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NO-COST SPIROMETER TO MEASURE

VITAL LUNG CAPACITY

Dr. G. NAGARAJ

Zoology Section

Regional Institute of Education (NCERT)

Mysore – 570 006

Indiagnriem@gmail.com

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Introduction

• Lung function tests are useful in assessing the Lung function tests are useful in assessing the

functional statusfunctional status of the respiratory system both in of the respiratory system both in

physiological and pathological conditions. physiological and pathological conditions.

• These tests are based on the measurement of These tests are based on the measurement of

volume of air volume of air breathed in and outbreathed in and out..

• Air in the lung is classified as Air in the lung is classified as Lung volumeLung volume and and

Lung capacities.Lung capacities.

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Lung Volume (LV)

It is the static volume of air breathed or volume of air present in lung under specific static condition. It is of four types:

1. Tidal Volume (TV): Volume of air breathed in and out of lungs in a single normal respiration (500 ml).

2. Inspiratory Reserve Volume (IRV): additional volume of air that can be inspired forcefully after normal inspiration (3300 ml).

3. Expiratory Reserve Volume (ERV): additional volume of air that can be expired out forcefully after normal expiration (3300 ml).

4. Residual Volume (RV): Volume of air remaining in the lungs even after forced expiration (1200 ml).

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Lung Capacity (LC)

It is the combination of two or more lung volumes

and of four types;

1.Inspiratory Capacity (IC): = TV + IRV = 3800 ml

2.Vital Capacity (VC): = TV + IRV = ERV = 4800 ml

3.Functional Residual Capacity (FRC): = ERV + RV = 2200 ml

4.Total Lung Capacity (TLC): = IRV + TV + ERV + RV = 6000 ml

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Measurement of LV and LC

Spirometry is the method to measure LV and LC. The instrument used is called SPIROMETER.

The above instrument is relatively complicated and costlier. Hence, I improvised a no-cost/ home-made instrument from the waste materials.

Pic-1. Regular Spirormeter

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A. Materials Required:

1. 2L/ 5L and 1L water bottles (waste)

2. One rubber cork/ bottle cap/ thermo coal

3. Two glass tube pieces (5mm dia.)/ empty ball pen case

4. Two feet rubber tube (5mm dia.)

Preparation of SPIROMETER

1L water bottle2L water bottle

glass tube

rubber tube

corkcap

Pic-2 Materials Required

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1. Make two holes in the rubber cork/ cap / thermo coal

2. Insert two glass tubes/ empty ball pen case in each hole; one short and one long reaching bottom

3. Fix one feet rubber tube on top of each glass tube (one for inflow and one for out flow)

4. Fix this cork / cap in the bottle mouth and make sure it is air tight (as shown in picture-3)

5. Convert 1L bottle as graduated measuring cylinder by calibrating it with regular measuring cylinder

B. Assembling the Instrument

Pic-3. Improvised Spirometer

Inflow

outflow

Gra

du

ate

d m

easu

rin

g b

ott

le

Water

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Working Mechanism & Procedure

1. The instrument works on ‘Archimedes Principle’

2. Remove the cork, fill 80% the bottle with water, fix

the cork again and insert the out-let tube in the

measuring bottle.

3. Inspire forcefully to the maximum and blow air

forcefully through the inlet pipe

4. The air entered in the bottle displaces equal amount

of water (Archimedes Principle) and it is collected &

measured in measuring bottle

5. Measured volume of water is equal to the VITAL

CAPACITY (VC) of lung (IRV + TV +ERV = 4800 ml)

6. Again fill water in the 2L bottle and repeat the

experiment with other persons at school, home and

neighbor area.

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ProjectTake up a small project to find out:

A. Is there any significant difference in VC between;

• Male & female

• Smokers & non-smokers

• Athletes & non-athletes

• Singers & non-singers

• Vegetarians &non-vegetarians

• Anemic &non-anemic

• Alcohol takers & non-takers

• Rural & urban subjects etc.

B. Whether VC has any relation with age, height,

weight, yoga, exercise, occupation, health status and

respiratory disorder.

Record your observation and present as project report.

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Advantages of this Instrument

1.The instrument is improvised from waste material hence, no expenditure

2.Archimedes Principle also learned together

3.Simple experiments/ projects can be conducted at schools and even at home

4.Develops creative thinking, enquiry and experimentation attitude

5.Learning by doing; so creates interest in learning.

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Thank you