respiratory function tests

Question 1

what are the 3 basic measurements of spirometry?

Answer 1

volume
time
flow

Question 2

what are the advantages of spirometry

Answer 2

Objective, non-invasive and sensitive to disease

Question 3

what is spirometry used for?

Answer 3

o Assess lung disease
o Quantify lung impairment
o Monitor the effects of occupational/environmental exposures
o Determine effects of medications

Question 4

how should a patient be positioned for spirometry?

Answer 4

Upright with feet flat on the floor. Legs uncrossed  no use of abdominal muscles for leg position.
• Loose clothing – tight clothing can cause lower volumes

Question 5

what technique should be used in spirometry?

Answer 5

o Deep breath taken in then full expiration performed through the mouthpiece
o Patient has to completely empty lungs then take in a quick inspiration, followed by a full expiration

Question 6

what techniques ensure a good quality spirometry?

Answer 6

• Explosive start
• Maximal inspiration and expiration
• No glottis closure or cessation of airflow occurred
• No coughs
• The manoeuvre should meet the end-of-test criteria (exhaling for 6 s with 50 mL being exhaled in the last 2 s)

Question 7

define tidal volume

Answer 7

amount of air you move into and out of your lungs during rest

Question 8

define forced vital capacity

Answer 8

maximum volume of air into and out of your lungs in a single respiratory cycle
o FVC = IRC + TV + ERV

Question 9

define inspiratory reserve volume

Answer 9

volume of air you can draw into your lungs

Question 10

define expiratory reserve volume

Answer 10

volume of air you can expel from your lungs

Question 11

define residual volume

Answer 11

volume of air that remains in the lungs even after maximal exhalation

Question 12

how should you interpret spirometry data?

Answer 12

• Compare against reference values or predicted values

* In adults; age, height, sex and race are the main determinants

Question 13

how does obstructive lung volume look on a flow-volume loop?

Answer 13

> normal – increased total lung capacity (TLC), functional residual capacity (FRC), residual volume (RV)

Question 14

what is the FEV1/FVC ratio in obstructive lung volume?

Answer 14

FEV1 more dramatically reduced compared with FVC – decreased FEV1/FVC

Question 15

how does a restrictive lung volume look on a flow-volume loop?

Question 16

how does the FEV1/FVC ratio change in restrictive lung volume?

Answer 16

increased/normal FEV1/FVC ratio

Question 17

what is considered a normal FEV1/FVC ratio?

Answer 17

Values above 70-80% = normal (age/gender/height adjusted

Question 18

what is the ethnic variability in spirometry?

Answer 18

Caucasians have the highest predicted FEV1, African Americans have the lowest predicted Fev1

Question 19

what is the benefit of exercise tests?

Answer 19

• Assess how much exercise a patient is able to manage
• Assess benefit of extra oxygen to help with daily activities
• Assess pre-operative fitness
• Part of a rehabilitation programme