Status asthmaticus is a critical emergency that requires prompt
intervention to avoid acute and possibly fatal, respiratory failure. In this
condition, the asthmatic attacks are unresponsive to medical therapeutics, with
severe bronchospasms creating decreased oxygenation and perfusion. During an
acute asthmatic attack, the individual may demonstrate varying degrees of
respiratory distress depending on the duration of the attack, and the severity
of spasm.
The underlying cause of asthma is still as yet unknown, but is
thought to be due to imbalances in adrenergic and cholinergic control of the
airways, and their response to the allergens, infections, or emotional factors
with which they come in contact. Intrinsic asthma occurs when the triggering
factors are irritation, infection, or emotions, and extrinsic asthma occurs
when precipitated by allergic or complement-mediated factors. Asthma may be
drug-induced by aspirin, indomethacin, tartrazine, propranolol, and timolol. In
asthma, the airways are narrowed due to the bronchial muscle spasms, edema,
inflammation of the bronchioles, and thick, tenacious mucous pro- duction. The
narrowing leads to areas of obstruction and these become hypoventilated and
hypoperfused. Eventually a ventilation/perfusion mismatch occurs and may lead
to hypoxemia and an increasing A-a gradient. When PaCO2, rises to the point of
respiratory acidosis, the patient is then considered to be in
respiratory failure. The three most common causes of status asthmaticus are
allergen exposure, noncompliance with medication regime, and respiratory
infection expo- sure. Environmental factors, such as excessively hot, cold, or
dusty areas, may initiate status asthmaticus because of the effect they
have on the air that is breathed. |
| Pathway STATUS ASTHMATICUS |
Wheezing may occur not only with asthma, but with chronic
obstructive pulmonary disease, congestive heart failure, pulmonary embolism,
and tuberculosis, and these diagnoses should be ruled out.
Patients who have status asthmaticus suffer pronounced fatigue due
to the continuous efforts of breathing, and they easily become dehydrated due
to the hyperpnea. The patient usually has dyspnea, tachypnea, wheezing,
tachycardia, pulsus paradoxus, and severe anxiety. The goals of treatment
include ventilatory support and maintenance of adequate airways, and the
prevention of respiratory failure or barotrauma.
MEDICAL CARE
Laboratory: CBC and sputum specimens
usually show eosinophilia
Chest x-ray: used to observe for
infiltrates or hyperinflation to the lungs; may be used to visualize
pneumothorax, hemothorax, or pneumomediastinum
Arterial blood gases: to identify problems with
oxygenation and acid-base balance
Spirometry: to provide information about
severity of an attack, and to assess for improvement with therapy; FEV, is the
forced expiratory volume for 1 second and is usually < 1500 cc during an asthmatic
attack and will increase 500 cc or more if treatment is successful
Oxygen: to provide supplemental
available oxygen Bronchodilators: used to relax bronchial smooth muscle to
dilate bronchial tree to facilitate air exchange
Beta-adrenergic agents: ephedrine, epinephrine, isoproterenol, metaproterenol,
terbutaline; used to relax bronchial smooth muscle
Corticosteroids: used to decrease
inflammatory response and decrease edema
Antibiotics: used when infective
process is documented; usually bacterial infection is not a common
precipitating factor
Mechanical ventilation: necessary when respiratory
failure is present and hypoxemia persists despite medical therapy
IPPB: used to assist the patient with deep inspiration to facilitate
more productive coughing of thick mucus and to deliver medication by an aerosol
route
NURSING CARE PLAN
Ineffective airway clearance
Related to: airway obstruction, edema
of bronchioles, inability to cough or to cough effectively, excessive mucous
production
Defining characteristics: adventitious breath
sounds, dyspnea, tachypnea, shallow respirations, cough with or without
productivity, cyanosis, anxiety, restlessness
Outcome Criteria
Patient will maintain
patency of airway and will be able to effectively clear secretions.
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INTERVENTIONS
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RATIONALES
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Administer bronchodilators as ordered.
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Nebulizers are usually the first line
treatment for asthma. Aminophylline is frequently prescribed to relax
bronchial smooth muscle and mediates histamine release and cAMD degradation,
which facilitates improved air flow.
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Monitor lab levels for
attainment and maintenance of therapeutic levels. Observe patient for
anorexia, nausea, vomiting, abdominal pain, nervousness,
restlessness, and tachycardia.
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Therapeutic levels range
between 10-20 mcg/ml. Symptoms may indicate theophylline toxicity, which
will require titration of the drug dosage.
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Administer sympathomimetics as ordered.
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Epinephrine is usually
given SQ every 20-30 minutes for 3 doses as needed to relieve
bronchoconstriction. Terbutaline is usually not the first drug of choice in
acute situations due to the delayed onset of action, but is frequently used
after the patient shows improvement.
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Assist/administer
inhalation therapy as ordered.
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Nebulizers and
intermittent positive pressure breathing treatments may be used in mild to
moderate episodes but should not be used during acute attacks because of the
potential for bronchospasm in response to the aerosol agent.
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Information, Instruction, Demonstration
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INTERVENTIONS
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RATIONALES
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Monitor for side effects,
such as tachycardias, tremors, nausea, vomiting, or bronchospasm.
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May occur as adverse
reactions from medications. May require change in specific drug used.
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Discharge or Maintenance Evaluation
· Patient will maintain
patent airway and be able to cough and clear own secretions.
· Patient will have clear
breath sounds with no adventitious sounds or airway compromise.
· Patient will have adequate
oxygenation.
Impaired
gas exchange
[See Mechanical
Ventilation]
Related to: bronchospasm, inflammation to bronchi, hypoxemia, fatigue
Defining characteristics: dyspnea, tachypnea, hypoxia, hypoxemia, hypercapnia,
restlessness, anxiety, abnormal ABGs, dysrhythmias, decreased oxygen saturation
Anxiety
[See Mechanical
Ventilation]
Related to: dyspnea, change in health status, threat of death
Defining characteristics: fear, restlessness, muscle tension, apprehension, helplessness,
sense of impending doom
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