Respiratory Cycle

Question 1

What defines Tidal Volume (VT)

Answer 1

Amount of air that is inspired (or expired) in a single normal breath. Normal value: 500 mL

Question 2

What defines Inspiratory Reserve Volume (IRV)

Answer 2

Total amount of air that one can breathe in, in addition to VT

Question 3

What defines Expiratory Reserve Volume (ERV)?

Answer 3

Amount of air that one can expel in addition to VT

Question 4

What defines Residual Volume (RV)

Answer 4

Amount of air that can not be forcefully exhaled

Question 5

How does one calculate Vital Capacity (VC)?

Answer 5

IRV + VT + ERV.

Inhale as deeply as one can and exhale as much as they can

Question 6

How does one calculate Inspiratory Capacity (IC) ?

Answer 6

IRV + VT.

How much air can be brought in from a resting point

Question 7

How does one calculate Functional Residual Capacity (FRC) ?

Answer 7

ERV + RV.

Amount of air that remains in the lungs at the ends of a normal respiration

Question 8

What functional measurement is usually increased in COPD patients?

Answer 8

FRC; d/t increased RV, can’t get air out

Question 9

How does one calculate Total Lung Capacity(TLC)?

Answer 9

TLC= ERV + RV + IRV + VT

The total amount of air in one lungs after a maximal inhalation

Question 10

How does one calculate Minute Ventilation V(dot)?

Answer 10

Vt x F
(VT: Tidal Volume, mL)
F: Frequency (1/min)
Units: mL/min

Question 11

How does one calculate minute ventilation V(dot)A?

Answer 11

V(dot)A= (Vt-Vds) x F

Vds: Volume of dead space