Lung Volumes

Question 1

Value of FRC

Answer 1

30 ml/kg

2. 3 L in men
3. 8 L in women

Question 2

Value of RV

Answer 2

15-20 ml/kg

1. 2 L in men
2. 1 L in women

Question 3

Value of ERV

Answer 3

15 ml/kg

1. 2 L in men
2. 7 L in women

Question 4

Value of TV

Answer 4

6 ml/kg

0.5 L in men & women

Question 5

Value of IRV

Answer 5

45 ml/kg

3 L in men
1.9 L in women

Question 6

Value of VC

Answer 6

60-70 ml/kg

4. 6 L in men
5. 1 L in women

Question 7

Value of TLC

Answer 7

80 ml/kg

5. 8 L in men
6. 2 L in women

Question 8

FRC = _____ + _____

Answer 8

ERV + RV

Question 9

Define closing capacity.

Answer 9

Closing capacity is the volume at which the small airways close during expiration.

Question 10

At what age does FRC = CC?

Answer 10

66 in standing position

44 in supine position

Question 11

Describe Fowler’s method and what it measures.

Answer 11

This is used to measure anatomical dead space.
A patient takes a breath of 100% oxygen to rid the conducting zone gases of nitrogen and then exhales through a mouthpiece capable of analyzing nitrogen concentration at the lips. Initially the exhaled gases contain no nitrogen as this is dead space gas; the nitrogen concentration will increase as the alveolar gases are exhaled. Nitrogen measured following the breath of 100% oxygen must have come only from gas exchanging areas of the lung and not dead space.

Question 12

Name 4 factors which correspond to a decrease in FRC.

Answer 12

a) obesity
b) general anaesthesia
c) supine posture
d) increasing age