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Managing Asthma
Warning Signs of Worsening Asthma
Your asthma is becoming unstable if:
- You require your bronchodilator (reliever inhaler) more often than usual, or the effect not lasting as long as usual (more than 3 times a week excluding once a day before exercise)
- You have early morning wheeze or tightness in chest which persist despite usual treatment
- You are waking through the night with cough, wheeze or shortness of breath
- You become short of breath during the day and find it difficult to do your usual activities
- You develop cough and sputum
Your peak flow metre shows:
- lower than usual morning readings
- lower than usual pre-bronchodilator readings
- less response to than usual bronchodilator
- a trend downward over several days
- a marked difference between morning and evening peak flows (greater than 20% difference)
Your peak flow is below a predetermined "danger zone" set by your doctor after inhaled bronchodilator
Parameters of Acceptable Asthma Control: Canadian Consensus Guidelines
- Daytime symptoms < 4 days / week
- Night - time symptoms < 1 night / week
- Need for short - acting B2 - agonist < 4 doses / week*
- Exacerbations Mild, infrequent
- FEV1 or PEF > 85% of personal best, ideally 90%
- PEF diurnal variation < 15% of diurnal variation
- Physical activity Normal
- Absence from work or school None
Adapted from Boulet L-P, et al. Canadian Asthma Consensus Report 1999. CMAJ, 1999.
FEV1 + forced expiratory volume in 1 second. PEF + peak expiratory flow obtained with a peak flow metre.
*May use 1 dose for prevention of exercise-induced symptoms. Diurnal variation is calculated by subtracting the lowest PEF from the highest and dividing by the highest PEF multiplied by 100.
