The document outlines pulmonary function testing (PFT), detailing its definition, purpose, indications, contraindications, and classifications of lung conditions. It explains how PFT evaluates lung function through various parameters, including lung volumes and capacities, and differentiates between obstructive and restrictive lung diseases. Additionally, it describes the interpretation of flow-volume curves and key respiratory metrics essential for clinical assessment.

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