ASTHMA
It is a disease affecting respiratory system.
Asthmatics have sensitive airways.
This sensitivity causes
narrowing of airways which makes difficulty in breathing.
During an asthma attack spasm in the airways is caused and
excessive mucous is produced.
Most of the asthmatic medications are inhaled, to facilitate it to the direct entry to the lungs, which indicates for the faster relief. There are basically 4 types of devices used to inhale medications.
INHALATION AEROSOL

Shake the inhaler well just before each use
Take off the cap and look at the mouthpiece to make sure it is clean
Test spray in the air before using for the first time or if the inhaler has not been used for a while (3 to 4 days)
Breathe out fully, trying to get as much air out of the lungs as possible. Put the mouthpiece just in front of your mouth with the
Open your mouth and breathe in slowly and deeply (like yawning), and at the same time firmly press down on the top of the canister once.
Hold your breath for about 5 to 10 seconds, then breathe out slowly. There after place the mouthpiece of the inhaler in your mouth between your teeth and close your lips around.
Tilt your head slightly backwards. Start breathing in slowly through your mouth. As you breath in, press down the canister to release one dose while continuing to breathe in steadily and deeply.
Remove the inhaler from your mouth and hold your breath for 10 seconds, or for as long is comfortable. Breath out slowly. After use replace the mouthpiece cover. If you are supposed to take more than one puff, wait 1 to 2 minutes between treatments. Repeat these steps for the next puff, starting with shaking the inhaler. After using the inhaler, either rinse your mouth or drink a glass of water, especially with steroid inhalers such as as beclomethasone, budesonide, fluticasone. 
How to use the Spacer

1. To assemble your Spacer, line up the notch of one half with the slot of the other half. Then push the two parts together firmly.
2. Remove the mouthpiece cover from the inhaler and check that the mouthpiece is clean.
3. Shake the inhaler well.
4. Fit the inhaler into the inhaler slot opposite the mouthpiece.
5. Hold the Spacer as shown. Breathe out gently.
6. Close your lips firmly around the mouthpiece as shown but do not bite it
7. Press the canister to release a dose of medicine into the chamber. Then breathe in steadily and deeply through your mouth.
8. Remove the Spacer from your mouth and hold your breathe for 10 seconds, or for as long as comfortable. Breathe out slowly.FOR ROTAHALER

1. Hold the Rotahaler vertically.
3. Press the Rotacap firmly such that the top end of the Rotacap is level with the top of the hole
4. Holding the mouthpiece firmly with one hand rotate the base. The fin separates the two halves of the Rotacap and can be seen through the transparent body of the Rotahaler. The rotahaler is now ready for use.
5. Breathe out fully. Grip the mouthpiece between your teeth and seal your lips around it. Tilt your head slightly backwards. Breathe in through your mouth as deeply as you can.
Nebuliser