Examination

A thorough examination of the cardio-respiratory system should be made to identify features consistent with an exacerbation of asthma e.g. wheeze on auscultation of the chest, tachypnoea, absence of pyrexia, absence of crepitations, and tachypnoea. Occasionally, the symptoms and findings on chest examination may point to another trigger for a sudden worsening of an alternative diagnosis such as pneumonia, pulmonary oedema, pneumothorax or pulmonary embolus.

Adverse clinical features can identify some patients with severe asthma:

• severe breathlessness (including too breathless to complete sentences in one breath)
• tachypnoea
• tachycardia
• silent chest
• cyanosis
• accessory muscle use
• altered consciousness or collapse.

None of these singly or together is specific, and their absence does not exclude a severe attack.

Chest percussion and tracheal position should be assessed since asthmatics are at risk of developing secondary spontaneous pneumothoraces. Failure to recognise a pneumothorax or tension pneumothorax as the cause of sudden deterioration in asthmatics is associated with a significant mortality. This will be exacerbated if the patient is intubated and ventilated.