RespiratoryVolumes & Capacities

2/1/00

Measurement of Respiration

• Respiratory flow, volumes & capacities are measured using a spirometer

Amount of water displacedgives you estimate of the air

required to displaces it

Air Chamber

Water

RecordingDrum

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

Respiratory Volumes

Total Capacity

Vital Capacity

ResidualVolume

Inspiratory Volume Reserve

Tidal Volume

Expiratory Volume Reserve

ResidualVolume

Per

cen

t V

ital

Cap

acit

y

Tot

al L

un

g C

apac

ity

TidalVolume

InspiratoryCapacity

Vit

al

Cap

acit

y

Expiratory Reserve Volume

Inspiratory Reserve Volume

Tidal Volume(Increasing Activity)

Residual VolumeResting

ExpiratoryLevel

FunctionalResidualCapacity

Spirometer for measuringrespiratory volume

Measurement of Respiration

cm H2OManometer

-Measures Pressure; more force used the higher the water rises

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

40%

Insp.60%

Exp.

Resting TidalVolume

Resting Volume

0

40

Per

cen

t of

Vit

al C

apac

ity

*Volume of air move called resting tidal volume

Vital Capacity based on Age & Gender

Male

Female

VC

(m

l)

Age (Years)

Typical Respiratory Volumes & Capacities in Adults

Volume/Capacity Males (cc)Females (cc) Average (in cc)

VC 4800 cc3200 cc 4000 cc

TLC 6000 cc4800 cc 5100 cc

Resting TV 600 cc450cc 525cc

Males: VC in ml= 27.63- (0.112 x age in years) x ht.in cm

Females: VC in ml= 21.78- (0.101 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

Lung

Chest Wall

High

Low

FRC

Lung Volume

Vit

al C

apac

ity

(%)

Alveolar pressure (cm H20)

Recoil Properties of Chest wall & Lung

Relaxation Pressure Curve

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

Vit

al C

apac

ity

(%)

Alveolar Pressure (cm H20)

IPRP EP

Pressure- Volume Diagram

Flow Volume Loop

• Relation between rate of airflow & LVfor inspiration & expiration.

• Expiration phase indicates peak exp.flow rate achievedat low LV (30%)

• Peak rate of airflowis 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)