Asthma, acute

J45.0/1/8/9

GENERAL MEASURES

Ensure adequate hydration.
In patients presenting with asthma without an atopic allergic background, the diagnosis of pulmonary oedema due to left ventricular heart failure should be considered.
Patients with severe asthma (characterised by one or more of: unable to complete sentences in one breath, altered mental status, paradoxical chest movement, absence of wheezes, peak expiratory flow (PEF) <50% of predicted/personal best - see PEF charts in Appendix V) should ideally be closely monitored in a High Care or an Intensive Care Unit.

MEDICINE TREATMENT

If hypoxaemic

  • Oxygen, if saturation <94%.

LoEI [1]

  • Salbutamol, nebulisation, 5 mg.
    • Initially nebulise continuously (refill the nebuliser reservoir every 20 minutes) at a flow rate of 6–8 L/minute until PEF >60% of predicted or >60% of personal best (see PEF charts in Appendix V).
    • Once patient reaches 60% of their predicted/personal best PEF, repeat salbutamol 5 mg 4 hourly.

LoEI [2]

Severe exacerbations:

ADD

  • Ipratropium bromide, nebulisation 0.5 mg.
    • Combination salbutamol/ipratropium UDV, 5/0.5 mg preferred.

LoEII [3]

Mild to moderate exacerbations, if response to nebulised salbutamol is poor:

ADD

  • Ipratropium bromide, nebulisation 0.5 mg with the 1st and subsequent refills of the nebuliser reservoir.

LoEII [4]

  • Corticosteroids (intermediate-acting) e.g.:
    • Prednisone, oral, 40 mg daily (start 1 hour of presentation) for 7 days.

LoEIII [5]

OR

In patients who cannot use oral therapy, or are vomiting or are suspected of having gastric atony from a severe asthma exacerbation:

  • Hydrocortisone, IV, 100 mg 6 hourly.

LoEII [6]

Once oral medication can be taken, switch to:

  • Corticosteroids (intermediate-acting) e.g.:
    • Prednisone, oral, 40 mg daily for 7 days.

Continue nebulisations until PEF returns to 80% of predicted/ personal best, at which point the patient can be converted to:

  • Salbutamol, MDI, 200 mcg, as needed.

LoEIII [7]

AND

  • Inhaled corticosteroid (ICS), e.g.:
    • Budesonide, inhalation, 200 mcg whenever salbutamol is taken.

In patients on protease inhibitors, replace ICS with beclomethasone:

  • Beclomethasone, inhalation, 200 mcg whenever salbutamol is taken.

LoEIII [8]

Monitor response with PEF and clinical signs. Patients who fail to respond within 1 hour (symptomatic improvement and PEF >60% of predicted/personal best):

  • Exclude upper airway obstruction/stridor, pneumothorax, and anaphylaxis.
  • Discuss management with a specialist.
  • Intubation and ventilator support may be required.
  • If referral to another facility is required, the patient needs to be stabilised prior to transfer and transported by the appropriate level of transport -discuss with the referral centre.

In patients with a poor response:

ADD

  • Magnesium sulfate, IV, 2 g in 100mL sodium chloride 0.9%, as a single dose, administered over 20 minutes.

LoEI [9]

Intravenous magnesium, single dose, has been shown to reduce the rate of hospitalisation.

There is good evidence to recommend against the use of intravenous aminophylline in acute asthma as its use together with high-dose nebulised ß2-agonists does not result in significant additional bronchodilation and leads to a significant increase in toxicity (vomiting and dysrhythmias).

LoEI [10]

Intercurrent bacterial respiratory infections

Bacterial infections are seldom present in acute exacerbations of asthma and yellow sputum production is usually related to presence of eosinophils. Antibiotics do not play a role in the management of asthma unless there is air space consolidation on CXR. See: Pneumonia, community acquired.