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AFFECTING ABOUT 300 million people worldwide, asthma is a complex health problem. Exacerbations of asthma can affect a child's attendance at school or take an adult away from work. Asthma medications are costly and inconvenient, especially if they have to be taken several times a day or involve complex devices to administer the medication. Besides creating a burden on the healthcare system, asthma can severely limit one's daily life, and can even cause death.1,2
This article explores the assessment and treatment of asthma according to the most recent updates to the 2009 Global Initiative for Asthma (GINA) guidelines and the accompanying Pocket Guide for Asthma Management (for Adults and Children Older than 5 Years), which was updated in 2010. Both of these documents are available online at http://www.ginasthma.com.
The GINA guidelines published in 1995 and 2002 used a classification system based on severity of asthma signs and symptoms to direct treatment decisions. Severity was divided into four classifications: intermittent, mild persistent, moderate persistent, and severe persistent. These classifications required determining severity before starting treatment. This approach-to classify first and then treat-was often difficult to follow because many patients were already receiving some treatment before the first formal assessment and classification could be done.
The 2006 GINA guidelines changed the main focus for asthma care from severity to control.3 The four severity classifications mentioned above have now been relegated to research only. The newer approach, also reflected in the 2009 guidelines, classifies asthma based on three levels of control: controlled, partly controlled, or uncontrolled. See http://www.ginasthma.com for a description of these levels along with guidelines for assessing future risk.
Asthma is thought to develop based on host factors and/or environmental factors. Host factors that increase the risk of asthma include genetic predisposition, obesity, and gender. Genetic risk factors are subdivided into genetic links to atopy or genetic links to airway hyperresponsiveness. Male gender carries a higher risk of asthma for children, but among adults, asthma prevalence is higher in women.
Environmental factors that increase the risk of asthma include:
* allergens (dog or cat dander, dust mites, mold, cockroach infestation)
* infection (respiratory syncytial virus or parainfluenza virus in infancy)
* occupational sensitizers (over 300 substances are associated with occupational asthma)
* tobacco smoke (prenatal exposure, exposure in infancy and childhood)
* indoor/outdoor air pollution (smoke from gas or biomass used for heating or cooking)
* diet (particularly for infants fed formula from intact cow's milk or soy protein).
Asthma involves airway inflammation and hyperresponsiveness. The inflammation is persistent even though signs and symptoms may be episodic.
Airway inflammation involves a complex relationship between inflammatory cells (mast cells, eosinophils, T-lymphocytes, macrophages, neutrophils) and inflammatory mediators (chemokines, cytokines, histamine, nitric oxide, leukotrienes, prostaglandin D2). Inflammation causes chronic airway narrowing and hyperresponsiveness. Airway edema, airway thickening due to structural changes, and mucus hypersecretion also contribute to airway narrowing. Acute airway narrowing (an exacerbation or "asthma attack") occurs when hyperresponsive smooth muscles contract and reduce the airway lumen further.
Signs and symptoms of asthma include dyspnea, wheezing, cough, and/or chest tightness, particularly when they occur after exposure to allergens or irritants, are worse at night, and improve after appropriate treatment. A reduction in ratio of forced expiratory volume in 1 second (FEV1) to the forced vital capacity (FVC), often called the FEV1/FVC or FEV1%, during spirometry is a hallmark of airflow obstruction and helps diagnose asthma. Pulmonary function tests (particularly the FEV1 measurement from spirometry) and peak expiratory flow (PEF) measurement can help clinicians assess the severity of airflow limitation and document response to therapy. These measurements can help diagnose asthma in patients who have poor perception of their symptoms (see Pulmonary function testing).
The description of asthma as a reversible disease rests on the patient's response to a rapid-acting beta2-agonist such as albuterol, as measured by spirometry. An increase of 12% coupled with a 200-mL increase in FEV1 (or FVC) is the generally accepted threshold for a significant response to the rapid-acting beta2-agonist (although not all patients with asthma will experience this amount of improvement with every pulmonary function test).1
PEF can help in both diagnosis and monitoring; limitations and precautions are outlined in the 2009 GINA guidelines. Spirometry is the preferred method of measuring airflow obstruction. PEF is often included in a self-monitoring asthma plan in which the patient measures values daily and tracks the numbers with a diary or chart.
Some patients who complain of asthma signs and symptoms have normal pulmonary function testing (PFT) results. They may need an airway response test to a bronchial challenge. The patient inhales an agent that can provoke bronchoconstriction in those who have hypersensitive airways. The agent may be direct-acting (inhaled histamine, methacholine) or indirect-acting (inhaled mannitol, exercise). A decrease of 15% to 20% from the baseline FEV1 measurement may help diagnose asthma.4
However, various other disorders can cause this decrease in FEV1 and other asthma signs and symptoms. For example, wheezing, cough, and dyspnea can indicate diseases such as gastroesophageal reflux, cystic fibrosis, foreign body aspiration, vocal cord dysfunction, heart disease, and chronic obstructive pulmonary disease (COPD). All of these should be considered and excluded before establishing asthma as the primary diagnosis.
Measuring a patient's allergic reaction by skin testing may also support a diagnosis of asthma. Skin testing will help diagnose atopy, which is a risk factor for asthma.
Classification involves obtaining a health history, performing a physical assessment, and measuring lung function-in particular, measuring FVC, FEV1, and/or PEF. These results are compared to the predicted values for someone of the patient's gender, height, and age.
Other elements that may contribute to classifying asthma (and prescribing treatment) include airway responsiveness as determined by the bronchial challenge or assessment of noninvasive markers of inflammation. Assessment of these noninvasive markers includes examining sputum for eosinophils or neutrophils and measuring exhaled nitric oxide or carbon monoxide levels.5
Validated standardized tests have also been developed to assess control. These include the Asthma Control Questionnaire, the Asthma Control Test, and the Asthma Therapy Assessment Questionnaire.
The 2009 GINA guidelines stress that control is the key; the patient's asthma may be severe at the initial presentation but become completely controlled with low-dose therapy. In addition, disease severity often changes over time. By assessing control, response to therapy, and future risk of adverse events, the healthcare team can help the patient keep asthma under control and live a nearly normal life.
The 2009 GINA guidelines classify asthma medications as either controllers or relievers. Controllers are taken daily to keep inflammation under control. Relievers (also called rescue medications) are used on an as-needed basis. They act quickly to bring about bronchodilation and relieve symptoms.
Controllers include corticosteroids (most often administered by inhalation, although they may also be given systemically), combination inhaled medications (containing both corticosteroids and long-acting inhaled beta2-agonists), leukotriene modifiers, sustained-release theophylline, cromones, and anti-immunoglobulin E (IgE) medications. Relievers include rapid-acting (and short-duration) inhaled beta2-agonists (albuterol sulfate), inhaled anticholinergics (ipratropium bromide), rapid-acting theophylline, and rapid-acting oral beta2-agonists (albuterol sulfate).
Most asthma medications are administered by inhalation to deliver the drug directly into the airway where it's most needed; this also minimizes systemic effects. Special considerations related to caring for children are given in the 2009 GINA guidelines with discussions divided into those younger and older than age 5.
Many devices are used to administer inhaled medications, including metered-dose inhalers, dry-powder inhalers, ultrasonic nebulizers powered by electricity, and aerosol nebulizers powered by an air compressor. Selection of the right medication depends on the severity of the disease and the patient's age (some medications aren't approved for children). The choice is also influenced by the patient's ability to use the drug's delivery system. For example, some require coordination to activate the device during inhalation or involve special preparation or manipulation of the drug and device to prepare it for use.
Inspiratory flow is another consideration. If the patient can't generate enough airflow to get an adequate dose from a dry-powder inhaler, another drug/device must be prescribed.
The 2009 GINA guidelines describe asthma management based on four components:
* Component 1: Develop patient/healthcare provider (HCP) partnership
* Component 2: Identify and reduce exposure to risk factors
* Component 3: Assess, treat, and monitor asthma
* Component 4: Manage exacerbations.
They also provide special considerations for managing asthma.
Develop the patient/HCP partnership. This component involves guided self-management and relies on education as an integral part of all interaction. The patient and HCP should work together to set goals for asthma management. Teach the patient about common signs and symptoms of worsening asthma, exacerbations, and adverse drug reactions, along with guidelines on how to take action according to a written action plan.
Identify and reduce exposure to risk factors. Reducing risk factors can lessen the impact of asthma on day-to-day activities and minimize the occurrence and severity of exacerbations. The 2009 GINA guidelines provide strategies for avoiding common allergens (fungi, pollen, cockroaches, domestic mites, furred animals), pollutants (tobacco smoke, sulfur dioxide, carbon dioxide, carbon monoxide, nitric oxide, nitrogen oxide), drugs (beta-blockers, aspirin and other nonsteroidal anti-inflammatories), and sulfites (common preservatives found in foods such as beer, wine, shrimp, dried fruits, processed potatoes) that are known to cause symptoms; and occupational sensitizers. The guidelines stress that patients shouldn't avoid exercise and advise them to prevent symptoms by taking a rapid-acting inhaled beta2-agonist before strenuous exercise.
The guidelines provide a list of reasonable avoidance measures that can be recommended but haven't been shown to have a clinical benefit. This includes getting rid of house dust mites and cockroaches, avoiding animals with fur (or using an air filter), and eliminating outdoor pollens and mold as well as indoor mold. Annual influenza vaccinations are also recommended for patients with moderate to severe asthma.2
Assess, treat, and monitor asthma. Based on the level of control, the patient's treatment is guided by stepping up or down over a series of five steps. If the asthma isn't under control, treatment is stepped up and assessed. Stepping up continues until control is achieved. If the patient's asthma is in control for at least 3 months, treatment can be stepped down. Across each step, a reliever medication is included for quick relief of symptoms as needed (see http://www.ginasthma.com for more information).
Patients with persistent asthma who are initiating treatment begin at Step 2 unless they have symptomatic or uncontrolled asthma; in that case, start at Step 3. Patients are reassessed 1 to 3 months after starting treatment to see if control has been achieved. If not, the guidelines recommend stepping up and another assessment. This repeats until control is achieved or all steps have been taken. If control is achieved and maintained for 3 to 4 months, the HCP may consider taking one step down in the recommended treatment. Follow-up is scheduled within 2 to 4 weeks after an exacerbation to assess control of symptoms. The ultimate goal in the care cycle of assessing, treating, and monitoring is to have the patient on the minimum drug treatment needed to maintain asthma control.
Some patients may be classified as having difficult-to-treat asthma if they don't reach the level of control at Step 4 or 5. Patients with difficult-to-treat asthma should be referred to a pulmonologist or allergist for specialized care.
Manage exacerbations. When an exacerbation occurs, the patient experiences increasing shortness of breath, coughing, wheezing, and chest tightness. These signs and symptoms may occur alone or in combination and may develop over minutes to hours depending on the nature and severity of the event. Decreased airflow causes acute respiratory distress and can be measured by checking FEV1 or PEF. Severe exacerbations can be life-threatening and call for immediate intervention and close supervision, usually in an acute care facility.
The 2009 GINA guidelines classify the severity of asthma exacerbations as mild, moderate, severe, and imminent respiratory arrest. The classifications are based on the patient's alertness, ability to talk, breathlessness, breath sounds (wheeze), respiratory rate, use of accessory muscles, heart rate, presence of pulsus paradoxus, PEF or FEV1, PaO2 and SaO2 on room air, and PaCO2.
Mild exacerbations are defined as a PEF of over 80% predicted or personal best after initial bronchodilator, nocturnal awakenings, and increased use of rapid-acting beta2-agonists. They can usually be treated on an outpatient basis. Moderate exacerbations, defined as a PEF 60% to 80% predicted or personal best after initial bronchodilator, may require care in a clinic or hospital.
Treatment for severe exacerbations, PEF less than 60% predicted or personal best after initial bronchodilator (less than 100 L/minute in adults or response to therapy lasts less than 2 hours), includes repeated administration of rapid-acting beta2-agonists as well as systemic corticosteroids and supplemental oxygen. Monitor patients for response to therapy. They shouldn't be discharged until the PEF or FEV1 has returned to an acceptable point and the distress is relieved.
Respiratory arrest is considered imminent if the patient exhibits drowsiness or confusion, bradycardia, paradoxical thoracoabdominal movement, no wheeze, and absence of pulsus paradoxus (suggesting respiratory muscle fatigue). Initial treatment includes the administration of oxygen, 1 hour of continuous inhaled rapid-acting beta2-agonists, and systemic glucocorticosteroids. Strict avoidance of sedation is advised. Depending on the patient's response, additional medications for consideration include inhaled anticholinergics, I.V. magnesium, and I.V. theophylline. Poor patient response may require endotracheal intubation, mechanical ventilation, and admission to the ICU.1
The 2009 GINA guidelines provide a detailed plan of care for managing an exacerbation in the acute care setting and give recommendations concerning discharge from the ED versus the need for hospitalization. These recommendations are based on pre- and post-treatment lung function.
Special considerations. The guidelines provide information for asthma in pregnancy, obesity, surgery, upper airway diseases (rhinitis, sinusitis, and nasal polyps), occupational asthma, respiratory infections, gastroesophageal reflux, aspirin-induced asthma, and anaphylaxis. Advise women with asthma who become pregnant that they'll need close monitoring. Asthma control remains the goal, and the drugs needed to maintain control haven't been tied to increased fetal abnormalities. Poorly controlled asthma appears to pose a greater risk to the baby.
For patients preparing for surgery, the guidelines recommend early assessment and possible step up in therapy to ensure the patient is in the best health possible.
Upper airway diseases are associated with asthma and are treated with topical nasal corticosteroids, nasal decongestants, and in cases involving polyps, corticosteroids or surgery to remove the polyps.
Occupational asthma calls for complete avoidance of the triggering substance.
Effective care requires a comprehensive assessment, appropriate nursing diagnoses, development and implementation of a plan of care, and evaluation of the patient's response to treatment. Nursing diagnoses associated with asthma include ineffective airway clearance, impaired gas exchange, anxiety, activity intolerance, and risk for contamination (being exposed to environmental substances that have the potential to produce ill effects).6
Ineffective airway clearance may be triggered by environmental factors such as exposure to smoke or an obstructed airway caused by retained or excessive secretions or bronchospasm. The patient with ineffective airway clearance may report shortness of breath and exhibit reduced or adventitious breath sounds, a weak or absent cough, trouble speaking, a change in respiratory rate and pattern, and cyanosis.6 Additional findings may include abnormal functional assessment measurements such as PEF, FEV1, arterial blood gases (ABGs), and oxygen saturation.1 Interventions include sustaining a sufficiently open airway, mobilizing pulmonary secretions, assessing for changes or complications, and encouraging wellness by educating the patient about avoiding asthma triggers.6 During the patient's initial visit, demonstrate the correct use of the selected inhaler and provide written or pictorial information. Reassess at each follow-up visit.
Closely monitor patients experiencing severe exacerbations. Obtain functional assessment measurements, such as PEF or FEV1 and ABGs as ordered, and monitor oxygen saturation levels via pulse oximetry.1 Administer bronchodilators and adequate fluids as ordered to help mobilize secretions.
Preferred patient outcomes include maintenance of a patent airway, the ability to expel sputum easily, demonstration of eupnea, and an oxygen saturation level within the patient's normal limits.6
Impaired gas exchange associated with asthma can be attributed to alveolar-capillary membrane changes brought on by obstructive lung disease and can produce various subjective and objective findings. Subjective findings include shortness of breath, vision changes, a headache when waking up, and a sense of impending doom. Objective findings include restlessness or irritability, sluggishness, confusion, altered breathing, tachycardia, diaphoresis, and abnormal ABGs, indicating hypoxemia. Assess the patient for factors that contribute to the impairment, evaluate the severity of the impairment, improve or correct the deficiencies, and promote wellness by advising the patient how to decrease risk and prevent declining lung function.6 Make sure your patient is using medications and inhalers correctly. Close monitoring is warranted, depending on the degree of severity. Complete functional assessment measurements as prescribed, and report any abnormal levels promptly to the HCP.
Administer supplemental oxygen as indicated. Administer medications as prescribed. Avoid central nervous system depressants in periods of acute asthma exacerbation.1 Preferred outcomes for the patient include improved ventilation and oxygenation as well as diminished respiratory distress.6
Anxiety may be due to a patient's progressively worsening health status or the perceived or actual threat of death. The anxiety may be exhibited subjectively and objectively by behavioral, affective, cognitive, physiologic, sympathetic, or parasympathetic means. Once anxiety is detected, identify the level of anxiety (panic, severe, moderate, mild). Encourage patients to talk about their feelings and their current situation, and suggest effective coping strategies such as meditation, positive visualization, elimination of negative self-talk, and increased physical activity to relieve tension. The desired outcomes are the patient's awareness of the anxiety, an effective use of support systems/resources, and the use of healthy strategies for expressing and managing anxiety.6
Activity intolerance may develop as oxygen demand exceeds supply. Depending upon the level of activity, BP or heart rate may respond abnormally and the patient may develop cyanosis or pallor. It's important to recognize which activities patients can and can't tolerate. Help patients complete activities within their limits and promote safe, effective techniques for improving their abilities to enhance their well being.6 Encourage activity and exercise, along with the use of medications before strenuous exercise.
Risk for contamination can be increased by exposure to various environmental substances such as pollutants, chemicals, pesticides, and tobacco smoke.6 An asthma exacerbation brought on by a trigger can result in pulmonary effects leading to other primary diagnoses such as impaired gas exchange and ineffective airway clearance. Estimate the severity and cause of exposure, aid in treating the effects of the exposure, and educate the patient and caregivers about health promotion and disease prevention. Goals are to help the patient verbalize a clear understanding of contributing factors, maintain a safe environment for the patient, and keep the patient free from injury.6 Personal asthma plans that include education, regular review, self-monitoring, and patient-directed self-management via a written self-management action plan are most effective for helping the patient control asthma.1
Asthma is a serious disease that can be controlled and managed if patients and caregivers follow the latest guidelines for treatment. Review the newest GINA guidelines so you can provide the best care possible for your patients with asthma.
1. Global Initiative for Asthma. GINA Report. Global strategy for asthma management and prevention. http://www.ginasthma.org/Guidelineitem.asp??l1=2&l2=1&intId=1561. [Context Link]
2. Global Initiative for Asthma. Pocket Guide for Asthma Management (for Adults and Children Older than 5 Years). Updated 2010. http://www.ginasthma.com. [Context Link]
3. Bousquet J, Busse W. Section 1. EPR-3 versus GINA 2008 guidelines-asthma control and step 3 care: highlights of the asthma summit 2009: beyond the guidelines. World Allergy Org J. 2010;3(2):16-22. [Context Link]
4. Crapo RO, Casburi R, Coates AL, et al. Guidelines for methacholine and exercise challenge testing-1999. This official statement of the American Thoracic Society was adopted by the ATS Board of Directors, July 1999. Am J Respir Crit Care Med. 2000;161(1):309-329. [Context Link]
5. Banovcin P, Jesenak M, Michnova Z, et al. Factors attributable to the level of exhaled nitric oxide in asthmatic children. Eur J Med Res.2009;14(suppl 4):9-13. [Context Link]
6. Doenges ME, Moorhouse MF, Murr AC. Nurse's Pocket Guide: Diagnoses, Prioritized Interventions, and Rationales. 12th ed. Philadelphia, PA: F.A. Davis Company; 2010. [Context Link]