Tuesday, 11 November 2014

Asthma - treatment

Moderate Severity Asthma Exacerbation
- 4 puffs salbutamol via a spacer, followed by 2 puffs every 2 minutes up to a maximum of 10 puffs
- Nebulisers if no spacer available or if the patient can't use it effectively.

Severe Acute Asthma
Early steroid administration in acute severe asthmatic exacerbations is associated with a reduced need for hospital admission. 

Steroids: Inhaled corticosteroids in the acute attack can help reduce hospitalisation. Little evidence that on discharge they improve things. Corticosteroids within an hour also help
Nebulisers: Allow concurrent oxygen administration.
    A nebuliser takes 15-30 minutes to fully administer the drug. Administering more than 10mg of salbutamol per hour is unlikely to improve effectiveness but may increase side effects, which include tremor and tachycardia. Special delivery systems can deliver “continuous” nebulisers at 10mg per hour but are not usually available in the ED.
  There is no evidence that 5mg nebulisers are superior to 2.5mg nebulisers. 
  Inhaled salbutamol can cause a lactic acidosis, worsening respiratory symptoms.

Salbutamol: No superiority of IV salbutamol over acute asthma. Systemic salbutamol has metabolic effects that may worsen respiratory function in asthma.
   May be helpful if drug not delivered effectively (patient pulling mask off/ poor air entry).
Adrenaline: Nebulised adrenaline has shown no superiority and is a less selective agonist.
Anticholinergic: advocated in cases which are severe, life-threatening, or poorly responsive to ß2 agonist therapy.

Magnesium:    Nebulised MgSO4 has no role
               Limited role for intravenous MgSO4

              2 g Magnesium Sulphate in 100 mls of normal saline given intravenously over 20 minutes

Aminophylline: 5mg/kg over 20minutes loading dose
              0.6mg/kg/hour IV infusion
             If the patient is on maintenance take a baseline theophylline/ aminophylline level before maintenance infusion. 
Furosemide: A theoretical bronchodilator of research interest, not better than nebulised ß2 agonists.

NIV:
There is limited evidence for NIV. This is not currently supported by the British Thoracic Society. The patient must be supervised by the intensivist that can proceed immediately to intubation.



Rapid Sequence Induction
Use at least a size 8.0 diameter
Ketamine --> 1-2mg/kg helps bronchodilate
Avoid atracurium
Disconnect circuit during CPR to allow chest to deflate
Bilateral thoracostomies.

Discharge
Non-pharmacological management:
      Advise parents with asthma about the the dangers to their children of smoking. 
      Weight loss and breathing exercise programmes can help with asthma symptoms
Inhalers
      Check technique
GP follow up within two working days of treatment

Steroids if PEFR initially <50% best or predicted.
Stop abruptly after five days as long as patient continues on inhaled steroids.
Careful discharging patients that present late in the evening or early hours of the morning since the airways are naturally at their narrowest at around 4am.
The British asthma guideline discourages routine antibiotic prescription in acute asthma. Infective triggers are most commonly viral.

Patients considered for discharge should meet all of the following criteria:
    No life-threatening features at any point (including pre-hospital)
    No features of severe asthma after initial treatment
    PEFR >75% best or predicted and stable one hour after initial treatment
    or
    PEFR >50% best or predicted and stable two hours after initial treatment

When any of the following features are present, admission may be appropriate:
    Still have significant symptoms
    Concern over compliance
    Lives alone
    Psychosocial problems
    Physical disability or learning difficulties
    History of severe asthma
    Presentation at night
    Pregnancy
    Exacerbation despite adequate dose steroids pre-presentation

Referral if:
    Two courses of systemic corticosteroids in the past year
    Two or more attendances at the ED for their asthma in the past year
    On step 4 or 5 of the BTS/SIGN guidelines treatment ladder
    Who has childhood asthma with concurrent food allergy

Deaths
There's a national review of asthma deaths (NRAD). All deaths where asthma is on the death certificate at all need to be reported.


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