Asthma Diagnosis & Spirometry

Question 1

What kind of graphs do spirometry generate? What does it plot?

Answer 1

Pneumotachographs
- plot the volume and flow of air coming in and out of the lungs from one inhalation & exhalation

Question 2

Can you prescribe Rx inhalers without proper spirometry results?

Answer 2

No

Question 3

How old do you have to be to have a spirometry? How often

Answer 3

6+
Once a year

Question 4

What do pulmonary function tests mean?

Answer 4

Include Spirometry AND other tests
- Gas exchange
- O2 saturation
etc..

Question 5

What are contrindications for spirometry? (7)

Answer 5

1. Recent surgery
2. Recent stroke
3. Aneurysms
4. Pregnancy (near term)
5. Recent concussion
6. Infection
7. Pneumothorax

Question 6

Define FVC.
What is it used for? restrictive/obstructive
What is the normal range

Answer 6

Volume of air forcibly exhaled from max inspiration to max exhalation
- function size of lungs

Used for: to test if restrictive lung disease

Normal: 80%+

Question 7

Define FEV1
What is it used for? restrictive/obstructive
What is the normal range

Answer 7

Used for: obstructive disease
Normal range: Above 80%

Question 8

Define FEV1/FVC
What is it used for? restrictive/obstructive
What is the normal range

Answer 8

Used for: obstructive
Normal range: 0.70+

Anything below indicates obstruction

Question 9

How to diagnose children 1-5 years ?
Preferred and alternative

Answer 9

Preferred
- HCP sees wheeze AND other signs of airflow obstruction
- improvement with SABA +/- corticosteroids

Alternative
- convincing caregiver report with wheezing OR other symptoms
- 3-month trial of medium dose ICS PRN or SABA response to symptoms

Question 10

What are predicted value factors? (4)

Answer 10

Height
Age
Gender
Ethnicity

Question 11

What are spirometry tests used for?

Answer 11

GOLD standard
- determines if restrictive or obstructive disease

Question 12

What is 2nd line pulmonary function test? What is the disadvantage of that? Who is it used for? How often is it measured?

Answer 12

Peak expiratory flow meter

Used for: “poor perceivers” (to help patient understand how well/poorly they are breathing)
Measured: daily or BID
Disadvantage
- underestimate obstruction

Question 13

When is a methacholine test done?
How is it done?

Answer 13

Used when spirometry results are inconclusive

How:
- provoke an asthma attack by a respirologist in a hospital and give B2 agonist

Question 14

Differentiate between restrictive vs obstructive disease
What is affected?
What rest results are affected (volume, air flow)
Example

Answer 14

Restrictive
- issue getting air in
- Affects extrapulmonary, pleural lung tissue that restricts lung expansion
- REDUCED volume, NORMAL air flow
eg. pulmonary fibrosis sacroidosis

Obstructive
- issue getting air out
- affects lumen of airways (mucous, inflammation)
- NORMAL volume, REDUCED air flow

Question 15

Which condition has both restrictive and obstructive features? What are the features?

Answer 15

Cystic fibrosis
- Obstructive: excess mucous production
- Restrictive: fibrosis damage to lung tissue

Question 16

Requirements of spirometry
How many?
How long (seconds) for kids vs adults, plateau?
Range of repeatability of FVC and FEV1 between results (mL)
Which test do you report?

Answer 16

How many?
- 3 pre and 3 post tests

How long (seconds) for kids vs adults, plateau?
- Adults: min 6 sec
- Children: min 3 sec with 2 sec plateau

Range of repeatability of FVC and FEV1 between results (mL)
- 150mL of each other

Which test do you report?
- highest FVC and FEV1 from any of the 3

Question 17

When would you refer to a specialist? (6)

Answer 17

• Diagnostic uncertainty
• Severe sx disproportionate to the degree of airflow obstructions
• Rapid decline in lung function
• Still symptomatic with aggressive treatment
• Rehab or O2 required or ventilatory support needed