Acute asthma exacerbation

Background

• 3 questions
  • 1. Does this pt have asthma?
    • Most wheezing in pt <3yr is not asthma
  • 2. What is the severity?
  • 3. Is there a treatable preciptant?

Diagnosis

• Dyspnea, wheezing, and cough
• Prolonged expiration
• Accessory muscle use

Work-Up

Consider CXR if:

1. Fever > 102.2
2. Worsening sx
3. Poor response to Rx
4. 1st wheeze

Treatment

1. Albuterol
   1. Continuous = 0.15mg/kg/hr (max 25mg/hr)
2. Ipratropium 0.5mg
3. Steroids
   1. Prednisone
      1. Inpatient - 1mg/kg Q6hr
      2. Outpt - 1mg/kg QD x 4days
   2. Dexamethasone PO 0.6mg/kg (max 16kg), 2nd dose 36hr after
4. Magnesium 75mg/kg (max 235gm IV over 20minutes)
5. Epi (1:1000) 0.01mg/kg (max 0.5mg) Q20min x 3 SQ OR
6. Terbutaline SQ = same as Epi (max 0.25)
   1. • Caution in elderly/CHF
7. Ketamine
8. Non-invasive Ventilation
   1. Consider as alternative to intubation
   2. Alleviates muscle fatigue which leads to larger tidal volumes
   3. Maximize inspiratory support
      1. Inspiratory pressure 8
      2. PEEP 0-3
9. Intubation
   1. Tidal volume 8cc/kg ideal wt
   2. PEEP 0
   3. Assist-control ventilation
   4. Flow rate 80
   5. Resp rate
      1. Start slow to avoid air-trapping
      2. RR ~ 10
      3. Make sure plateau pressure <30
         1. If >30 must lower resp rate
   6. Use bronchodilators even when intubated
   7. If pt desats/codes while on ventilator:
      1. Immediately disconnect from vent
         1. Allows for expiration of stacked breaths
      2. Connect to BVM
         1. Allows for troubleshooting of ventilator
      3. Verify tube placement (end-tidal CO2)
      4. Verify if tube is obstructed
         1. Place suction catheter
      5. Is this a tension ptx?
         1. Ultrasound; tx if necessary

Disposition

• Peak Flow = (30 x age (yrs)) + 30
• Severe = <50% predicted Peak flow
• Severe = <91% SaO2

Source

Rosen's, Tintinalli, EMcrit Podcast 15