Asthma and COPD in the ICU



Asthma and COPD in the ICU





This chapter describes the management of acute exacerbations of asthma and chronic obstructive pulmonary disease (COPD), including the use of noninvasive and invasive ventilatory assistance. The recommendations in this chapter are drawn from clinical practice guidelines and pertinent reviews (1,2,3).


I. Acute Asthma

The flow diagram in Figure 18.1 shows the recommendations of the National Asthma Education Program for the initial management of adults with acute exacerbations of asthma (1). This protocol uses objective measures of airway obstruction (FEV1 and peak expiratory flow rate) to determine disease severity, but these measures are difficult to obtain in acutely ill patients, so clinical assessment of disease severity is used to guide management (2,3). The drugs and dosing regimens used for acute asthma are shown in Table 18.1.


A. Short-Acting β2 Agonists

Short-acting β2-receptor agonists are the preferred bronchodilators for acute exacerbations of asthma, and are given as an inhaled aerosol, which is more effective than parenteral drug therapy, and has fewer side effects (4). Bronchodila-tor effects are usually apparent in 2–3 minutes, reach a peak at 30 minutes, and last for 2–5 hours (5).







FIGURE 18.1 Flow diagram for the management of acute exacerbations of asthma. From the National Asthma Education Program (1). FEV1 = forced expiratory volume in one second, PEFR = peak expiratory flow rate.









Table 18.1 Inhaled Bronchodilator Therapy in Acute Asthma































Drug Dosing Regimens
Albuterol Neb: 2.5–5 mg every 20 min for 3 doses, or 10–15 mg by continuous inhalation for 1 hr, then 2.5–10 mg every 1–4 hr as needed.
  MDI: 4–8 puffs (90 βg/puff) every 20 min up to 4 hr, then every 1–4 hr as needed. Use a holding chamber for inhalations.
Levalbuterol Neb: Same regimen for intermittent dosing as albuterol, but at half the dose. Has not been evaluated for continuous inhalation.
  MDI: Same dosing regimen as albuterol (45 βg/puff).
Ipatropium Neb: 0.5 mg every 20 min for 3 doses (can be added to albuterol or levalbuterol neb solution), then as needed.
  MDI: 8 puffs (18 βg/puff) every 20 min, as needed, for up to 3 hr. Use a holding chamber for inhalations.
Ipatropium with albuterol Neb: 3 mL (0.5 mg ipatropium + 2.5 mg albuterol) every 20 min for 3 doses, then as needed.
  MDI: 8 puffs (18 βg ipatropium + 90 βg albuterol per puff) every 20 min, as needed, for up to 3 hr. Use holding chamber.
From Reference 1. Neb = nebulizer; MDI = metered dose inhaler.



  • The most widely used drug in this class is albuterol, which is a racemic mixture of two isomers, only one being active. Levalbuterol is the active isomer in albu-terol, and was introduced as a more powerful bronchodilator than albuterol. However, clinical studies have shown no advantages with levalbuterol in acute asthma (6).



  • The dosing regimens for albuterol are shown in Table 18.1. Treatment usually begins with a series of 3 consecutive aerosol treatments at 20 minute intervals, and nebulizers are preferred to MDIs for moderate-to-severe airflow obstruction (1).


  • Albuterol can also be given as a continuous aerosol using a large-volume nebulizer and a dose of 10–15 mg for the first hour (1). This method has become popular, and is more effective than intermittent aerosol therapy for severe airflow obstruction (7).


  • When the acute episode begins to resolve, albuterol is given by intermittent aerosol treatments every 4–6 hours for the duration of the hospital stay.


  • Adverse effects of high-dose aerosol therapy with β2-agonists include tachycardia, fine tremors, hyperglycemia, and electrolyte “hypos” (i.e., hypokalemia, hypomagnesemia, and hypophosphatemia) (8,9). Albuterol may also be responsible for the increase in serum lactate levels that are observed during acute exacerbations of asthma (10).


B. Anticholinergic Aerosols



  • Anticholinergic aerosols offer only marginal benefits in acute asthma, and their use is restricted to combination therapy with short-acting β2-agonists for the first 3–4 hours of treatment in patients with moderate-to-severe airflow obstruction (1,11).


  • The only anticholinergic agent approved for use in asthma in the United States is ipatropium bromide, a derivative of atropine that blocks muscarinic receptors in the airways.


  • The dosing regimen for aerosolized ipatropium is shown in Table 18.1. Ipatropium can be mixed with albuterol for nebulizer treatments, and a premixed
    preparation of albuterol and ipatropium is commercially available for nebulizers and MDIs (see Table 18.1).


  • Systemic absorption of ipatropium is minimal, and there is little risk of anticholinergic side effects (e.g., tachycardia, dry mouth, blurred vision, urinary retention).


  • Ipatropium has no proven benefit beyond the first few hours of treatment, and it should not be used for daily maintenance therapy in asthma (1).


C. Aerosol Intolerance

For the occasional patient that does not tolerate bronchodilator aerosols (usually because of excessive coughing), consider one of the following regimens (1):



  • Epinephrine: 0.3–0.5 mg subcutaneously every 20 minutes for 3 doses.


  • Terbutaline: 0.25 mg subcutaneously every 20 minutes for 3 doses.


  • Following the initial bronchodilator response, patients are more likely to tolerate aerosol treatments.


D. Corticosteroids

Systemic therapy with corticosteroids can accelerate the rate of improvement and reduce the risk of relapses (12), although not all studies show a benefit from corticosteroids in acute asthma (13,14).


1. Relevant Observations

The following observations about steroid therapy in acute asthma deserve mention:

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Nov 8, 2018 | Posted by in CRITICAL CARE | Comments Off on Asthma and COPD in the ICU

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