Acute Asthma Exacerbation¶

Rafael J. Fernandez III, Stacy McIntyre¶

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
Peak flows can help and are often cited in literature but do not change management acutely, can be useful as baseline for assessing response to therapy.
PEF <200 L/min or PEF <50% predicted indicates severe obstruction, PEF <70% predicted indicates moderate exacerbation)

Generally aimed at ruling out causes for exacerbation and other diagnoses; these are not required but should be considered in pts being admitted for inpatient management:
- 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

Good asthma care requires frequent re-evaluation. Generally, reassess q1h after treatment initiation. If deteriorating, step up the ladder of management
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
Further work-up: Not required, but aimed at ruling out causes of exacerbation and other dx
CBC w/ diff (looking at eosinophils)
CXR to rule out underlying process (PNA, PTX, atelectasis)
Corticosteroids: dosing based on severity of illness
- Oral equivalent to IV (Lancet 1986;1:181-184)
- Transition to PO and lower dose after improving air movement, work of breathing and gas exchange
- Will need minimum of 5-7 days of oral corticosteroids.
- Good data for no need to taper in general population, sometimes considered in someone with multiple severe exacerbations.
Step down SABA-Nebulizer treatments based on wheezing
Inspiratory/Expiratory wheezing q2 -> q3; Mostly Expiratory wheezing q3 -> q4; Minimal Wheezing q4 -> q6 or PRN. (Pediatrics 2000; 106 (5): 1006–12)
No need for empiric antibiotics unless there is concern for bacterial infection, then treat as Pneumonia (see Pneumonia chapters)

Ensure that pt is on appropriate controller medications (see outpatient management)
See outpt management section but consider starting an ICS/LABA as part of SMART (JAMA 2018; 319(14):1485–1496)
Evaluate for causes of acute exacerbation to prevent future events (noncompliance, resp viruses, allergies, exposures, etc.). Evaluate for asthma inflammatory phenotype after recovery (IgE, peripheral eos, ABPA)
Can consider writing a simple asthma action plan (https://ginasthma.org/wp- content/uploads/2021/05/GINA-Pt-Guide-2021-copy.pdf)
Consider follow up with PCP vs. pulmonologist for evaluation of outpt regimen