Asthma

Definition of Asthma:

1. Chronic airway inflammatory disorder

2. Recurrent episodes of wheezing, chest tightness, shortness of breath, and coughing at night or in the early morning

3. Reversible airway limitation

Diagnosis of Asthma[5]

1. History:: cough worse at night, recurrent wheezing/chest tightness

recurrent difficult breathing

2. Symptoms occur or worsen at night, awakening the patient

3. Physical examination: wheezing, silent chest when severe asthma

4. Lung function test ( FEV1 and PEFR )

- PEFR increases > 15% after inhalation of short-actingβ2 –agonists 15~20 mins

- PEFR varies > 20% from morning to 12 hours later

- PEFR decreases > 15% after 6 mins of exercise

5. Risk factors:

- Allergic IgE-mediated diseases, allergic rhinitis, atopic dermatitis, and eczema

- Familial members with asthma

- exacerbation associated with weather change, foods, drugs…

Classification of Asthma Severity [5]

Classification / Clinical Features Before Treatment
DaysSymptoms / Night-time Symptoms / Lung Function Test
STEP 1:
Intermittent
/ < 1 times/week / < 2 times/month / -FEV1 or PEF= 80% predicted
-PEF variability <20%
STEP 2:
Mild persistent
/ 1 times /week, but
< 1/day / > 2/month / -FEV1 or PEF = 80% predicted
-PEF variability 20-30%
STEP 3:
Moderate persistent
/ Daily symptoms / 1 /week / -FEV1 or PEF in 60%~80% predicted
-PEF variability >30%
STEP 4:
Severe persistent
/ Continual symptoms / Frequent / -FEV1 or PEF 60% predicted
-PEF variability >30%

Stepwise Approach for Managing Asthma in Adult [5]

Quick Relief
All Patients / - Short-acting bronchodilator with inhaled β2 -agonists as needed for symptoms.
-Intensity of treatment will depend on severity of exacerbation.
- Use of bronchodilator > 1/week over a 3 months period in intermittent asthma may indicate the need to“step-up” therapy
Classification / Daily Control Medicines / Other Treatment Options
STEP 1:
Intermittent
/ - No daily medication
STEP 2:
Mild persistent / -Anti-inflammatory: inhaled corticosteroid (low doses) / -Sustained-release theophylline toserum concentration of 5-15 μg/mL
- Cromone or
- Leukotriene modifier
STEP 3:
Moderate persistent / - Low~mideum-dose of inhaled corticosteroid+long-acting inhaledβ2 –agonist / - Medium-dose of inhaled corticosteroid + sustained-release theophylline, or
- Medium-dose of inhaled corticosteroid + long-acting oral β2 –agonist,or
- High-dose inhaled corticosteroid, or
- Medium-dose of inhaled corticosteroid
+ leukotriene modifier
STEP 4:
Severe persistent / -Inhaled corticosteroid (high dose) + long-acting inhaledβ2 –agonist + if needed:
•sustained-release theophylline
• leukotriene modifier
• long-acting inhaledβ2 –agonist
• oral glucocorticosteroid

* Step down:Review treatment every 1 to 6 months. If control is sustained for at least 3 months, a gradual stepwise reduction in treatment maybe possible.

* Step up:If control is not achieved, consider step up. Inadequate control is indicated by increased use of short-actingβ2-agonists and in:

- step 1 when patient uses a short-actingβ2-agonist more than two times a week;

- steps 2 and 3 when patient uses short-actingβ2-agonist ona daily basis OR more than three to four times a day.

- But before stepping up: review patient inhaler technique, compliance, and environmentalcontrol (avoidance of allergens or other precipitant factors).

Criteria for Hospitalization [1-2]

1.Any symptoms of asthma with a FEV1 or peak-expiratory flow rate (PEFR) < 50% of predicted value

2.PaCO2 ↑

3.Prolonged attack of asthma of > 24 hours duration

4.Age > 40 years

5.Poor responseafter 4 hours of bronchodilator therapy

6.Recent or multiple emergency department or hospitalizations for treatment of asthma that occurred within the last year

7.History of ET intubation for asthma

8.Poor access to medical follow-up

9.Psychiatric conditions that are interfering with medical compliance

The initially quick assessment of ASTHMA in admission[2,5]

Examination finding / Level of Severity

Mild

/

Moderate

/ Severe
ConsciousState / Normal / Normal / Altered
Speaking Ability / Sentences / Phrases / Words
Respiratory rate (b/min) / <20 / 20 – 30 / 30
ABGs:
PaO2
PaCO2
SaO2 / Normal
< 45 mmHg
> 95% / > 60 mmHg
< 45 mmHg
91 – 95% / < 60 mmHg, cyanosis
> 45 mmHg
<90%
Air Entry / Good / Moderate Poor / may have
silent chest

Recommendations regarding initial treatment of an acute episode [2]

1. Oxygen therapy at a minimum of 6 L/min via face mask to achieve SaO2 > 95%. (Grade B)

2. Administration of high-dose inhaled bronchodilator (salbutamol 5mg via nebuliser, q15 minutes up to a maximum of 20mg). (Grade A)

3. Corticosteroids should be given within 1 hour of presentation. (Grade A)

4. Antibiotics are not required unless there is radiological evidence of pneumonia or proven or suspected bacterial bronchitis. (Grade B)

Quick Reference Guide - In Hospital Management of Asthma[2]References:

  1. Status asthmaticus and hospital management of asthma, Spagnolo SV - Immunol Allergy Clin North Am - Aug; 21(3); 503-533, 2001
  2. Guidelines for the Hospital Management of Acute Asthma, Evidence Based Guidelines in RoyalMelbourneHospital, Review date: October 2000
  3. Acute Asthma in Adults-A Review, CHEST 125:1081–1102, 2004
  4. BTS/SIGN. British guideline on the management of asthma. Thorax; 58 (Supple I ):i1–94. 2003
  5. Global Initiative for Asthma: Guideline for Asthma Management and Prevention - updated November, 2003.

1