Pulmonary function tests (PFTs) are noninvasive tests that show how well the lungs are working. The tests measure lung volume, capacity, rates of flow, and gas exchange. This information can help your healthcare provider diagnose and decide the treatment of certain lung disorders.

1. PULMONARY FUNCTION TESTS
Dr. Chavan P. R.
Pharm D

2. PFT
 Pulmonary function tests is a generic term used to
indicate a battery of studies or maneuvers that may
be performed using standardized equipment to
measure lung function.
Evaluate one or more aspects of the respiratory
system
Respiratory mechanics
Lung parenchymal function/ Gas exchange
Cardiopulmonary interaction

3. ASPECTS OF PULMONARY FUNCTION:
 Perfusion- Blood flow.
 Diffusion- Movement of O2 & CO2.
 Ventilation- Air exchange btwn alveolar spaces &
the atmosphere.

4. SIGNIFICANCE
1. Investigation of patients with symptoms/signs/
investigations that suggest pulmonary disease e.g.
• (Cough/Wheeze/Breathlessness/Crackles)
2. Monitoring patients with known pulmonary disease
for progression and response to treatment e.g.
• Interstitial fibrosis
• COPD
• Asthma
• Pulmonary vascular disease

5. 3. Investigation of patients with disease that may
have a respiratory complications e.g.
• Connective tissue disorders
• Neuromuscular diseases
4. Preoperative evaluation prior to e.g.
• Lung resection
• Abdominal surgery
• Cardiothoracic surgery

6. 5. Evaluation patients a risk of lung diseases e.g.
• Exposure to pulmonary toxins such a radiation/
medication/environmental/occupational exposure
6. Surveillance following lung transplantation to
assess for
• Acute rejection
• Infection
• Obliterative bronchiolitis

7. CONTRAINDICATIONS
Myocardial infarction within the last month
Unstable angina
Recent thoraco-abdominal surgery
Recent ophthalmic surgery
Thoracic or abdominal aneurysm
Current pneumothorax

8. LUNG VOLUME
 Four Lung volumes:
• Tidal volume (500-750ml)
• Inspiratory reserve volume(2500-3000ml)
• Expiratory reserve volume(1000-1500ml)
• Residual volume( 1300-1500ml)

9. LUNG CAPACITIES
 Five capacities:
• Inspiratory capacity ( TV + IRV )
• Expiratory capacity ( TV + ERV )
• Vital capacity ( IRV + TV + ERV )
• Functional residual capacity ( RV + ERV )
• Total lung capacity(IRV+TV+ERV+RV)

11. TESTS
 Bed side pulmonary function tests
 Spirometry
 N2 Washout Technique
 Helium Dilution technique
 Body Plethysmography
 Cardiopulmonary interaction

12. BED SIDE PULMONARY FUNCTION TESTS
1. SABRASEZ BREATH HOLDING TEST
>25 SEC.-NORMAL Cardiopulmonary Reserve
15-25 SEC- LIMITED CPR
<15 SEC- VERYPOOR CPR (Contraindication for
elective surgery)
 25-30 SEC - 3500 ml VC
 20 -25 SEC - 3000 ml VC
 15 -20 SEC - 2500 ml VC
 10 -15 SEC - 2000 ml VC
 5-10 SEC - 1500 ml VC

14. 2. SCHNEIDER’S MATCH BLOWING
TEST
MBC < 60 L/min
FEV1 < 1.6L Able to blow
out a match
MBC > 60 L/min
FEV1 > 1.6L
Modified match test:
DISTANCE MBC
9” >150 L/MIN.
6” >60 L/MIN.
3” > 40 L/MIN

15. 3. COUGH TEST
 Deep breath followed
by cough
 Inadequate cough if:
FVC<20 ml/kg FEV1 <
15 ml/kg PEFR < 200
l/min.
 VC ~ 3 times TV for
effective cough.

16. 4.FORCED EXPIRATORY TIME
Normal FET – 3-5 SECS.
Obstructive Lung Disease. - > 6 SEC
Restrictive Lung Disease.- < 3 SEC

17. 5. SINGLE BREATH COUNT
After deep breath, hold it and start counting till the
next breath.
N- 30-40 COUNT
Indicates vital capacity

18. 6. WRIGHT PEAK FLOW METER:
Measures PEFR (Peak Expiratory Flow Rate)
N – MALES- 450-700 L/MIN.
FEMALES- 350-500 L/MIN.

19. 7. DE-BONO WHISTLE BLOWING TEST:
MEASURES PEFR.
Patient blows down a wide bore tube at the end of
which is a whistle, on the side is a hole with
adjustable knob.
As subject blows → whistle blows, leak hole is
gradually increased till the intensity of whistle
disappears.
At the last position at which the whistle can be blown ,
the PEFR can be read off the scale.

20. 8. WRIGHT RESPIROMETER :
 measures TV,MV Instrument- compact, light and
portable.
 Can be connected to endotracheal tube or face
mask MV- instrument record for 1 min.
 And read directly TV-calculated and dividing MV by
counting Respiratory Rate.
Disadvantage: It under- reads at low flow rates and
over- reads at high flow rates.

21. SPIROMETRY

22. PREREQUESITE
Do not smoke for at least 1 hour before the test.
Do not drink alcohol for at least 4 hours before the
test.
Do not exercise heavily for at least 30 minutes
before the test.
Do not wear tight clothing that makes it difficult for
you to take a deep breath.
Do not eat a large meal within 2 hours before the
test.

23. SPIROMETRY

24. DISADVANTAGE
• Only for single use due to CO2 accumulation & O2
cannot be supplied.
• Residual Volume, Functional Residual Capacity and
Total Lung Capacity cannot be measured.

25. N2 WASHOUT TECHNIQUE
 The patient breathes
100% oxygen, and all the
nitrogen in the lungs is
washed out.
 The exhaled volume and
the nitrogen concentration
in that volume are
measured.
 The difference in nitrogen
volume at the initial
concentration and at the
final exhaled concentration
allows a calculation of
intrathoracic volume,
usually FRC.

26. HELIUM DILUTION TECHNIQUE
 Pt breathes in and out
from a reservoir with
known volume of gas
containing trace of
helium.
 Helium gets diluted by
gas previously present
in lungs.
 eg: if 50 ml Helium
introduced and the
helium concentration is
1% , then volume of
the lung is 5L.

27. BODY PLETHYSMOGRAPHY
 Plethysmography (derived
from greek word meaning
enlargement).
 Based on principle of
BOYLE’S LAW(P*V=k) A
patient is placed in a sitting
position in a closed body box
with a known volume The
patient pants with an open
glottis against a closed
shutter to produce changes
in the box pressure
proportionate to the volume
of air in the chest.
 As measurements done at
end of expiration, it yields
FRC

28. CARDIOPULMONARY INTERACTION
 Stair climbing test
 Shuttle walk test
 6min walk test
 Cardiopulmonary exercise test

29. STAIR CLIMBING TEST

30. SHUTTLE WALK TEST
 Walk test is based on 20m
shuttle walk test
 Measures maximum distance
walked by the patient at a
pace set by audio signals
 Requires patients to walk at
increasing speads up and
down a 10m course
 Speed walking is increased
every minute by 0.17m/s

31. 6MIN WALK TEST
 The tester will measure your blood pressure, pulse and
oxygen level usually with a pulse oximeter before you start
to walk.
 You should be given the following instructions: The object
of the test is to walk as far as possible for six minutes. You
will walk at your normal pace to a chair or cone, and turn
around. And you continue to walk back and forth for six
minutes.
 Let the staff know if you are having chest pain or
breathing difficulty.
 It is acceptable to slow down, rest or stop. After every
minute interval, you will be given an update.

33. CARDIOPULMONARY EXERCISE TEST

34. THANK YOU