2. DEFINITION
• PFT’S are a group of maneuvers carried out using standardized
equipments to diagnose , determine the nature , progress and severity of
an underlying pulmonary disease as well as to assess the effectiveness of
treatment.
3. GOALS
To predict the presence of pulmonary dysfunction
To know the functional nature of disease (obstructive or restrictive. )
To assess the severity of disease
To assess the progression of disease
To assess the response to treatment
To identify patients at increased risk of morbidity and mortality,
undergoing pulmonary resection.
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To wean patient from ventilator in icu.
Medicolegal- to assess lung impairment as a result of occupational
hazard.
Epidemiological surveys- to assess the hazards to document
incidence of disease
To identify patients at perioperative risk of pulmonary complications
5. CLASSIFICATION
STATIC FUNCTION TESTS: measure volumes and capacities e.g. body
plethysmography
DYNAMIC FUNCTION TESTS: measure flow and airway resistance e.g.
spirometry
DIFFUSION CAPACITY: assess the alveolar- capillary membrane
RESPIRATORY MUSCLE STRENGTH
CARDIOPULMONARY PULMONARY EXERCISE TEST
METABOLIC measurements.
6. INDICATIONS
DIAGNOSTIC:
• to evaluate symptoms , signs or abnormal laboratory tests .
• to measure the effect of disease on pulmonary function: obstructive or
restrictive
• to assess pre-operative risk
• part of routine physical examinations
• to assess health status before enrollment in strenuous physical activity
programs
• to screen individuals at risk of having pulmonary disease.
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MONITORING:
• to assess therapeutic interventions:( bronchodilator therapy)
• to assess the course of diseases affecting lung function
( pulmonary, obstructive, interstitial lung disease, cardiac disease
neuromuscular disease, to monitor persons in occupations with
exposure to injurious agents.)
8. CONTRAINDICATIONS
• Hemoptysis of unknown origin
• Pneumothorax
• Recent myocardial infarction
• Unstable angina pectoris
• Thoracic, abdominal and cerebral aneurysm
• Recent abdominal or thoracic surgical procedure
10. HOW WE DO PFT?
• BED SIDE PFT.
• SPIROMETRY.
• DIFFUSION CAPACITY.
11. BED SIDE PFT
• Sabrasez breath holding test.
• Snider’s match blowing test.
• Cough test.
• Watch & stethoscope test(FORCED EXPIRATORY TIME)
• Wheeze test.
• Wright peak flow meter test.
• Debono whistle blowing test.
• Single breath count test.
12. SABRASEZ BREATH HOLDING TIME
• Ask the patient to take a DEEP BREATH & hold it as long as possible.
1. >25 SEC.‐NORMAL Cardiopulmonary Reserve (CPR).
2. 15‐25 SEC‐ LIMITED CPR.
3. <15 SEC‐ VERY POOR CPR.
13. SNIDER’S MATCH BLOWING TEST
• Ask to blow a match stick from a distance of 6” (15 cms) with‐
Mouth wide open
Chin rested/supported
No purse lipping
No head movement
Mouth and match at the same level
15. COUGH TEST
• Ask the patient to take deep inspiration & cough once.
• Test is POSITIVE if the 1st cough leads to recurrent coughing.
16. WATCH & STETHOSCOPE TEST
After deep breath, exhale maximally and forcefully & keep stethoscope over
trachea & listen.
• NORMAL FET – 3‐5 SECS.
• OBS.LUNG DIS. ‐ > 6 SEC
• RES. LUNG DIS.‐ < 3 SEC
17. WHEEZE TEST
• Patient is asked to take five deep inspirations/expirations.
• pt is auscultated between the shoulder blades posteriorly to determine the
presence or absence of wheeze.
19. DEBONO WHISTLE BLOWING TEST
• MEASURES PEFR.
• PRINCIPLE: for a given size of a leak hole a minimum rate of
airflow is required to sound the whistle.
The pt blows forcibly into the cardboard mouthpiece initially with the
smallest leak hole & then with gradually increasing size till the whistle
cannot be sounded.
The last size of the leak hole at which a whistle can be obtained is the pt’
PEFR which can be read from the scale.
20. SINGLE BREATH COUNT TEST
• Ask the patient to count out loud numbers from 1 onwards after maximum
inspiration.
• Normal individual can count upto 50.
• Less than 15 indicates severe impairment of vital capacity.
21. SPIROMETRY
• Spirometry is a medical test that measures the volume of air an individual
inhales or exhales as a function of time.
• John hutchinson – invented spirometer.
• CAN’T MEASURE – FRC, RV, TLC
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FRC, RV & TLC CAN BE MEASURED BY:
Nitrogen washout technique.
Helium dilution method.
Body plethysmography.
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• Simple, office based , Measures flow, volumes
• Volume vs. Time
• Can determine:
Forced expiratory volume in one second (FEV1)
Forced vital capacity (FVC)
FEV1/FVC
Forced expiratory flow 25%-75% (FEF25-75)
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• SPIROMETRY done to differentiate between OBSTRUCTIVE &
RESTRICTIVE LUNG DISEASE.
• Measures the rate at which the lungs change volume during quiet and
forced breathing maneuvers.
• Can only measure lung volume compartments that exchange gases with
the atmosphere.
• Often done as a maximal expiratory maneuver.
25. ATS (American Thoracic Society) STANDARDS
1 No coughing: especially during first second of FVC
2 Good start of test: <5% of FVC exhaled prior to a max
expiratory effort.
3 No early termination of expiration: exhalation time of six
seconds or a plateau of 2 seconds.
4. No variable flows: flow rate should be consistent and as fast as
possible throughout exhaled VC
5. Good reproducibility or consistency of efforts: 2 best FVC's
and 2 best FEV1's should be within 0.150 L of each other.
27. FORCED VITAL CAPACITY
• Performed by having the patient inhale maximally & then forcefully
exhaling as rapidly & thoroughly as possible into a spirometer.
• Normal people can exhale in less than 3 seconds.
• Normal value is 80-120% of predicted.
• 80-120% : normal
• 70-79%: mild reduction.
• 50-69 % : moderate reduction.
• Less than 50% : severe reduction
28. FORCED EXPIRATORY VOLUME
• Volume of air forcefully expired from maximal inspiration in the first
second.
• It reflects the mechanical properties of both the large and medium sized
airways.
• Can be decreased by both obstructive & restrictive lung diseases.
Normal Value:
- 75-85% within 1 second.
95% within 2 second.
97% within 3 second.
29. FORCED EXPIRATORY FLOW AT 25-75%
OF VITAL CAPACITY
• It is the mean FEF during middle half of FVC measured in L/SEC.
• It reflects effort independent expiration & status of small airways( less
than 2mm diameter).
• It is an indicator of obstruction & depends on FVC.
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Interpretation of percentage predicted:
• Greater than 60% : normal
• 40-60% : mild obstruction.
• 20-40% : moderate.
• Less than 10% : severe obstruction.
31. PEAK EXPIRATORY FLOW RATE
• Gives the maximum flow rate achieved during FVC maneuver.
• Sensitive test for obstructive lung disease.
• Useful to assess effectiveness of treatment.
• Normal values: 4-5 L/sec.
32. MAXIMUM VOLUNTARY VENTILATION
• Maximum amount of air that can be inhaled & exhaled with in 1
MINUTE.
• It reflects the status of respiratory muscle strength, lung compliance &
airway resistance.
• It is effort dependent.
• Normal value:
Male: 140-180 L.
Female: 80-120 L.
33. FLOW VOLUME LOOPS
• Graphical analysis of flow at various
lung volumes.
• First 1/3rd of expiratory flow is effort
dependent and the final 2/3rd near the
RV is effort independent.
• Inspiratory curve is entirely effort
dependent.
37. VALUE OBSTRUCTIVE
Airway obstruction to
expiratory flow
RESTRICTIVE
Decrease in all lung volumes
TLC
RV
FVC
FEV1
FEV1/FVC
FEF 25-75%
DC
FRC
Normal/increase
Increase
Normal/increase
Decrease
Decrease
Decrease
Normal(decrease in emphysema)
Normal/increase
Decrease
Decrease
Decrease
Decrease
Normal
Normal
Decrease
Decrease
38. Classification of COPD Severity by
Spirometry
STAGE SEVERITY SPIROMETRY
FEV1/FVC FEV1%
PREDICTE
D
Stage 1 Mild < 0.70 > 80%
Stage 2 Moderate < 0.70 50-80 %
Stage 3 Severe < 0.70 30-50%
Stage 4 Very Severe < 0.70 < 30%
39. BRONCHO DILATOR REVERSIBILITY
TESTING
• Tests should be performed when pts. Are clinically stable and free from
respiratory infections.
• FEV1 should be measured twice before bronchodilator given.
• An increase in FEV1 that is both greater than 200 ml and 12% above the
pre-bronchodilator FEV1 is considered significant.
41. CARBON MONOXIDE DIFFUSING
CAPACITY
• It is a test that measures the rate of gas transfer across alveolar capillary
membrane.
• Most widely used test is SINGLE BREATH METHOD.
• Normal value: 17-25 ml/min/mm of Hg.
