Exacerbation of asthma

Question 1

What is an acute exacerbation of asthma?

Answer 1

Asthma exacerbation is an acute or subacute episode of progressive worsening of symptoms of asthma, including shortness of breath, wheezing, cough, and chest tightness.
Exacerbations are marked by decreases from baseline in objective measures of pulmonary function, such as peak expiratory flow rate and FEV1.

Question 2

The severity of exacerbation of asthma

Answer 2

Mild
Moderate
Severe
Life-threatening

Question 3

Features of mild exacerbation of asthma

Answer 3

Dyspnoea only with exertion
Peak expiratory flow rate (PEFR) >70% of predicted or personal best
Oxygen saturation >95%
Prompt relief with inhaled short-acting beta-2 agonist.

Question 4

Features of moderate exacerbation of asthma

Answer 4

Dyspnoea limits usual daily activity
PEFR 40% to 69% of predicted or personal best
Oxygen saturation 91% to 95%
Relief from frequent inhaled short-acting beta-2 agonist
Some symptoms last for 1 to 2 days after treatment is started.

Question 5

Features of severe exacerbation of asthma

Answer 5

Dyspnoea at rest (interferes with conversation)- inability to complete sentences
Pulse >110 bpm
RR > 25/min
PEFR <40% of predicted or personal best
Oxygen saturation can be <95%
Partial relief from frequent inhaled short-acting beta-2 agonist
Some symptoms last for >3 days after treatment is started.

Question 6

Features of life-threatening exacerbation of asthma

Answer 6

Too dyspnoeic to speak
PEFR <25% of personal best
Oxygen saturation can be <92%
Minimal or no relief from frequent inhaled short-acting beta-2 agonist
Exhaustion (altered conscious level) 
Silent chest 
Hypotension 
Arrhythmias  
Presence of cyanosis and respiratory acidosis despite tachypnoea indicates need for urgent ICU admission.

Question 7

Signs of exacerbation of asthma

Answer 7

Wheezing, widespread or polyphonic
Pulsus paradoxus (fall of systolic BP > 10mmHg during inspiration)
Tachypnoea and/or tachycardia
Visible efforts to breathe, including upright posture, pursed lips and difficulty speaking.
Expiration phase prolonged
Hyper-inflated chest
Hyper-resonant percussion

Question 8

Investigations to confirm exacerbation of asthma

Answer 8

PEFR
Oxygen Sats
ABG
Chest X-ray

Question 9

Risk factors for asthma exacerbation

Answer 9

Viral infection 
Current smoker 
Atopic eczema
Exposure to allergens
Poor indoor air quality 
Environmental irritants
Non-compliance to asthma medications
History of hospitalisation for asthma exacerbations
Use of oral corticosteroids 
GORD 
History of asthma

Question 10

Treatment of mild exacerbation

Answer 10

SABA-
salbutamol inhaled: (100 micrograms/dose metered-dose inhaler) 400-800 micrograms (4-8 puffs) every 20 minutes for up to 4 hours, then every 1-4 hours when required;
Or 2.5 to 5 mg nebulised every 20 minutes for 3 doses, followed by 2.5 to 10 mg every 1-4 hours when required;
Or 10-15 mg/hour nebulised continuously
WITH
Oral corticosteroids-
Prednisolone: 40-80 mg/day orally given in 1-2 divided doses
Treatment course: at least 5 days and until recovery from acute exacerbation; this course does not need tapering before cessation.

Question 11

Treatment of moderate to severe exacerbation

Answer 11

Oxygen (>90 achieved)
Salbutamol (same as mild exacerbation)
Oral prednisolone (same as mild exacerbation)
Inhaled Anti-Muscarinics: Ipratropium inhaled: 500 micrograms nebulised given in combination and dosed with each administration of short-acting beta-2 agonist (usually every 20 minutes for 3 doses and then when required)
Magnesium sulfate: 2 g intravenously given over 20 minutes

Question 12

Should Magnesium sulfate be used in all asthma exacerbations?

Answer 12

Intravenous magnesium sulfate is not recommended for routine use in asthma exacerbations.
However, a single infusion has been shown to reduce hospital admission rates in certain patients, including adults with an FEV1 25% to 30% of predicted and those who fail initial treatment.
Magnesium is thought to inhibit calcium influx into airway smooth muscle, thereby acting as a bronchodilator.

Question 13

Treatment of life-threatening asthma exacerbation

Answer 13

ICU admission
Oxygen plus consider assisted ventilation
SABA + SAMA (as described earlier)
Systemic corticosteroid:
1st line: Hydrocortisone: 100 mg intravenously every 8 hours
2nd: Prednisolone
Magnesium
Heliox- Co-administration of a helium-oxygen gas mixture (heliox) and bronchodilators may be helpful in selected patients with respiratory failure but is controversial
Mechanical ventilation: Mechanical ventilation should be given to patients who are refractory to therapy and remain in severe respiratory distress.
With fever or thick sputum: Antibiotic therapy

Question 14

Complications of asthma exacerbation

Answer 14

Pneumonia
Pneumothorax
Respiratory failure

Question 15

How can you manage an asthma exacerbation whilst waiting for an ambulance?

Answer 15

Using a salbutamol metered-dose inhaler with a spacer has been shown to be as effective as jet nebuliser therapy.
Different treatment regimens can be used, from one puff every five minutes, to six puffs in the spacer at once.

Question 16

What is the SBAR tool?

Answer 16

SBAR communication tool –
situation,
background,
assessment,
recommendation
SBAR helps to provide a structure for an interaction that helps both the giver of the information and the receiver of it.
It helps the giver by ensuring they have formulated
their thinking before trying to communicate it to someone else.
The receiver knows what to expect and it helps to ensure the giver of information is not interrupted by the receiver
with questions that will be answered later on in the conversation.