Saturday, July 8, 2017

Acute Asthma - Management



Acute severe asthma
(also referred to in Latin as status asthmaticus, or asthmatic status) is an acute exacerbation of asthma that does not respond to standard treatments of bronchodilators (inhalers) and steroids.
Initial treatment
Follow the steps as summarized below:

• Provide high flow O 2 .
• Put the trolley back and side rails up so the patient is sitting up and holding on to the side rails (to use pectoral muscles as accessory muscles of respiration).
• If the patient cannot talk, start treatment, but get senior Emergency department and ICU help in case intubation and ventilation are required.
• Check trachea and chest signs for pneumothorax.
• Ask about previous admissions to ICU.
• Administer high dose nebulized B 2 agonist (eg salbutamol 5mg or terbutaline 10mg), or 10 puffs of salbutamol into spacer device and face mask.
For severe asthma or asthma that rseponds poorly to the initial nebulizer, consider continuous nebulization.
• Give a corticosteroid: either prednisolone 40–50mg PO or hydrocortisone (preferably as sodium succinate) 100mg IV.
• Add nebulized ipratropium bromide (500mcg) to B 2 agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to B 2 agonist therapy.
• Consider a single dose of IV magnesium sulphate (1.2–2g IVI over 20min) after consultation with senior medical staff, for patients with acute severe asthma without a good initial response to inhaled bronchodilator therapy or for those with life-threatening or near-fatal asthma.
• Use IV aminophylline only after consultation with senior medical staff.
Some individual patients with near-fatal or life-threatening asthma with a poor response to initial therapy may gain additional benefit. The loading dose of IVI aminophylline is 5mg/kg over 20min unless on maintenance therapy, in which case check blood theophylline level and start IVI of aminophylline at 0.5–0.7mg/kg/hr.
• IV salbutamol is an alternative in severe asthma, after consultation with senior staff. Draw up 5mg salbutamol into 500mL 5 % dextrose and run at a rate of 30–60mL/hr.
• A patient who cannot talk will be unable to drink fluids and may be dehydrated.
• Avoid ‘routine’ antibiotics.
• Repeat ABG within an hour.
• Hypokalaemia may be caused or exacerbated by B 2 agonist and/or steroid therapy.



Criteria for admission
Admit patients with any features of
• A life-threatening or near-fatal attack.
• Severe attack persisting after initial treatment.

Management of discharge
Consider for discharge those patients whose peak flow is > 75 % best or predicted 1hr after initial treatment. Prescribe a short course of oral prednisolone (eg 40–50mg for 5 days) if initial peak expiratory flow rate (PEFR) <50 % , and ensure adequate supply of inhalers. If possible arrange for
review by an asthma liaison nurse before discharge. At a minimum, inhaler technique and peak expiratory fl ow monitoring should be reviewed.
Arrange/advise GP/asthma liaison nurse follow-up within 2 days. Advise to return to hospital if symptoms worsen/recur.

Referral to intensive care unit
Refer any patient requiring ventilatory support or with acute severe or life-threatening asthma failing to respond to therapy, evidenced by:
• Drowsiness, confusion.
• Exhaustion, feeble respiration.
• Coma or respiratory arrest.
• Persisting or worsening hypoxia.
• Hypercapnoea.
• ABG showing d pH.
• Deteriorating peak fl ow.

Cardiac arrest in acute asthma
The underlying rhythm is usually pulseless electrical activity (PEA). This may reflect one or more
of the following:

  • prolonged severe hypoxia (secondary to severe bronchospasm and mucous plugging), 
  • hypoxia-related arrhythmias or
  • tension pneumothorax (may be bilateral). 
Give advanced life support according to the guidelines of Cardiac arrest,  and treat tension pneumothorax if present. Aim to achieve tracheal intubation early in view of the higher than normal required lung inflation pressures and the attendant risk of gastric inflation in the absence of a tracheal tube.

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