Overview

Management of acute asthma is determined by the severity of the exacerbation. For a patient with a suspected asthma exacerbation, immediately perform a rapid severity assessment to determine initial management. After starting treatment, perform a more detailed secondary severity assessment to determine subsequent management. See Summary of management of acute asthma for a summary of management.

The most important indicators of severity in acute asthma are the patient’s general appearance or mental state, and work of breathing (eg accessory muscle use, chest wall recession in children).

While individual features can help identify the severity of an asthma exacerbation, assessing multiple signs and symptoms gives a better indication of severity. Of particular note:

• Wheezing is an unreliable indicator of the severity of an acute asthma exacerbation. In severe acute asthma, wheeze may be essentially absent (‘silent chest’), and only become apparent as the airway obstruction is relieved.
• Cyanosis is only visible with marked hypoxaemia; it indicates life-threatening acute asthma, but its absence does not exclude life-threatening acute asthma.
• Pulsus paradoxus is not a reliable indicator of the severity of acute asthma.

Continuous reassessment of severity and monitoring of response to therapy is critical. If the patient is not responding to treatment at the assessed level of severity, treat according to the next level.

The severity category can change with time, either as more information becomes available (eg results of pulse oximetry, spirometry or blood gases) or because the patient’s condition has improved or deteriorated.