Peak flow

Question 1

Name the components of a peak flow

Answer 1

Consists of a disposable mouthpiece with a one way valve that prevents patient from breathing in from the peak flow
The valves should be facing the patient
A disposable mouthpiece used to reduce infection risk

Question 2

Explain how to perform a peak flow

Answer 2

1. Attach mouthpiece to flow meter
2. move the pointer to the zero position
3. Ask the patient to take a very deep breath to TLC & place lips around mouthpiece
4. Ensure patients fingers do not obstruct the pointer
5. Ask the patient to give a short forceful breath out
6. Remove the peak flow & record the value
7. Reset the pointer and repeat 2 more times
8. Report the best attempt out of 3

Question 3

What can cause errors in peak flow measurement?

Answer 3

Poor effort from the patient
Leaks around the mouthpiece, need to create a seal with the lips
inadequate rest between attempts, need a chance to recall breath
Fingers obstructing the pointer on the peak flow, preventing it from moving or moving as far

Question 4

What is Sequential peak flow monitoring?

Answer 4

Records peak flow over a period of time to help manage asthma or aid in a diagnosis
symptoms should also be recorded, use of inhalers, aggravating factors

Question 5

What is the variability in peak flows?

Answer 5

A normal variation in peak flow is 8%
A variation of greater than 20% indicates asthma

Question 6

How is variability calculated?

Answer 6

% change= (max PEF-min PEF) x100/ Max PEF

Question 7

What are the limitations of peak flow meters?

Answer 7

• PEF is effort dependent so results depend on patients’ motivation
• Patients can give high readings if they cough or splutter into peak flow
• Patients can falsify results
• If patients do not clean meters, moisture can build up & cause errors