Acute asthma in adults - emergency department
Acute asthma exacerbations range from self‑limited episodes to life‑threatening ventilatory failure. Emergency department (ED) care focuses on rapid recognition of severity, reversal of airflow obstruction and hypoxaemia, close monitoring, and timely escalation to critical care.
This summary follows current UK guidance (NICE/BTS‑SIGN pathway, Resuscitation Council, RCEM) and highlights practical, exam‑relevant actions.
Pathophysiology
- Exacerbations result from acute airway inflammation with bronchospasm, mucosal oedema and increased secretions, producing variable airflow obstruction.
- Rising PaCO2, falling respiratory effort or an altered conscious level are late and ominous signs of ventilatory failure.
Recognition and severity classification
- Assess severity by combining clinical features, SpO2 and peak expiratory flow (PEF) when safe and feasible.
- Measure SpO2 and, if possible, PEF before bronchodilator therapy; if PEF cannot be performed, document this and treat based on clinical severity (NICE NG245).
- Key clinical red flags that require immediate treatment: inability to speak in full sentences, use of accessory muscles, silent chest, cyanosis, exhaustion, altered consciousness, new arrhythmia or hypotension.
Severity bands (practical)
Initial assessment and triage (first minutes)
- Perform a rapid clinician assessment to identify life‑threatening features and treat without delay (NICE/Resuscitation Council).