Types of spirometer

Question 1

What are the subdivisons of spirometers?

Answer 1

-volume displacement spirometers
-flow sensing spirometers

Question 2

Name the types of volume displacement spirometers

Answer 2

-water spirometer
-dry rolling seal spirometer
-wedge bellows spirometer

Question 3

List the types of flow sensing spirometers

Answer 3

-common ypes of pneumotachometers
-pressure-differential flow sensor
-ultrasonic
-rotary vane

Question 4

Describe pressure-differential flow sensors

Answer 4

detects flow as pressure drops across a screen (metal, nylon, acetate) flow measurement is then integrated to give volume

Question 5

Descibre ultrasonic spirometers

Answer 5

detects flow as changes in speed of ultrasonic signal from source to detector

Question 6

Describe rotary vane spirometers

Answer 6

measures flow as a speed of rotation of vane

Question 7

List some pros and cons of different devices

Answer 7

-cost
-portability
-ease of use
-display
-infection control

Question 8

What are some advantages of volume displacement spirometers?

Answer 8

-simple to use
-robust
-reliable, accurate, reproducible
-hard copy display
-stable measurements

Question 9

What are some disadvantages of volume displacement spirometers?

Answer 9

-not portable
-difficult to clean
-prone to leaks from tubing and bellows
-require regular servicing
-flow signal may be noisy
-older devices with limited software

Question 10

What are some advantages of flow sensing spirometers?

Answer 10

-excellent portability
-ultrasonic and rotary vane are easy to clean and so maintain infection control
-relatively inexpensive
-reliable

Question 11

What are some disadvantages of flow sensing spirometers?

Answer 11

-rotary vane is fragile
-pneumotach readings may drift if temp changes
-pneumotach readings sensitive to condensation
-calibration is factory set