pulmonary volumes and capacities

8/8/2019 Pulmonary Volumes and Capacities

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Pulmonary Volumes andPulmonary Volumes and

CapacitiesCapacities


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SpirometrySpirometry Is the process of measuring volumes of airIs the process of measuring volumes of air

that move into and out of the respiratorythat move into and out of the respiratorysystem.system.


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SpirometerSpirometer Is the device that is used to measureIs the device that is used to measure

these pulmonary volumesthese pulmonary volumes

Measurements of the respiratory volumesMeasurements of the respiratory volumescan provide information about the healthcan provide information about the healthof the lungs.of the lungs.


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SpirometerSpirometer


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F

our Pulmonary VolumesF

our Pulmonary Volumes Tidal VolumeTidal Volume

Inspiratory Reserve VolumeInspiratory Reserve Volume Expiratory Reserve VolumeExpiratory Reserve Volume

Residual VolumeResidual Volume


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T

idal VolumeT

idal Volume Is the volume of air inspired and expiredIs the volume of air inspired and expired

with each breathwith each breath

At rest, quiet breathing results in a tidalAt rest, quiet breathing results in a tidalvolume of aboutvolume of about 500 milliliters500 milliliters (mL).(mL).


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I

nspiratory Reserve VolumeI

nspiratory Reserve Volume Is the amount of air that can be inspiredIs the amount of air that can be inspired

forcefully after inspiration of the restingforcefully after inspiration of the restingtidal volume (about 3000 mL).tidal volume (about 3000 mL).


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Ex

piratory Reserve VolumeEx

piratory Reserve Volume Is the amount of air that can be expiredIs the amount of air that can be expired

forcefully after expiration of the restingforcefully after expiration of the resting

tidal volume (about 1100 mL)tidal volume (about 1100 mL)


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Residual VolumeResidual Volume

Is the volume of air still remaining in theIs the volume of air still remaining in therespiratory passages and lungs afterrespiratory passages and lungs after

maximum expiration (about 1200 mL)maximum expiration (about 1200 mL)


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The tidal volume increases when a personThe tidal volume increases when a personis more active. Because the maximumis more active. Because the maximum

volume of the respiratory system does notvolume of the respiratory system does notchange from moment to moment, thechange from moment to moment, theincrease in the tidal volume causes aincrease in the tidal volume causes a

decrease in the inspiratory and expiratorydecrease in the inspiratory and expiratoryreserve volumes.reserve volumes.


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Lung Volumes and Lung CapacitiesLung Volumes and Lung Capacities


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Pulmonary CapacityPulmonary Capacity

Is the sum of two or more pulmonaryIs the sum of two or more pulmonaryvolumesvolumes

Examples:Examples:

Functional Residual CapacityFunctional Residual Capacity

Inspiratory CapacityInspiratory Capacity

Vital CapacityVital Capacity

Total Lung CapacityTotal Lung Capacity


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Functional Residual CapacityFunctional Residual Capacity

Is the expiratory reserve volume plus theIs the expiratory reserve volume plus theresidual volume, which is the amount ofresidual volume, which is the amount of

air remaining in the lungs at the end of aair remaining in the lungs at the end of anormal expiration (about 2300 mL at rest)normal expiration (about 2300 mL at rest)


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Inspiratory CapacityInspiratory Capacity

Is the tidal volume plus the inspiratoryIs the tidal volume plus the inspiratoryreserve volume, which is the amount of airreserve volume, which is the amount of air

that a person can inspire maximally after athat a person can inspire maximally after anormal expiration (about 3500 mL at rest)normal expiration (about 3500 mL at rest)


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Vital CapacityVital Capacity

Is the sum of the inspiratory reserveIs the sum of the inspiratory reservevolume, the tidal volume and thevolume, the tidal volume and the

expiratory reserve volumeexpiratory reserve volume

It is the maximum volume of air that aIt is the maximum volume of air that aperson can expel from his respiratory tractperson can expel from his respiratory tract

after a maximum inspiration (about 4600after a maximum inspiration (about 4600mL)mL)


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Is the sum of the inspiratory andIs the sum of the inspiratory andexpiratory reserves and the tidal andexpiratory reserves and the tidal and

residual volumes (about 5800 mL).residual volumes (about 5800 mL).

The total lung capacity is also equal to theThe total lung capacity is also equal to thevital capacity plus the residual volume.vital capacity plus the residual volume.


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FormulasFormulas

CapacityCapacity

Vital Capacity (VC)Vital Capacity (VC)

Inspiratory Capacity (IC)Inspiratory Capacity (IC)

Functional ResidualFunctional Residual

CapacityCapacity


(TLC)(

TLC)

FormulaFormula

TV + IRV + ERVTV + IRV + ERV

TV + IRVTV + IRV

ERV + RVERV + RV

TV + IRV + ER + VRVTV + IRV + ER + VRV


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Factors influencing respiratoryFactors influencing respiratory

volumesvolumes SexSex

AgeAge

Body SizeBody Size


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Forced Expiratory Vital CapacityForced Expiratory Vital Capacity

Is the rate at which lung volume changes duringIs the rate at which lung volume changes duringdirect measurement of the vital capacitydirect measurement of the vital capacity

It is a simple and clinically important pulmonaryIt is a simple and clinically important pulmonarytesttest

How is it done?How is it done?

The individual inspires maximally and tehnThe individual inspires maximally and tehn

exhales maximally and as rapidly as possible intoexhales maximally and as rapidly as possible intoa spirometer. Then, the spirometer records thea spirometer. Then, the spirometer records thevolume of air expired per second.volume of air expired per second.


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This test can be used to help identifyThis test can be used to help identifyconditions in which the vital capacityconditions in which the vital capacity

might not be affected, but in which themight not be affected, but in which theexpiratory flow rate is reduced.expiratory flow rate is reduced.

Abnomalities that increase the resistanceAbnomalities that increase the resistanceto airflow slow the rate at which air can beto airflow slow the rate at which air can beforced out of the lungs.forced out of the lungs.

pulmonary volumes and capacities

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