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Information ⬇

Author: Swapna Mandal

  • Asthma (Box 60.1) is one of the commonest causes of breathlessness and wheeze, but other causes should be considered, especially if the response to initial treatment is slow (Table 60.1).
  • The severity of an attack is easily underestimated (Table 60.2).
  • It is important to establish the severity of the exacerbation to monitor progress and determine if early involvement of the intensive care team is required.

Priorities ⬆ ⬇

Outline

Is This Acute Asthma? If So, How Severe?!!navigator!!

Many other diseases can mimic acute asthma (Table 60.1). Important diagnoses to consider include:

  • An exacerbation of chronic obstructive pulmonary disease (Chapter 61). The patient tends to be older, with a smoking history.
  • Upper airway obstruction (Chapter 59). PEF is disproportionately lower than the FEV1.
  • Vocal cord dysfunction. Symptoms can be similar to asthma, but usually the periods of breathlessness are short, with difficulty in inspiration (as opposed to expiration in asthma).
  • Anaphylaxis may also present with wheeze and breathlessness, but typically there are additional features such as urticarial rash and hypotension (Chapter 38).

The severity of acute asthma can be judged by the clinical features and PEF (Table 60.2).

Immediate management (Figure 60.1)Immediate management (Figure 60.1)
  • All patients presenting with an acute exacerbation of asthma should receive oxygen therapy to maintain an arterial oxygen saturation between 94–98%.
  • High-dose nebulized β-agonists (5 mg salbutamol) should be given as quickly as possible (the nebulizer should preferably be driven by oxygen); doses can be repeated every 15–30 min.
  • Ipratropium bromide (500 μgm 6-hourly) can be given to those with acute severe or life-threatening asthma, or in those who have a poor initial response to salbutamol.
  • Corticosteroids should be administered immediately. Either 40–50 mg of oral prednisolone daily or hydrocortisone 100 mg 6-hourly IV or IM should be given. Corticosteroids should be given for a minimum of 5 days.
  • In those with acute severe asthma with poor response to initial therapy or life-threatening asthma, a single dose of magnesium sulphate (1.2–2g IV over 20 min) can be given.
  • Aminophylline may be considered in those with life-threatening asthma. A loading dose of 5 mg/kg should be given parenterally over 20 minutes (omit if the patient is on oral aminophylline) followed by an infusion of 0.5 mg/kg/h.
  • Consider referral to ITU if: hypoxia worsens, hypercapnia or acidaemia is evident, the patient is exhausting, GCS is deteriorating or PEF is deteriorating.
  • Non-invasive ventilation (NIV) is not recommended for asthma and should not be given outside the intensive care environment.

Other Treatments!!navigator!!

  • Antibiotics may be considered in those with signs of infection but should not be routinely used in the management of acute asthma.
  • Patients who are dehydrated may require IV fluids.
Investigations and monitoring (Table 60.3)Investigations and monitoring (Table 60.3)

Whilst treating these patients, investigations can be initiated, these include:

  • PEF (once the patient is stabilized PEF should continue to be monitored)
  • Arterial blood gas (ABG)
  • Serum electrolytes (as patients will be receiving salbutamol they may become hypokalaemic)
  • Chest X-ray to rule out exacerbating factors including pneumothorax or pneumonia

Further Management ⬆ ⬇

All patients with life-threatening asthma must be admitted. Those with moderate or acute severe asthma may be considered for discharge home (Figure 60.2). Pitfalls to avoid are summarized in Box 60.2.

Asthma in Pregnancy

Asthma control can deteriorate in pregnancy. Pregnant women with acute asthma should be treated in exactly the same manner as those who are not pregnant. In addition, there should be continuous foetal monitoring and involvement of the obstetric team.

Further Reading ⬆

British Thoracic Society and Scottish Intercollegiate Guidelines Network (2016) British guideline on the management of asthma: A national clinical guideline. https://www.brit-thoracic.org.uk/document-library/clinical-information/asthma/btssign-asthma-guideline-2016/