management of acute severe asthma in an adult

Last edited 11/2019

Management of acute asthma in adults

Criteria for admission

• Admit patients with any feature of a life-threatening or near-fatal asthma attack
• Admit patients with any feature of a severe asthma attack persisting after initial treatment
• Patients whose peak flow is greater than 75% best or predicted one hour after initial treatment may be discharged from ED, unless there are other reasons why admission may be appropriate

Treatment of acute asthma in adults:

Oxygen

• Give controlled supplementary oxygen to all hypoxaemic patients with acute severe asthma titrated to maintain an SpO2 level of 94-98%. Do not delay oxygen administration in the absence of pulse oximetry but commence monitoring of SpO2 as soon as it becomes available
• In hospital, ambulance and primary care, nebulisers for giving beta 2 agonist bronchodilators should preferably be driven by oxygen

Beta 2 agonist bronchodilators

• Use high-dose inhaled beta 2 agonists as first line agents in patients with acute asthma and administer as early as possible. Reserve intravenous beta2 agonists for those patients in whom inhaled therapy cannot be used reliably
  • In patients with acute asthma with acute severe or life-threatening features the nebulised route (oxygen-driven) is recommended.
• In patients with severe asthma that is poorly responsive to an initial bolus dose of beta2 agonist, consider continuous nebulisation with an appropriate nebuliser.

Ipratropium bromide

• Add nebulised ipratropium bromide (0.5 mg 4- 6 hourly) to beta2 agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to beta2 agonist therapy

Steroid therapy

• Give steroids in adequate doses to all patients with an acute asthma attack.
• Continue prednisolone (40-50 mg daily) until recovery (minimum 5 days)

Other therapies

• Consider giving a single dose of IV magnesium sulphate to patients with acute severe asthma (PEF <50% best or predicted) who have not had a good initial response to inhaled bronchodilator therapy.
  • Magnesium sulphate (1.2-2 g IV infusion over 20 minutes) should only be used following consultation with senior medical staff.

Routine prescription of antibiotics is not indicated for patients with acute asthma

Referral to intensive care

Refer any patient:

• requiring ventilatory support
• with acute severe or life-threatening asthma, who is failing to respond to therapy, as evidenced by:
  • deteriorating PEF
  • persisting or worsening hypoxia
  • hypercapnia
  • ABG analysis showing reduced pH or increased H+
  • exhaustion, feeble respiration
  • drowsiness, confusion, altered conscious state
  • respiratory arrest

Follow-up

• It is essential that the patient's primary care practice is informed within 24 hours of discharge from the emergency department or hospital following an asthma attack.
• Keep patients who have had a near-fatal asthma attack under specialist supervision indefinitely
• A respiratory specialist should follow up patients admitted with a severe asthma attack for at least one year after the admission.

Reference:

• SIGN (July 2019). British Guideline on the management of asthma (SIGN158)