Asthma: Acute Severe

Key points

• Stratify: moderate PEFR 50-75% best/predicted; severe PEFR 33-50%, cannot complete sentences, RR over 25, pulse over 110; life-threatening PEFR under 33%, SpO2 under 92%, silent chest/cyanosis/poor effort, bradycardia/arrhythmia/hypotension, exhaustion/confusion/coma.
• ANY one life-threatening feature → treat as life-threatening.
• Immediate treatment: oxygen to keep SpO2 94-98%; nebulised salbutamol 5 mg (oxygen-driven; repeat every 15-30 min or give continuously 5-10 mg/hour); add nebulised ipratropium 0.5 mg in acute severe or life-threatening attacks; prednisolone 40-50 mg orally (or IV hydrocortisone 100 mg if unable to take oral), continued for at least 5 days.
• If not responding: IV magnesium sulphate 1.2-2 g over 20 min; discuss with a senior clinician/ICU. Little evidence for IV aminophylline; consider IV salbutamol. Give no sedatives.

Decision points in this pathway

• ANY life-threatening feature? (PEFR < 33% · sats < 92% · silent chest · bradycardia/hypotension · exhaustion/confusion)
• Not responding?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.