Use of Peak Flow Meter

A peak flow meter is a device that measures how well air moves out of a patient's lungs. During an asthma episode, the airways of the lungs begin to narrow slowly. The peak flow meter can be used to find out if there is narrowing in the airways, hours - even days - before the patient has any symptoms of asthma. By taking the medicine early (before symptoms), your patient may be able to stop the episode quickly and avoid a serious episode of asthma. So its role in preventing severe asthma attack is very important.

The peak flow meter can also be used to help you:

• Decide if the medicine plan is working well.
• Decide when to add or stop medicine.
• Decide when patient should seek emergency care.
• Identify triggers - that is, what causes patient's asthma symptoms to increase.

All patients age 5 and older who have moderate to severe asthma should be advised to use a peak flow meter. Some children as young as age 3 can also use it.

How to use a peak flow meter (advice for patient)

1. Place the indicator at the base of the numbered scale.
2. Stand up/or sit in upright posture.
3. Take a deep breath.
4. Place the meter in your mouth and close your lips around the mouthpiece. Do not put your tongue inside the hole. Do not put your finger over the indicator.
5. Blow out as hard and fast as you can.
6. Write down the number you get.
7. Repeat steps I through 6 two more times.
8. Write down the highest of the three numbers achieved.

Personal Best Peak Flow Number

Personal best peak flow number is the highest peak flow number your patient achieve over a 2-week period when his/her asthma is under good control. Good control means when they feel well and do not have any asthma symptoms.

Each patient's asthma is different and your patients' best peak flow may be higher or lower than average usual number for someone of similar height, weight, and sex. This means that it is important for your patients to find his/her own personal best peak flow number. Because his/her own medicine plan needs to be based on his/her own personal best peak flow number.

To find out your patients' personal best peak flow number, take peak flow readings:

• • Every day for 2 weeks.
• • Mornings and evenings (when they wake up and about 10-12 hours later).
• • Before and after taking inhaled b2 - agonist (if they take this medicine).

These reading should be written down on Peak Flow Diary/chart.

The Peak Flow Zone System

Once you know your patient's personal best peak flow reading, you should give them a chart for recording their daily peak flow readings at home. This peak flow chart is divided into three zones that are set up like a traffic light. 100% to 80% of personal best peak flow reading is coloured as green, 80% to 50%of personal best peak flow reading is coloured as yellow and bellow 50% of personal best peak flow reading is coloured as red. This will help them know what to do when their peak flow number changes. For example: No asthma symptoms are present, and patients should take their medicines as prescribed.

Yellow Zone (50% to 80% of personal best number) signals caution. Patients may get an attack of asthma. It requires an increase in their medicines. Or it means, their overall asthma management is not optimum, and it may be necessary to change the medicine plan.

Red Zone (below 50% of personal best number) signals a medical alert. Patient must take an inhaled b2 - agonist immediately and contact a physician at the earliest. Patient will record his/her personal best peak flow number and peak flow zones in the prescribed chart or Peak flow diary.

Advice for patient:

• A decrease in peak flow of 20% to 30% of your personal best may indicate the start of an asthma episode.
• When this happens follow asthma control plan for treating an asthma episode.

Weekly Asthma Symptom and Peak Flow Diary

Patient will take peak flow reading every morning on waking up and every night at bedtime. Peak flow readings should be taken at the same time each day. If he/she takes inhaled b2-agonist medicine, peak flow reading should be taken before taking that medicine. Patient should record the highest value of three readings by putting a dot in the box that correlates his/her reading.

Patients should note how many times they took extra reliever asthma medicine to stop their symptoms every day. They will also write down if they were exposed to any trigger factors initiating an attack.

The patient should always be aware whether his/her reading is in the green, yellow, or red zone. They will look at their “Asthma Control Plan” for what to do when they are in a specific zone.

PREDICTED VALUES (P.V) OR PERF (LIT/MIN)

Predicted Values (P.V) of PEFR (Lit/min)

Age

Height

 

60''

65''

70''

75''

80''

20

554

602

649

693

740

25

543

590

636

679

725

30

532

577

622

664

710

35

521

565

609

651

695

40

509

552

596

636

680

45

498

540

583

622

665

50

486

572

569

607

649

55

475

515

556

593

634

60

463

502

542

578

618

65

452

490

529

564

603

70

440

477

515

550

587

 

Age

Height

 

60''

65''

70''

75''

80''

20

554

602

649

693

740

25

543

590

636

679

725

30

532

577

622

664

710

35

521

565

609

651

695

40

509

552

596

636

680

45

498

540

583

622

665

50

486

572

569

607

649

55

475

515

556

593

634

60

463

502

542

578

618

65

452

490

529

564

603

70

440

477

515

550

587

 

Children ( Male & Female )

Height

P.V

43''

147

44''

160

45''

173

46''

187

47''

200

48''

214

49''

227

50''

240

51''

254

52''

267

53''

280

54''

293

55''

307

56''

320

57''

334

58''

347

59''

360

60''

373

61''

387

62''

400

63''

413

64''

427

65''

440

66''

454