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Acute Asthma in Adults. Tintinalli Chapter 72. Asthma definition. Chronic inflammatory disorder characterized by increased responsiveness of the airways to multiple stimuli Abnormal accumulation of eosinophils , lymphocytes, mast cells, macrophages. Pathophysiology.
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Acute Asthma in Adults Tintinalli Chapter 72
Asthma definition • Chronic inflammatory disorder characterized by increased responsiveness of the airways to multiple stimuli • Abnormal accumulation of eosinophils, lymphocytes, mast cells, macrophages
Pathophysiology • Reduction in airway diameter • Smooth muscle contraction • Vascular congestion • Bronchial wall edema • Thickened secretions • Consequences • Air trapping (intrinsic PEEP) • Increased work of breathing • V/Q imbalance w/ resulting hypercapnea/hypoxia
Clinical features • Classic triad • Dyspnea • Wheezing ( may be absent in severe cases) • Cough • Other sxs • Chest tightness • Prolonged expiration • Accessory muscle use • Tachypnea • Paradoxical abd breathing* • AMS* *signs of impending resp failure
Disorders w/ wheezing may mimic asthma • CHF “cardiac asthma” • Upper airway obstruction • FB aspiration • Multiple pulmonary emboli • Vocal cord dysfunction • Pneumonia
Key elements of history in asthma exacerbations • Present management and medications • Hospital admissions for exacerbations • ER visit in past year/month for exacerbations • Exposure to asthma triggers • Use of home peak flow meters • Best way to predict future exacerbation before it occurs • History of intubations/ICU admissions
diagnosis • PEF (Peak Expiratory Flow) • Can determine severity and response to therapy if pt is cooperative • Assess hypoxemia • Pulse ox • ABG • Indicated in severe exacerbation to assess hypercapnea and acidosis. • CXR unnecessary unless indicated by physical exam findings
Treatment • Goal- reverse airway obstruction • Adrenergic agents • β-adrenergic agents preferred as initial tx for bronchospasm • Albuterol, xopenex (continuous/intermittent) • Common side effects • Tachycardia • Nervousness/anxiety • Palpitations • Insomnia • Tremors
Treatment (cont) • Corticosteroids • IV solumedrol 125mg • PO prednisone 40-60mg • Mechanism unknown, but benefit believed to be from • Effect to restore β-adrenergic responsiveness • Anti-inflammatory effects • Evidence suggests that steroid given within 1 hour of arrival to ED reduces need for hospitalization
Treatment (cont) • Anticholinergics • Can be given to pt in form of nebulized treatment alone or in combination with β-adrenergic (additive) • Magnesium • Indicated for severe asthma exacerbation. • 1-2g IV over 30 min • Mechanical ventilation • Required pts who • Have signs of impending resp failure • Fail NIPPV • Does not resolve airflow obstruction, but reduces work of breathing
Treatment (cont) • Evidence does not support use of the following for acute exacerbations: • Heliox • Theophylline • Mast Cell Modifiers • Leukotriene Inhibitors • Ketamine and Halothane
Disposition • Decision to admit pt vs. discharge to home should be based on • Resolution of wheezing and improvement in air exchange • Pt with PEFR ≥ 70% predicted can be safely discharged to home. • Decision should also be guided by past/recent admissions for exacerbation indicating poor control/compliance • Poor response to treatment: Admit • FEV1 or PEF <40% predicted
Disposition • Checklist for ED Discharge • MDI • Short acting B-agonist • Inhaled corticosteroid (studies show ↓ relapse rate) • Oral Steroid • Peak Flow Meter • PCP follow up • Action plan
