| Mild–moderate (all of): | Severe (any of): | Life-threatening (any of): | |
| Consciousness | Alert | N/A | Drowsy or unconscious |
| Speech | Can finish a sentence in one breath | Can only speak a few words in one breath | Cannot speak |
| Posture | Can walk, sit up straight, lie flat | Unable to lie flat due to dyspnoea Sitting hunched forward | Collapsed or exhausted |
| Breathing | Respiratory distress is not severe | Paradoxical chest wall movement: inward movement on inspiration and outward movement on expiration (chest sucks in when person breathes in) or Use of accessory muscles of neck or intercostal muscles or ‘tracheal tug’ during inspiration or Subcostal recession (‘abdominal breathing’) | Severe respiratory distress or Poor respiratory effort |
| Skin colour | Normal | N/A | Cyanosis |
| Respiratory rate | <25 breaths/min | ≥25 breaths/min | Bradypnoea (indicates respiratory exhaustion) |
| Heart rate | <110 beats/min | ≥110 beats/min | Cardiac arrhythmia or Bradycardia (may occur just before respiratory arrest) |
| Chest auscultation | Wheeze or Normal lung sounds
| N/A | Silent chest or Reduced air entry |
| Oxygen saturation | >96% | 92–96% | <92% or Clinical cyanosis |
Additional information
N/A: Not applicable – may be the same as moderate and does not determine severity category