Asthma is a disease of the airways that is characterized by airway inflammation and hyperreactivity (increased responsiveness to a wide variety of triggers). Hyper-reactivity 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. Lastly, the mucous glands increase in number, hypertrophy, and secrete thick mucus.
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) and the FEV1 to the forced vital capacity (FVC). 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 and 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.
Causes 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.
Nursing care plan assessment and examination
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. Children with an impending asthma attack may have been vomiting because of the tendency to swallow coughed up mucus rather than expectorating it.
The patient with an acute attack of asthmaappears 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 hyper-resonance, 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. 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.
Nursing care plan primary diagnosis: Ineffective airway clearance related to obstruction from narrowed lumen and thick mucus.
Nursing care plan intervention and treatment
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 nonsteroidal anti-inflammatory agents 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 metered-dose inhalers (MDIs), and the indications for use. It is important that the patient use the bronchodilator MDIs first, then use the steroid inhalers. Explain to patients on steroid inhalers need to rinse their mouths out after using them to avoid getting thrush.
Nursing care plan discharge and home health care guidelines
To prevent asthma attacks, teach patients the triggers that can precipitate an attack. 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. In rare instances, asthmacan 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.