Pulmonary Volumes

Question 1

Capacity equations

Answer 1

IC = TV + IRV
FRC = ERV + RV
VC = IRV + TV + ERV
TLC = IRV + TV + ERV + RV = VC + RV = IC + FRC

Question 2

Obstructive

Answer 2

Limitation in airflow
Inc RV/TLC, inc RV, dec FEV1/FVC
Inc FRC

Question 3

Restrictive

Answer 3

Limitation of lung expansion
Inc RV/TLC, dec TLC, inc FEV1/FVC
Dec FRC

Question 4

Forced Midexpiratory Flow

Answer 4

Sensitive and indicates small airway disease if slope is steeper

Question 5

Bohr Method

Answer 5

Measures volume of gas trapped in alveoli as well as gas in conducting airway
Percentage of tidal volume that does not eliminate CO2
VD = VT (PaCO2-PECO2/PaCO2)

Question 6

Alveolar Ventilation

Answer 6

VA =f(TV-VD)

VA = (VCO2/PaCO2)K

Question 7

Spirometry

Answer 7

Does not measure RV

Question 8

Whole Body Plethysmography

Answer 8

Measures total volume of air in lung
Under normal, helium dilution and whole body same
Pathological, use whole body