Acute Asthma Exacerbation

Rafael J. Fernandez III, Stacy McIntyre, Spencer Scott

Presentation

  • Sub-acute to acute progressive worsening of dyspnea, chest tightness, wheezing, and cough 
  • Important historical cues: Prior hx of asthma, adherence to controller medications, triggers (exercise, allergens, cold)
  • Risk stratifying: Hx of intubations/exacerbations, recent steroid course for exacerbation 
  • Physical exam: wheezing, poor air movement, tachypnea, ↑ work of breathing, hypoxemia

Evaluation

  • Generally aimed at ruling out causes for exacerbation and other diagnoses: 
    • Consider EKG, trop, BNP, D-dimer to assess for cardiac cause (ACS, CHF, PE) 
    • CXR to rule out underlying process (PNA, PTX, atelectasis) 
    • ABG/VBG not routinely needed unless ill-appearing, tachypneic, or lethargic/altered

Dangerous signs and possible ICU if: 

  • Tachypnea >30 and/or significantly increased work-of-breathing 
  • Hypercapnia or even normocapnia (these pts are usually hyperventilating; a normal CO2 in a severe asthma exacerbation could indicate impending respiratory failure) 
  • Altered mental status 
  • Requiring continuous nebulizers

Management

  • Frequent re-evaluation is key. Reassess q1h after treatment initiation 
  • ABC: if not protecting airway, intubate and admit to ICU 
  • Peak expiratory flow (Order in EPIC “Peak Flow Measurement”) 
    • If pt cannot do it: Consider A/VBG if ill-appearing, tachypneic, lethargic/AMS, or thinking about engaging ICU 
  • SpO2 goal 93-95%. Avoid hyperoxia

Mild/Moderate

Severe

ICU
Assessment Physical Exam
Wheezing
Phrase Dyspnea
W/o accessory muscle use
Tachypnea
Tachycardia 100-120

Objective Data
O2 Sat 90-95% on RA
PEF > 50% Predicted 		Physical Exam
Wheezing
Single Word Dyspnea
+ Accessory muscle use
Tripoding
Tachypnea >30
Tachycardia >120

Objective Data
O2 Sat <90% on RA
PEF < 50% Predicted 		Physical Exam
Drowsy, AMS, silent chest
Increased work of breathing

Objective Data
CO2 on Blood Gas:
- Low at first (Hyperventilation)
- Normal or High → Impending Respiratory Failure

Requiring Continuous Nebulizers to maintain O2 sats
Management SABA ± Ipratropium
Supplemental O2 to 93-95%
Begin Oral Prednisone 40mg 		SABA & Ipratropium Nebulizer
Supplemental O2 to 93-95%
Begin Oral Prednisone 40-60mg

Consider:
IV Magnesium 4g 20 minutes
Consider High Dose ICS 		Continuous DuoNebs
IV Methylprednisolone 125 q6hr

IV Magnesium 4g 20 minutes
Consider High Dose ICS

NPO

IV Fluids to make up insensible losses (consider comorbidities though)

Adapted from GINA 2024 Guidelines (https://www.ginasthma.org)

Further Management

  • Corticosteroids: dosing based on severity of illness (see above) 
    • Transition to PO/lower dose after improving air movement, work of breathing, and gas exchange 
    • Minimum of 5-7 days 
    • No need to taper in general population (Sometimes considered in if persistent wheezing at end of course or multiple severe exacerbations) 
  • No need for empiric antibiotics unless there is concern for bacterial infection, then treat as pneumonia

Prior to discharge

  • Ensure that pt is on appropriate controller medications 
  • Start ICS-LABA (for both reliever and maintenance) 
  • Evaluate for causes of acute exacerbation to prevent future events (noncompliance, resp viruses, allergies, exposures (tobacco), etc.). 
  • Evaluate for asthma inflammatory phenotype after recovery, typically done outpatient (IgE, peripheral eos, ABPA)
  • Can consider writing a simple asthma action plan (https://ginasthma.org/wpcontent/ uploads/2021/05/GINA-Pt-Guide-2021-copy.pdf) 
  • Schedule follow up with PCP vs. pulmonologist for evaluation of outpt regimen
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