Asthma


















Oxygen
Inhaled beta-agonists
Inhaled anticholinergics
Corticosteroids
Adjunctive medications
Noninvasive ventilation
Intubation as needed
Ventilator management





  • Manage ABCs

    • Oxygen: Patients should be placed on supplemental oxygen therapy as needed to maintain adequate oxygen saturations.
    • Patients must be monitored for signs of impending respiratory failure.

  • Medications (see Table 30.1)

    • Inhaled beta-agonists:

      • Inhaled albuterol is the initial rescue medication of choice.
      • Side effects include tremor, nervousness, tachycardia, palpitations, headache, and hyperglycemia.
      • Delivered by nebulizer or metered-dose inhaler (MDI) with spacer device. In severe exacerbations, albuterol should be delivered as a continuous nebulized treatment.

    • Inhaled anticholinergics:

      • Ipratropium bromide is an effective adjunctive therapy by addressing airway smooth muscle constriction and airway secretions.
      • Should not be used alone, but has additive effect with inhaled beta-agonists.

    • Corticosteroids:

      • Address the inflammatory component of the disease.
      • Administer early in treatment, as they do not take effect for a few hours.
      • There is no difference in treatment effect between enteral (prednisone) and parenteral (methylprednisone) administration; use intravenous/intramuscular route when the patient is unable to take oral medications.

    • Subcutaneous epinephrine:

      • An effective adjunct for patients with severe disease or those unable to tolerate inhaled therapy.
      • May produce tachycardia, arrhythmia, vasoconstriction; use with caution in patients with heart disease.

    • Subcutaneous terbutaline:

      • Long-acting beta2-agonist.
      • Adjunct for patients with severe disease.
      • May produce tremor or tachycardia.

    • Intravenous magnesium sulfate:

      • An adjunctive medication indicated for patients with severe asthma that works by dilating airways and relaxing smooth muscle.

    • Heliox:

      • An inhaled mixture of helium and oxygen that is indicated only in severe asthma exacerbations.
      • Works by decreasing the density of any inhaled gas thereby reducing the airflow resistance and work of breathing.
      • A temporary intervention intended to “buy time” while other therapies take effect.

  • Airway and ventilatory support

    • Noninvasive positive-pressure ventilation (NPPV):

      • Constant positive airway pressure (CPAP) and bi-level positive airway pressure (Bi-PAP) may be considered for patients with severe asthma.
      • NPPV works by decreasing the work of breathing but requires a patient with a patent airway and who will be compliant with the therapy.
      • Patients receiving noninvasive positive-pressure ventilation must be carefully monitored for signs of decompensation including altered mental status, hemodynamic instability, hypercarbia, vomiting, and increased dyspnea.
      • If noninvasive methods fail, the patient will require intubation

    • Intubation:

      • Patients with altered mental status, severe acidosis, or hemodynamic instability should not be given a trial of NPPV but should be immediately intubated.
      • Lidocaine pretreatment blunts the bronchospastic response from airway manipulation.
      • Consider ketamine for induction, as this may improve bronchodilation.

    • Ventilator management:

      • The goal of ventilator management in the asthmatic is to oxygenate and ventilate without worsening hyperinflation, which causes barotrauma and hemodynamic instability.
      • Often requires low tidal volumes, low respiratory rates, long expiratory times, and high inspiratory flow rates.
      • Permissive hypercapnia may be required.
      • Aggressive pharmacological therapy should continue once the patient is intubated.

Feb 17, 2017 | Posted by in CRITICAL CARE | Comments Off on Asthma

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