
Mouthpiece: located on the reference instrument. Compare its shape and position with the apparatus used in your practical.
Zoom in, then drag to inspect. Keyboard: + / − to zoom, arrows to pan, 0 to reset. Tap the numbered markers to explore parts.
Peak expiratory flow meter — reference view
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Peak expiratory flow meter
PEFR meter · peak flow meter
What is its use?
Measures peak expiratory flow during a forceful expiratory effort.
Tap a number to locate its part. Zoom, drag or use full screen to inspect the reference. Models and graduations can differ; check the actual apparatus used in your laboratory.
How to recognise it.
- Handheld graduated device
- Mouthpiece at one end
- Indicator moves along a flow scale
It does not replace full spirometry and does not provide all spirometric volumes or ratios.
Point them out.
Choose a part to bring its numbered marker into view.
The science behind the reading.
Expiratory flow moves a mechanical indicator or is measured electronically; the peak value is retained for reading.
Think first. Then reveal.
Explain your answer aloud before opening it.
01What is PEFR?+
The highest flow achieved during a forceful expiration from a maximal inspiration.
02What units are commonly used?+
Litres per minute; verify the device scale.
03Why is it effort-dependent?+
The initial expiratory effort strongly influences the maximum flow achieved.
04Can it measure residual volume?+
No. It measures a peak flow, not the gas volume left in the lungs.
Read the references.
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