Acute Asthma Exacerbation

Acute Asthma Exacerbation – Stacy Blank

Background

  • History of asthma or a history concerning for asthma
  • Progressive worsening of symptoms:  dyspnea, chest tightness, wheezing, and cough
  • Physical exam with wheezing, poor air movement (if severe obstruction may just not hear good breath sounds, which is worse than wheezing), tachypnea, increased work of breathing (accessory muscle use), hypoxemia
  • Often use of peak flows is cited in the literature (PEF <200 L/min or PEF <50% predicted indicates severe obstruction, PEF <70% predicted indicates moderate exacerbation)
    • These can be ordered as an RT order and may be useful; although often does not change management acutely

 

Evaluation

  • 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, HF, PE)
    • CXR to rule out underlying process (PNA, PTX, atelectasis)
    • ABG/VBG not routinely needed but if pt 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

  • Continuous pulse ox with oxygen therapy to maintain O2 >92 %
  • Continuous albuterol nebulizer or Duonebs until able to space to q1h>>q2h, etc (ED almost always starts with continuous if pt is severe enough to warrant inpatient management)
  • Steroids with dosing base on severity of illness (there is no data behind exact dosing of steroids).  Start with IV methylpred 125mg q6h in severe exacerbation/ICU patients. Can start with oral prednisone 60mg q12h in less severe exacerbation/floor pts. Plan to transition from IV to PO and then likely to send pt home to finish course of 40-60 mg pred daily for 5-7 days.
  • IV mag sulfate 4g over 20 minutes for severe exacerbation (anyone going to the ICU)
  • Keep pt NPO until off continuous nebs/respiratory effort is improved to safely swallow, consider IV fluids with pt’s comorbidities (HFrEF, renal disease) vs. increased insensible losses with resp effort
  • If pt is not responding to therapies, has worsening respiratory status or blood gas concerning for respiratory acidosis: use BiPAP in patients whose mental status is appropriate vs. intubation/MV (i.e., it’s time to call your MICU fellow)
  • Note:  We do not start empiric antibiotics unless there is concern for bacterial infection

 

Prior to discharge:

  • Ensure that pt is on appropriate controller medications (see outpatient management)
  • Evaluate for causes of acute exacerbation to prevent future events (noncompliance, resp viruses, allergies, exposures, etc.)