Acute Asthma

Question 1

What is acute asthma?

Answer 1

An acute exacerbation of asthma is characterised by a rapid deterioration in symptoms.

This could be triggered by any of the typical asthma triggers such as infection, exercise or cold weather.

Question 2

Presentation

Answer 2

• Progressively worsening shortness of breath
• Use of accessory muscles
• Fast respiratory rate (tachypnoea)
• Symmetrical expiratory wheeze on auscultation
• The chest can sound tight on auscultation with reduced air entry

Question 3

Moderate acute asthma

Answer 3

PERF 50-70% predicted

Question 4

Severe acute asthma

Answer 4

• PERF 33-50% predicted
• Resp rate more than or equal to 25
• Heart rate > 110
• Unable to complete sentences

Question 5

Life- threatening Acute Asthma

Answer 5

PEFR <33%
Sats <92%
Becoming tired
No wheeze. This occurs when the airways are so tight that there is no air entry at all. This is ominously described as a “silent chest”.
Haemodynamic instability (i.e. shock)

Question 6

Treatment for Moderate Acute Asthma

Answer 6

Nebulised beta-2 agonists (i.e. salbutamol 5mg repeated as often as required)

Nebulised ipratropium bromide

Steroids. Oral prednisolone or IV hydrocortisone. These are continued for 5 days

Antibiotics if there is convincing evidence of bacterial infection

Question 7

Treatment for Severe Acute Asthma

Answer 7

Oxygen if required to maintain sats 94-98%

Aminophylline infusion

Consider IV salbutamol

Question 8

Treatment for Life Threatening Acute Asthma

Answer 8

IV magnesium sulphate infusion

Admission to HDU / ICU

Intubation in worst cases – however this decision should be made early because it is very difficult to intubate with severe bronchoconstriction

Question 9

ABGs in Asthma

Answer 9

Initially patients will have a respiratory alkalosis as tachypnoea causes a drop in CO2.

A normal pCO2 or hypoxia is a concerning sign as it means they are tiring and indicates life threatening asthma.

A respiratory acidosis due to high CO2 is a very bad sign in asthma.

Question 10

Monitoring Acute Asthma

Answer 10

Respiratory rate
Respiratory effort
Peak flow
Oxygen saturations
Chest auscultation