Synopsis
Grade an adult asthma attack objectively, deliver oxygen, bronchodilator and steroid treatment without delay, and escalate early when response or blood gases indicate life-threatening disease.
- Treat first and assess in parallel: ABCDE, help, continuous monitoring, oxygen target 94-98%, bronchodilator and systemic corticosteroid.
- Acute severe asthma is any of PEF 33-50%, respiratory rate at least 25/min, heart rate at least 110/min, or inability to complete sentences in one breath.
- Life-threatening features include PEF below 33%, SpO2 below 92%, silent chest, cyanosis, poor effort, arrhythmia, hypotension, exhaustion or altered consciousness.
Key red flags
Increasing symptoms with PEF above 50-75% best/predicted and no acute severe features. Still assess risk and response; prior near-fatal asthma lowers the admission threshold.
Investigation priorities
Objectively grade airflow and response.
Management branches
Any acute severe or life-threatening feature.
- Call senior help; use ABCDE, continuous SpO2/ECG, IV access and document PEF if possible without delaying treatment.
- Give oxygen to SpO2 94-98%. For initial nebulised salbutamol, the 2026 BTS/RCEM/SAM pathway specifies 2.5 mg and SIGN 158 specifies 5 mg; use the current adopted emergency pathway and document the source. Add ipratropium 500 micrograms nebulised in severe/life-threatening disease.
Key medicines
SalbutamolInitial nebulised dose: 2.5 mg in the 2026 BTS/RCEM/SAM emergency pathway; 5 mg in the SIGN 158 acute algorithm. Repeat every 15-30 minutes if response is inadequate; monitored continuous nebulisation at 5-10 mg/hour may be used in refractory severe attacks. Spacer alternative: 4 puffs initially, then 2 puffs every 2 minutes up to 10 puffs.
Ipratropium bromide500 micrograms nebulised with the initial beta2 agonist in acute severe or life-threatening asthma; repeat according to the acute protocol, commonly every 4-6 hours once improving.