Medical Care: After confirming the diagnosis and assessing the severity of the asthma attack, direct treatment toward controlling bronchoconstriction and inflammation.
" Bronchodilator treatment with beta-2 agonists
o The first line of therapy is bronchodilator treatment with a beta-2 agonist, typically albuterol.
o Handheld nebulizer treatments may be administered either continuously (10-15 mg/h) or by frequent timing (eg, q5-20min), depending on the severity of the bronchospasm.
o The dose of albuterol for intermittent dosing is 0.3-0.5 mL of a 0.5% formulation mixed with 2.5 mL of normal saline. Many of these preparations are available in a premixed form with a concentration of 0.083%.
o Studies have also shown an excellent response to well-supervised use of albuterol via an MDI with a chamber. The dose is 4 puffs, repeated at 15- to 30-minute intervals as needed. Most patients respond within 1 hour of treatment.
o Recently, the US Food and Drug Administration approved the use of the R isomer of albuterol known as levalbuterol, for treating patients with acute asthma. This isomer has fewer effects on the heart rhythm (ie, tachyarrhythmia) and is associated with fewer occurrences of tremors, while having the same or greater clinical bronchodilator effects as racemic albuterol.
o The decreased prevalence of adverse effects with this new medication may allow physicians to use nebulizer therapy in patients with acute asthma more frequently with less concern over the adverse effects of other bronchodilators (eg, albuterol, metaproterenol). The dose of levalbuterol is either a 0.63-mg vial for children or a 1.26-mg vial for adults.
o These drugs, especially albuterol, are safe to use during pregnancy.
" Nonselective beta-2 agonists
o Patients whose bronchoconstriction is resistant to continuous handheld nebulizer treatments with traditional beta-2 agonists may be candidates for nonselective beta-2 agonists (eg, epinephrine [0.3-0.5 mg] or terbutaline [0.25 mg]) administered subcutaneously. However, systemic therapy has no proven advantage over aerosol therapy with selective beta-2 agents.
o Exercise caution in patients with other complicating factors (eg, congestive heart failure, history of cardiac arrhythmia).
o Intravenous isoproterenol is not recommended for the treatment of asthma because of the risk of myocardial toxicity.
" Ipratropium treatment
o Ipratropium, which comes in premixed vials at 0.2%, can be synergistic with albuterol or other beta-2 agonists.
o Ipratropium is administered every 4-6 hours.
o Because children appear to have more cholinergic receptors, they are more responsive to parasympathetic stimulation than adults.
" Oxygen monitoring
o Monitoring the patient's oxygen saturation is essential during the initial treatment.
o ABG values are usually used to assess hypercapnia during the patient's initial assessment.
o Oxygen saturation is then monitored via pulse oximetry throughout the treatment protocol.
" Oxygen therapy
o Oxygen therapy is essential. It can be administered via a nasal canula or mask, although patients with dyspnea often do not like masks.
o With the advent of pulse oximetry, oxygen therapy can be easily titrated to maintain the patient's oxygen saturation above 92% (>95% in pregnant patients or those with cardiac disease).
" Glucocorticosteroids
o Steroids are the most important treatment for status asthmaticus.
o The usual dose is oral prednisone at 1-2 mg/kg/d.
o In the authors' experience, methylprednisolone provides excellent efficacy when given intravenously at 1 mg/kg/dose every 6 hours.
o Some authorities report that pulse therapy with steroids at a high dose (eg, 10-30 mg/kg/d as a single dose) is associated with a more rapid response and shorter hospitalization and has similar adverse effects; however, this is not standard therapy. Adverse effects of pulse therapy, in the authors' experiences, are minimal and comparable to the traditional doses of intravenous steroids. The adverse effects may include hyperglycemia, which is usually reversible once steroid therapy is stopped; increased blood pressure; weight gain; increased striae formation; and hypokalemia. Long-term adverse effects depend on the duration of steroid therapy after the patient leaves the hospital.
o Steroid treatment for acute asthma is necessary but has potential adverse effects. The serum glucose value must be monitored, and insulin can be administered on a sliding scale if needed. Monitoring a patient's electrolyte levels, especially potassium, is essential. Hypokalemia can cause muscle weakness, which may worsen respiratory distress and cause cardiac arrhythmias.
" Nebulized steroids
o The use of nebulized steroids for treating status asthmaticus is controversial. Recent data comparing nebulized budesonide with prednisone in children suggest that the latter therapy is more effective for treating status asthmaticus.
o No good scientific evidence supports using nebulized dexamethasone or triamcinolone via a handheld nebulizer. In fact, in the authors' experiences, more adverse effects, including a cushingoid appearance and irritative bronchospasms, have occurred with these nebulizers.
" Fluid replacement: Intravenous fluids are administered to restore euvolemia.
" Antibiotics
o The routine administration of antibiotics is discouraged.
o Patients are administered antibiotics only when they show evidence of infection (eg, pneumonia, sinusitis).
" Aminophylline
o Conflicting reports on the efficacy of aminophylline therapy have made it controversial.
o Starting intravenous aminophylline may be reasonable in patients who do not respond to medical treatment with bronchodilators, oxygen, corticosteroids, and intravenous fluids within 24 hours.
o Recent data suggest that aminophylline may have an anti-inflammatory effect in addition to its bronchodilator properties.
o The loading dose is usually 5-6 mg/kg, followed by a continuous infusion of 0.5-0.9 mg/kg/h.
o Physicians must monitor a patient's theophylline level. Traditionally, the level was targeted to the higher end of the local therapeutic range; however, many authorities suggest that the lower portion of the range (ie, >5 but <10) may be preferable if the patient can obtain the benefits of the drug in the lower range.
o Adverse effects can include tachyarrhythmia, nausea, seizures, and anxiety.