Acute severe asthma

Also known as status asthmaticus.
This is a medical emergency caused by an abrupt and severe attack of asthma. 

 

Assessment of severity

Moderate acute asthma

• Increasing symptoms
• Peak flow > 50-75% best or predicted
• No features of acute severe asthma

Severe acute asthma
Any one of the following:

• Peak flow 33-50% best or predicted
• Respiratory rate ≥ 25/min
• Heart rate ≥ 110/min
• Inability to complete sentences in one breath

Life-threatening acute asthma
Any one of the following, in a patient with severe asthma:

• Peak flow < 33% best or predicted
• Arterial oxygen saturation (SpO₂) < 92%
• Partial arterial pressure of oxygen (PaO₂) < 8 kPa
• Normal partial arterial pressure of carbon dioxide (PaCO₂) (4.6–6.0 kPa) (type 1 respiratory failure)
• Silent chest
• Cyanosis
• Poor respiratory effort
• Arrhythmia
• Exhaustion
• Altered conscious level
• Hypotension

Near-fatal acute asthma

• Raised PaCO₂ (type 2 respiratory failure)
• Requiring mechanical ventilation 
• Requiring mechanical ventilation with raised inflation pressures

 

Management

• Airway management
• Tracheal intubation
• Mechanical ventilation