A peak flow meter is a device that measures how quickly you can push air out of your lungs. Monitoring your breathing with a peak flow meter can help you and your healthcare professional assess how open your airways are. That way, you'll be aware of times when your asthma may be worsening. 

Instructions: 

Your peak flow is a measure of how fast you can push air out of your lungs. Your healthcare team will tell you when and how often to measure your peak flow. Below are simple instructions for using a peak flow meter. Be sure to write down your results. Take the results with you when you visit your healthcare team. Regular monitoring tells you how well your treatment plan is working. 

Move the marker to 0 or to the lowest point/position on the scale. Stand. If you can't stand, be sure to sit up straight. Make sure you're in the same position each time you test. 
Take in as deep a breath as you can. 

Put the mouthpiece of the peak flow meter in your mouth between your teeth. Close your lips tightly around it. Be sure your tongue does not block the opening. Blow into the mouthpiece once, as hard and as fast as you can. 

Take the peak flow meter out of your mouth. Look at the marker. It will have moved along the numbered scale. Write this number down. Move the marker back to 0 or to the lowest point/position on the scale. 

Repeat the test two more times. 

Write the highest of the three numbers on your chart or in your diary. This is your peak flow meter number. 

What the results mean: 

Your healthcare professional can help you create an Asthma Action Plan that tells you what to do if your asthma gets out of control. Action plans are often based on the asthma zone you're in at a given point in time. Your healthcare team will explain how your symptoms or peak flow numbers can help you know which asthma zone you are in. 

Green zone: under control 

When you're in your green zone, you feel good. Your asthma doesn't get in the way of work, activities, or sleep. You're doing a good job helping to control your asthma. 

Action: Keep following your daily treatment plan. 

Yellow zone: caution 

When you're in your yellow zone, your airways are becoming swollen, inflamed, and narrower. You may have warning signs such as coughing, wheezing, chest tightness, or shortness of breath. Your asthma may keep you from doing some normal activities. If you don't take action right away, you may move into the red zone and have an asthma attack. 

Action: Take the medications suggested in your action plan. Get away from your triggers. 

Red zone: medical alert 

When you're in your red zone, you're having an asthma attack. You're most likely coughing, wheezing, and having a lot of trouble breathing. Stop and take action. 

Action: Take your fast-acting inhaler and any other medications your action plan suggests. Then talk to your healthcare provider right away or go to the hospital. You’re your local emergency number (1066 in India) instead if you are struggling to breathe, can't walk or talk because of shortness of breath, or your lips or fingernails are turning blue. 

Note: If you are not staying in your green zone, discuss your daily treatment plan with your healthcare professional.