Spirometery

Question 1

How do you calculate FRV and IC?

Answer 1

FRV = ERV + RV

TV + IRV = IC

Question 2

What is the FEV1 to FVC ratio in obstructive diseases such as asthma and COPD?

Answer 2

Less than 70%

Question 3

Explain why in obstructive disorders such as asthma the descent of the graph shows scalloping?

Answer 3

Large airways are normal and not narrowed - small airways are narrow
The ascent of the graph - represents large airways due to rapid movement of air occurring here
Descent of graph above X axis shows movement of air through small airways.

Movement of air through narrow small airways is more affected in asthma due to narrowing.

Question 4

Name a variable and fixed upper award obstruction.

Answer 4

Laryngeal polyp

Tracheal stenosis