Measuring Lung Capacity Using Portable Spirometer

BIOLOGY LAB REPORT TITLE

: MEASURING LUNG CAPACITY USING PORTABLE SPIROMETER 

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Abstract Lung capacity varies with individual depending o n certain criteria’s such as age, gender and bod y size. Lung capacity can be ca lculated using vital capacity (VC), tidal volume (TV) and expiratory reserve volume (ERV). This experiment was conducted to investigate breathing using a dry portable spirometer. Each students are given disposable mouthpiece with spirometer (shared in a gro up) to measure VC, TV and ERV. E RV. This is done by exhaling air a ir through the mouth piece in different ways (refer procedure) and record the reading. Using the data obtained, other measurements such as IC, IRV and TLC were obtained (refer formula below). The experiment is done by manipulating body’s body’s state, at rest and after exercise. Introduction (1)

1. The Lungs

The lungs are the main organ of the body responsible for gas exchange, namely the transfer of oxygen into the body and the transfer of carbon dioxide out of the body. The biomechanical properties of the lungs are integral in how well they can t ransfer air in and out. The gas exchange o f oxygen and carbon dioxide in the body takes p lace in three steps. 

Ventilation (refers to the moving air in and out o f the lungs) occurs.

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Gas diffusion and uptake occurs.

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The gas is transported by the blood.

The muscles that control respiration create a difference in lung pressures. This pressure difference, which is also a function of the elastici e lasticity ty of the lungs, causes air to flow. The diaphragm is the ma in muscle that is used for breathing. When the diaphragm d iaphragm contracts it causes the lungs to inflate and the thoracic cavity becomes enlarged. As a result, the pleural space in the chest cavity enlarges. This increase in space volume causes a decrease in pressure which causesthe lung to expand and fill with air. This is an example of Boyle’s Bo yle’s Law in action. Boyle’s Law states that For a constant temperature, the volume of any an y gas varies inversely with the pressure. Pressure ∞ 1/ Volume = Constant

2. The measurements of breathing

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Figure 1: Descriptions and average measurements

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Figure 2: Indicating measurements

3. Spirometer 

Figure 3 : Usage of spirometry

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Spirometry is the classic pulmonary function test, which measures the capacity of the lungs to exhale and inhale air, and the amount of air left remaining in the lungs after voluntary exhalation. It can monitor quiet breathing and thereby measure tidal volume, and also trace t race deep inspirations and expirations to give information about vital capacity. The instrument use for this procedure is called spirometer. This device also considered as an essential tool in the detection of chronic obstructive pulmonary disease, which includes emphysema and chronic bronchitis. In addition, spirometers are typically used to track the breathing capability of individuals with respiratory ailments such as asthma. Spirometers are also used to estimate limits of activity for people with respiratory problems.

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Figure 4: Portable dry spirometer with mouthpiece

The normal, healthy values measured by the spirometer for the amount of air exhaled vary f rom person to person. Your results are compared to the average expected in someone of the same age, height, sex, and race, according to the National Heart, Lung, and Blood Institute (NHLBI). However, if  the values fall below 85 percent of the average, it may indicate a lung disease or other airflow obstruction. If a person has abnormal spirometer measurements, he/she may be referred for other lung tests to establish es tablish a diagnosis.

Figure 5: Spirometer reading

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In this experiment we use the Carolina Portable Dry Spirometer which provides a simple but accurate means for measuring pulmonary volumes and capacities in the laboratory. The principle of operation is similar to that of a rotametric dry gas meter. Since the water canister associated with a conventional conventional wet spirometer is not used, setup time and the mass associated with spirometry are virtually eliminated.

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Objective To measure student’s lung capacity using a po rtable spirometer. Problem Statement What is the total lung capacity of o f the student? Does body state effect the total lung capacity or the  breathing rate? Hypothesis Total lung lung capacity of a student depend the body’s state (rest/active). This can be calculated by obtaining tidal volume, vital capacity and exp iratory reserve volume.

Variable : Types of Variables

Ways to control the variables

Manipulated Variable: State of body

Measurement were taken at rest and after a fter exercise

Responding Variables: Vital Capacity, Tidal Volume, and Expiratory Reserve Volume of the Students

Following procedure below, find VC, TV and ERV via reading the scale on the dry spirometer.

Fixed Variables: Age

Same age student was examined.

Body size

Same student was used.

Apparatus Spirometer, disposable mouthpiece.

Materials Tissue, human subjects (students).

Procedure 1. A mouthpiece is attached to t he side limb of the spirometer. 2. The spirometer spiro meter dial is rotated until the needle is aligned with t he ‘0’ mark. The dial, marked in increments of 100cc, will register up to 7.0 liters liters of expired air. 3. The spirometer is held by the base/ put on a table so that the t he air holes are not blocked and in a horizontal positi pos ition. on. 4.  Nostrils are pinched with free free hand to keep air from from escaping through the nose. The breathing maneuver for vital capacity, tidal volume and e xpiratory reserve volume is performed. a) i. ii. iii.

Vital Capacity (VC) The nasal airway is closed by pinching the nose. The subject inhaled as deeply deep ly as possible and exhaled all of the air a ir through the spirometer. The value shown on o n the spirometer gauge is recorded

b) Tidal Volume (TV) i.  Nose is pinched. The spirometer mouthpiece is placed loosely between lips, lips, and breathed normally through the corner of the mouth for several breaths. ii. After a regular breathing pattern is established, five successive normal breaths are exhaled into the spirometer. iii. The meter reading for the total of five breaths are recorded and divided by 5 to calculate the average tidal volume at rest. c) Expiratory Reserve Volume (ERV) i.  Nose is pinched. The spirometer mouthpiece is placed between lips, lips, and breathed normally through the corner of the mouth for several breaths. ii. After a regular breathing pattern is established, remaining air is expired forcefully as much as  possible into the spirometer. iii. The value shown on o n the spirometer gauge is recorded

5. Both Tidal Volume and Expiratory Reserve Volume experiments were repeated thrice. 6. The results of the experiments are used to calculate value for Total Lung Capacity (TLC) , Inspiratory Reserve Volume (IRV), and Inspiratory Capacity (IC) using formula formula below.

For IRV : VC - ( TV + ERV ) For IC : VC - ERV For TLC : VC + RV( 900 cc for for female) 7. All the steps above are repeated repeat ed on the subject after a fter undergo exercise.

Safety precaution In order to avoid any accident or injury during the experiment in laboratory, the precaut ionary steps should be be taken and applied. Wearing lab coat and a pair of suitable shoes are compulsory compulsory when conducting an experiment in the lab at all times to protect the skin and clothing from spillage of any chemical substance. Hands need to be thoroughly washed before be fore and after performing the experiment to avoid infection of saliva. Furthermore, t he glassware such as spirometer should be handled with full care because they are fragile. After using the mouthpiece at the end of  experiment, they should be rinsed properly pro perly and returned back to t heir respective beakers. The same should be done with the spirometer, where it shou ld be cleaned and dried before place p lace it inside its box. Student should take care of surrounding so that t hey don’t collide with any glassware while undergoing exercise.

Risk Assessment

The spirometer base is a moisture trap which should be cleaned frequentlyto avoid inaccuracy in results. The spirometer should be hold upright horizontally or best put on a flat surface that is leveled with body’s sitting positi po sition on and screw the top portion counter-clockwise to separate the two parts. Wipe the moisture trap with a tissue ever y time after finish one stage of experiment and  before storing the spirometer. spirometer. Besides that, subjects must not cover up the small holes holes which are at the side of the upper bod y of the spirometer with hands.

Results

Rest After Exercise

Rest After Exercise

Rest After Exercise

Trial 1 2500 2700

Vital Capacity (VC) Trial 2 Trial 3 2900 3100 3200 3300

VC Highest Volume 3100 3300

Tidal Volume (TV) Total for Five Breaths 2200 2275 Expiratory Reserve Volume (ERV) Trial 1 Trial 2 Trial 3 2000 2200 2100 1900 2500 2200

Rest After Exercise

Inspiratory Reserve Volume (IRV): VC  –  (TV + ERV) 3100 – (440 3100 –  (440 + 2100) = 600 3300 –  3300 – (455 (455 + 2200) = 645

Rest After Exercise

Inspiratory Capacity (IC): VC  –  ERV 3100 – 2100 3100 –  2100 = 1000 3300 –  3300 – 2200 2200 =1100

Rest After Exercise

Residual Volume (RV) 900 900

Rest After Exercise

Total Lung Capacity (TLC): VC + RV 3100 + 900 = 4000 3300 + 900 = 4200

Average 440 455

Average 2100 2200

Table 1 : VC, TV, ERV, IRV, IC, RV and TLC of student at rest and after exercise state

Data Analysis Analysis Table 1 above show the comparison done between two different body state (rest and after  exercise) to calculate vital capacity (VC), tidal vo lume (TV), expiratory reserve volume (ERV), inspiratory reserve volume (IRV), inspiratory capacity (IC) and total lung capacity (TLC). After  exercise, we can see there are some different compared to the value before exercise (rest) for the student. It can be see that o verall all measurement increase except residual volume which was kept constant. The highest increase can be seen in IRV and VC while the smallest increase can be noted in TV.

DISCUSSION From this experiment, it can be seen that t hat the state of o f body influences the breathing rate of o f the student. The ventilation rate is higher after exercise compared to rest state indicating that more a ir is inhaled after exercise to fulfill the lungs. During rest, amount of oxygen needed by the body is lesser since oxygen is needed to respire thus ventilation rate is smaller. During exercise, the presence o f the anatomical dead space o f the respiratory system (air in the nose, mouth, larynx, tracheas, bronchi and bronchioles) cause the depth of breathing increases. This air reaches the a lveoli first upon inspiration. This air also has a higher  concentration of carbon dioxide because of its prolonged exposure to the t he tissues. Therefore, as the depth of a breath increases, the proportion of "fresh air" that gets to the alveoli also incr eases and the result is rate of gaseous exchange will also increase. Vital capacity is how much the lungs can breathe in, so it will not change, unless lung capac ity changes. Exercise increases vital capacity because the lungs need more oxygen to supply the muscles with vital nutrients (oxygen and glucose) and the intense the exercise the more nutrients nut rients needed. The lungs expand during this to account for the extra need hence increasing the vital capacity. This is  positively correlated with the data in Table 1. When exercising the tidal volume also increase because the student is breathing at a faster rate and their muscles are using up the oxygen at a quicker rate. Hence more oxygen is needed and these will increase the tidal volume to allow more ox ygen to be co nsumed and meet the muscles oxygen demands. The residual volume vo lume is kept control because it cannot be measured and normally stays the same disregarding body state. Thus, I can be seen that exercise increases total lung capacity at the end of exercise.

Limitations and Sources of errors There are several sources of error and limitations limitations that have bee n identified throughout this experiment. 

The way student exhale. The strength g iven while exhaling out the air is different in term of  strength. This is because, the student is unable to exhale as usual but blow which co ntribute to the inaccuracy of data.

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The exercise done by student is not fixed in term of the type of exercise and du ration of time. This is because the student needed to complete the experiment in the given time and space for  exercise to be done is too small and not safe.

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The experiment is not compared with the other ot her students or not repetitive measurement is taken. Thus, the data is unreliable.

Conclusion Body state of person do affect vital capacity (VC), tidal volume (TV), expiratory expiratory reserve volume (ERV), inspiratory reserve volume (IRV), inspiratory capacity (IC) and total lung capacity capac ity (TLC). Thus, the hypothesis is accepted. Further Investigation Another experiment can be carried out o ut using same steps but by manipulating the body size of student. References 1. Gan W.Y . 2007. Biology 2007. Biology SPM Success. Edition 4. 287.p.Shah Alam : Oxford Fajar Sdn.Bhd. 2. http://www.sciencebuddies.org/science-fair-projects/project_ideas/HumBio_p009.shtml. th Accessed on 8 October 2012 th

3. http://www.brianmac.co.uk/diagram spirometer trace.htm. Accessed on 8 October 2012 th

4. http://www.angela.co.uk/diagram spirometer use adam.htm. Accessed on 8 October 2012 th

5. http://www.gogoscience _spirometer diagram/diagram spirometer.Accessed on 8 October  2012 th

6. http://lanwebs.lander.edu/faculty/rsfox/ireads/spirometertrace.html. Accessed on 8 October  2012 7. Portable Dry Spirometer Instructions- 69-2670. Carolina Biological Supply Company.2700, York Road,Burlington, North Carolina