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In our previous blogs we have discussed about Oxygen Concentrator, Medical Device Product Life Cycle, Telemedicine, Infant Incubator. Please check out for the link below.

Today we are going to discuss about Spirometer.

The Spirometer is a important medical device used to diagnose the lung condition. Being a healthcare professional, its important to know in detail about Spirometer

Let's get into the topic.

WHAT IS SPIROMETER?

The spirometer is a medical device used to gain understanding about how well the lung functions. The spirometer measures the amount air inhaled and exhaled by the lungs and the speed at which the air is inhaled and exhaled into the lungs. Spirometer is also called as respirometer. The spirometer is used to understand conditions like asthma and also to understand the recovery of lungs after a chronic lung disease. The study done using spirometer is called spirometry. The spirometry is a type of pulmonary function test. The spirometry is used to determine whether the lung conditions is obstructive (exhalation is impaired) or restrictive (inhalation is impaired).

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OBSTRUCTIVE LUNG DISEASE

In obstructive lung disease there is a difficulty in exhaling and emptying the air in the lungs completely due to damage of the lungs and narrowing of airways.

RESTRICTIVE LUNG DISEASE

The restrictive lung disease is a condition in which there is a little air in the lungs and it does a poor job in transferring oxygen into the blood.

HOW SPIROMETRY TEST IS PERFORMED?

1. Patient’s nostrils will be closed by placing a clip onto the patient’s nose.

2. A hose attached with mouth piece at one end is given to the patients. Then the patients are asked to seal the mouth piece with their lips.

3. Patient’s have to take deep breathe in and breathe out into the tube. This step is repeated atleast three times to verify the consistency in patient’s breathing. The highest reading out of three is taken as a final result.

4. There should not be any air leaks between patient’s mouth and the mouth piece of the spirometer.

WHAT ARE THE COMPONENTS OF SPIROMETER?

The components of spirometer include mouthpiece, hose and an electronic setup to measure air flow. The patient breaths using the mouth piece, which generates air flow into the tube. This air is then converted into an electrical signal using a sensor.

WORKING PRINCIPLE OF SPIROMETER

A jar is kept inverted in a chamber of water. The height of jar in the water chamber is proportionate to the amount of air inside the jar. One end of the jar is attached to the mouth piece through which the patient breaths. The other end of the jar is connected to the weight via pulleys. When the patient exhales via mouth piece, the pressure inside the jar increases greater than atmospheric pressure which makes the height of the jar increase above the water. When the patient inhales via mouth piece, the pressure inside the jar decreases than the atmospheric pressure which makes the height of the jar decrease in the water. When the jar moves inside the water chamber due to the exhalation and inhalation of the patient, the weight attached to the jar also moves accordingly. The movement of the jar is then converted into electrical signal and displayed in the form of a graph called spirogram.

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WHAT IS SPIROGRAM?

When spirometry test is performed, the result is shown in a graph called spirogram. The volume of air inhaled and exhaled is shown along X axis in litres and flow rate is shown along Y axis in litres per second. The inspiration results are plotted below the X axis and the expiration results are plotted above the X axis. Based on the shape and magnitude of the graph, many airway obstruction diseases are diagnosed.

IMPORTANT PARAMETERS OF SPIROMETRY TEST

FORCED VITAL CAPACITY

The largest amount of air that can be forcefully exhaled after breathing in as much as you can. The value which is lower than normal forced vital capacity indicates a restricted breathing.

FORCED EXPIRATORY VOLUME

The amount of air that can be exhaled from lungs in one second. The value lower than normal forced expiratory volume indicates significant obstruction.

Now I hope you have acquired some knowledge about Spirometer. We will meet again with another valuable topic related to Biomedical Engineering, Medical Device, Healthcare.

NOTE: Dear friends!!!... Please do comment a topic related to Biomedical, so that we can discuss it in future blogs.

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