Assessment of Severity of Acute Asthma
| Moderate exacerbation of asthma | Acute severe asthma | Life-threatening asthma | |
|---|---|---|---|
| Symptoms | Worsening chest tightness, breathlessness, wheeze, cough | Worsening chest tightness, breathlessness, wheeze, cough | |
| PEF | 50–75% of best/predicted | 33–50% of best/predicted | <33% of best/predicted |
| Physiological variable | RR ≥25 breaths/min HR ≥110 breaths/min | SaO2<92% PaO2<8kPa PaCO2 4.6–6.0kPa | |
| Other signs | Unable to complete sentences in one breath | Reduced GCS Exhaustion Silent chest Poor respiratory effort Arrhythmia |
Adapted from BTS/SIGN guidelines.