Here is a picture of a traffic light. There are three traffic lights red, yellow and green. Red means stop, green
means go, and yellow means careful, slow down. Yellow is a warning signal that tells us that the light will change. Our bodies also give us signals like the yellow traffic light. For example, how does your body tells you when you are hungry? When we are hungry our stomachs growl; when it gets late, we get tired. These are warning signals.

Signals of Asthmatic Attack

People with asthma usually say that they often get warning signals that tell them they are going to have an asthma episode. These signs are just like the yellow light. They mean, be careful and do something special to manage wheezing or coughing. You may have different signals at different times. 

Based on symptoms and peak expiratory flow rate (PEFR) parameters zone criteria for measurement of severity of asthma and based on that drug therapy has been proposed. The zone system of severity can be compared to three colours of traffic lights; green, yellow and red zones and are defined as follows:

Zones

• Symptom free.
• PEFR: > 80% of personal best. Click here to know about PEFR.
• PEFR variability: < 20%. Click here to know about PEFR variability.

It means that your treatment plan is working hence pursue your regular activities and medicines. During this period mild trigger factors are well tolerated such as jogging, cold air, fumes etc. If symptoms are controlled or peak flow reading persists in the green zone for two weeks you may reduce medicines.

Yellow: Signals of Asthma

• Chest tightness.
• Nasal congestion or sneezing.
• Pits in the neck during inhalation.
• Intermittent deep breathe.
• Cough or wheeze after climbing one floor stairs.
• Excessive perspiration.
• Uncomfortable or restlessness.
• Tightness in neck, shoulder or chest muscles.
• Change in voice.
• Faltering of the tongue.
• 20% or more decrease in personal best peak flow.
• Itchy, scratchy throat.
• Difficulty in breathing or shortness of breath.
• PEFR: 50–80% of best.
• PEFR variability: 20-30%.

It indicates varying degrees of airway obstruction. Yellow zone is called "caution zone". In this zone trigger factors such as throat infection, a cold drink or ice-cream can precipitate asthma. PEFR in Yellow zone means you should add more medicines to come back again in green zone.

Red: A patient must visit a doctor, when

• Sleep is frequently disturbed by asthma.
• House work or job can not be carried out or with great difficulty.
• Effect of bronchodilator spray lasts for less than 3 hours.
• PEFR: < 50% of personal best.
• PEFR variability: > 30 %

This is red or crisis zone. At this time do not delay medication. If you know what medicines are to be taken, start these immediately. If you do not, consult your doctor right away.
Two types of patients have been found to run into serious asthma. One type adjust to the symptoms such as cough and wheeze but their breathing reserve is quite low so much so that even slightest trigger can cause trouble quickly. The other type overreacts to symptoms and often take more medicine than needed. The peak flow meter can help both type of patients to learn when to start, adjust and stop medication.

Emergency Signals : A patient must go straight to hospital, when:

• Asthma ties him to chair or cot.
• Too breathless to feed.
• Can not speak, or speak only single word.
• Too distressed to measure PEFR.
• Temporary confusion or loss of consciousness.
• PEFR < 33% of best.
• Turns blue and exhausted.