II. History

  1. See Asthma Evaluation (complete history, exam)
  2. See Asthma-Related Death Risk Factors
  3. See Asthma Differential Diagnosis
  4. Current Episode
    1. Onset?
    2. Trigger?
    3. Medications?
      1. Which ones and when were they taken?
      2. Response (Symptoms and Peak Flow)?
  5. Asthma History
    1. Baseline medications?
      1. Consistent use of controller medication (i.e. Inhaled Corticosteroid or combination such as Advair)?
      2. Frequency of rescue Inhaler use (e.g. Albuterol)
    2. Last Systemic Corticosteroid use?
    3. Frequency of symptoms (Wheezing, cough, or Dyspnea)?
    4. Associated Conditions
      1. Atopy (Asthma, Eczema, Allergic Rhinitis)
      2. Samter's Triad (Aspirin or NSAID Intolerance, Nasal Polyps, Asthma)
    5. Frequency of episodes requiring medical care?
      1. Emergency visits?
      2. Hospitalizations?
      3. Intensive Care unit admissions?
      4. Intubations?
  6. Social history and Medications
    1. Tobacco exposure (including passive smoking)?
    2. Other medications or herbal use?
  7. PMH: Adults
    1. COPD
    2. Coronary Artery Disease
    3. Congestive Heart Failure
    4. Venous Thromboembolism
    5. Sleep Apnea
    6. Pulmonary Hypertension
  8. PMH: Children
    1. Bronchopulmonary Dysplasia
    2. Pulmonary Hypertension
    3. Bronchiolitis (e.g. RSV, Influenza)
    4. Atopy (Asthma, Eczema, Allergic Rhinitis)

III. Pathophysiology: Presentations

  1. Bronchospasm predominant (less common)
    1. Fast-on, Fast-off exacerbation
    2. Triggers include Allergic Rhinitis, cold exposure or Exercise
    3. Typically severe presentations respond quickly to beta Agonists (Albuterol, Atrovent)
    4. Also responds to Magnesium
    5. In severe cases, lungs will be tight, silent without excursion (due to Breath Stacking)
      1. Severe cases with air trapping typically respond poorly to NIPPV (e.g. BiPaP)
  2. Airway edema predominant (more common)
    1. Poorly responsive to beta Agonists (Albuterol, Atrovent)
    2. Triggers include viral Upper Respiratory Infections
    3. Associated with poor underlying Asthma control (e.g. no controller medication use)
    4. Responds to Corticosteroids, Epinephrine
    5. Severe cases progress to respiratory muscle Fatigue and hypercapnia, and respond well to NIPPV (e.g. BiPaP)

IV. Evaluation: Initial Assessment

  1. See Pediatric Asthma Score
  2. See Asthma Exacerbation Severity Evaluation
  3. See Asthma Evaluation
  4. See Asthma Management
  5. See Pediatric Assessment Triangle
  6. Vital Signs
    1. Heart Rate (Tachycardia)
    2. Respiratory Rate (Tachypnea)
    3. Oxygen Saturation
      1. Poor indicator of need for admission or prognosis
      2. Oximetry may transiently drop as airway obstruction decreases (due to initial increase in V-Q mismatch)
      3. Supplemental Oxygen indicated for Oxygen Saturation <92%
    4. End-Tidal CO2
      1. Should be suppressed in an Asthma Exacerbation
      2. Higher than normal End-Tidal CO2 may predict impending Respiratory Failure (specific but not sensitive)
    5. Peak Expiratory Flow Rate (PEF) or FEV1
      1. See protocol below
      2. Compare with personal best or height-based predicted values
      3. Limited use in young children or moderate to severe exacerbations
      4. May not be accurate in the emergency department, and not required for ED standard of care
  7. Respiratory Status
    1. Increased work of breathing (e.g. Tachypnea, flaring and retractions, Air Hunger)
    2. Lung auscultation (Wheezing, rales, rhonchi)
      1. Quiet lungs may be more ominous than Wheezing (minimal air movement)
    3. Assess accessory Muscle use
      1. Scalene and suprasternal retractions are most correlated with severe Asthma Exacerbation
  8. Cardiovascular evaluation
    1. Electrocardiogram
      1. Indicated in age over 50 years old with history of cardiovascular disease
  9. Assessment if patient in extremis
    1. See Status Asthmaticus
    2. Arterial Blood Gas (see below)
      1. ABG may be considered in near Respiratory Failure (typically not indicated)

VI. Diagnostics: Peak Expiratory Flow Rate (PEF) or FEV1

  1. May not be accurate in the emergency department
    1. Not required for emergency department standard of care
    2. May instead use the Pediatric Asthma Score (PAS)
  2. Indications
    1. All Asthma Exacerbations if possible
    2. Ability to comply with test by age 5-6 years old
  3. Timing
    1. Obtain at presentation
    2. Obtain again 30-60 minutes after interventions
    3. Consider again prior to discharge
  4. Interpretation
    1. See Asthma Exacerbation Severity Evaluation
    2. Compare actual PEF or FEV1 to historical best or predicted
      1. See Peak Expiratory Flow Rate for predicted PEF (based on height, age, gender)
    3. Mild Asthma Exacerbation
      1. Peak Expiratory Flow (PEF) or FEV1: >70%
      2. Pediatric Asthma Score (PAS): 5 to 7
    4. Moderate Asthma Exacerbation
      1. Peak Expiratory Flow (PEF) or FEV1: 40-69%
      2. Pediatric Asthma Score (PAS): 8 to 11
    5. Severe Asthma Exacerbation
      1. Peak Expiratory Flow (PEF) or FEV1: 25-39%
      2. Pediatric Asthma Score (PAS): 12 to 15
    6. Life-threatening Asthma Exacerbation
      1. Peak Expiratory Flow (PEF) or FEV1: <25%

VII. Imaging: Chest XRay

  1. See Chest XRay in Asthma
  2. Low yield in acute exacerbations
  3. Associated with Antibiotic Overuse (Atelectasis with Asthma may resemble Pneumonia)
  4. Indications
    1. Consider if admitting for Asthma Exacerbation
    2. Pneumonia suspected
    3. Barotrauma (e.g. risk of Pneumothorax)
    4. Fever
    5. Pulmonary Rales
    6. New onset Wheezing (first Asthma episode)
    7. Failed response to therapy

VIII. Labs

  1. Lab testing is not indicated for stable patients, with typical Asthma Exacerbations
  2. Labs are indicated to exclude other plausible diagnoses
  3. Arterial Blood Gas
    1. Decisions should be made clinically (e.g. intubation indications)
      1. Observe for Altered Level of Consciousness, lethargy, failing respiratory effort
    2. Consider End-Tidal CO2 as an alternative, real-time monitoring of CO2
      1. Also useful in monitoring response to BiPap and Mechanical Ventilation
    3. ABG may be considered in near Respiratory Failure (typically not indicated)
    4. Venous Blood Gas may be used as an alternative, to monitor status (e.g. Bipap)
    5. PaCO2 is expected to be low in acute Asthma Exacerbation
      1. PaCO2 >42 mmHg suggests Respiratory Failure (ominous)
      2. However pCO2 exact number itself is not an indication to intubate (base on clinical evaluation)

IX. Management: General

  1. Reassessment after each round of therapy is critical

X. Management: Step 1

  1. Inhaled Short-acting Beta Agonist (Nebulized Albuterol)
    1. Albuterol Neb 0.15-0.3 mg/kg (max 2.5 to 5 mg) up to every 15-20 minutes for one hour (rapid sequence nebs)
    2. Albuterol Metered Dose Inhalers at 4-8 puffs per dose with spacer and proper technique is equivalent to nebulizer
    3. Continuous nebulizer dosing (15-25 mg/h)
      1. Variable benefit over intermittent nebulizer dosing
      2. One study showed 10% fewer hospitalizations with continuous neb
        1. Camargo (2003) Cochrane Database Syst Rev (4): CD001115 [PubMed]
  2. Anticholinergic (Ipratropium Bromide or Atrovent)
    1. Smooth Muscle relaxant
    2. Add Ipratropium Bromide 0.25 to 0.5 mg to Nebulized Albuterol solution (or deliver as duoneb)
    3. Indication: FEV1 or PEF <40-50% of predicted (Moderate to Severe Asthma Exacerbation)
      1. Associated with a decreased rate of hospitalization for Asthma Exacerbation
      2. Used in pediatric emergency departments down to age 4-6 months
  3. Systemic Corticosteroid (oral, IV or IM)
    1. When indicated, start Corticosteroids in the first hour of presentation (reduces admissions by 1 in 8)
      1. Rowe (2001) Cochrane Database Syst Rev (1): CD002178 [PubMed]
    2. Indications
      1. Most Asthma Exacerbation cases presenting to emergency department benefit from Systemic Corticosteroids
      2. Severe episode (FEV1 or PEF <40-50% predicted) or
      3. No immediate response to immediate management or
      4. Oral Corticosteroid recently taken by patient
    3. Oral Preparations (as effective as intravenous)
      1. Tapering not needed if use <2 weeks
      2. Prednisone or Prednisolone 1-2 mg/kg IV daily or divided twice daily to 40-60 mg/day orally for 3-5 days
      3. Dexamethasone 0.3 to 0.6 mg/kg (up to 10 mg) orally daily for 1-2 days
        1. Consider for children with adverse effects on Prednisone (e.g. hyperactivity)
        2. Consider for patients who may have difficulty maintaining compliance with a 5 day regimen
        3. Dex. 0.3 mg/kg x1 dose as effective as Prednisolone 1 mg/kg for 3 days in moderate exacerbation
          1. Cronin (2015) Ann Emerg Med +PMID:26460983 [PubMed]
    4. Intravenous preparations
      1. Methylprednisolone (Solu-Medrol) 1 mg/kg/dose (up to 60 mg) IV every 6 hours (or 80 mg IV every 8 hours)
  4. Oxygen indications
    1. Oxygen Saturation to keep Oxygen Saturation >90-92%

XI. Management: Step 1b - Life threatening or Severe Asthma presentation

  1. See Status Asthmaticus
  2. Noninvasive Positive Pressure Ventilation (CPAP, BIPAP, HHFNC)
    1. See High Humidity High Flow Nasal Oxygen (HHFNC)
    2. See Non-Invasive Positive Pressure Ventilation (BIPAP)
    3. See Delayed Sequence Intubation (e.g. Ketamine with initial BiPap)
  3. Endotracheal Intubation and Mechanical Ventilation Indications
    1. See Status Asthmaticus for specific intubation indication list
    2. Impending or actual respiratory arrest
    3. Intubation in Asthma has many risks including Barotrauma (Exercise caution)
    4. Intubation however should be performed without delay (semi-electively before crisis) when indicated clinically
  4. Consider Additional measures for severe exacerbation
    1. Epinephrine (Anaphylaxis dosing)
      1. Dose: 0.01 mg/kg up to 0.3 mg SC and may be repeated every 5 minutes
      2. Consider continuation as infusion (see Status Asthmaticus for dosing)
    2. Magnesium Sulfate
      1. Dose: 40-75 mg/kg IV (up to 2 grams) for 1 dose over 20 minutes
        1. Consider continued Magnesium infusion at 2 g/hour (not part of standard guideline)
      2. Smooth Muscle relaxant and Histamine release inhibitor
      3. Monitor for sedation, Hypotension
      4. Some recommend for all moderate to Severe Asthma exascerbations
      5. Variable efficacy, but one study demonstrated reduced hospitalizations by 1 in 3
        1. Rowe (2000) Cochrane Database Syst Rev (2): CD001490 [PubMed]
    3. Inhaled Corticosteroids (3 inhalations in <30 min)
      1. Effective for adults and children in acute Asthma attacks
      2. Cochrane review - not enough evidence for use in acute exacerbations in combination with systemic steroids
        1. Edmonds (2012) Cochrane Database Syst Rev :CD002316 [PubMed]
      3. One study showed even better efficacy than Systemic Corticosteroids
        1. Most effective if used early in treatment plan
        2. Rodrigo (2006) Chest 130:1301-11 [PubMed]

XII. Management: Step 2 - Reassess

  1. Criteria: Repeat measures in initial evaluation
    1. See Asthma Exacerbation Severity Evaluation
    2. Repeat Peak Expiratory Flow (PEF) or FEV1
  2. Base management on severity of episode
    1. Moderate episode (PEF 40-70% of predicted, PAS 8 to 11)
      1. Nebulized Albuterol hourly
      2. Oral Systemic Corticosteroids
      3. Continue management for 1-3 hours while improving
      4. Decide within 4 hours on admission versus discharge
    2. Severe episode (PEF <40% predicted, PAS 12 to 15, accessory Muscle use, retractions, severe rest symptoms)
      1. See Status Asthmaticus
      2. ABC Management
      3. Nebulized Albuterol hourly or continuous
      4. Nebulized Epinephrine
        1. Racemic Epinephrine 2.25% solution 0.5 ml nebulized or
        2. Standard Epinephrine 1:1000 solution 5 ml nebulized
        3. Consider in cases where patient does not respond to Albuterol and Atrovent nebs
          1. Lack of response to standard nebs
            1. Suggests airway edema which may be better treated by Epinephrine
          2. In children, consider croup and Bronchiolitis
            1. Etiologies with poor response to standard Bronchodilators
        4. Weibe and Herbert in Majoewsky (2012) EM: Rap 12(8): 6-7
      5. Ipratroprium bromide added to nebulizer every 4 hours
      6. Oxygen to keep Oxygen Saturation >92%
      7. Consider Status Asthmaticus management in Step 2b
      8. Systemic Corticosteroids
        1. Prednisone
          1. Prednisone 1-2 mg/kg/day divided daily to twice daily
          2. Maximum: 40-60 mg/day for 5-10 days
          3. No tapering needed if use less than 2 weeks
        2. Dexamethasone
          1. Dose: 0.3 to 0.6 mg/kg/day PO/IV/IM up to 15 mg for 1-2 days
          2. Keeney (2014) Pediatrics 133(3): 493-9 [PubMed]

XIII. Management: Step 3a - Good Response

  1. Indications
    1. Response sustained >60 minutes after last treatment
    2. Normal physical examination and no distress
    3. FEV1 or PEF >70%
    4. Oxygen Saturation >92%
  2. Management: Discharge Home
    1. Observe in ED at least 30-60 minutes following intervention prior to discharge
    2. Continue Inhaled Beta Agonist
    3. Corticosteroids
      1. Oral Systemic Corticosteroids
        1. Adult: Prednisone 40 to 60 mg per day divided daily to twice daily for 5-10 days
        2. Child: Prednisolone (Prelone) 1-2 mg/kg/day to maximum 60 mg/day for 5-10 days
        3. No tapering needed if use less than 2 weeks
      2. Alternative: Methylprednisolone
        1. Methylprednisolone 160 mg IM Depot injection (adults)
        2. As effective as 8 day taper on oral steroids
        3. Lahn (2004) Chest 126:362-8 [PubMed]
      3. Alternative: Dexamethasone
        1. Dose: 0.3 to 0.6 mg/kg/day PO/IV/IM up to 10-16 mg/dose for 1-2 days
        2. Keeney (2014) Pediatrics 133(3): 493-9 [PubMed]
    4. Patient Education on medications and plan
      1. Include Asthma Action Plan if not already in place
      2. Consider starting an Inhaled Corticosteroid if meets criteria for persistent Asthma
        1. See Mild Persistent Asthma, Moderate Persistent Asthma, Severe Persistent Asthma
    5. Establish close follow-up
    6. Avoid ineffective or potentially harmful home measures
      1. Avoid adding Long acting beta Agonists acutely (if not already using)
      2. Avoid Theophylline
        1. No added benefit to Bronchodilators and risk of toxicity
      3. Avoid Antibiotics
        1. Unless Bacterial Infection identified such as Pneumonia
      4. Avoid Mucolytics
        1. Risk of increased cough and airway obstruction
      5. Sedatives
        1. Increased risk of respiratory depression

XIV. Management: Step 3b - Incomplete response in 1-3 hours

  1. Indications
    1. FEV1 or PEF 40-70%
    2. High risk patient with mild to moderate symptoms (see Asthma-Related Death Risk Factors)
    3. Oxygen Saturation not improved on room air
  2. Management: Admit to hospital or discharge home
    1. Home discharge criteria in Moderate Asthma Exacerbation (PEF 40-70%)
      1. Adequate Oxygen Saturation on room air AND
      2. Close follow-up arranged AND
      3. Patient must be reliable with a good understanding of their Asthma home management AND
      4. Low risk patient without Asthma-Related Death Risk Factors
    2. Observation Unit Admission
      1. Inclusion Criteria for observation stay
        1. Vital Signs stable (Oxygen Saturation >89% and Respiratory Rate <40) AND
        2. Patient alert and oriented AND
        3. Incomplete Bronchodilator response (still Wheezing, but improved) AND
        4. Persistent symptoms despite 3 nebulizer treatments and Corticosteroids administered
      2. Exclusion Criteria (full hospital admission instead)
        1. Vital Signs unstable (Oxygen Saturation <89%, Respiratory Rate >40, temp >38.5 C)
        2. New EKG changes (aside from Sinus Tachycardia)
        3. Unable to perform Spirometry
        4. Trending toward Respiratory Failure, respiratory muscle Fatigue, lethargy
        5. Continuous nebulizer treatment >3 hours without improvement
      3. Observation Unit Management
        1. Observe for 6 to 8 hours and disposition home or to admission
        2. Systemic Corticosteroid (e.g. solumedrol IV or Prednisone orally) if not already given as above
        3. Bronchodilator (e.g. duoneb, AlbuterolInhaler)
          1. Start every 2 hours and wean to every 4 hours with intermittent rescue
    3. Inpatient Admission (if home discharge and observation criteria not met)
      1. See Asthma Inpatient Management
  3. References
    1. Lee (2018) Crit Dec Emerg Med 32(1): 3-8

XV. Management: Step 3c - Poor response within 1 hour

  1. Indications
    1. High risk patient with severe symptoms
    2. FEV1 or PEF <40%
    3. pCO2 >42 mmHg
    4. pO2 <60 mmHg
  2. Management: Admit to Intensive Care Unit
    1. Admit to Intensive Care Unit
    2. See Asthma Inpatient Management
    3. Consider Additional measures for severe exacerbation
      1. See Status Asthmaticus

XVI. Precautions: Avoid potentially harmful interventions

  1. Theophylline or Aminophylline
    1. No benefit over inhaled beta-Agonists
    2. Narrow therapeutic window
    3. Rare indication may be a patient in such distress that will not tolerate the nebulizer
  2. Agents effectively used in Asthma maintenance that do not offer benefit or may worsen an Asthma Exacerbation
    1. Long acting beta Agonists
    2. Leukotriene modifying agents (e.g. Montelukast)

XVII. Management: Disposition

  1. Expect a 25% hospitalization rate of ED Asthma Exacerbation visits
  2. Relapse rate (bounce-back) is 7-15% after emergency department discharge
  3. Discuss with patients prior to discharge the potential for relapse and the indications for urgent or emergent re-evaluation
    1. All Asthma patients should have an Asthma Action Plan (typically generated at routine clinic visits)
    2. All ED discharged Asthma patients should be prescribed Albuterol MDI with spacer (if they do not have one)
    3. Oral Corticosteroids are indicated in all but the mildest Asthma Exacerbations in the emergency department
    4. Schedule short-interval follow-up for all Asthma patients with their primary medical provider after ER discharge
    5. Inhaled Corticosteroids reduce relapse rate
      1. Those already using Inhaled Corticosteroids should continue while on Systemic Corticosteroids
      2. Consider prescribing an Inhaled Corticosteroid for those with persistent symptoms and not already on one

XVIII. Prognosis: Risks for Asthma Related Death

  1. History of sudden severe Asthma Exacerbations
  2. Prior Endotracheal Intubation for Asthma
  3. Prior Intensive Care admission for Asthma
  4. More than one Asthma-related hospital admission or more than 2 emergency visits in past year
  5. Use of more than 2 Inhaled Beta Adrenergic Agonist MDIs (e.g. Albuterol) per month
  6. Current or recent Systemic Corticosteroid use
  7. Poor perceivers of Asthma severity (under-recognize their Asthma severity)
  8. Comorbidities (e.g. cardiopulmonary disease, psychosocial factors)
  9. Illicit Drug Use

XIX. References

  1. (1997) Management of Asthma, NIH 97-4053
  2. (1995) Global Strategy for Asthma, NIH 95-3659
  3. Fuchs and Yamamoto (2011) APLS, Jones and Bartlett, Burlington, p. 62-71
  4. Serrano (2014) Crit Dec Emerg Med 28(6):2-10
  5. Sherman (2014) Crit Dec Emerg Med 28(2): 12-18
  6. Swadron (2019) Pulmonary 1, CCME Emergency Medicine Board Review, accessed 5/28/2019
  7. Swadron and Herbert in Herbert (Feb, 2016) EM:Rap C3
  8. Pollart (2011) Am Fam Physician 84(1): 40-7 [PubMed]

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