A disease caused by increased responsiveness of the trachea-bronchial tree to various stimuli, which results in episodic narrowing and inflammation of the airways. Clinically, most patients present with wheezing and shortness of breath. Cough is also a common symptom. Between attacks the patient may have normal respiratory function. Although most asthmatics have mild disease, in some cases the attacks become continuous. This condition, called status asthmaticus, may be fatal.
ETIOLOGY: The recurrence and severity of attacks is influenced by a variety of triggers, including allergens, dust, fumes, medicines, dyes, odors, exercise, occupational exposures, or infection. The role of emotional disturbance in asthmatic attacks has been difficult to quantify.
TREATMENT: Mild episodic asthma is well managed with intermittent use of beta agonists, such as albuterol. Patients with more severe disease or frequent exacerbations rely on medications to control the disease, such as corticosteroids, mast cell stabilizing drugs (e.g., cromolyn), long-acting beta agonists (e.g., salmeterol), inhibitors of leukotrienes (e.g. montelukast), and short-acting beta agonists. Acute asthmatic attacks may require high doses or frequent dosing of beta-agonists and steroids. Oxygen therapy is an important part of treatment in most asthma attacks. For persistent asthma, hospitalization with monitoring of peak airflow, oxygen saturation, blood gases, and cardiac rhythm is often indicated. Intubation and mechanical ventilation are needed in severe attacks. Antibiotics are used for bacterial infection only.
EPIDEMIOLOGY: Asthma occurs most often in childhood or early adulthood but may plague adults of all ages as well. Before puberty, twice as many boys as girls have asthma; in adults, the disease is equally distributed between the sexes.
PREVENTION: Limiting exposure to indoor inhalants such as house dust, cockroach antigen, dander, molds, tobacco smoke, and strong odors can help prevent asthmatic attacks. Asthmatics with outdoor allergies may benefit from relocation to new climates or judicious use of medications. Regular use of drugs such as cromolyn sodium is effective in preventing asthmatic attacks and respiratory decompensation. Immunization and desensitization to allergens is often desirable.
PATIENT CARE: The patient is observed closely to see how well he or she adapts to the demands imposed by airway obstruction. Key elements of the patient’s response are subjective sense of breathlessness, fatigue experienced during breathing, and whether the attack is worsening or improving with treatment. How well the patient tolerates any administered medications should also be noted. Assessments best made by the nurse, respiratory therapist, and physician are whether respiratory rate, adventitious sounds such as inspiratory and expiratory wheezes and rhonchi, respiratory muscle use, air movement, mental status, oxygen saturation, and arterial blood gases are improving or deteriorating. Exhaustion or altered mental status may be signs of impending respiratory failure, which might warrant close monitoring or endotracheal intubation. The patient who is experiencing labored breathing should be closely monitored and reassured. He or she should be seated in an upright (high-Fowler’s) position to ease ventilatory effort and given low-flow oxygen and other prescribed medications per instructions. Elevating the patient’s arms on pillows at the sides or on a pillow placed on an over-bed table may ease ventilatory effort. If the patient is coughing, his or her ability to clear secretions and the character of the sputum should be noted. Purulent sputum should be sent to the laboratory for culture and sensitivity, gram stain, or other ordered studies. When the acute attack subsides, the nurse or respiratory therapist instructs the patient in the proper use of inhaled medications, paying special attention to how well the patient manages the metered dose inhalers and adding a spacer device as necessary to improve utilization. The health care provider educates the patient about eliminating exposure to allergens or irritants (e.g., second-hand smoke, cold air) and teaches home measures to prevent or decrease the severity of future attacks. Caregivers ascertain that patient and family understand the prescribed maintenance regimen, including the rationale for the order in which inhalers are to be used and any adverse effects to be reported, as well as the use of emergency treatment if an attack threatens. Preventive therapies (such as vaccinations against the influenza virus and pneumococcal pneumonia and desensitization to specific allergens in children) are administered if they have not already been given. Follow-up is arranged with home health and/or the primary care provider so that the patient can be carefully re-evaluated and any questions or concerns that the patient or family may have can be addressed.
