ATrain Education

 

Continuing Education for Health Professionals

Asthma: Calming the Airways

Module 2

Classifying and Assessing Asthma

The 2007 Expert Panel Report 3 (EPR 3), published by the National Heart, Lung, and Blood Institute, updated the 1997 guidelines to help practitioners in diagnosing and managing asthma. The working definition of asthma, identified in 1997 and quoted above, remains unchanged, with its emphasis on classifying asthma in terms of the severity of symptoms and control measures. In EPR 3, control and severity are now broken out into two different sections that address:

  • Degree of impairment as well as risk
  • Impairment reflecting the actual symptoms experienced, including nighttime cough
  • Change in activities of daily living (ADLs)
  • Use of short-acting inhaled bronchodilators
  • Spirometry for children over the age of five with risk assumed by the need for oral corticosteroids such as prednisone to manage exacerbation of symptoms. (NIH, NHLBI, 2007)

Whether a healthcare practitioner is assessing a client presenting in the early or initial stages of asthma, during a routine followup to evaluate status, or during an exacerbation of symptoms, the diagnostic strategies and management of asthma are organized around four governing principles:

  • Objective tests: Tests such as pulmonary function and spirometry along with the physical examination, client history, and client report of symptoms allow a practitioner to diagnose and assess the characteristics and severity of asthma and to monitor whether asthma control is achieved and maintained.
  • Education: One of the most critical components of assessment and management of asthma. It creates an effective partnership and promotes self-identification and reporting of symptoms.
  • Control: The means for controlling and preventing asthma symptoms are well established. Control of asthma symptoms includes the identification and management of environmental factors and co-morbid conditions that affect asthma.
  • Pharmacologic therapy: Based on symptoms, which may be stepped up or down according to changes in the status of the disease (NIH, NHLBI, 2007). Treatment includes use of medication for short-term relief, daily medication to avert attacks, monitoring of early symptoms, and avoiding factors that trigger attacks (Akinbami, 2011).

Classification Guidelines

The 2007 EPR 3 guidelines established definitions to assist in determining the classification of asthma during the initial assessment and as part of ongoing treatment:

  • Severity: the intrinsic intensity of symptoms. This is best established if the client is not already receiving long-term control therapy such as inhaled corticosteroids.
  • Control: the degree to which symptoms, functional impairment, and risks are minimized and the goals of therapy are met.
  • Responsiveness: the ease with which recommended therapy controls symptoms.
  • Impairment: any functional limitations the client is experiencing or has recently experienced that reflect frequency and intensity of symptoms.
  • Risk: the likelihood of asthma exacerbations, progressive decline in lung function (or, for children, reduced lung growth), or adverse effects from medication. (NIH, NHLBI, 2007)

Classification Tables

To further aid in the classification of asthma, the National Asthma Education and Prevention Program (NAEPP) established classification tables—organized by age groups—as part of their guidelines for treatment. Symptoms can be categorized during initial evaluation using these tables. Note that the components of severity and impairment are identified and further classified as intermittent, mild persistent, moderate persistent, and severe persistent according to frequency.

 

Source: NHLBI, NIH, 2011. Modified from EPR 3: Classifying Asthma Severity and Initiating Treatment in Children 0–4 Years of Age.

Classifying Asthma Severity for Children 0 to 4 Years of Age

 

Intermittent

Mild, persistent

Moderate, persistent

Severe, persistent

Symptom onset

≤2 days per week

>2 days per week but not daily

Daily

Throughout the day

Nighttime awakening

0

1–2x per mo

3–4x per mo

>1x per wk

Short-acting beta2-agonist use for symptom control (not prevention of EIB)

≤2 days per week

>2 days per wk but not daily

Daily

Several times per day

Interference with normal activity

None

Minor limitation

Some limitation

Extremely limited

In children ages 0 to 4 years, persistent asthma symptoms include such findings as cough, wheeze, chest tightness, shortness of breath that occurs more than 2 days a week, nighttime cough ≥1–2 times per month, use of bronchodilator more than 2 days per week but not daily, and interference with activity—which in this age group may include feeding along with routine movement. These factors comprise the impairment criteria new to the EPR 3 (NIH, NHLBI, 2007).

 

Source: NHLBI, NIH, 2007. Modified from EPR 3: Classifying Asthma Severity and Initiating Treatment in Children 5–11 Years of Age.

Classifying Asthma Severity for Children 5 to 11 Years Old

 

Intermittent

Mild, persistent

Moderate, persistent

Severe, persistent

Symptom onset

≤2 days per wk

>2 days per wk but not daily

Daily

Throughout the day

Nighttime awakening

≤2x per mo

3–4x per mo

>1x/wk but not nightly

Often 7x per wk

Short-acting beta2-agonist use for symptom control (not prevention of EIB)

≤2x days per wk

>2 days per wk but not daily

Daily

Several times per day

Interference with normal activity

None

Minor limitation

Some limitation

Extremely limited

Lung function

Normal FEV1 between exacerbations

FEV1 >80% predicted

FEV1/FVC >85%

FEV1 = >80% predicted

FEV1/FVC >80%

FEV1 = 60−80% predicted

FEV1/FVC = 75−80%

FEV1 <60% predicted

FEV1/FVC <75%

Note: In this age group, pulmonary function test factors are included (FEV1, FEV/FVC ratio). This meets the objective testing criteria and will be discussed more fully following the tables.

 

Note: Under impairment criteria, normal FEV1/FVC percentages change. These changes allow for normal physiologic processes associated with aging.
Source: NHLBI, NIH, 2011. Modified from EPR 3: Classifying Asthma Severity and Initiating Treatment in Youths ≥12 Years of Age and Adults.

Classifying Asthma Severity in Youths ≥12 Years of Age and Adults

 

Intermittent

Mild, persistent

Moderate, persistent

Severe, persistent

Symptom onset

≤2 days per wk

>2 days per wk but not daily

Daily

Throughout the day

Nighttime awakening

≤2x per mo

3–4x per mo

>1x/wk but not nightly

Often 7x per wk

Short-acting beta2-agonist use for symptom control (not prevention of EIB)

≤2 days per wk

>2 days per wk but not daily and not more than 1x on any day

Daily

Several times per day

Interference with normal activity

None

Minor limitation

Some limitation

Extremely limited

Lung function

Normal FEV1 between exacerbations

FEV1 >80% predicted

FEV1/FVC normal

FEV1 = >80% predicted

FEV1/FVC normal

FEV1 >60% but <80% predicted

FEV1/FVC reduced 5%

FEV1 <60% predicted

FEV1/FVC reduced >5%

Normal FEV1/FVC:

8−19 yr = 85%
20−39 yr = 80%
40−59 yr = 75%
60−80 yr = 70%

 

Using the preceding three tables to classify severity, pulmonary function (FEV1, FEV1/FVC) measures range from none in the 0 to 4 age group to specific percentages for ages 5 and up. Children under the age of 5 are presumed unable to comply with instructions sufficiently to achieve reliable results. Because this data is critical to establishing classification, it is useful to review definitions and the process for calculating percentages.

Assessment

The initial assessment of asthma severity is made immediately after diagnosis or when the client is first encountered, ideally before the client requires some form of long-term control medication. Assessment is made on the basis of current spirometry, history, and the client’s recall of symptoms over the previous 2 to 4 weeks (detailed recall of symptoms decreases over time). If the assessment is made during a visit in which the client is treated for an acute exacerbation, then asking the client to recall symptoms in the period before the onset of the current episode helps to determine the appropriate interval for followup visits.

Spirometry (Pulmonary Function Testing)

Pulmonary function testing (PFT) uses spirometry to measure flow/volume loops to assess response to short-acting beta agonists (SABA) such as albuterol. Measures are made before and after use of the SABA and compared against predicted normal values for age, height, and gender. The three primary measures that pertain to asthma are:

  1. FEV1 (amount that can be forcefully exhaled in 1 second)
  2. FVC (total amount of air exhaled starting from a full inhalation to the end of a full, forced exhalation)
  3. FEV1/FVC (ratio of the two values expressed as a %)

The following frequencies for spirometry testing are recommended by EPR 3 (NIH, NHLBI, 2007) during initial and ongoing management of asthma:

  • At the time of initial assessment (children 5 and above)
  • After treatment was initiated and symptoms stabilized
  • During periods of progressive or prolonged loss of asthma control
  • At least every 1 to 2 years if symptoms are stable

In a symptomatic person, the FEV1 and FVC are measured and compared to the reference values. Values above 80% of reference are generally considered normal but this varies somewhat depending on age.

In a typical asthma case, initial evaluation shows a decrease in FEV—often below the 80% reference range—and reduced FEV1/FVC indicating airflow obstruction. A pre-and-post bronchodilator test should be performed using a SABA to see whether airflow obstruction is reversible. Reversibility is determined when there is at least a 12% change and ≥200mL increase in capacity.

This testing is simple to perform and is often done during an outpatient office visit—assuming the equipment is present and staff are appropriately trained. Reference ranges are readily available through the Centers for Disease Control (CDC) website. Worksheets to calculate values can be viewed there. To illustrate how simple this is to calculate, look at the upcoming theoretical case.

Physical Examination

The upper respiratory tract, chest, and skin are the focus of the physical examination for asthma. Physical findings that increase the probability of asthma include:

  • Hyperexpansion of the thorax—especially in children, use of accessory muscles, appearance of hunched shoulders, chest deformity.
  • Sounds of wheezing during normal breathing, or a prolonged phase of forced exhalation. Wheezing may only be heard during forced exhalation but it is not a reliable indicator of airflow limitation.
  • Increased nasal secretion, mucosal swelling, and/or nasal polyps.
  • Atopic dermatitis/eczema or any other manifestation of an allergic skin condition.

The absence of these findings does not rule out asthma, because the disease is by definition variable, and signs of airflow obstruction are often absent between attacks.

If cough is the primary symptom being addressed and the client or caretaker is unable to supply an adequate history, a useful strategy is to evaluate above (cough related to rhinitis or other allergic symptoms of the upper airway) and below (cough coming from GERD, or reflux). These two conditions should always be considered when evaluating a persistent cough because they are common and can exacerbate or mimic many of the respiratory symptoms associated with asthma.

Patients with atopy—the genetic tendency to develop allergic responses—are currently thought to be disposed to overproduce immunoglobulin E (IgE) and often have an asthma variant that is severe and persistent. The common triad of symptoms in clients presenting with atopy are:

  • Asthma
  • Perennial allergies and hay fever
  • Skin rash or eczema

The last two conditions can cause varying degrees of itching at the affected sites. These clients require comprehensive history and assessment because their symptoms are often difficult to control and they require multi-system management to achieve good control of their asthma.

Flares in one arm of the triad may precede asthma or predict that asthma symptoms—potentially life-threatening—are worsening. Although asthma is typically associated with an obstructive impairment that is reversible, neither this finding nor any other single test or measure is adequate for diagnosis.

Other diseases are also associated with this pattern of abnormality. This is why it is vital to include a thorough history for both the client and immediate family members, and to assess for the presence of environmental triggers when considering which type of therapy is needed.

 

Tom, a 20-year-old Caucasian college student, was diagnosed with asthma as a child but has had no episodes of wheezing or coughing in more than 8 years. He is 71 inches tall. He does not smoke, is on no medication, and started experiencing symptoms after moving in with a roommate who has a cat. Because his history is positive for asthma—his symptoms are present during the day (causing him to miss classes), and he has been awakened by cough an average of 3 nights a week—a decision is made to go ahead with the pulmonary function test to see whether he meets the criteria for asthma.

Here are the results of his pre-bronchodilator test, which compares the measured and reference ranges and expresses the findings as a % of reference. Recall that 80% of reference is generally considered normal in this age group.

  • FEV1 (measured): 3.61 (reference = 4.81, % reference = 75%)
  • FVC (measured): 5.21 (reference = 5.77, % reference = 90%)
  • FEV, % (measured): 69

These numbers are obtained by dividing the part (measured) by the whole (reference) in the case of FEV1 and FVC; the FEV% is calculated by dividing the measured FEV1 by the FVC.

Tom is given a nebulizer treatment with a SABA (albuterol), and then allowed to wait 15 to 20 minutes for the medication to become effective. Here are the results of the post-bronchodilator spirometry:

  • FEV1 (measured): 4.35 (% reference = 90, % change = 20)
  • FVC (measured): 5.39 (% reference = 93, % change = 3)
  • FEV, % (measured): 81

Tom meets the criteria for significant change because he shows improvement in his FEV1 (at least 12%) and his symptoms are reversible after treatment with a SABA. In fact, his change of 20% shows robust response to treatment.

 

We can now assess Tom’s status by comparing his level of symptoms against criteria on the age-appropriate asthma severity chart and begin to plan for his treatment needs. To do this we refer to the four components of care outlined earlier: (1) objective testing, (2) education, (3) control of environmental factors, and (4) pharmacologic therapy.

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