EE 416 Fundementals of Biomedical Engineering Laboratory Spring 2006
Objectives: To make respiratory volume measurements using a spirometer.
Equipment: Spirometer
Average Time to Complete: 1.5 hrs
The respiratory system consists of a number of anatomic passageways through which the air we breathe travels to the delicately structured lungs. During expiration, the movement of air from the atmosphere into the lungs, air is moved through the nose, pharynx, larynx, trachea and successively smaller division of the bronchial tree, until it reaches the numerous tiny air sacs, the pulmonary alveoli. During the expiration the movement of air is from the lungs into the atmosphere, the path is reversed. Air flows through the passageways during respiration because of the above pressure effects: a.
Atmospheric pressure: The pressure exerted by the air surrounding the body. b.
Intrapulmonary pressure: The pressure within the respiratory space of lungs. c.
Intraplueral pressure: The pressure within the pleural space between the lungs and the walls of the thoratic cage.
The instrument used to measure lung capacities, volumes of air exchanged and rate of respiration is the spirometer. Table 1 shows respiratory volume measurements and Figure 1 shows the normal spirometric values for female and male.
The test result on a spirometer is expressed in ATPS (ambient temperature) conditions. This result must be converted into BTPS with the correction factors given in Table 2.
1

EE 416 Fundementals of Biomedical Engineering Laboratory Spring 2006
III.
Respiratory Rate:
1.
Have your partner sit quietly for 5 minutes.
2.
After the test period, count the number of complete respiratory cycles (inspiration and expiration) in 60 seconds. Make two additional counts while your partner is still sitting.
3.
Make three counts with your partner standing and three counts in the prone position.
4.
Instruct your partner to breathe normally for 4 respiratory cycles and then on the fifth cycle to inhale as deeply as possible and to exhale as forcefully and steadily as possible into the spirometer mouthpiece.
5.
Record the volume and time the expiratory portion of the last cycle. Determine the average EVC value. Repeat the procedure two more times.
6.
Change places with your partner and repeat procedure.
Results And Observations:
1.
Make tables for respiratory rate, tidal volume, expiratory reserve volume and forced expiratory vital capacity measurements.
2.
Find the normal values for EVC from Fig. 1. Discuss the differences between theoretical and experimental results.
2

EE 416 Fundementals of Biomedical Engineering Laboratory Spring 2006
Measurement
Tidal volume (TV)
Respiratory rate (RR)
Minute volume (MV)
Brief Description Normal Values For Adults volume (IR) volume (ERV)
Vital capacity (VC)
Residual air (RA)
Total lung capacity (TLC)
Dead space
Quantity of air moved into and out of the lungs during a normal breath
Number of breaths per minute
Quantity of air moved into and out of the lungs in minute (MV=TV x RR) volume that can be forcefully expired after a normal inhilation volume that can be forcefully expired after a normal inhilation
Maximum quantity of air that can be moved into and out of the lungs
( VC = IR + TV + ERV )
Quantity of air left in the lungs after maximum expiration
Quantity of air that the lungs can hold
(TLC = VC + RA)
Air which is not available for gas exchange
Table 1. Respiratory Volume Measurements
500 ml
12 - 15
6.000 ml / min
3.000 ml
1.200 ml
4.500 – 5.500 ml
1.200 ml
5.900 ml
100 m (Female)
150 (Male)
3

EE 416 Fundementals of Biomedical Engineering Laboratory Spring 2006
Temperature in o
C ATPS to BTFS Correction Factor
25
26
27
28
29
30
31
19
20
21
22
23
24
32
33
34
35
36
37
11
12
13
14
15
16
17
18
1.014
1.007
1.000
Table 2. Correction Factors From ATPS to BTPS
1.107
1.103
1.097
1.091
1.085
1.080
1.074
1.069
1.063
1.057
1.051
1.045
1.039
1.032
1.026
1.020
1.149
1.144
1.139
1.134
1.129
1.124
1.119
1.113
4

EE 416 Fundementals of Biomedical Engineering Laboratory Spring 2006
Figure 1. Scales for the determination of normal spirometric values for females and males. These values are expressed in terms of a normal range for age, height, and sex.
To use these scales place the edge of a ruler at the correct point on the age scale. The points at which the ruler intersects the FEV 1.0 (forced expiratory volume in one second) and FVC (forced vital capacity) scales give the normal values for those measurements.
5

EE 416 Fundementals of Biomedical Engineering Laboratory Spring 2006
Figure 2. A spirogram, showing the devisions of the respiratory air.
References
[1] ed. J. G. Webster, Medical Instrumentation.
New York: Wiley, 3 rd
ed.
6