Data interpretation: Peak Expiratory Flow

Question 1

What does Peak Expiratory Flow (PEF) measure?

Answer 1

Volume of air forcefully expelled from the lungs in one quick
exhalation

Peak Expiratory Flow Rate (PEFR)

Question 2

Why is PEF useful in monitoring asthma severity?

Answer 2

PEFR value indicates how controlled asthma is and can indicate when a flare up will occur

Question 3

How do you instruct a patient to measure their PEFR in 6 steps?

Answer 3

1. Patient should be standing up
2. Set indicator on Peak Flow Meter to 0 on the numbered scale
3. Patient should take a deep breath then put mouthpiece in mouth between teeth, and seal lips around mouthpiece to prevent air escaping
4. Tell patient to blow out as hard and fast as possible in a single breath
5. Record reading
6. Reset indicator to 0 and repeat until patient has 3 PEFR readings

Question 4

How is PEFR used to set up a patient’s asthma action plan?

Answer 4

Patient’s personal best PEFR reading is used to set zones in the plan, to help them recognise and manage variable symptoms and prevent asthma attacks

Question 5

What are the 3 zones on an asthma action plan?

Answer 5

Green zone

Yellow zone

Red zone

Question 6

What is the green zone on an asthma action plan in terms of PEFR and symptoms, and what should the patient do to manage this?

Answer 6

PEFR: At least 80% of personal best reading
+
No SOB, wheezing, chest tightness, cough

Take daily prescribed medications, no extra medication needed

Question 7

What is the yellow zone on an asthma action plan in terms of PEFR and symptoms, and what should the patient do to manage this?

Answer 7

PEFR: Between 50-80% of personal best reading
+
1 or more symptoms: SOB, cough, wheeze, chest tightness, waking at night

Take quick-relief medicine, if still in yellow zone after 1 hr then take quick-relief medicine and oral steroid

Question 8

What is the red zone on an asthma action plan in terms of PEFR and symptoms, and what should the patient do to manage this?

Answer 8

PEFR: 50% of personal best reading
+
EMERGENCY SYMPTOMS and was in yellow zone for 24 hours

Take quick-relief medicine and oral steroid, call doctor immediately

Question 9

If an asthmatic patient is in the red zone, what 2 things should they do after taking quick-relief medicine and oral steroids?

Answer 9

1. If symptoms don’t improve after 15 min: Go to hospital or call 911
2. Watch for DANGER SIGNS eg. trouble walking, trouble talking, cyanosis

If patient has danger signs, go to hospital or call 911 immediately

Question 10

Describe the peak flow pattern that normally occurs in asthma patients?

Answer 10

Diurnal variation: Readings are lowest in morning and highest at night

Night readings 20% or more variation to morning readings