March 5, 2007
Posted in Category :

Breathing Tests

These are the most important tests for asthma as they identify how well you breathe and how efficiently your lungs function. These tests measure the amount of air that you breathe out and its rate of expulsion in each breath which enables the doctor to detect narrowing of the respiratory passages, if any. The breathing tests are simple, easy to perform and do not cause you any discomfort. You may however become tired, if you have asthma, because of the effort required to breathe in and out deeply.

There are two common types of breathing tests:

Spirometry is a simple machine that measures your vital capacity and forced expiratory volume (FEV). Vital capacity is the amount of air your lungs can hold when they are completely full. Forced expiratory volume is the measurement of the amount of air forced out from the lungs in one second. It measures how long and how fully you are able to blow the air out of the lungs.

The procedure using spirometry involves taking a deep breath and then blowing the air out quickly: You need to empty out the lungs before taking in a deep breath. If the initial tests indicate abnormal breathing, you will be asked to take medicine and repeat the test after the narrowed airways are relaxed and open. If your breathing improves after taking asthma medicines, it means that symptoms of asthma are present. Asthma is diagnosed if the volume of air or the rate of flow of air improves by more than fifteen per cent after taking the asthma medicines.

It is important to remember that no improvement in breathing after taking asthma medicines does not mean that you do not have asthma. If your asthma is mild, you may have normal spirometry readings in¬ between two attacks. In case you have severe asthma, you may need to take medicines continuously for a few weeks in order to open the airways.

Peak expiratory flow: This is used for a simple test to measure how fast you expel air from your lungs. It measures the peak expiratory flow. Although this test is not as sophisticated as a spirometry, it is used because it is less expensive, easy to use and the required machine is portable. In order to measure the peak flow, you need to take a deep breath and then blow very hard into the mouthpiece of the peak flow meter. The air that enters the meter from your lungs pushes a piston attached to a spring upwards on a dial. This dial indicates your peak flow. Measurement of the peak flow helps your doctor determine the severity of your asthma. Your doctor may also recommend that you use a hand peak flow meter in your house regularly to monitor your own airways. The results of the peak flow meter can vary in different situations. In case of a serious attack, a peak flow can help detect the severity of the attack. Depending upon the severity of the attack, you can decide if you need to seek medical help to relieve the asthmatic symptoms.