Lung Volumes and Lung Capacities: TV, IRV, ERV, RV, VC, IC, FRC, TLC by Nursesnote

 Lung Volume and Lung Capacities 

Lung Volumes 

Tidal Volume: 

Symbol: VT or  TV 

Description: The volume of air inhaled and exhaled with each breath

Normal Value: 500 mL or 5-10 mL/kg

Significance: The tidal volume may not vary, even with severe disease. 

Inspiratory reserve volume

Symbol: IRV 

Description: The maximum volume of air that can be inhaled after a normal inhalation. 

Normal Value: 3000 mL

Significance: A sigh takes advantages of the IRV potential. 

Expiratory reserve volume 

Symbol: ERV 

Description: The maximum volume of air that can be exhaled forcibly after a normal exhalation. 

Normal Value: 1100 mL

Significance: Expiratory reserve volume is decreased in restrictive disorders, such as obesity, ascites, and pregnancy. 

Residual Volume 

Symbol: RV

Description: The volume of air remaining in the lungs after a maximum exhalation. 

Normal Value: 1200 mL

Significance: Residual volume may be increased in obstructive disease. 

Lung Capacities 

Vital Capacity 

Symbol: VC 

Description: The maximum volume of air exhaled from the point of maximum inspiration. 

VC = TV + IRV + ERV

Normal Values: 4600 mL

Significance: A decrease in vital capacity may be found in neuromuscular disease, generalized fatigue, atelectasis, pulmonary edema and COPD. 

Inspiratory Capacity 

Symbol: IC 

Description: The maximum volume of air inhaled after normal expiration. 

IC = TV +IRV 

Normal Value: 3500 mL

Significance: A decrease in inspiratory capacity may indicate restrictive disease. 

Function residual capacity 

Symbol: FRC

Description: The volume of air remaining in the lungs after a normal expiration. 

FRC = ERV + RV

Normal Value : 2300 mL

Significance: Functional residual capacity may be increased in COPD and decreased in ARDS. 

Total Lung Capacity

Symbol:TLC 

Description: The volume of air in the lungs after a maximum inspiration 

TLC = TV + IRV + ERV + RV

Normal Value: 5800 mL 

Significance: Total lung capacity may decreased in restrictive disease ( atelectasis, pneumonia ) and increased in COPD.