Pulmonary function testing is the process of having the patient perform specific inspiratory and expiratory maneuvers while breathing in and out of tubing attached to the equipment that measure a variety of variables

1. Dr.Nidhi Ahya
Assistant Professor
Cardio-Vascular & Respiratory PTDVVPF
College of Physiotherapy,
Ahmednagar 414111

2. Definition
Purpose
Indications & contra-indication
 lung volumes & capacities
Flow – volume curve
Classification : obstructive & restrictive
Clinical interpretation.

3. Pulmonary function testing is the process of
having the patient perform specific inspiratory
and expiratory maneuvers while breathing in and
out of tubing attached to the equipment that
measure a variety of variables

4. To determine the functional status of the
lungs
How much gas can be moved in and out of the lungs
How fast gas can be moved
The stiffness of the lung and chest wall
The diffusion characteristics of the alveolar-capillary
membrane
How well lung responds to the therapy

6. • To evaluate symptoms, signs or abnormal
laboratory tests
• To measure the effect of disease on pulmonary
function
• To differentiate between obstructive and
restrictive disease
• To screen individuals at risk of having pulmonary
disease
• To assess pre-operative risk
• To assess prognosis, response to therapy

7. • Hemoptysis of unknown origin
• Pneumothorax
• Unstable cardiovascular status or recent MI or
pulmonary embolus
• Thoracic, abdominal or cerebral aneurysms
• Presence of an acute disease process that might
interfere with test performance
• Recent surgery of thorax and abdomen

8. Nosocomial infection contracted from improperly
cleaned tubing, mouthpiece

9.  Height and weight:
Taller person, larger lung size, and larger predicted
lung volume
Muscular person-increase in lung size
Obese person-reduction in lung size
 Gender: Males>females
 Age:
Vital capacity increases in person until mid 20s
Average predicted VC for 20yrs is slightly over 5lt
By age 70, approx 4lt
Race
Environmental factors
Personal Factors

11. Volume of air exhaled and inhaled during quiet
breathing
350-600ml
Decrease Vt can occur both in restrictive an
obstructive defects

12. The inspiratory reserve volume is the extra volume
of air that can be inspired over and above the normal
tidal volume when the person inspires forcefully.
 It is usually equal to about 3000 ml

13. The expiratory reserve volume is the maximum
extra volume of air that can be expired by forceful
expiration after the end of a normal tidal expiration
 It normally amounts to about 1100 ml

14. The residual volume is the volume of air remaining in
the lungs after the most forceful expiration
 This volume averages about 1200 Ml
Is reduced in restrictive defects
Increased in obstructive defects
Expressed as ratio to TLC and VC

17. The inspiratory capacity equals the tidal volume
plus the inspiratory reserve volume.
It’s the amount of air a person can breathe in,
beginning at the normal expiratory level and
distending the lungs to the maximum amount.
about 3500 milliliters

18.  The vital capacity equals the inspiratory reserve
volume plus the tidal volume plus the expiratory
reserve volume.
This is the maximum amount of air a person can
expel from the lungs after first filling the lungs to
their maximum extent and then expiring to the
maximum extent
About 4600 ml
If the person forcefully exhales the volume, it is
called Forced vital capacity(FVC)

19. Three phases of FVC maneuver:
Maximal inspiratory effort
Initial expiratory blast
Forceful emptying of the lungs
Both restrictive and obstructive defects can cause
decrease in VC
Important preoperative assessment factor useful in
evaluating the patient’s need for mechanical
ventilation

20. FRC = ERV+RV
Resting volume of the lungs after exhalation of Vt
breath
This is the amount of air that remains in the lungs at
the end of normal expiration
About 2300 ml
Represents balance between the expanding chest
wall forces and the contractile rebound forces of
lung tissue

21. Sum of VC and RV
Is increased with most obstructive lung defects and
decreased with restrictive lung defects
To measure TLC, RV must be determined

22. The lung volumes that can be directly measured
using a spirometer include- Tidal Volume, Inspiratory
Reserve Volume, Expiratory Reserve Volume and
thus Vital Capacity
Total Lung Capacity can be measured if RV and
FRC are known.
RV and FRC is obtained in one of indirect methods:
Body plethysmograph (body box)
Open-circuit nitrogen washout
Closed-circuit helium dilution

23. Generated by integrating
flow with volume on graph
Volume is plotted on the
horizontal axis
Flow on the vertical axis
Expiratory loop is shown
above the line

24. Generated by
integrating volume
with time on graph
Volume is plotted on
the vertical axis
Time on the
horizontal axis
Volume – Liters
Time- secs

25. The expiratory side of the FVC curve provides data
regarding the contractile state of the airways
This part of the curve evaluates the amount of the
obstruction present in the patient’s airways
Routinely identified flows are:
FEV1 --FEV25%-75%
FEV3 --PEF

26. Measures the maximal volume of air exhaled during
the first second of expiration
Reflects the flow characteristics in the larger airways
Best indicator of obstructive diseases
Expressed as percentage of the observed FVC
(FEV1/FVC)
Normal: 75% of VC in 1 second
Decreased: acute and chronic obstructive pulmonary
disease
Normal in restrictive disorders

27. Look at the 3-second point of the expired curve
Indication of the flow in smaller airways
Decrease normally with age
Normal: approx 95%

28. FEV25%-75%
Expressed in liters/second
Indicator of flow
First 25% is disregarded because of the lung’s initial
inertia
Last 25% is disregarded because of effort
dependency
Middle 50% reflects the degree of airway patency
Early indicator of obstructive disease
Can also be reduced in restrictive dysfunction

29. Is the maximum flow rate achieved by the patient
during the FVC maneuver
PEF < 100L/min : severe obstructive disease
PEF= 100 to 200L/min : moderate obstructive
disease
PEF > 200L/min : mild obstructive disease

30. Indicates the respiratory muscle endurance
Requires the patient to inhale and exhale as quickly
as possible for a period of 12 secs
Normal: 170L/min for healthy young adult

31. Pulmonary function abnormalities can be
grouped into two main categories-
• Obstructive
• Restrictive

32.  Obstructive defects:
• Can occur in upper and larger airways or in smaller
airways(less than 2mm)
• Upper airways obstruction will reduce flow rates in the
initial 25% of a FVC maneuver
• Smaller airway obstruction will reduce flow rates in the
later portion of the exhaled volume
 Restrictive defects:
• Present when the lung volume are reduced to less
than 80% of the predicted levels
• Includes chest wall dysfunction, neurologic disorders,
scarring of lung, obesity

36. Measurement Obstructive Restrictive
FVC N or decrease Decrease
FEV1 Decrease Decrease
FEV1/FVC N or decrease N or increase
FEF25%-75% Decrease N or decrease
PEF Decrease N or decrease
FEF50 Decrease N or decrease
Slope of FV curve Decrease Increase
MVV Decrease N or decrease

38. Based on the initial results of a baseline spirometry,
additional testing of pulmonary mechanics is often
desirable.
If the baseline test indicates airway obstruction,
determining the reversibility of obstruction is
indicated.
In the laboratory , FVC maneuver is often repeated
after the patient has received a bronchodilator
Reversibility is defined as 15% or greater
improvement in FEV1

39. What is PFT & purpose of PFT.
Indications & contra-indication.
 lung volumes & capacities.
Flow – volume curve .
Classification : obstructive & restrictive.
Clinical interpretation.

40. 1. WHAT IS PFT AND ITS PURPOSE? 5MARKS
2. WRITE THE INDICATION AND
CONTRAINDICATIONS OF THE PFT. 5MARKS