pft presentation

1. Pulmonary Function Testing
Training Module
Presenter : Dr. Siddharth Jain
Moderator: Dr. Mitul Jain
Preceptor: Dr. Vignesh MantharamDate: 27/06/2015
Under the able guidance of
Prof. S.K. Sharma and Dr. Ragesh R. Nair

2. Learning objectives
At the end of this training program, the residents should :
• Understand the basics of pulmonary functions
• Be aware of pretest evaluation
• Have a clear understanding about the various maneuvers
• Become adept at interpreting pulmonary function testing

3. Preview
• History
• Indications
• Pre‐test evaluation
• Lung volumes and capacities
• Pulmonary function tests
• Performing a PFT
• Interpretation of PFT
• Case vignette
• Quiz

4. History of Pulmonary Function Testing
• 1846 Hutchinson – Spirometer
• 1979 ATS standardization of PFT
• 2002 ATS statement on 6‐minute walk test
• 2003 ATS/ACCP statement on cardiopulmonary
exercise testing
• 2005 ATS/ERS Task Force: General considerations,
spirometry, diffusion capacity, lung volumes
and interpretation
• 2014 ATS/ERS Technical Standards: Field walking
tests in chronic respiratory disease
4
ATS: American Thoracic Society
ERS: European Respiratory Society
ACCP: American College for Chest Physicians
PFT Pulmonary Function Testing

5. Indications of Pulmonary Function Testing
• Diagnosis of a respiratory disease
• Assessment of disease activity
• Monitoring response to therapy
• Assessment of disability
• Evaluation of prognosis
• Pre‐operative assessment

6. • Name
• Age
• Sex
• Ethnicity
• Height
• Clinical diagnosis
• Smoking
• Alcohol
• Drugs
Pre­test Evaluation

7. Pre­test evaluation
For reversibility and provocation test, if feasible,
avoid the following drugs for a specified duration
prior to the study:
• SABA inhaler 12 hours
• SAMA inhaler 24 hours
• Leukotriene Response modifiers 24 hours
• LABA inhaler 48 hours
• Theophyllines 48 hours
• Anti‐ Histaminic agents 72 hours
SAMA = Short acting muscarinic antagonist
SABA = Short acting beta agonist
LABA = Long acting beta agonist
LAMA = Long acting muscarinic antagonist

8. Pre­test Evaluation
• Active pulmonary infection
• Hemodynamic instability
• Myocardial infarction within past 1 month
• Ocular or Cardiothoracic surgery within past1 ½ years
• Impaired mental state
• Chest or abdominal pain
• Oral ulcers and facial pain

9. Advise prior to PFT
• Patient is given an appointment
• To come in loose clothes that will allow full chest
and abdominal expansion
• No caffeine based drinks on the day of the study
• No alcohol 4 hours prior
• No large meal 2 hours prior
• No smoking 1 hour prior
• No vigorous exercise 30 min prior

10. The Respiratory Laboratory

11. Tidal
volume
Vital
capacit
y
Expiratory
Reserve
Volume
Residual Volume
Functional
Residual
Capacity
Inspiratory
Reserve
Volume
Total
Lung
capacit
y
Lung volumes and capacities
Inspiratory
capacity
Expiratory
capacity
t(s)

12. Factors influencing lung functions
• Age
• Sex
• Height
• Ethnicity
• Posture
• Respiratory muscle strength
• Technique
• Disease states

13. Bedside Pulmonary Function assessment
• Breath holding Test
– Breath hold up to 25 seconds indicate adequate
cardiopulmonary reserve
• Single breath count
– A healthy adult can count to 30‐40 in a single breath
• Cough after deep breath
• Candle blowing test

14. • A measure of maximum breathing capacity
• Patient is asked to blow an illuminated candle from a distance of
6 inches with wide open mouth, chin rested, without head
movement
• Blowing a candle at 6” indicates a
maximum breathing capacity of > 60 L/min
and FEV1 of >1.6 L
Candle blowing test
FEV1:Forced Expiratory Volume
at the first second of expiration

15. List of Pulmonary Function Tests
Spirometry
SVC maneuver
FVC maneuver
Maximum Voluntary Ventilation
Maximal Respiratory Pressures
Tests of Absolute Lung Volume measurements
Body Plethysmography
Nitrogen wash‐out method
Helium dilution method
Tests of gas exchange
Diffusion Lung Capacity of Carbon Monoxide
Tests of cardiopulmonary interaction
6‐minute walk test
Cardio‐Pulmonary Exercise Testing SVC = Slow vital capacity
FVC = Forced vital capacity

16. Slow vital capacity

17. A good manoeuvre
• Acceptibility criteria
• No. of attempts
• Time gap between each attempts
• Repeatabilty criteria

18. Acceptable SVC curve
IC EV
C
IC‐ Inspiratory capacity

19. Curve selection
• Maximum no. of attempts: 4
• Time between each attempt: 1 minute
• Minimum no. of acceptable curves: 3
• Repeatability criteria:
– Differences in vital capacity not >150 mL between
the two manoeuvres with largest values .
• Maximum value is reported as the slow vital capacity
• Mean value is taken for reporting inspiratory capacity.

20. Interpreting an SVC manoeuvre
Attempt
no.
Expiratory
Vital
Capacity (L)
Inspiratory
capacity ( L)
1 4.32 3.01
2 4.42 3.05
3 4.37 2.97
‐ Mean IC : 3.01
Slow vital capacity is: 4.42 L (86% predicted, >LLN)
Inspiratory capacity : 3.01 L ( No reference equation)
LLN: Lower limit of normal

21. FORCED VITAL CAPACITY

22. FVC manoeuvre
Volume‐Time CurveFlow‐Volume Curve

23. Acceptable volume­time
curve
• Good start
No artifacts
hesitation
cough
sub‐maximal effort
air leak
obstructed mouthpiece
• Satisfactory exhalation
Duration of exhalation > 6s or
Plateau in the volume time
curve >1 s
No artifacts
Early termination
Glottic closure

24. Flow volume loop

25. Unacceptable curves
Hesitant start Sub maximal effortCough at 1st
second
Valsalva manoeuvrePremature termination

26. Curve selection
Attempt
no.
FVC (L) FEV1 (L) FEV1 + FVC(L)
1 4.68 3.85 8.53
2 4.65 3.64 8.29
3 4.63 3.78 8.41
• Maximum no. of attempts: 8
• Time between each attempt: 1 minute
• Minimum no. of acceptable curves: 3
• Repeatability criteria:
The two largest values of FVC must be within 150 mL of each other
The two largest values of FEV1 must be within 150 mL of each
other
• Curve with maximum sum of both FEV1 and FVC is taken as the best
curve for interpretation.

27. Concept of obstruction and restriction
Respiratory disease Obstruction Restriction
Basic pathology Airway obstruction Parenchymal or extra
parenchymal damage
restricting the chest wall
expansion
Functional defect Increased airway resistance Reduced compliance
Forced Vital capacity Normal
May be declined in severe
obstruction
Reduced
May be normal in early
stages of restriction
Slow vital capacity Normal even in severe stages
(Dynamic airway narrowing)
Reduced
e.g. Chronic obstructive airway
disease
Bronchial Asthma
Interstitial Lung Disease
Morbid Obesity
Kyphoscoliosis

28. Variables assessed in FVC and SVC maneuver
Parameters Utility in disease states
FEV1 Forced expiratory volume in the first second Obstruction
FVC Forced vital capacity Restriction
Severe obstruction
SVC
(EVC/IVC)
Slow Vital Capacity
(Expiratory /Inspiratory Vital Capacity)
Restriction
FEV1/FVC Ratio of FEV1 to FVC Obstruction
PEFR Peak expiratory flow rate Obstruction
PEF25‐75 Peak expiratory flow from
25% to 75% of expiration
Small airway disease
Normal variant
MEF50 Maximum expiratory flow at mid expiration Variable intra‐thoracic /
Fixed intra‐thoracic
obstruction
MIF50 Maximum inspiratory flow at mid
inspiration
Variable extra‐thoracic
Fixed intra‐thoracic
obstruction

29. Obstruction and Restriction in Flow Volume Loop
Normal Obstruction Restriction

30. Interpreting FVC/SVC manoeuvre
FEV 1/VC
VC
Possible
restrictio
n
Normal
V
C
Severe Obstruction/
Obstruction with
possible
restriction.
Obstruction
Normal
Normal
VC manoeuvre
Normal Reduce
d
Reduced*
Reduced*
*Reduced infers that the variable is < LLN
VC = Vital Capacity, FEV1 Forced Expiratory Volume at the first second

31. Interpreting FVC manoeuvre

32. Response to bronchodilator
Obstruction in a baseline FVC manoeuvre
Increase in FEV1 and/or FVC by
> 12% or 200 mL
Salbutamol MDI with spacer
100 mcg per actuation
every 30 seconds
For 4 times
Repeat the FVC manoeuvre after 15 mins
Significant
broncho dilationMDI‐ Metered Dose Inhaler

33. Response to Bronchodilator

34. Severity of obstruction
Severity of
obstruction
FEV1% predicted
( ATS/ERS)
Mild >70
Moderate 60 ‐ 69
Moderately
severe
50 – 59
Severe 35 – 49
Very severe <35
Severity of
obstruction
FEV1% predicted
( GOLD)
Mild 80+
Moderate 50 ‐ 79
Severe 30 – 49
Very severe <30
ATS = American thoracic society
ERS = European Respiratory Society
GOLD = Global initiative against Obstructive Lung
Disease

35. Upper airway obstruction
Extra‐thoracic airway Intra‐thoracic airway
obstruction obstruction

36. Upper airway obstruction
Variable
Intra thoracic
Obstruction
Variable
Extra thoracic
Obstruction
Fixed
Extra thoracic
Obstruction
Pathology Defective Expiration Defective Inspiration Defective
inspiration and
expiration
PEF Decreased Normal Decreased
MIF50/MEF50 >1 <1 1
e.g. Bronchial adenoma Vocal cord palsy Tracheal stenosis

37. Broncho­provocative testing
History suggestive of asthma with normal spirometry and no
reversibility
Episodic chest tightness with cough but no wheezing
Chronic cough which is often worse at night but without wheezing
Unexplained dyspnea
Recurrent episodes of cold, bronchitis or recurrent pneumonia which
does not occur in the same lung region.
Used in the detection of hyperactive airways if :

38. Broncho­provocative testing
Baseline spirometry, FEV1 > 70%
Methacholine administered by
customised nebulisers
at increasing concentrations
from 0.03 mg/mL to 16 mg/mL as needed
Repeat spirometry 30 & 90 s after each nebulisation
Decline in FEV1 > by 20%Ye
s
N
o
Bronchial hyper responsiveness
present
Repeat after 5 minutes with
increasing concentrations
till 16 mg/mL
PC20 calculated
PC ‐ Provocative Concentration

39. Maximum Voluntary Ventilation

40. Acceptable MVV curve
• Minimum no. of breaths in 12 seconds: 19
• Amplitude of breaths > 50% of vital capacity

41. • Maximum no. of attempts : no recommendation
• Time between each attempts: no recommendation
• Minimum no. of acceptable curves: 2
• Repeatability criteria: MVV between the curves do not differ
by more than 20%
• Curve with largest MVV is selected for reporting
• MVV/ FEV1 > 0.32 indicates good effort and normal
respiratory muscle strength
• Has high negative predictive value. Normal MVV goes against
the presence of muscle weakness.
Curve selection
Attempt
no.
MVV(L/min) LLN Predicted % predicted
1 139.5 115.4 145.5 96
2 126.4 115.4 145.5 86 MVV‐ Maximum Voluntary attempts
FEV1 Forced Expiratory Volume at 1st
second
LLN – Lower limit of normal

42. Maximal Respiratory Pressures
Inspiratory / Expiratory

43. Maximal Inspiratory Pressure
Forceful inspiration against
closed shutter at the
residual volume
Maximal Expiratory Pressure
Forceful expiration against
closed shutter at the
total lung capacity
Maximal Respiratory Pressures

44. • Used to assess respiratory muscle strength
• MIP – a function of diaphragm and other
inspiratory muscles.
• MEP – a function of expiratory muscles
• Isolated decline in MIP indicates diaphragmatic
dysfunction
• Isolated decline in MEP is rare.
• Decrease in both MIP and MEP indicates either a
generalized muscle weakness or poor effort.
Utility of maximal respiratory pressures
MIP ‐Maximum inspiratory Pressure
MEP ‐ Maximum Expiratory Pressure

45. Tests of absolute lung volume
measurement

46. Absolute lung Volumes
• Measurement of total lung capacity
• Spirometer cannot measure any capacity that
include residual volume(RV).
• Functional residual capacity(FRC) and total lung
capacity(TLC) are such capacities.
– FRC = RV + ERV
– TLC = FRC + IC
• Inspiratory capacity(IC) from SVC maneuver
• FRC from any of the lung volume assessment
methods.

47. Absolute lung volumes
• Techniques to measure the total lung capacity
– Body Plethysmography
– N2 washout method
– Inert gas dilution method
– Radiological techniques

48. • Raw = Alveolar driving pressure ‐ mouth pressure
Flow rate
• Specific airway resistance(sRaw) is airway resistance
corrected for lung volumes.
• Raw: elevated in both obstructive lung diseases and
states of hyperinflation
• sRaw elevated only in obstructive lung diseases.
Airway resistance

49. Body plethysmography

50. Acceptable plethysmographic curve

51. Body plethysmography
• Maximum no. of attempts: No recommendation
• Time between each attempt : 1 minute
• Minimum no. of acceptable curves: 3
• Repeatability criteria
Highest FRCpleth – Lowest FRCpleth < 0.05
mean FRCpleth
• Mean FRC is finally reported
• Add IC to FRC to generate the TLC
FRCpleth – Functional Residual Capacity
as measured by plethysmography

52. Interpretation of body plethysmography
Attempt no. FRCpleth(L)
1 2.78
2 2.80
3 2.67
• Mean FRC = 2.725 L
• Repeatability criteria
Highest FRCpleth – Lowest FRCpleth = 0.04 which is < 0.05
mean FRCpleth
• Mean IC derived from SVC manouvre = 3.01 L
• TLC = 2.725 + 3.01= 5.735 L (>LLN, 81% predicted)

53. Interpretation of TLC
TL
C
Normal
RestrictionPossible hyperinflation
Reduced*Increased*
*Reduced infers that the variable is <
LLN
*Increased infers the variable is > LLN

54. Diffusion Lung Capacity for
Carbon Monoxide

55. Diffusion capacity contd…
• Choice of gas for measuring DL :
Readily available
Easily measurable
Transfer should be diffusion limited
• O2 and N2O exhibit perfusion limited transfer and hence under
estimate the DL
• CO exhibits diffusion limited transfer and hence is the ideal
gas to measure DL
DL ‐ Diffusing capacity of the lungs
CO – Carbon monoxide

56. Diffusion of CO across the alveolar wall
Pulmonary Surfactant
Alveolar Epithelium
Alveolar Interstitium
Capillary Endothelium
Plasma
Red Blood Cell
Hemoglobin

57. Indications
1. Severity assessment in restrictive lung disease
2. Diagnosis of pulmonary vascular disease
3. Differentiation of parenchymal and extra parenchymal
restriction.
4. Diagnosis of early ILD in high risk patients (eg; chronic
amiodarone use, history of chest radiation, stage 1
sarcoidosis)
ILD = Interstitial lung disease;

58. Physiologic variation
Parameters DLCO
Age Decreases with age
Gender Low in females
Weight High in obese
Ethnicity Low in African Americans
Hb concentration Low in anemia
CO Hb Low in smokers
Postural High in supine
State of activity Increases with exertion
Diurnal High in the morning
Menstrual Highest on day prior to menses
Lowest on D5 of menses
Hb -

59. Diffusing capacity contd…
• Five methods:
1.Single‐breath method
2.Steady‐state method
3.Re‐breathing method
4.Three‐Gas Iteration method
5.Intra‐breath method
• Of these the single‐breath method is the best
standardized and most validated.

60. DLCO by single breath

61. Acceptable DLCO curve
• Use of proper quality‐controlled
equipment
• IV of 85% of largest VC in <4s
• A stable calculated breath hold for 10
seconds.
• No cough, leak, Muller’s , Valsalva
manoeuvre
• Expiration in <4 seconds
• Sample collection time< 3 seconds
• Washout volume 750‐1000mL
• Sample volume 500‐1000mL
IV ‐ Inspiratory volume
VC – Vital capacity
85%
VC

62. • Maximum no. of attempts : 5
• Time between each attempts: 4 minutes
• Minimum no. of acceptable curves: 2
• Repeatability criteria: Difference in DLCO not more than
3mL CO (STPD)/min/mmHg or 10%
• Mean DLCO of the two acceptable manouevers
corrected for Hb and COHb is considered for
interpretation.
DLCO contd..
Attempt
no.
DLCO
ml/min/mmHg
LLN Predicted %
predicted
1 28.43 27.16 33.96 83
2 30.54 27.16 33.96 90
Mean 29.49 27.16 33.96 86

63. Recap of FVC manouever
FEV1/VC
VC
Possible
restrictio
n
Normal
V
C
Obstruction with
Possible
co‐existent
restriction.
Obstruction
Normal
Normal
VC manoeuvre
Normal Reduce
d
Reduced*
Reduced*
*Reduced infers that the variable is < LLN
*Increased infers the variable is > LLN

64. Recap of TLC
TL
C
Normal
RestrictionPossible hyperinflation
Reduced*Increased*
*Reduced infers that the variable is <
LLN
*Increased infers the variable is > LLN

65. Interpreting DLCO in restriction
DLC
O
Normal
Extra
parenchymal
restriction
Normal
DLCO/
Va
Extra
parenchymal
Restriction
Like
kyphoscoliosis
Increased*
Reduced*
*Reduced infers that the variable is < LLN
*Increased infers the variable is > LLN
Va‐alveolar volume
Decreased*
Coexistent
Pulmonary
hypertension
Increased*
Obesity
Parenchyma
l restriction

66. Assessment of severity of restriction
Severity DLCO %Predicted
Mild >60% ‐ < LLN
Moderate 40‐60%
Severe < 40%

67. Interpretation of DLCO.. Miscellaneous
Diseases DLCO
Respiratory muscle weakness Low
Isolated Pulmonary vascular disease Low
Emphysema Low
Early ILD Low
Chronic bronchitis High
Bronchial asthma High
Left to Right shunts High
Diffuse Alveolar hemorrhage High

68. Preoperative evaluation in lung resection
• Post operative predicted FEV1 and DLCO used to assess the feasibility
of lobar or segmental resections.
• Calculated as:
Predicted post‐operative(PPO) FEV1 = pre operative FEV1(1‐ y/z)
Predicted post operative(PPO) DLCO = pre operative DLCO(1‐y/z)
y= number of lung segments to be removed.
z= total number of functional segments.
PPO FEV1 and
DLCO % predicted Plan
>60 Surgery
30 – 60 6‐minute walk test
< 30 Cardio pulmonary exercise
test Chest 2013;143(5)(Suppl):
e166s­190s

69. Evaluation of the need for in­flight O2 requirement
Resting SpO2
> 95% < 95%92‐95%
No indication for
in‐flight
O2 requirement
Indication for
in‐flight
O2 requirement
Risk factor for
in‐flight
hypoxemia
• FEV1 < 50% predicted
• Reduced DLCO
• 6‐min walk distance <50m
• AE‐COAD within 6 weeks
• Restrictive lung disease
• Pulmonary hypertension

70. Conclusion
• PFT is widely underutilised and has a wider scope
• Pre‐test evaluation should be given importance
prior to pulmonary function testing
• Patient’s performance is directly proportional to the
pre‐test counselling
• Always assess test performance prior to interpreting
results
• PFT graphics are as important as absolute values
• Always interpret results with clinical context in mind

71. Thank you