ABIM - PCCU Lesson 19 Volume 13

ED=emergency department; NIH=National Institutes of Health; PEF=peak expiratory flow

In February 1997, the National Institutes of Health (NIH) released the Expert Panel Report II Guidelines for the Diagnosis and Management of Asthma. The first report was released in 1991, and the new updated report was compiled using new knowledge about the pathophysiology and treatment of asthma obtained during the ensuing 6 years. The report is divided into a series of categories. True "pearls" are highlighted in each category.

General Knowledge Concerning Asthma in the United States

Asthma is the third leading cause of preventable hospitalizations in the United States. There are approximately 5,200 deaths occurring each year from asthma. Airway inflammation plays a central role in asthma and can be successfully managed. Many different environmental factors can provoke increases in inflammation in patients with asthma.

Pearl. The four key components of comprehensive long-term management of asthma are as follows: (1) initial assessment and monitoring; (2) aggressive pharmacologic therapy; (3) control of asthma "triggers" that contribute to severity; and (4) patient and family education. The recommended goals of asthma therapy are the following:

Classification of Asthma

The new guidelines classify asthma as (1) mild intermittent, (2) mild persistent, (3) moderate persistent, or (4) severe persistent (Table 1). This classification is based on days with symptoms, frequency of nocturnal awakenings, measurement of peak expiratory flow (PEF) or FEV₁, and PEF variability. Patients are assigned the most severe class in which any one feature occurs (Table 2). A single individual classification can change over time, and this should be recorded in the patient's medical record. An acute exacerbation of asthma can occur in any of the four classifications and can be severe and life threatening. One of the most important distinctions in the new classification is between mild intermittent and mild persistent. This is a very important distinction because the treatment of mild intermittent asthma is the use of a b₂-specific agonist as needed only, while the treatment of mild persistent asthma requires the daily use of an anti-inflammatory agent, as well a b₂-specific agonist as needed.

**Table 1**—Classification of Asthma Severity: Clinical Features Before Treatment*
	Symptoms	Night-time Symptoms	Lung Function
Mild Intermittent	Symptoms <2 times a weeks Asymptomatic and normal PEF between exacerbations Exacerbations brief (from a few hours to a few days); intensity may vary	<2 times a month	FEV₁ or PEF >80% predicted PEF variability <20%
Mild Persistent	Symptoms >2 times a week but <1 time a day Exacerbations may affect activity	>2 times a month	FEV₁or PEF >80% predicted PEF variability 20-30%
Moderate Persistent	Daily symptoms Daily use of inhaled or short-acting b₂-agonist Exacerbations affect activity Exacerbations >2 times a week; may last days	>1 time a week	FEV₁ or PEF >60% - <80% predicted PEF variability >30%
Severe Persistent	Continued symptoms Limited physical activity Frequent exacerbations	Frequent	FEV₁ or PEF <60% predicted PEF variability >30%
*Presence of one of the features of severity is sufficient to place a patient in this category. Modified from NIH Publication 97-4051.

**Table 2**—*Classifying Severity of Asthma Exacerbation*
	Mild	Moderate	Severe
Breathlessness	Walking May lie down	Talking Prefers sitting	Unable to talk Unable to lie down*
Wheeze	End expiratory	Throughout expiration	Inspiratory and expiratory; no breath sounds
Use of accessory muscles	Absent	Absent	Present*
Pulse rate	<100/min	100-120/min	>120/min
Pulsus paradoxus	Normal	10-25 mm Hg	Elevated, >25 mm Hg*
PEF/FEV₁	80%	50-80%	<50%*
PaO₂	Normal	> 60 mm Hg	< 60 mm Hg
PaCO₂	<42 mm Hg	42 mm Hg	Usually >42 mm Hg
*Key features in determining severity of attack. Modified from NIH Publication 97-4051.

Pearl. If a patient (A) uses their b₂-specific agonist more than twice per week, or (B) awakens more than twice per month with nocturnal asthma, or (C) refills a b₂-inhaler more than twice/year, then the patient's asthma is mild persistent or greater and daily anti-inflammatory therapy is required.

Pearl. If a patient has daily asthma symptoms or nocturnal asthma greater than once per week, the asthma is moderate persistent (or greater), and the patient requires daily inhaled corticosteroids.

Pearl. If a patient with moderate persistent asthma has exacerbations of asthma while receiving inhaled corticosteroids, the patient will have a more rapid and greater increase in PEF by adding a long-acting inhaled b₂-stimulant than by doubling the dose of inhaled steroid.

Pearl. If a patient's daily PEF is <60% of predicted, the patient's asthma is severe persistent.

Pearl. Daily peak flow measurements are not recommended for patients with mild intermittent or mild persistent asthma unless they have developed a severe exacerbation.

Pearl. Corticosteroids (inhaled) are the most potent chronic anti-inflammatory therapy for asthma classified as mild persistent or greater.

Determining Patient's "Personal Best"

Measure and record daily PEF over 2 to 3 weeks when the patient's asthma is in good control. Measure PEF between 12 noon and 2:00 PM. A short course of oral corticosteroids may be needed to establish the personal best PEF.

Pearl. Periodically reassess the patient's personal best PEF to account for progression of the disease and for growth in children.

Daily Asthma Procedures

When using a metered-dose inhaler, the patient should open his mouth and activate with the inhaler 1 to 2 inches away. The patient should inhale slowly over 3 to 5 s. Alternately, patients can use a spacer device or a holding chamber and place their mouth around the device's mouthpiece.

Pearl. Breath-activated inhalers require the inhaler mouthpiece being put directly into the mouth.

Pearl. Inhaled dry powder capsules require patients to close their mouth tightly around the mouthpiece and to inhale rapidly (1 to 2 s or 60 L/min) and deeply.

Home Management of Asthma

A written action plan for the asthmatic is important if they are going to treat themselves at home (Fig 1). Patients with moderate persistent or severe persistent asthma should learn how to monitor their PEF and have a peak flowmeter at home. They should use the same peak flowmeter over time. They should also measure morning peak flow BEFORE using a bronchodilator. The Expert Panel recommended that spirometry tests be done (1) at the time of initial assessment; (2) after treatment is initiated and symptoms and PEF have stabilized, to document attainment of (near) normal airway function; and (3) at least every 1 to 2 years to assess the maintenance of airway function. If a patient is having an exacerbation, then PEF should be measured at that time.

**Figure 1.** Asthma action plan: adult self-management instructions.
Important Peak Flow Numbers Baseline________________________ L/min _______% Baseline=__________________L/min If your peak flow drops below ___________or you notice: —Increased use of inhaled treatments to manage asthma —Increased asthma symptoms upon awakening or at night Follow these treatment steps: Increase inhaled steroids Take ______ puffs of ____________________ times a day. Begin/increase treatment with oral steroids Take ______ mg of prednisone at _______ AM and/ or _______ PM If your peak flow number drops below __________or if you continue to get worse after treatment according to the directions above, follow these treatment steps. Begin/increase treatment with oral steroids Take ______mg of prednisone at _______AM and/ or _______PM Contact your health-care provider. Contact your health-care provider if: Your peak flow number drops below__________________ Asthma symptoms worsen while you are taking oral steroids Inhaled bronchodilators treatments are not lasting four hours If you can not contact your health care provider go directly to the ED. If you have questions call __________________ Date _________________ Physician signature ________________Patient/Family signature_____________

Pearl. A severe at-home exacerbation is a PEF of <50% of the patient's best (Fig 2).

The patient should begin initial treatment with a short-acting b₂-agonist, 4 puffs every 20 min for 1 h. The patient can also use a single handheld nebulized dose as their initial treatment.

Pearl. (1) If after 1 h, the PEF is >80%, then continue the b₂-agonist, 2 puffs every 4 h while awake for 1 to 2 days. Double the inhaled steroid dose for 1 week. Schedule a doctor visit. (2) If after 1 h the PEF is between 50% and 80%, then add oral corticosteroids and continue a b₂-agonist. Contact a physician the same day. (3) If after 1 h the PEF is still <50%, then add oral corticosteroids, continue b₂-agonist treatment. Contact physician immediately and if unable to do so, go to the emergency department (ED).

Pearl. DO NOT use warm humidified air, antihistamines, or over-the-counter bronchodilators for a home asthma attack.

Emergency Department Treatment

In the ED, a patient presenting with an asthma attack should receive a rapid evaluation, and if severely obstructed or at high-risk for ventilatory failure, the patient should be quickly identified (Fig 3).

Figure 3. Summary of treatment in the emergency department. MDI=metered-dose inhaler; SaO₂ = arterial oxygen saturation. *If peak flow > 80% after 1 h of treatment, oral steroids may not be necessary. **No proven difference in adults between continuous or intermittent nebulization and MDI (6 to 12 puffs) of albuterol. +Consider noninvasive ventilation, heliox, magnesium, and aminophylline.

Pearl. Patients at high risk for possible ventilatory failure include patients with PEF <50% after at least 1 h of home therapy, patients who are already receiving oral steroids, patients with altered mental states, patients who are extremely fatigued, patients who cannot talk or lie down, patients with a pulsus paradoxus of >25 mm Hg, and patients with a PaO₂ on room air of <60 mm Hg or a PaCO₂ >42 mm Hg. Any history of prior intubations or more than three ED visits or two hospitalizations during the prior year are also risk factors for ventilatory failure and death resulting from asthma.

Pearl. Do not delay intubation if deemed necessary. Treat patients in the ED who have a severe exacerbation with b₂-agonist therapy, either three treatments in the first hour or continuously by nebulization. Give systemic corticosteroids immediately, and give O₂ by nasal cannula or mask to keep saturation >90% (Table 3).

Pearl. Continuous administration of b₂-agonists is usually more effective in children than in severely obstructed adults. Anticholinergics (ipratropium bromide, 0.5 mg in adults or 0.25 mg in children), aerosolized with b₂-agonists, cause additional bronchodilation. This may be important in patients with severe airway obstruction.

Pearl. Chest radiographs should only be done in patients with a suspected complicating cardiopulmonary process (eg, pneumonia, pneumothorax). Arterial blood gases should be obtained if the PEF or FEV₁ <30%. ECGs should be done in patients older than 50 years of age or patients with coexistent heart disease.

Pearl. Oral prednisone has been shown in patients in the ED to have effects equivalent to those of IV methylprednisolone. Aggressive hydration is not recommended but may be needed in infants and young children. Chest physical therapy is not recommended. Mucolytics or sedation is not recommended. A physician may treat a severe exacerbation with IV magnesium sulfate and/or the use of a mixture of helium and oxygen (heliox) if a patient is not responding to conventional therapy in the ED (but these are not considered to be standard or proven therapy).

Pearl. In patients already taking a theophylline compound, obtain a serum theophylline level to rule out theophylline toxicity (>15 g/mL). Routine antibiotics are not presently recommended for patients unless a source of infection is found.

Pearl. Intubation is difficult in an asthmatic patient, so try to do it electively before a respiratory arrest.

Pearl. "Permissive hypercapnia" or "controlled hypoventilation" is the recommended ventilator strategy if a patient requires mechanical ventilation.

Pearl. Patients with a rapid response should be observed 60 min after the most recent dose of the bronchodilator before going home.

Pearl. When leaving the patient on their inhaled corticosteroids at the standard dose, tapering of oral corticosteroids is not necessary. If you are just beginning inhaled corticosteroids, start them prior to discharge, and taper the oral corticosteroids.

General Control of Factors Contributing to Asthma Severity

Asthma patients should avoid irritants, mediators, or allergens to which they have known sensitivity.

Pearl. (1) No smoking in the home; (2) no b-blockers, including b-blocker eyedrops; and (3) patients with severe persistent asthma should avoid aspirin and nonsteroidal anti-inflammatory drugs. Up to 39% of severe asthmatics may have aspirin sensitivity.

Immunotherapy

Allergen immunotherapy may be considered for asthma patients when (1) there is clear evidence of a relationship between symptoms and exposure to an unavoidable allergen to which the patient is sensitive; (2) symptoms occur all year or during a major portion of the year; and (3) there is difficulty controlling symptoms with pharmacologic management either because the medication is ineffective, multiple medications are required, or the patient is not accepting the medication. If use of allergen immmunotherapy is elected, it should be administered only in a physician's office where facilities and trained personnel are available to treat any life-threatening reaction that can, but rarely does, occur.

Pearl. Studies of immunotherapy that have shown effectiveness have all been performed with single allergens and include grass, cat, house-dust mites, ragweed, Cladosporium, and Alternaria. In clinical practice, multiple allergen mixes are often used.

Pearl. The course of allergen immunotherapy is normally between 3 and 5 years.

Pearl. Influenza vaccinations are recommended yearly for asthmatics with mild persistent or greater disease.

Special Asthma Situations

Seasonal Asthma

Pearl. Begin anti-inflammatory agents 2 weeks prior to the anticipated onset of the season and continue through the season.

Cough Variant Asthma

Seen more in young children. Use same stepwise approach as for the long-term management of asthma.

Pregnancy and Asthma

Poorly controlled asthma during pregnancy results in increased perinatal mortality, increased prematurity, and low birth weight.

Pearl. Controlling the mother's asthma with the use of bronchodilators and anti-inflammatory medication is best for the baby.

Surgical Patients Receiving Systemic Corticosteroids During the Last 6 Months

Pearl. Give 100 mg hydrocortisone q8h IV during the surgical period and reduce dose rapidly 24 h following surgery.

Risk Factors for Death Due to Asthma

There are specific situations that can occur that increase the known risk for death in asthmatic patients. These questions should be asked and the answers recorded on initial assessment of a new patient:

Guidelines for Referral to Asthma Specialist

Most patients with asthma are treated by primary care physicians (>60%). Some asthmatics have management problems that should be referred to a specialist in asthma.

Pearl. Refer patients in whom there are problems with the differential diagnosis.

Pearl. Refer patients who require special diagnostic testing such as allergy skin testing, rhinoscopy, provocative challenge testing, bronchoscopy, or complete pulmonary functions.

Pearl. Refer patients with severe persistent asthma that are not responding to their daily medication. Consider referring patients with moderate persistent asthma if not responding.

ABIM • PCCU

Lesson 19, Volume 13—Pearls From the National Institutes of Health Asthma Guidelines

Objectives

Key words

Abbreviations

General Knowledge Concerning Asthma in the United States

Classification of Asthma

Determining Patient's "Personal Best"

Daily Asthma Procedures

Home Management of Asthma

Emergency Department Treatment

General Control of Factors Contributing to Asthma Severity

Immunotherapy

Special Asthma Situations

Seasonal Asthma

Cough Variant Asthma

Pregnancy and Asthma

Surgical Patients Receiving Systemic Corticosteroids During the Last 6 Months

Risk Factors for Death Due to Asthma

Guidelines for Referral to Asthma Specialist

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