Acute asthma: management

Acute asthma: management

The British Thoracic Society (BTS) classify patients with acute asthma into moderate, severe or life-threatening categories.


Note that a patient having any one of the life-threatening features should be treated as having a life-threatening attack.

A fourth category, 'Near-fatal asthma', is also recognised characterised by a raised pCO₂

raised pCO2

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and/or requiring mechanical ventilation with raised inflation pressures.

Further assessment

• the BTS guidelines recommend arterial blood gases for patients with oxygen sats < 92%
  arterial blood gases for patients with oxygen sats < 92%
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• a chest x-ray is not routinely recommended, unless:
  • life-threatening asthma
  • suspected pneumothorax
  • failure to respond to treatment

Management

• admission
  • all patients with life-threatening should be admitted in hospital
  • patients with features of severe acute asthma should also be admitted if they fail to respond to initial treatment.
  • other admission criteria include a previous near-fatal asthma attack
    previous near-fatal asthma attack
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    , pregnancy
    Pregnant women who have a severe asthma attack should be admitted to hospital, even if they initially improve with treatment
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    Importance: 98
    , an attack occurring despite already using oral corticosteroid and presentation at night
• oxygen
  • if patients are hypoxaemic, it is important to start them on supplemental oxygen therapy
  • if patients are acutely unwell they should be started on 15L of supplemental via a non-rebreathe mask, which can then be titrated down to a flow rate where they are able to maintain a SpO‚‚ 94-98%
    SpO‚‚ 94-98%
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    .
• bronchodilation with short-acting beta‚‚-agonists (SABA)
  • high-dose inhaled SABA e.g. salbutamol, terbutaline
  • in patients without features of life-threatening or near-fatal asthma, this can be given by a standard pressurised metered-dose inhaler (pMDI) or by an oxygen-driven nebulizer
  • in patients with features of a life-threatening exacerbation of asthma, nebulised SABA
    nebulised SABA
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    is recommended
• corticosteroid
  • all patients should be given 40-50mg of prednisolone orally
    prednisolone orally
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    (PO) daily, which should be continued for at least five days or until the patient recovers from the attack
  • during this time, patients should continue their normal medication routine including inhaled corticosteroids.
• ipratropium bromide: in patients with severe or life-threatening asthma
  ipratropium bromide: in patients with severe or life-threatening asthma
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  , or in patients who have not responded to beta2-agonist and corticosteroid treatment, nebulised ipratropium bromide, a short-acting muscarinic antagonist
• IV magnesium sulphate
  • the BTS notes that the evidence base is mixed for this treatment that is now commonly given for severe/life-threatening asthma
• IV aminophylline may be considered following consultation with senior medical staff
• patients who fail to respond require senior critical care support
  senior critical care support
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  and should be treated in an appropriate ITU/HDU setting. Treatment options include:
  • intubation and ventilation
    intubation and ventilation
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  • extracorporeal membrane oxygenation (ECMO)

Criteria for discharge

• been stable on their discharge medication (i.e. no nebulisers or oxygen) for 12-24 hours
  stable on their discharge medication (i.e. no nebulisers or oxygen) for 12-24 hours
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• inhaler technique checked and recorded
  inhaler technique checked and recorded
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• PEF >75% of best or predicted
  PEF >75% of best or predicted
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+PassMedicine Notes

The British Thoracic Society (BTS) classify patients with acute asthma into moderate, severe or life-threatening categories.

Moderate_ Severe_ Life-threatening | PEFR 50-75% best or predicted Speech normal RR < 25 / min Pulse < 110 bpm _ PEFR 33 - 50% best or predicted Can't complete sentences RR > 25/min Pulse > 110 bpm _ PEFR < 33% best or predicted Oxygen sats < 92% 'Normal' pCO2 (4.6-6.0 kPa) Silent chest, cyanosis or feeble respiratory effort Bradycardia, dysrhythmia or hypotension Exhaustion, confusion or coma|

Note that a patient having any one of the life-threatening features should be treated as having a life-threatening attack.

A fourth category, 'Near-fatal asthma', is also recognised characterised by a raised pCO2 and/or requiring mechanical ventilation with raised inflation pressures.

Further assessment

• the BTS guidelines recommend arterial blood gases for patients with oxygen sats < 92%
• a chest x-ray is not routinely recommended, unless:
• life-threatening asthma
• suspected pneumothorax
• failure to respond to treatment

Management

• admission
• all patients with life-threatening should be admitted in hospital
• patients with features of severe acute asthma should also be admitted if they fail to respond to initial treatment.
• other admission criteria include a previous near-fatal asthma attack, pregnancy, an attack occurring despite already using oral corticosteroid and presentation at night
• oxygen
• if patients are hypoxaemic, it is important to start them on supplemental oxygen therapy
• if patients are acutely unwell they should be started on 15L of supplemental via a non-rebreathe mask, which can then be titrated down to a flow rate where they are able to maintain a SpO‚‚ 94-98%.
• bronchodilation with short-acting beta‚‚-agonists (SABA)
• high-dose inhaled SABA e.g. salbutamol, terbutaline
• in patients without features of life-threatening or near-fatal asthma, this can be given by a standard pressurised metered-dose inhaler (pMDI) or by an oxygen-driven nebulizer
• in patients with features of a life-threatening exacerbation of asthma, nebulised SABA is recommended
• corticosteroid
• all patients should be given 40-50mg of prednisolone orally (PO) daily, which should be continued for at least five days or until the patient recovers from the attack
• during this time, patients should continue their normal medication routine including inhaled corticosteroids.
• ipratropium bromide: in patients with severe or life-threatening asthma, or in patients who have not responded to beta2-agonist and corticosteroid treatment, nebulised ipratropium bromide, a short-acting muscarinic antagonist
• IV magnesium sulphate
• the BTS notes that the evidence base is mixed for this treatment that is now commonly given for severe/life-threatening asthma
• IV aminophylline may be considered following consultation with senior medical staff
• patients who fail to respond require senior critical care support and should be treated in an appropriate ITU/HDU setting. Treatment options include:
• intubation and ventilation
• extracorporeal membrane oxygenation (ECMO)

Criteria for discharge

• been stable on their discharge medication (i.e. no nebulisers or oxygen) for 12-24 hours
• inhaler technique checked and recorded
• PEF >75% of best or predicted