DRG Category: 202
Mean LOS: 3.8 days
Description MEDICAL: Bronchitis and Asthma With CC or Major CC
Nursing Type Primary: acute care
Nursing Type Secondary: critical care
System Primary: pulmonary
System Secondary: not applicable
Asthma is classified as an intermittent, reversible, obstructive disease of the lungs. It is a growing health problem in the United States, with approximately 25 million people affected. In the past 20 years, the number of children with asthma has increased markedly, and it is now the leading serious chronic illness in children. Unfortunately, approximately 75% of children with asthma continue to have chronic problems in adulthood. The total deaths annually from asthma have increased by over 100% since 1979 in the United States.
Asthma is a disease of the airways characterized by airway inflammation and hyperreactivity (increased responsiveness to a wide variety of triggers). Hyperreactivity leads to airway obstruction due to acute onset of muscle spasm in the smooth muscle of the tracheobronchial tree, thereby leading to a narrowed lumen. In addition to muscle spasm, there is swelling of the mucosa, which leads to edema. Although asthma can result from infections (especially viral) and inhaled irritants, it often is the result of an allergic response. An allergen (antigen) is introduced to the body, and sensitizing antibodies such as immunoglobulin E (IgE) are formed. IgE antibodies bind to tissue mast cells and basophils in the mucosa of the bronchioles, lung tissue, and nasopharynx. An antigen-antibody reaction releases primary mediator substances such as histamine, slow-reacting substance of anaphylaxis (SRS-A), and others. These mediators cause contraction of the smooth muscle and tissue edema. In addition, goblet cells secrete a thick mucus into the airways that causes obstruction. Intrinsic asthma results from all other causes except allergies, such as infections (especially viral), inhaled irritants, and other causes or etiologies. The parasympathetic nervous system becomes stimulated, which increases bronchomotor tone, resulting in bronchoconstriction.
In asthma, the total lung capacity (TLC), functional residual capacity (FRC), and residual volume (RV) increase, but the hallmark of airway obstruction is a reduction in ratio of the forced expiratory volume in 1 second (FEV1) to the forced vital capacity (FVC). Complications include pneumonia, atelectasis, respiratory failure with hypoxemia, and status asthmaticus (severe and refractory asthma). The classification for asthma is described in Table 1.
Classification of Asthma
The main triggers for asthma are allergies, viral infections, autonomic nervous system imbalances that can cause an increase in parasympathetic stimulation, medications, psychological factors, and exercise. Of asthmatic conditions in patients under 30 years old, 70% are caused by allergies. Three major indoor allergens are dust mites, cockroaches, and cats. In older patients, the cause is almost always nonallergic types of irritants, such as smog. Heredity plays a part in about one-third of the cases.
The genetic contributions to the development of asthma have been estimated at between 30% and 50% for various asthma phenotypes and up to 70% for overall IgE levels in plasma. Familial factors thus far appear to be autosomal dominant. There are at least 11 candidate genes that contribute to asthma susceptibility. These include PTGDR, GPRA, IRAK3, CHI3L1, HNMT, ADRB2, IL13, SCGB3A2, TNF, HLA-G, and PLA2G7.
Although the incidence of asthma is estimated at 5% to 10% in the general population, children have a higher incidence of 12%. Children make up one-third of the people with asthma; in the United States, 7 million children are affected, and trends suggest an increasing incidence of asthma in children under the age of 6 years. Asthma is diagnosed more frequently in males under 14 years and over 45 years of age and in females between the ages of 15 and 45. Black/African American children have higher morbidity and mortality rates than white children. Most experts agree that environmental factors play a more important role in asthma etiology than do genetic factors. Approximately 80% to 85% of childhood asthma episodes are associated with a prior exposure to a virus.
Asthma prevalence varies widely across many nations, with a range from 1% to over 30% in children. Approximately 300 million people globally have asthma, and the prevalence increases by 50% every 10 years. Prevalence is high in developed countries in North America, Europe, and Australia and is increasing in developing countries as they become more industrialized. Examples include increases in South Africa, Eastern Europe, and the Baltic States. The greatest increases are seen in children. The more urbanization and affluence in a nation, the higher the prevalence.
Because patients (especially children) with asthma have a history of allergies, obtain a thorough description of the response to allergens or other irritants. The patient may describe a sudden onset of symptoms after exposure, with a sense of suffocation. Symptoms include dyspnea, wheezing, and a cough (either dry or productive) and also chest tightness, restlessness, anxiety, and a prolonged expiratory phase. Ask if the patient has experienced a recent viral infection. Determine the speed of onset of symptoms, the number of asthma attacks in the past year, and the number of emergency department visits and hospitalizations from asthma in the past year. Children with an impending asthma attack may have been vomiting because of the tendency to swallow coughed up mucus rather than expectorating it.
The most common symptoms are wheezing, coughing, shortness of breath, and chest tightness. The patient with an acute attack of asthma appears ill, with shortness of breath so severe that he or she can hardly speak. In acute airway obstruction, patients use their accessory muscles for breathing and are often profoundly diaphoretic. Some patients have an increased anteroposterior thoracic diameter. Children with asthma often prefer standing or sitting leaning forward to ease breathing. As airway obstruction becomes more serious, children may develop sternocleidomastoid contractions that indicate an increased expiratory effort, supraclavicular contractions that indicate an increased expiratory effort, and nasal flaring. If the patient has marked color changes such as pallor or cyanosis or becomes confused, restless, or lethargic, respiratory failure may be on the horizon. Percussion of the lungs usually produces hyperresonance, and palpation may reveal vocal fremitus. Auscultation reveals high-pitched inspiratory and expiratory wheezes, but with a major airway obstruction, breath sounds may be diminished. As the obstruction improves, breath sounds may actually worsen as they can be auscultated throughout the lung fields. During the most severe attacks of asthma, wheezing may be absent because of severe reduction of airflow, or its absence. Usually, the patient also has a prolonged expiratory phase of respiration. A rapid heart rate, mild systolic hypertension, and a paradoxic pulse may also be present.
The emergency situation and an unfamiliar environment can aggravate the symptoms of the disease, especially if this is the patient's first experience with the condition. If the patient is a child and the parent is anxious, the child's level of anxiety increases and the attack may worsen.
|Test||Normal Result||Abnormality With Condition||Explanation|
|FVC: Maximum volume of air that can be forcefully expired after a maximal lung inspiration||4.0 L||Decreased||Airway obstruction decreases flow rates|
|FEV1: Volume of air expired in 1 second from the beginning of the FVC maneuver||3.0 L||Decreased||Airway obstruction decreases flow rates; hospitalization is recommended if FVC is less than 1 L; FEV1/FVC should be 80% normally, but in asthma, it decreases to as low as 25%|
|Forced expiratory flow (FEF): Maximal flow rate attained during the middle (25%–75%) of FVC maneuver||Varies by body size||Decreased||Predicts obstruction of smaller airways|
|RV: Volume of air remaining in lungs at end of a maximal expiration||1.2 L||Increased up to 400% normal||Increased RV indicates obstruction; may remain increased for up to 3 weeks after the attack|
|FRC: Volume of air remaining in lungs at end of a resting tidal volume||2.3 L||Increased up to 200%||Increased FRC indicates air trapping|
Other Tests: Chest x-ray, high-resolution computed tomography (for chronic symptoms), skin testing, pulse oximetry, arterial blood gases, ECG, serum IgE. Peak expiratory flow rates (maximal flow rate attained during the FVC maneuver; decreased from baseline during periods of obstruction) may be used at home daily for patients who require daily medications.
Diagnosis: Ineffective airway clearance related to obstruction from narrowed lumen and thick mucus as evidenced by shortness of breath, wheezing, and/or chest tightness
Outcomes: Respiratory status: Gas exchange; Respiratory status: Ventilation; Symptom control behavior; Treatment behavior: Illness or injury; Comfort level
Interventions: Airway management; Anxiety reduction; Oxygen therapy; Airway suctioning; Airway insertion and stabilization; Cough enhancement; Mechanical ventilation; Positioning; Respiratory monitoring
For all but the most seriously ill patients, the primary goal is to prevent symptoms and reduce adverse events when acute episodes occur. Airway obstruction is generally managed with quick relief medications such as short-acting bronchodilators, systemic corticosteroids, and ipratropium (Atrovent). During severe exacerbations, patients may require IV fluid replacement. Unless contraindicated by a cardiac problem, 3,000 to 4,000 mL/day of fluid is usually administered intravenously, which helps loosen secretions and facilitates expectoration of the secretions. Low-flow oxygen therapy based on arterial blood gas results is often administered to treat hypoxemia. For the patient with increasing airway obstruction, endotracheal intubation and perhaps mechanical ventilation may be needed to maintain adequate airway and breathing. Close follow-up is needed when patients are discharged from the hospital because airway hyperactivity usually persists for 4 to 6 weeks after the event. To prevent symptoms, long-term control medications such as inhaled corticosteroids, inhaled cromolyn, long-acting bronchodilators, theophylline, leukotriene modifiers, and anti-IgE antibodies are used.
|Medication or Drug Class||Dosage||Description||Rationale|
|Bronchodilators||Varies by drug||Inhaled beta2-adrenergic agonists by metered-dose inhaler (MDI); albuterol sulfate, pirbuterol acetate, levalbuterol||Reversal of airflow obstruction; relieve reversible bronchospasm by relaxing bronchial smooth muscles; used to treat bronchospasm in acute asthmatic episodes; used to prevent bronchospasm associated with exercise-induced asthma or nocturnal asthma|
|Systemic and inhaled corticosteroids||Varies by drug||Methylprednisolone IV; prednisone PO; inhaled corticosteroids (ciclesonide, beclomethasone, fluticasone, budesonide, mometasone)||Decrease inflammatory response; ideal dose is not defined well, but desired outcome is to speed recovery and limit symptoms|
|Leukotriene antagonists||Varies by drug||Montelukast 10 mg PO daily; zafirlukast 20 mg PO daily||Inhibits leukotrienes, fatty acids that mediate inflammation, from binding to airway smooth muscle cells; prevents rather than reduces symptoms; used for long-term prevention|
Other Drugs: Xanthines, such as theophylline, have been used successfully in treating chronic severe steroid-dependent asthmatics. Cromolyn sodium decreases bronchospasm, but it is not effective for acute bronchospasms and is used as a preventive measure.
Maintenance of airway, breathing, and circulation is the primary consideration during an acute attack. Patients should be on bedrest to minimize their oxygen consumption and to decrease the work of breathing. Note that patients usually assume a position to ease breathing; some patients breathe more easily while sitting in an upright position: Do not impose bedrest on a patient who can breathe only in another position. Ask questions that can be answered by nodding or a brief one-word answer so the patient can conserve energy for breathing. If the patient is a child, allow the parents to stay with the child during acute attacks. Have the parents identify a security item that reassures the child, such as a special blanket or toy, and keep the item with the child at all times. Reinforce coping strategies to the parents, and allow them to express any feelings of guilt and helplessness.
For strategies to prevent future attacks, discuss triggers that can induce asthma attacks and ways to avoid them. If the attack is triggered by an allergen, explore with the patient or family the source and discuss possible strategies for eliminating it. Cold air and exercise may increase symptoms. Aspirin and NSAIDs can cause sudden, severe airway obstruction.
Outline the signs and symptoms that require immediate attention. Instruct the patient to notify the physician should she or he develop a respiratory infection that could trigger an attack. Instruct patients regarding their medications, particularly MDIs, and the indications for use. It is important that the patient uses the bronchodilator MDIs first and then uses the steroid inhalers. Explain to patients on steroid inhalers the need to rinse their mouths out after using them to avoid getting thrush.
George, M., Abboud, S., Pantalon, M., Sommers, M.S., Mao, J., & Rand, C. (2016). Changes in clinical conversations when providers are informed of asthma patients' beliefs about medication use and integrative medical therapies. Heart & Lung, 45(1), 70–78.
PATIENT TEACHING. To prevent asthma attacks, teach patients the triggers that can precipitate an attack. In rare instances, asthma can lead to respiratory failure if patients are not treated immediately or are unresponsive to treatment (status asthmaticus). Explain that any dyspnea unrelieved by medications and accompanied by wheezing and accessory muscle use needs prompt attention from a healthcare provider. Encourage patients to identify and avoid things that make their asthma worse and to keep track of their symptoms. The National Institutes of Health provides excellent information for patient and families about asthma: https://www.nhlbi.nih.gov/health-topics/asthma.
MEDICATIONS. Teach the patient and family the correct use of medications, including the dosage, route, action, and side effects. Provide instructions about the proper use of MDIs. Note that many patients use complementary and alternative medications (CAM) for asthma or do not use their prescribed dose of medication. Assess the patient's use of CAM therapy and discuss with him or her the long-term consequences.
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