmatics have several allergies, measures which decrease or eradicate the levels of allergen to which susceptible asthmatics are exposed, have been shown to reduce symptoms and prevent or delay the onset of allergic disease especially in children (Hide & Hakim, 1994). Removal of an offending pet can eradicate symptoms completely, but if this is not possible, exposure can be limited by keeping the pet outdoors or in the kitchen; ensuring the pet does not go in the bedroom and washing the animal (if possible) weekly. Dust mites thrive in a humid, warm atmosphere and collect in carpets, bedding, soft toys and upholstered furniture. Walking around the house or shaking the bedclothes is all that is required to produce a cloud of allergen which is easily inhaled. Although it is not possible to completely eradicate dust mites they can be reduced. Avoidance measures can be time consuming and costly but should be advised, these could include the use of special covers for mattresses, duvets and pillows; limiting soft toys and furnishings; washing sheets etc. weekly at 5560°C; vacuuming carpets daily; ventilating all rooms regularly and minimising humidity by not drying washing indoors. Hay fever sufferers can limit exposure to pollens by checking the pollen count regularly; wearing sunglasses and avoiding grassy areas; showering/washing hair on coming indoors.
Drug therapy: Treatment is aimed at reducing airways inflammation with sufficient medication to control symptoms and optimise lung function as quickly as possible. Once control is achieved, treatment can be stepped down in order to maintain this optimum level on the minimum of medication.
Corticosteroids are the most effective anti-inflammatory drugs used in asthma. Available in both an oral and inhaled form, they stabilise eosinophils, reduce bronchial oedema and mucous hypersecretion and can reverse epithelial damage. A strategy starting with oral steroids (prednisolone) or moderately high dose inhaled steroids which can be reduced once control is achieved is recommended (BTS, 1997).
Inhaled steroids are available as Beclamethasone Dipropionate (Becotide, Becloforte, Beclasone, Aerobec and Qvar) Budesonide (Pulmicort) and Fluticasone (Flixotide). Used as prophylactic agents they have no immediate effect on asthma symptoms and are safe. The long term use of oral steroids, however, can affect growth in children and bone density in adults and is, therefore, to be avoided.
Sodium Cromoglycate (Intal) for use in children and Nedocromil Sodium (Tilade) in adults are non-steroidal anti-inflammatory agents. Although less effective than steroids, they may be tried as an alternative in those with mild to moderate asthma. Sodium Cromoglycate is a recommended first line preventative treatment in children under five. These drugs are known as 'preventers'.
Bronchodilators such as short acting B2 agonists, ie salbutamol (Ventolin) and terbutaline (Bricanyl) are used for relief therapy and may be the only drug used in very mild cases. Primarily available in an inhaled form, oral preparations are now also available. They act on the B2 receptors of the sympathetic nervous system relaxing bronchial smooth muscle thereby dilating the bronchi. Their effects can be immediate. These are known as 'relievers'.
Long acting B2 agonists, salmeterol (Serevent) and Eformotorol (Oxis) have been more recently developed and are successfully used in those with more persistent symptoms.
Methylxanthines (aminophylline, theophylline) are older, respiratory stimulants whose exact mode of action is unclear. Recent evidence suggests they act as an immunomodulator in lower doses (Barnes, 1994). Though effective, their toxic effects can make them unsuitable for some patients.
Leucotreines are one of the mediators of inflammation in asthma. New drugs, blocking the leukotrine receptor sites have been shown to have both anti-inflammatory and bronchodilatory effects. These are montelukast sodium (Singulair) and zafirlukast (Accolate) and come in tablet form only.
Inhaled medication directly targets lung receptors, allowing smaller doses to be used and reducing possible side effects. It is vital that patients are able to manage their inhaled device correctly in order for them to receive optimum therapy.
There are a large number on the market and when choosing a device patient preference and cost should be taken into account. Nurses play a vital role in training patients in their use.
Ineffective use of inhaled medication can result in significant loss of bronchodilation (van der Palen, 1997) but is also likely to lead to the individual believing that the medication itself does not help which results in negative attitudes towards medication use in the long term (Partridge, 1995).
Problems which patients experience are well documented and (Blackler, 1993; Hall, 1996; van der Palen, 1997) confirm that although time consuming, the need to check and improve technique is essential, not only to ensure optimum delivery of the drug, but most importantly because the ability to self-manage and regulate treatment is dependant upon it.
Special considerations
Table 2: Dust mite control measures
In the bedroom:
· Use special covers for mattress, duvet and pillows
And/Or
· Wash sheets, pillow cases, duvet cover weekly at 5560°C
· Wash pillows and duvet covers monthly at 5560°C
· Limit soft toys and furnishings e.g. blinds instead of curtains, smooth flooring instead of carpets
· Freeze soft toys weekly defrost then wash at 60°C
Other rooms:
· Limit soft furnishings e.g. non-fabric covers on furniture, not upholstered
· Vacuum carpets daily, soft furnishings weekly (vacuum cleaner should have good filtration and good suction power)
Other measures:
· Ventilate all rooms daily
· Minimise humidity avoid drying washing indoors
· Anti-house dust mite chemicals (acaricides) are available but are expensive and need frequent use to be effective
Asthma in children: There is evidence that acute viral wheezy episodes in the very young represent a type of airway diseases clinically distinct from atopic asthma (BTS, 1997) posing diagnostic difficulties in the under fives and which may require specialist referral and management.
School age children are presented with new challenges from the external environment and the impact of the disease depends upon the distress caused by symptoms and the inconvenience caused by the treatment.
Teenagers often question treatment and have difficulties accepting the diagnosis of a chronic disease, despite the high prevalence and morbidity in this age group. Severity, time course and the nature of asthma are all important considerations for the nurse when assessing the impact on the individual and family.
Factors influencing parental response and their ability to cope include professional advice, social support and the finances required to maintain an adequate physical environment. Mites et al. (1997) suggests asthma severity affects the stability of family life, while unstable family dynamics may predispose to severe asthma. Managing asthma at home is a complex challenge for the family unit and Jerret (1994) suggests that the experience cannot be merely reduced to a scientific account of the disease or to prescribed treatment, rather it needs to be considered within the context of their actual lives.
Asthma in the elderly: Asthma may present at any age and is though to be underdiagnosed in the elderly population (Dyer & Bone, 1995). Cough, breathlessness and wheeze are symptoms of a wide range of conditions common in the elderly e.g. chronic obstructive airways disease, myocardial disease or left ventricular failure (Melillo, 1996). The presence of co-existing diseases, difficulty in measuring lung function, a reduced association with allergy, under-reporting of symptoms and altered perception of breathlessness further complicate matters (Dow et al., 1992; Connolly et al., 1992) making it difficult to diagnose in this group.
The BTS Guidelines (1997) do not distinguish between adults and the elderly in its management and for the most part this is quite appropriate. However, there are some considerations reduced awareness of symptoms leads to under-use of 'reliever' medication, the effectiveness of beta-agonists reduces with age, there is an increased risk of medication side effects and decreased coordination results in poor inhaler technique (Renwick, 1996). Drugs such as beta-blockers (even in eye drops), NSAIDS and ACE inhibitors can produce or worsen asthma symptoms.
Self management
Table 3: Pollen avoidance
· Check pollen count
· Wear sunglasses
· Avoid grassy areas (mid morning pollen count is lowest)
· Close windows/vents when pollen count high
· Holiday by sea/mountains
· Keep car windows shut (some cars have filters)
· Shower/wash hair on coming indoors
Asthma is characterised by fluctuations in symptom severity. Self management requires considerable patient awareness and skill in altering medication in response to symptoms.
Walsh (1989) advocates the use of Orems (1985) self-care model of nursing as an ideal framework with which to assist the individual with asthma to lead as normal a life as possible. On the grounds of theory and meanings related to the concepts of nursing and empowerment, the authors recognise the movement of the patient along a continuum from being totally dependent on nursing care, to being totally self-caring yet requiring education and support and find Orems model ideally suited to facilitating self management skills in asthma.
Comparing with Kings (1981) model of nursing, Hanucharurncal (1989) suggests the nurse occupies a more dominant role in Orems (1985) model. However, this is perhaps favourable given that community nurses are frequently required to act as coordinators of care within the multi-disciplinary team and that clients expect professional leadership to guide them in the early days of diagnosis and coming to terms with managing a chronic illness.
Giving information alone does not alter behaviour, however, there is real evidence of benefit from patient education and the development of mutually agreed self-management plans (BTS, 1997). All patients should be given information about worsening symptoms and what action to take. Action levels and thresholds for intervention should be individually tailored.
Anderson and Elfert (1989) suggests the biggest impact on the management of asthma lies in a coordinated approach by all members of a district healthcare team. Recent legislation (Department of Health, 1997) has provided the mechanism for radical change and Gardiner (1998) calls for nurses to exert their leadership in primary care and focus on 'mobilising patient power'. Clearly nurses have a key role to play in restructuring asthma care for local communities, minimising disparity of client expressed need and professional perceived need. Management of asthma requires nurses to address both adverse health and environmental behaviour which necessitates working across traditional boundaries to form new alliances with local residents, voluntary bodies (e.g. National Asthma Campaign, British Lung Foundation) and health care professionals, thereby, enabling individuals to take control of their asthma and ultimately improve their quality of life.
For the future, community nurses have a key role in placing greater emphasis on secondary prevention through a collaborative approach to health promotion at community level, ensuring provision of services to best effect, to those who need them most.
However, the success of community intervention initiatives in addressing such a major health deficit lies equally in the success of the governments agenda of tackling inequalities in health. Narrowing the great divide between rich and poor may be the single most important factor in changing prevalence of asthma for the future.
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