Asthma Guidelines: Management of Acute Asthma

Asthma Guidelines: Management of Acute Asthma

Hiromi Yoshida, MD, MBA, FAAP

Introduction/Etiology/Epidemiology

•In 2014, the asthma attack rate among U.S. children with active asthma <18 years of age was about 48%.

•Viral upper respiratory tract infections are the most common trigger for wheezing in children.

Pathophysiology

•Hyperresponsiveness of the airways, which is caused by external stimuli (irritants, exercise, chemicals, allergens, and infection), leads to bronchospasm and inflammation that results in airflow obstruction.

•Mucosal edema, hypersecretion of mucus, infiltration of inflammatory cells, vasodilation, hypertrophy of the mucus gland, desquamation of the airway epithelium, and mucus plugging leads to decrease in expiratory airflow.

Clinical Features

•History

—Recent or current viral illness

—Environmental or airborne allergens

•Early signs

—Cough, breathlessness

•Common signs and symptoms

—Persistent cough

—Increased respiratory rate

—Retractions (belly breathing, subcostal retractions, intercostal retractions, tracheal tugging, nasal flaring, head bobbing)

—Audible wheezing, dyspnea

—Inability to drink and/or eat

•Peak expiratory flow usually <80% of predicted or personal best

Differential Diagnosis

•Pneumonia

•Bronchiolitis in younger children

•Bacterial tracheitis

•Anaphylaxis

•Foreign-body aspiration

•Esophageal foreign body

•Bronchitis

•Vocal cord dysfunction

Diagnostic Considerations and Severity Assessment

•Asthma severity scores help stratify the severity of asthma exacerbation.

•Scores are based on a variety of signs and symptoms, including respiratory rate, work of breathing, lung examination (air entry, wheezing), degree of dyspnea, oxygen saturation, inspiratory-to-expiratory time ratio, respiratory rate, and peak expiratory flow rate.

•Several validated asthma severity scores have been developed, but no one score has been adopted universally (Box 31-1 and Table 31-1).

Management

•Early recognition of an asthma exacerbation and early intervention are crucial.

•Reverse airway obstruction

—Inhaled bronchodilators

Albuterol: Selective short-acting β₂-adrenergic agonist (SABA) is the most effective bronchodilator for reversing bronchospasm in asthma.

~This medication facilitates smooth muscle relaxation and dilation of the bronchial passages.

~Onset occurs in <5 minutes, and the effects last 2–4 hours.

~The delivery method is a metered-dose inhaler (MDI) or nebulizer.

♦Using a spacer or holding chamber can improve the delivery of inhaled medications through an MDI, especially in younger children.

~Repetitive administration leads to incremental bronchodilation.

~Use of this medication does not alter the inflammatory process.

~Dosage:

♦For nebulizer solution: 2.5–5.0 mg per dose

♦For MDI with spacer (90 mg per puff): 4–8 puffs per dose

♦2.5 mg = 4 MDI puffs

♦5.0 mg = 8 MDI puffs

~Give the patient ≤3 doses of inhaled SABA over 1 hour and reassess after each dose.

Box 31-1. Respiratory Scoring Tools

•Pediatric Asthma Severity Score (“PASS”): Ages 1–18 years

—Gorelick MH, Stevens MW, Schultz TR, Scribano PV . Performance of a novel clinical score, the Pediatric Asthma Severity Score (PASS), in the evaluation of acute asthma . Acad Emerg Med. 2004;11(1):10–18 .

•Pediatric Respiratory Assessment Measure (“PRAM”): Ages 2–17 years

—Ducharme FM, Chalut D, Plotnick L, et al . The Pediatric Respiratory Assessment Measure: a valid clinical score for assessing acute asthma severity from toddlers to teenagers . J Pediatr. 2008;152(4):476–480 .

•Pulmonary Index Score (“PIS”): Ages 1–18 years

—Scarfone RJ, Fuchs SM, Nager AL, Shane SA . Controlled trial of oral prednisone in the emergency department treatment of children with acute asthma . Pediatrics. 1993;92(4):513–518 .

•Pulmonary Score: Ages 5–17 years

—Smith SR, Baty JD, Hodge D III . Validation of the pulmonary score: an asthma severity score for children . Acad Emerg Med. 2002;9(2):99–104 .

•Respiratory rate, Accessory muscle use, Decreased breath sounds (“RAD”) Score: Ages 5–17 years

—Arnold DH, Gebretsadik T, Abramo TJ, Moons KG, Sheller JR, Hartert TV . The RAD score: a simple acute asthma severity score compares favorably to more complex scores . Ann Allergy Asthma Immunol. 2011;107(1):22–28 . y Respiratory Clinical Score: Ages 0–19 years

—Liu LL, Gallaher MM, Davis RL, Rutter CM, Lewis TC, Marcuse EK . Use of a respiratory clinical score among different providers . Pediatr Pulmonol. 2004;37(3):243–248 .

•Grading scale (Table 31-1)

—Mild: Dyspnea with activity, end-expiratory wheeze, mild work of breathing, tachypnea

—Moderate: Dyspnea at rest that interferes with usual activity, wheezing, moderate work of breathing, tachypnea

Mild to moderate exacerbations may be managed in the office setting

—Severe: Dyspnea at rest, wheezing or diminished lung sounds, clinically significant work of breathing, tachypnea, possible hypoxia

For severe exacerbations, initiate treatment while arranging for transfer of the patient to an emergency department .

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