RespiratoryVolumes &
Capacities
2/1/00
Measurement of Respiration
• Respiratory flow, volumes & capacities are
measured using a spirometer
Amount of water displaced
gives you estimate of the air
required to displaces it
Recording
Drum
Air Chamber
Water
Spirometry
• The measurement of air volumes and
capacities
– Volume: subdivision of the total amount of
air that can be contained in the lungs
– Capacity: Sum of two or more volumes
Spirometer
Percent Vital Capacity
Respiratory Volumes
Inspiratory Volume
Reserve
Vital Capacity
Total Capacity
Tidal Volume
Expiratory Volume
Reserve
Residual Residual
Volume Volume
Tidal
Volume
Resting
Expiratory
Level
Functional
Residual
Capacity
Inspiratory Reserve Volume
Vital
Capacity
Total Lung Capacity
Inspiratory
Capacity
Tidal Volume
(Increasing Activity)
Expiratory Reserve Volume
Residual Volume
Spirometer for measuring
respiratory volume
Measurement of Respiration
Manometer
-Measures Pressure;
more force used the
higher the water rises
cm H2O
Respiration for Life
• Quiet respiration
– Economy of effort
– Minimum departure from the resting volume
– Relaxed balance exists between tendencies of thorax
expansion & lung collapse
– Balance is typically at 35-40% of vital capacity
(amount available for use)
– Quiet inspiration= the volume of air that can be
inhaled from a resting level with muscle contraction
– Quiet expiration= Passive process by elastic recoil of
lungs & abdomen
Quiet Respiration
Insp.
Exp.
Percent of Vital Capacity
40%
60%
40
Resting Volume
Resting Tidal
Volume
0
*Volume of air move called resting tidal volume
Vital Capacity based on Age & Gender
VC (ml)
Male
Female
Age (Years)
Typical Respiratory Volumes & Capacities in
Adults
Volume/
Capacity
VC
Resting TV
TLC
Females (cc) Males (cc) Average (in cc)
3200 cc
4800 cc
4000 cc
450cc
600 cc
525cc
4800 cc
6000 cc
5100 cc
Females: VC in ml= 21.78- (0.101 x age in years) x ht.in cm
Males: VC in ml= 27.63- (0.112 x age in years) x ht.in cm
Breathing for Speech
• Same respiratory equipment and measures of
air volume &lung capacity apply for speech
breathing
• Difference? How & Why they are used!
– Life- Objective to move O2 & CO2 in & out of
lungs
• resistance interferes
– Speech- Objective to have air under pressure;
force vocal folds to vibrate
• Achieve pressure by resisting airflow
Passive & Active Forces
• Active Forces = Muscles (Rib Cage,
Abdomen, diaphragm)
• Passive Forces = Generated by elastic
properties of respiratory tissue (lungs,
muscles, tendons) when returning to rest
High
Recoil Properties of
Chest wall & Lung
Relaxation Pressure Curve
Lung
Volume
Chest Wall
FRC
Vital Capacity (%)
Lung
Alveolar pressure (cm H20)
Low
Recoil: Chest Wall & Lung
• High LV = Both chest wall & lung collapse
due to extension beyond rest
• 50% VC = Chest wall is neutral, but lungs
tend to collapse
• FRC = Tendency of expansion of chest wall
is equal to opposite tendency of lungs to
collapse
• Low LV = Chest wall tends to expand &
lungs tend to collapse
Relaxation-Pressure Curve
• Passive conditions- absence of muscular effort
• Passive alveolar pressures generated at a particular
lung volume
– High LV = combined recoil forces contribute to high
alveolar pressure
– 38% LV = Equilibrium; alveolar pressure is 0
– 38% & below = relaxation pressure is negative
(alveolar pressure less than atmospheric); inspiratory
forces are passive
Vital Capacity (%)
Pressure- Volume Diagram
IP
RP
Alveolar Pressure (cm H20)
EP
Flow Volume Loop
• Relation between
rate of airflow & LV
for inspiration &
expiration.
• Expiration phase
indicates peak exp.
flow rate achieved
at low LV (30%)
• Peak rate of airflow
is greater for expiration
Respiratory Kinematics
Introduction
• Dynamic aspects of the chest wall function during
speech via motion of the chest wall
• Measuring changes in the anteroposterior
diameters (RC & AB)
• Motions of RC, AB & Diaphragm sum to match
movements of the lung (LV can be determined)
• Individual volume displacements of RC & AB
• Contributions to LV from RC & AB
Magnetometer Position
Method
• Equipment:
– Rib cage & abdominal magnetometers
• Two generator-sensor coil pairs
– Catheter-balloon techniques
• esophageal & gastric pressures
• Measurements:
– made in supine and upright positions
– VC
– Isovolume maneuvers at specified LV’s (20% VC)
• Created relaxation curve
Method
• Utterances:
– Sustained production of /a/
• At 130 Hz
• 3 loudness levels- soft, comfortable, loud
– Repeated syllable task /pa/
• 4 per/second
• 3 loudness levels- soft, comfortable, loud
– Spontaneous conversation
– Normal reading “The Rainbow Passage”
Results
• Motion Diagrams:
– Left of relaxation = pressures operating to make
RC larger &AB smaller
– Right of relaxation = pressures operating to
make RC smaller & AB larger compared to
relaxation
Motion Diagram: Relaxation
Sustained Vowel & Syllable Repetition
•High lung volumes for initiation
•Chest wall configuration different than relaxation
•RC expanded more than AB during speech (left of relaxation)
•RC larger than AB for loud productions
Relative Motion Charts: Supine
•Both RC & AB decrease in LV
•Majority of volume change above FRC
•Gravity acts on RC & AB in expiratory position
Discussion
• Regulation of alveolar pressure in accordance with
the demands of the utterance
– Accomplished by adding muscular pressure
• Chest wall exerted increasingly more positive
effort as lung volume decreased
– Decreased passive recoil from relaxation pressure
means more active muscular forces are necessary
• Louder speech
– Higher lung volumes (relaxation pressure high)