Rosen & Barkin's 5-Minute Emergency Medicine Consult (81 page)

Medical Wards

• PEFR <40% and minimal air movement
  
• Persistent respiratory distress:
  
  • Factors that should favor admission:
    
    • Prior intubation
      
    • Recent ED visit
      
    • Multiple ED visits or hospitalizations
      
    • Symptoms for more than 1 wk
      
    • Failure of outpatient therapy
      
    • Use of steroids
      
    • Inadequate follow-up mechanisms
      
    • Psychiatric illness
      

Observation Unit

• PEFR >40% but <70% of predicted
  
• Patients without subjective improvement
  
• Patients with continued wheeze and diminished air movement
  
• Patients with moderate response to therapy and no respiratory distress
  

• PEFR >70% should be >300
  
• Patient reports subjective improvement
  
• Clear lungs with good air movement
  
• Adequate follow-up within 48–72 hr
  

Encourage patients to contact their PMD or pulmonologist for asthma related problems over the next 3–5 days.

• Altered mental status in asthma equals ventilatory failure.
  
• Patients should be able to demonstrate the correct use of their inhaler or nebulizer:
  
  • Discharge with a peak flow meter
    
• If no signs or symptoms of dehydration, no evidence that IVF will clear airway secretions.
  
• Antibiotics should generally be reserved for patients with purulent sputum, fever, pneumonia, or evidence of bacterial sinusitis.
  

• Camargo CA Jr, Rachelefsky G, Schatz M. Managing asthma exacerbations in the emergency department: Summary of the National Asthma Education and Prevention Program Expert Panel Report 3 guidelines for the management of asthma.
  J Emerg Med
  . 2009;37(2):S6–S17.
  
• Fanta CH. Asthma.
  N Engl J Med
  . 2009;360:1002–1014.
  
• Lazarus SC. Emergency treatment of asthma.
  N Engl J Med
  . 2010;363(8):755–764.
  
• Marx JA.
  Rosen’s Emergency Medicine
  . 7th ed. Asthma. 2009.
  
• National Asthma Education and Prevention Program Expert Panel Report 3. Guidelines for diagnosis and management of asthma. U.S. Dept of Health and Human Services, October 2007.
  

CODES

• 493.90 Asthma, unspecified type, without mention of status asthmaticus
  
• 493.91 Asthma, unspecified type, with status asthmaticus
  
• 493.92 Asthma, unspecified type, with (acute) exacerbation
  

BASICS

• 2.7 million children (<18 yr) affected in US
  
• 850,000 ED visits per year in US
  
• Inflammatory events, usually viral, lead to bronchoconstriction:
  
  • Compounded by hyper-reactivity of airways
    
  • Mediators of the inflammatory cascade exacerbate symptoms
    
• Airway obstruction produces increased airway resistance and gas trapping:
  
  • Mucosal edema
    
  • Bronchospasm
    
  • Mucous plugging
    
• Infants more vulnerable to respiratory failure:
  
  • Increased peripheral resistance
    
  • Decreased elastic recoil with early airway closure
    
  • Unstable rib cage
    
  • Mechanically disadvantaged diaphragm
    
• Family history of allergy
  
• Medical history of early injury to airway (bronchopulmonary dysplasia, pneumonia, intubation, croup, reflux, passive exposure to smoking), reactions to foods and drugs, other allergic manifestations
  
• Environmental exposures such as pets, smoke, carpets, or dust may trigger or exacerbate
  

• Infection:
  
  • Viral
    
  • Bacterial
    
• Allergic/irritant:
  
  • Environment: Pollens, grasses, mold, house dust mites, and animal dander
    
  • Occupational chemicals: Chlorine, ammonia—food and additives
    
  • Irritants: Smoke, pollutants, gases, and aerosols
    
  • Exercise
    
  • Cold weather
    
  • Emotional: Stress, phobia
    
  • Intoxication: β-blockers, aspirin, NSAIDs
    

DIAGNOSIS

• Fatigue, somnolence
  
• Diaphoresis, agitation
  
• Hypoxia, cyanosis
  
• Tachycardia
  
• Dehydration
  
• Pulsus paradoxus
  

• Wheezing, rales, rhonchi
  
• Cough, acute or chronic
  
• Tachypnea
  
• “Tight chest”
  
• Dyspnea, shortness of breath with prolonged expiratory phase
  
• Retractions, accessory muscle use, nasal flaring
  
• Hyperinflation
  
• Often a history of recurrent episodes and chronic restrictions
  
• Complications:
  
  • Recurrent pneumonia, bronchitis
    
  • Atelectasis
    
  • Pneumothorax, pneumomediastinum
    
  • Respiratory distress/failure/death
    

• Precipitating events or known triggers
  
• Chronicity of symptoms
  
• Comorbid illnesses
  
• History of disease:
  
  • Previous hospitalizations for asthma
    
  • Previous intubations and intensive care
    
  • Regular and sporadic medications
    

• Vital signs, including oximetry and respiratory status
  
• Wheezing: Absence of wheezing may be associated with markedly impaired air movement and decreased breath sounds
  
• Signs of hypoxia
  
• Skin and nail bed color bluish
  
• Signs of respiratory fatigue, distress, or failure:
  
  • Use of accessory muscles of respirations or retractions
    
  • Lethargy or confusion
    

• Clinical diagnosis based primarily on physical exam and history; assess ventilation by observation for retractions and use of accessory muscles as well as auscultating for air exchange.
  
• Follow response to bronchodilator therapy with present illness and past episodes.
  
• Exclude other differential considerations.
  
• Pulse oximetry:
  
  • Initial SaO
    ₂
    <91% (sea level) associated with significant illness: Admission, relapse, prolonged course
    
• Peak flow meters in cooperative patients (usually >5 yr old)
  
  • <50–70% predicts moderate to severe obstruction.
    
  • >70–90% associated with mild to moderate obstruction
    
  • >90% considered normal
    

• Arterial blood gas (ABG) may be an adjunct to pulse oximetry to measure oxygenation and clinical exam to assess ventilation; not mandatory or routinely done.
  
• CBC as a nonspecific marker of infection
  
• Theophylline level: Only for patients on theophylline (not recommended)
  

Chest radiograph considered in the following patients, esp. focusing on the presence of infiltrates, bronchial wall thickening, or hyperexpansion.

• <1 yr of age to exclude foreign body or atelectasis
  
• First episode of significant wheezing (suggested to assess chronicity of illness and assist in excluding other conditions)
  
• Increasing respiratory distress or minimal response to therapy
  
• Respiratory distress/failure
  
• Shortness of breath in the absence of wheezing
  

Peak flow measurement (see above)

• Infection/inflammation:
  
  • Bronchiolitis: Clinically difficult to differentiate except by age and clinical history.
    
  • Pneumonia: Viral, bacterial, chemical, or hypersensitivity
    
  • Aspiration
    
  • Retropharyngeal/mediastinal abscess/mass
    
  • Anaphylactic reaction
    
• Anatomic:
  
  • Pneumothorax
    
  • Foreign body
    
• Vascular disorder:
  
  • Compression of trachea by vascular anomaly
    
  • Pulmonary embolism
    
  • CHF
    
• Congenital disease:
  
  • Cystic fibrosis
    
  • Tracheoesophageal fistula
    
  • Bronchogenic cyst
    
  • Congenital heart disease
    
• Intoxication: Metabolic acidosis
  
• Neoplasm
  
• Vocal cord dysfunction (VCD)
  
• Pulmonary edema—cardiogenic or noncardiogenic
  
• Gastroesophageal reflux
  

TREATMENT