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Lung volumes & Lung Capacities By Dr. Mudassar Ali Roomi (MBBS, M.Phil.) Assist. Prof. Physiology

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Lung volumes & Lung Capacities. By Dr . Mudassar Ali Roomi (MBBS, M.Phil. ) Assist. Prof. Physiology. LUNG VOLUMES AND CAPACITIES. SPIROMETER. 4 Lung Volumes. TV (Tidal Volume) = 500 ml I.R.V ( Inspiratory Reserve Volume) = 3000 ml = 3 L - PowerPoint PPT Presentation

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Page 1: Lung volumes &  Lung  Capacities

Lung volumes & Lung Capacities

By Dr. Mudassar Ali Roomi (MBBS, M.Phil.)

Assist. Prof. Physiology

Page 2: Lung volumes &  Lung  Capacities

LUNG VOLUMES AND CAPACITIES

Page 3: Lung volumes &  Lung  Capacities

SPIROMETER

Page 4: Lung volumes &  Lung  Capacities

4 Lung Volumes• TV (Tidal Volume) = 500 ml

• I.R.V (Inspiratory Reserve Volume) = 3000 ml = 3 L

• E.R.V (Expiratory Reserve Volume) = 1100 ml

• R.V (Residual Volume) = 1200 ml

Page 5: Lung volumes &  Lung  Capacities

Tidal Volume (VT)• Volume of air inspired or expired with each normal

quiet breath.• Value = 500 ml in adult male.

Page 6: Lung volumes &  Lung  Capacities

Inspiratory Reserve Volume (IRV)

• Extra volume of air that can be inspired over & above normal tidal volume, when person inspires with full force.

• Value = 3000 ml.

Page 7: Lung volumes &  Lung  Capacities

Expiratory Reserve Volume (ERV)• Maximum extra volume

of air, that can be expired by forceful expiration after the end of normal tidal expiration.

• Value = 1100 ml.

Page 8: Lung volumes &  Lung  Capacities

Residual Volume (RV)

• Volume of air remaining in the lungs after most forceful expiration.

• Value = 1200 ml

Page 9: Lung volumes &  Lung  Capacities

LUNG CAPACITIES(sum of 2 or more lung volumes)

• T.V = 500 ml• I.R.V = 3000 ml = 3 L

I.C (Inspiratory Capacity)= 3500 ml = 3.5 L

E.R.V = 1100 mlR.V = 1200 ml

F.R.C (Functional Residual Capacity) = 2300 ml

V.C (Vital Capacity)= TV + IRV + ERV= 500 + 3000+ 1100= 4600 ml

T.L.

C (T

otal

Lun

g Ca

paci

ty) =

580

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l

Page 10: Lung volumes &  Lung  Capacities

Inspiratory Capacity (IC)

• TV + IRV• Amount of air a person

can breathe in beginning at normal expiratory level & distending the lungs to maximum amount.

• Value= 3500 ml.

Page 11: Lung volumes &  Lung  Capacities

Functional residual capacity (FRC)

• ERV+ RV• Amount of the air that

remains in the lungs at the end of normal expiration.

• Value: 2300 ml.

Page 12: Lung volumes &  Lung  Capacities

Vital capacity (VC)

• VC = IRV + TV + ERV• Maximum amount of air a

person can expel from the lungs after 1st filling the lungs to their max. extent & then expiring to max. extent.

• value= 4600 ml• Calculations based on height • Females:(27.63 - (0.112 x age) x

(height in cm) • Males: (21.78 - (0.101 x age) x

(height in cm)

Page 13: Lung volumes &  Lung  Capacities

Total lung capacity (TLC)

• Max. volume to which the lungs can be expanded with greatest possible effort.

• VC + RV = TLC• Value= 5800 ml

Page 14: Lung volumes &  Lung  Capacities

FACTORS AFFECTING LUNG VOLUMES & CAPACITIES

• Sex: 20 -25 % less in women than in men.

• Height & built: Greater in larger people.

• Athletes: larger

• Small & Asthenic people: Smaller

Page 15: Lung volumes &  Lung  Capacities
Page 16: Lung volumes &  Lung  Capacities

• The Forced vital capacity (FVC) of the lung is the volume of air that can be forcibly expelled from the lung from the maximum inspiration to the maximum expiration.

Page 17: Lung volumes &  Lung  Capacities

• Forced expiratory volume in 1 second (FEV1) is the volume of air that can be expelled from maximum inspiration in the first second.

Page 18: Lung volumes &  Lung  Capacities
Page 19: Lung volumes &  Lung  Capacities

• Restrictive pattern• Due to conditions in which the lung volume is

reduced e.g fibrosing alveolitis, scoliosis. The FEV1 and FVC are reduced proportionately.

Page 20: Lung volumes &  Lung  Capacities

• Obstructive pattern• Due to conditions in which the airways are

obstructed e.g. asthma or COPD. The FEV1 and FVC are reduced disproportionately.

Page 21: Lung volumes &  Lung  Capacities
Page 22: Lung volumes &  Lung  Capacities

• Grading or Severity of COPD on the basis of FEV1%

FEV1%

<80% = mild <60% = moderate <40% = severe

Page 23: Lung volumes &  Lung  Capacities

Forced expiratory ratio (FEV1/FVC ratio)

• The FEV1/FVC ratio is the FEV1 expressed as a percentage of the FVC (or VC if that is greater) i.e the proportion of the vital capacity inhaled in the first second.

• It distinguishes between restrictive and obstructive lung diseases.

• Obstruction is defined as an FEV1/FVC ratio of <70%

Page 24: Lung volumes &  Lung  Capacities
Page 25: Lung volumes &  Lung  Capacities
Page 26: Lung volumes &  Lung  Capacities

• Restrictive ventilatory pattern

• FVC reduced <80%FEV1 reducedFEV1/FVC ratio normal

• Obstructive ventilatory pattern

• FVC normal or reducedFEV1 reduced <80%FEV1/FVC ratio reduced

Page 27: Lung volumes &  Lung  Capacities

Flow volume loops

• This is the same forced expiration converted electronically to illustrate flow rate as the lung empties.

• The x axis represents volume - from full inspiration to full expiration.

• The y axis represents the flow rate.

• Obstructive disease: ?• Restrictive disease:?