Asthma Exacerbation

 

• Investigations

  • O2 sats.
  • Obs: HR, RR.
  • Peak flow rate (PEFR). May not be possible if seriously unwell.
  • ABG if severe: bad sign if there is normal CO2 or ↑CO2, ↓O2, or ↓pH.

• Mild and moderate asthma exacerbations

  Criteria

  • Mild exacerbation: increasing symptoms.
  • Moderate exacerbation: increasing symptoms and PEFR <75%.

  Management

  SABA inhaler through spacer:

  • 4 puffs initially (30s apart), then further 2 (30s apart) every 2 minutes up to 10 puffs.
  • Can repeat every 10-20 minutes if remains symptomatic, otherwise return to 2 puffs QDS PRN dosing.

  If PEFR <75%:

  • Consider O2-driven SABA nebulizer.
  • Prednisolone PO. Start early, and continue for 3 days in children, 5 days in adults, or until recovery if longer.

  Consider stepping up usual treatment and advise to monitor for any PEFR decline.

• Severe asthma exacerbations

  Criteria

  Acute severe asthma

  ≥1 of:

  • PEFR 33-50%.
  • RR>25. >30 if 5-12 years old, >50 if <5 years old.
  • HR>110. >120 if 5-12 years old, >130 if <5 years old.
  • Can't talk fully.

  Life-threatening asthma

  ≥1 of:

  • PEFR <33%.
  • SpO2 <92%, PaO2 <8 kPa, or normal PaCO2.
  • Altered mental status.
  • Arrhythmias, ↓BP.
  • Silent chest or poor respiratory effort, cyanosis.
  • If they are drowsy/sleeping, check if they can be roused to determine if it is pathological.

  Near-fatal asthma

  ↑CO2 or needing ventilation.

  Management

  Basics, SONSIS:

  • Sit up.
  • 100% O2, aiming for SpO2 94-8%.
  • Oxygen-driven, Nebulized SABA ± Ipratropium.
  • Steroids PO/IV. Takes up to 4 hours to have an effect so give early, preferably PO.

  Further options, MAGAS:

  • IV MAGnesium sulfate.
  • IV Aminophylline – including a loading dose if not on theophylline already – or IV SABA.

  ITU transfer if there is ↑CO2 or ventilation is required.

  Discharge when stable, PEFR>75%, and on discharge drugs for 12 hours:

  • Prednisolone PO: at least 3 days in children, 5 days in adults, or until recovery.
  • ICS
  • Written treatment plan.
  • GP visit in 2 days.
  • Outpatient clinic in 4 weeks.