Spirometry

Question 1

What does it measure

Answer 1

FVC (lung size)
FEV1 - airway calibre
FEV1/FVC - indicates airflow obstruction

Question 2

Used for

Answer 2

Diagnosis
Improvement of medical management
Monitoring of progression of disease

Question 3

Can tell us the difference between normal lungs and (3)

Answer 3

airflow obstruction
restrictive disease
response to inhalers/tmt

Question 4

What is FEV1

Answer 4

forced expiratory volume - 1 sec
volume of air blown out in 1st second
reduced for both restrictive and obstructive disease

Question 5

What is FVC

Answer 5

Forced Vital Capacity

max volume bown out following a full inspiration.
reduced in restrictive disease and in obstructive (if air trapping occurs)

Question 6

FEV1/FVC

Answer 6

Forced exp ration
% of FVC blown out in 1st sec of a forced expiration
FEV1/FVC x 100

reduced in obstructive
normal in restrictive

Question 7

PEF

Answer 7

Peak expiratory flow
max flow achievable from a forced expiration starting at a full inspiration with an open glottis.

achieved w/in 100ms of blow

Question 8

VC

Answer 8

Vital capacity - max air breathed out steadily from full inspiration to max expiration

> 80% of predicted in normal - reduced in restrictive disease.

Question 9

Important factors for spirometry

Answer 9

age 
weight 
height 
time 
race 
patient histroy 
smoking history 

Are they able to do the test? - Contraindications?

Question 10

Contraindications

Answer 10

hyperventilation 
hypoxaemia 
fatigue 
heavily sedated/comatose
severe dyspnoea 
patients unable to take a deep breath due to pain

Question 11

interpretation of results

Answer 11

• FEV ratio reduced < 70% indicates airflow obstruction
• A reduced FEV1% predicted indicates how severe airway obstruction is
• A reduced FVC% predicted indicates restriction