Author: Leia Kessler, MD

Editors: David Guernsey, MD, Ellen Duncan, MD/PHD

Introduction:  

  • Asthma is a chronic inflammatory airway disease characterized by reversible lower airway obstruction due to bronchoconstriction, mucosal edema, and mucus plugging 
  • Common triggers include viral respiratory infections, exercise, and allergen exposure.  
  • Asthma is one of the most common chronic pediatric conditions and a leading cause of emergency department (ED) visits and hospitalizations. 
  • Early recognition and management of exacerbations is essential to prevent life-threatening complications such as respiratory failure, cardiopulmonary arrest, and death. 

Clinical Manifestations:  

  • Patients typically present with a combination of: 
    • Shortness of breath 
    • Wheezing 
    • Chest tightness 
    • Cough (especially nocturnal or triggered by exercise) 
  • Risk factors for severe disease and asthma-related mortality include:  
    • Prior ICU admission or need for respiratory support (i.e., HFNC, BiPAP, or intubation) 
    • Frequent ED visits or hospitalizations for asthma  
    • Poor symptom perception, incorrect inhaler technique, or nonadherence to controller medications 
  • Vital sign abnormalities may include tachypnea, tachycardia, and/or hypoxemia; because asthma is an obstructive disease of the lower airways, significant hypoxemia (SaO2<92%) suggests marked airflow limitation and impaired gas exchange  
  • Patients may have inspiratory, expiratory, or biphasic wheeze; while expiratory wheeze typically indicates mild-moderate obstruction, inspiratory and/or biphasic wheeze suggest more significant airflow limitation. 
  • Absence of wheeze (“silent chest”) reflects critically reduced airflow, worsening of obstruction, and impending respiratory failure. 

Physical Exam Findings 

Mild/Moderate  

Severe 

Wheezing  

Tripod position 

Prolonged expiratory phase  

Inability to speak in more than 1-2 words at a time 

Accessory muscle use  

Central cyanosis 

Nasal flaring 

Grunting  

 

Silent chest 

Differential Diagnosis:  

Condition  Typical Context  Key Distinguishing Features 
Viral bronchiolitis  Children < 2 years; winter season  URI prodrome (fever, nasal congestion, rhinorrhea), crackles plus wheeze, poor feeding; often limited response to bronchodilators. 
Pneumonia  Any age; possible preceding viral syndrome  Focal crackles, wheezing or decreased breath sounds; fever, cough and fatigue; CXR with focal consolidation. 
Foreign body aspiration  History of choking episode  Unilateral wheeze or decreased air entry; asymmetric exam; CXR may show unilateral hyperinflation or visible foreign body. 
Cystic fibrosis exacerbation  Known CF or chronic respiratory and/or GI symptoms  Chronic cough, recurrent pneumonia, failure to thrive, clubbing; CXR with bronchiectasis and hyperinflation. 
Pneumothorax  Sudden pleuritic pain, dyspnea; may be spontaneous, traumatic, or iatrogenic  Unilateral absent/decreased breath sounds, hyperresonance; absent lung sliding on POCUS; CXR with air in pleural space and lung collapse. 
Pulmonary edema / congestive heart failure  Known or suspected heart disease  Crackles > wheeze, hepatomegaly, peripheral edema, poor feeding or sweating with feeds, failure to thrive, cyanosis; CXR with enlargement of cardiothymic silhouette and pulmonary vascular congestion. 
Anaphylaxis  Exposure to food, drug, insect sting, or other allergen   Involvement of 2 systems: skin and mucosa (e.g. urticaria, angioedema), respiratory (e.g., wheezing, stridor), gastrointestinal (e.g., abdominal pain, vomiting, diarrhea), or cardiovascular (e.g., tachycardia, hypotension). Upper airway swelling may be prominent. 
Upper airway obstruction (e.g., croup)  Younger children; barky cough, hoarseness, or drooling  Stridor (usually inspiratory) and hoarseness; lung fields often clear aside from transmitted upper airway sounds. 

Assessment and Risk Stratification:  

  • Pulse oximetry: SaO₂ <92% suggests a more severe exacerbation 
  • End-tidal / PaCO₂: Early exacerbations → low PaCO₂ from tachypnea; normal or high PaCO₂ in a tachypneic patient suggests fatigue and impending respiratory failure 
  • Blood gas: Not routine in mild–moderate exacerbations; obtain if severe exacerbation or impending respiratory failure suspected 
  • Chest X-ray: Not routine; consider if concern for alternative pathology (pneumonia, pneumothorax, foreign body, heart failure, atypical presentation) 
  • Clinical scores: Pediatric Asthma Score (PAS), Pediatric Respiratory Assessment Measure (PRAM), Pulmonary Index Score (PSI) and the Clinical Respiratory Score (CRS) can help standardize severity assessment and disposition 

Management:

  • Initial management: Rapid assessment (ABCs), early bronchodilators, systemic corticosteroids, and supplemental O₂/respiratory support as needed 
  • Mild–Moderate Exacerbation: 3 back-to-back albuterol + ipratropium (DuoNebs) → albuterol PRN; early steroids; consider magnesium and IV fluids 
  • Severe Exacerbation: Above therapies plus consider IM epinephrine or terbutaline (poor air movement), continuous albuterol, and subdissociative ketamine 

 

Medication  Mechanism  Dosing  Key Notes 
Albuterol (neb, intermittent)  SABA → bronchodilation  0.15 mg/kg (max 5 mg) q20 min ×3, then PRN 
Practical: <10 kg 1.25–2.5 mg; 10–20 kg 2.5–3.75 mg; ≥20 kg 5 mg 		 First-line rescue. Monitor HR, K⁺. AE: tachycardia, tremor, hypokalemia. 
Albuterol (neb, continuous)  Continuous β₂ stimulation  0.5–1 mg/kg/hr (max 20 mg/hr) 
Typical: 10 mg/hr (10–20 kg), 15 mg/hr (20–30 kg), 20 mg/hr (>30 kg) 		 Severe/status asthma. Continuous monitoring; check electrolytes. 
Ipratropium (neb)  Anticholinergic → ↓ vagal bronchoconstriction  <20 kg: 0.25 mg 
≥20 kg: 0.5 mg 
Usually ×3 with albuterol 		 Add-on to SABA early. Short course only. AE: dry mouth, blurred vision. 
Dexamethasone (PO/IV/IM)  Systemic steroid → ↓ airway inflammation  0.6 mg/kg (max 10–16 mg) once; may repeat in 24–36 hr  Give early (<1 hr). Reduces admission/relapse. 
Methylprednisolone (IV)  Systemic steroid  1–2 mg/kg IV q6h (max ~60–80 mg/dose)  Severe/status asthma. Monitor cumulative steroid exposure. 
Magnesium sulfate (IV)  Ca²⁺ antagonism → smooth muscle relaxation  50 mg/kg IV over 20 min (max 2 g)  Moderate–severe refractory asthma. Monitor BP; give with IV fluids. 
Epinephrine (IM)  α/β agonist → bronchodilation + ↓ mucosal edema  0.01 mg/kg IM (max 0.3–0.5 mg)  Use when poor air movement or impending arrest. 
Terbutaline (SQ)  Systemic β₂ agonist  0.01 mg/kg SQ (max 0.25 mg) q20 min ×3  Bridge when inhaled therapy inadequate. Monitor HR, K⁺. 
Terbutaline (IV)  Continuous β₂ agonist  Load 10 mcg/kg → 0.1–0.4 mcg/kg/min infusion  ICU-level therapy for refractory status asthmaticus. 
Ketamine (sub-dissociative)  NMDA antagonist; bronchodilation  0.2–0.5 mg/kg IV bolus → infusion  Helps tolerate NIV and reduces agitation. 
Ketamine (RSI)  Dissociative anesthesia  1–2 mg/kg IV (RSI)  Preferred induction agent in severe asthma. 
IV fluids  Volume support  10–20 mL/kg isotonic crystalloid bolus PRN  Treat dehydration and medication-related hypotension. 

Respiratory Support:

Noninvasive Ventilation (CPAP, BiPAP) 

Mechanism 

  • IPAP: ↑ tidal volume → improves ventilation 
  • EPAP: stents open airways → ↓ airway collapse → improves oxygenation 

Typical Pediatric Starting Settings 

  • IPAP: 8–16 cm H₂O 
  • EPAP: 4–8 cm H₂O 
  • Titrate to comfort and gas exchange 

Best Candidates 

  • Alert, cooperative patients 
  • Able to protect airway and manage secretions 

Contraindications 

  • Decreased level of consciousness 
  • Active vomiting / high aspiration risk 
  • Facial trauma or poor mask seal 
  • Hemodynamic instability 

Invasive Mechanical Ventilation 

Indications 

  • Impending or actual respiratory failure (refractory hypoxemia or hypercapnia) 
  • Altered mental status 
  • Hemodynamic instability 
  • Fatigue, rising PaCO₂, or worsening acidosis despite maximal therapy and NIV 

Goals 

  • Reverse hypoxemia 
  • Relieve respiratory muscle fatigue 
  • Maintain ventilation while minimizing barotrauma 

Approach 

  • RSI: ketamine + paralytic (per institutional protocol) 
  • Vent strategy: 
  • Low tidal volume 
  • Slow respiratory rate 
  • Prolonged expiratory time → reduce air trapping / auto-PEEP 
  • Permissive hypercapnia acceptable if pH and hemodynamics remain stable 

Potential Complications 

  • Worsening hypercarbia during apnea → risk of arrest 
  • Barotrauma (pneumothorax, pneumomediastinum) 
  • Dynamic hyperinflation / auto-PEEP → hypotension 
  • ↓ venous return from positive pressure ventilation → shock 

Disposition: 

Consider Admission: 

  • Persistent respiratory distress requiring frequent albuterol (>q3–4 hr) 
  • Need for supplemental O₂ or respiratory support 
  • SaO₂ <90–92% on room air (institution dependent) 
  • High-risk comorbidities: congenital heart disease, chronic lung disease, neuromuscular disease 

Consider Discharge: 

  • Stable vitals with sustained clinical improvement 
  • Minimal/no retractions; able to speak in full sentences 
  • Albuterol spaced ≥q4 hr without symptom recurrence 
  • Controller therapy optimized (if indicated) 
  • Correct inhaler/nebulizer technique demonstrated 

Social and Structural Considerations:

Environmental triggers 

  • Tobacco smoke exposure 
  • Indoor allergens/irritants: dust mites, mold, cockroaches, rodents, pets, cleaning chemicals, incense 
  • Housing quality: poor ventilation, mold, pests, overcrowding, poorly ventilated gas stoves 

 For pediatric patients with asthma, especially those with frequent ED visits or severe exacerbations, consider the following: 

 Asthma-specific factors 

  • Home environment: tobacco smoke, indoor allergens/irritants, dampness, visible mold, pests, poor ventilation, gas stoves without ventilation 
  • Caregiver/patient asthma skills: understanding triggers, controller vs rescue medications, written asthma action plan 
  • Inhaler technique: correct use of inhalers and spacers 
  • School/community exposures: inhaler access at school, nurse availability for inhalers/nebulizers, neighborhood air pollution, high-pollution or substandard housing environments 

Factors relevant to many chronic pediatric conditions 

  • Socioeconomic constraints: ability to afford medications/devices, insurance and pharmacy access, food insecurity, unstable housing 
  • Access to care: transportation, language barriers, interpreter availability, limited school-based health centers or community programs 
  • Caregiver capacity: health literacy, ability to manage a chronic regimen, work schedules limiting appointments or medication administration 
  • School/community context: school nurse availability, ability to administer medications, access to safe spaces for physical activity 

Discussion Questions:

  1. When managing a child with severe asthma exacerbation, under what specific clinical conditions would you proceed to intubation, and how do you minimize the risks associated with positive pressure ventilation in obstructive lung disease? 
  2. In a pediatric patient who does not respond adequately to initial nebulized albuterol and ipratropium, what additional medications can be used, and what are their mechanisms of action and major risks? 

Sources: 

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  2. 2020 Focused Updates to the Asthma Management Guidelines: A Report from the National Asthma Education and Prevention Program Coordinating Committee Expert Panel Working Group. J Allergy Clin Immunol. 2021;147(4):1526‑1538. doi:10.1016/j.jaci.2021.02.009. 
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  5. National Asthma Education and Prevention Program Expert Panel Report 3 (EPR‑3): Guidelines for the Diagnosis and Management of Asthma‑Summary Report 2007. J Allergy Clin Immunol. 2007;120(Suppl 5):S94‑ 
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