Pulmonary function tests (PFT) are critical procedures to evaluate lung function, categorize pulmonary diseases, and assess therapeutic effectiveness. They include dynamic and static tests, with spirometry being a key method for measuring airway function and capacity. Proper administration and interpretation of PFTs are essential in diagnosing respiratory diseases and preparing patients for surgery.

1. Presented by : Kaustubh Singh
Pharm.D (PB) 1st Year
School of Pharmaceutical Sciences
SGRR University

2. INTRODUCTION
-It is a group of procedures that measures the function of
the lungs.
-Pulmonary function tests can provide valuable information
about the important individual processes that support gas
exchange.
CATEGORIES OF PFT
There are 2 categories of PFT measuring
i. Dynamic lung function test.
ii. Static lung function test.
.

3. PURPOSE OF PFT
- T
o identify and quantify the changes in pulmonary function
due to any disease.
- Evaluate effectiveness of therapy.
- Perform epidemiological surveillance for pulmonary disease.
- Assess patients for risk of postoperative complications.
- Determine pulmonary disability.

4. PATHOPHYSIOLOGY
*Pulmonary disease are divided into two major categories:
-Obstructive pulmonary disease. Eg. COPD
-Restrictive pulmonary disease. Eg. Asthma
-Some pulmonary disease can cause both obstructive and
restrictive pulmonary disease.
*Comparison of obstructive & restrictive pulmonary disease

5. * Obstructive pulmonary disease
- The primary problem in obstructive pulmonary disease is
an increased airway resistance.
- In simple terms difficulty in expiration.
Fig. Obstructive Pulmonary Disease

6. * Restrictive pulmonary disease
- The primary problem in restrictive pulmonary disease is
reduced lung compliance, lung volume or both.
- In simple terms difficulty in inspiration.
Fig. Restrictive Pulmonary Disease

7. PULMONARY FUNCTION TEST EQUIPMENT
• Two general types of measuring devices exist, those that:
- Measure volume
- Measure flow
• Volume-measuring devices - spirometers
• Flow-measuring devices - pneumotachometers
• Every measuring device has capacity, accuracy, error,
resolution, precision, linearity, & output

8. SPIROMETRY
*It is the measurement of air entering and leaving lungs
which includes measurement of several values of forced
airflow and volume during inspiration and expiration.
• Tests of pulmonary mechanics:
-Forced vital capacity (FVC)
-Forced expiratory volume in 1 second (FEV1)
-Other forced expiratory flow measurements
-Maximum voluntary ventilation
• These measurements assess ability of lungs to move large
volumes of air quickly through airways

9. PURPOSE/IMPORTANCE OF SPIROMETRY
• The purpose of spirometry is to assess the ability of the
lungs to move large volumes of air quickly through the
airways to identify airway obstruction.
• Measuring flow rates is a surrogate for measuring airway
resistance.
• T
o a lesser extent spirometry can also identify and quantify
a restrictive type of pulmonary disease.

10. TYPES OF SPIROMETRY
-Computerized spirometer
-Incentive spirometer
-Tilt compensated spirometer
-Windmill type spirometer
-Tank type spirometer

11. Computerized spirometer Incentive spirometer Windmill type spirometer
Tank type spirometer
Tilt compensated spirometer

12. CONTRAINDICATIONS OF SPIROMETRY
It should not be indicated for persons with,
-Haemoptysis of unknown origin
-Pneumothorax
-Unstable angina pectoris
-Recent myocardial infarction
-Thoracic aneurysms, abdominal aneurysms, cerebral
aneurysms.
-Recent eye surgery ( intraocular pressure during forced
expiration)
-History of syncope associated with forced expiration
-Patient with active Tuberculosis should not be tested

13. PRECAUTIONS TO BE TAKEN FOR SPIROMETRY
-Persons with high blood pressure
-Semi-comatic patients
-Patients with age of 80yrs or more
-The subject should be healthy (free from asthma)
-No air leaks in the apparatus (or else will give inaccurate
readings)
-The mouth piece should be sterilized
-The water chamber should not be overfilled (or it may
enter air tubes)

14. PARAMETERS OF PFT
 Forced vital capacity (FVC)
 Forced expiratory volume (FEV)
 Respiratory minute volume (RMV)
 Maximal voluntary ventilation (MVV)
 Peak respiratory flow rate (PEFR)
*Forced vital capacity
Volume of air that can be exhaled forcefully and rapidly after deep inspiration.
 DYNAMIC LUNG FUNCTION TEST
It is based on time i.e. rate at which air flow into and out of the
lungs.

15. *Forced vital capacity for Obstructive and Restrictive Disease

16. * Forced expiratory volume
Volume of air which can be expired forcefully in a given unit of time (after
deep inspiration).
It is also known as timed vital capacity.
* Respiratory minute volume
Volume of air breathed in and out every minute.
 RMV= TV x RR

17. *Maximal voluntary ventilation
Maximum volume of air which can be breath in and out by forcefully
respiration in one minute.
It is also known as maximum breathing capacity.
 150-170 L/Min
* Peak respiratory flow rate
Maximum rate at which air can be expire after a deep inspiration.
 400 L/Min

18.  STATIC LUNG FUNCTION TEST
Volume of air that flows into or out of the lungs.
*Lung Volumes * Lung Capacities
 Tidal volume
 Inspiratory reserve volume
 Expiratory reserve volume
 Residual volume
 Total lung capacity
 Inspiratory capacity
 Functional residual capacity
 Vital capacity

19. * Tidal volume
“Amount of air inhaled & exhaled at rest”.
TV = 0.5 liters
* Inspiratory reserve volume
“Additional volume of air
, that a person can inhale (via forceful
inspiration)”.
IRV = 3.1 liters
* Expiratory reserve volume
“Additional volume of air
, that a person can exhale(via forceful
exhalation)”
ERV = 1.2 liters

20. * Residual volume
“Volume of air remaining in the lung, even after forceful exhalation”
 RV = 1.2 liters
Lung Capacities
* Total lung capacity
T
otal volume of air a person can inspire after normal expiration”
 IC = (TV + IRV) = (0.5 + 3.1 ) liters = 3.6 liters.
* Inspiratory capacity
T
otal amount of air contained in the lungs after maximal inhalation”
 TLC = (RV + ERV + TV + IRV) = (1.2 + 1.2 + 0.5 + 3.1) liters = 6 liters.

21. * Functional residual capacity
Volume of air remaining inside lungs after normal expiration”
 FRC = (ERV + RV) = (1.2 + 1.2) liters = 2.4 liters.
* Vital capacity
 VC = (ERV + TV + IRV) = (1.2 + 0.5 + 3.1) litres = 4.8 litres.

22. CONCLUSION
-Pulmonary function tests are an important tool in the
assessment of patients with suspected or known respiratory
disease.
-They are also important in the evaluation of patients prior to
major surgery.
-Interpretation of the tests, which requires knowledge of normal
values and appearance of flow volume curves, must be
combined with the patient’s clinical history and presentation.

23. THANK YOU!