2. DR S RAGHU M.D.,
ASST PROF
DEPT. T B & CD
GUNTUR MEDICAL
COLLEGE
GUNTUR
Dr s. raghu m.d.,
Associate professor
Department of TB & CD
R I M S medical college
ONGOLE
3. •11,000 Lts air every day
• Patency of airways
VENTILATION
PERFUSION
• 11,000 Lts blood every day
• Lung Volume available
• Diffusibility across
membrane
550 L of O2 consumes every day
4. THE STETHOSCOPE
• Presence or absence
of air entry
• Presence of airway
narrowing
•Cavities in the Lung
BUT NO REAL OBJECTVE
MEASURE OF LUNG
FUNCTION
Laennec’s Stethoscope
9. DISCOVERY OF THE
SPIROMETER
Sir John Hutchinson, 1846
Hutchinson J, The Lancet 1846; 1: 630-632
Vital capacity
- More sensitive to
detect Tuberculosis
than auscultation
- Can predict life
expectancy.
Suggested this test for
routine life insurance
cover.
10. spirometry
• John Hutchinson (1811-1861)—inventor of the
spirometer and originator of the term vital capacity
(VC).
• “Spirometry is a physiological test that measures the
volume of air an individual inhales or exhales as a
function of time. (ATS / ERS 2005 ) .
• Simple, office-based
16. Introduction
• The term encompasses a wide variety of objective
methods to assess lung function. They Provide
quantifiable, reproducible measurement of lung
function .
• They do not act alone.
• They act only to support or exclude a diagnosis.
• A combination of a thorough history and physical
exam, as well as supporting laboratory data and
imaging will help establish a diagnosis.
17. The various components of
pulmonary function tests
• Tests for ventilation : spirometry with helium
dilution technique & body plethysmography.
• Tests for diffusion : diffusion capacity for CO
(DLCO) .
• Tests for ventilation / perfusion : V/Q scan ,
nitrogen wash out test.
• Exercise testing :
18. 5. Arterial blood gas analysis
6. Bedside tests : Peak expiratory flow (PEF), trans-cutaneous O2
(SpO2) and CO2 (tCO2) monitoring
7. Tests for respiratory muscle function: PI max and PE max
8. Tests for respiratory center function: CO2 stimulation test
9. Tests for sleep related respiratory disorders: poly-somnography (PSG)
However spirometry is the most basic and widely used method of
evaluating pulmonary functions
19. Peak expiratory flow
(PEF) is measured by a maximal
forced expiration through Peak flow
meter
Correlates well with the FEV1
and is used as an estimate of airway
caliber.
PEFR should be measured
regularly in asthmatics to monitor
response to therapy and disease control.
22. Indications of
spirometry
• Diagnostic
• To evaluate symptoms, signs or abnormal laboratory tests
• To measure the effect of disease on pulmonary function
• To screen individuals at risk of having pulmonary disease
• To assess pre-operative risk
• To assess prognosis
• To assess health status before beginning strenuous physical
activity programmes.
23. • Monitoring
• To assess therapeutic intervention
• To describe the course of diseases that affect lung
function
• To monitor people exposed to injurious agents
• To monitor for adverse reactions to drugs with
known pulmonary toxicity.
24. • Disability/impairment evaluations
• To assess patients as part of a rehabilitation
programme
• To assess risks as part of an insurance evaluation
• To assess individuals for legal reasons
• Public health
• Epidemiological surveys
• Derivation of reference equations
• Clinical research
25. Acceptable & reproducible
criteria
(ATS / ERS 2005 guidelines)
• Acceptable criteria :
a. Free from artefacts ( cough , glottis closure )
b. Free from leaks
c. Good starts ( extrapolation back from the peak flow
– “new time zero” should occur with in 5% / with in
150 ml.)
d. Acceptable exhalation : (adults – 6 secs & a
plateau& in children < 10yrs – 3 secs )
26. • Repeatability criteria :
a. Three acceptable manoeuvers ( meeting above
criteria )
b. The two largest FVC measurements with in 150 ml
of each other
c. The two largest FEV 1 measurements with in 150
ml of each other
Upto 8 manoeuvers should be performed
until criteria met
27. Performance of FVC maneuver
• Check spirometer calibration.
• Explain test.
• Prepare patient.
– Ask about smoking, recent illness, medication use, etc.
(adapted from ATS/ ERS 2005 ) .
28. Performance of FVC maneuver
(continued)
• Give instructions and demonstrate:
– Show nose clip and mouthpiece.
– Demonstrate position of head with chin slightly
elevated and neck somewhat extended.
– Inhale as much as possible, put mouthpiece in
mouth (open circuit), exhale as hard and fast as
possible.
– Give simple instructions.
31. Information we get from a
spirometer
• A spirometer can be used to measure the following:
– FVC and its derivatives (such as FEV1, FEF 25-
75%)
– Forced inspiratory vital capacity (FIVC)
– Peak expiratory flow rate
– Maximum voluntary ventilation (MVV)
– Slow VC
– IC, IRV, and ERV
– Pre and post bronchodilator studies
32. The spirometric recording is
represented in 2 forms:
absolute values and graphic
forms
– Flow-volume curve---flow
meter measures flow rate in
L/s upon exhalation; flow
plotted as function of volume
– Classic spirogram---volume as
a function of time
Volume
F V C
F E V 1
1 s e c o n d
F E T
T im e
volume
f
l
o
w
33. Acceptable and Unacceptable
Spirograms (from ATS, 1994)
c o u g h
0 1
p o o r s ta r t
0
a c tu a l F V C
n o t a t T L C p rio r
to b lo w
0
Volume
T im e
g o o d e ffo rt
0
S u b m a x im a l e ffo rt
0
a c tu a l F V C
p re m a tu re te rm in a tio n
o r g lo ttic c lo s u re
0
34. Spirometry Interpretation: So what
constitutes normal
•Normal values vary and depend on:
–Height
–Age
–Gender
Ethnicity
Spirometry can demonstrate two basic
patterns of disorders
42. is the airway obstruction reversible?
Bronchodilator response
Asthma versus COPD
• Degree to which FEV1 improves with inhaled
bronchodilators.
• Documents reversible airflow obstruction
• Significant response if:
- FEV1 increases by 12% and >200ml
• Request if obstructive pattern on spirometry
43. • FEV1 improvement by
• 12% and ≥ 200mL
with
• 200-400mcg Salbutamol
by inhaler
• or
• 40-80mcg Ipratropium
Bromide by inhaler
Reversible airway disease diagnostic of
asthma
44. Staging Severity of Asthma
• Rule “60-80”
• FEV1/FVC%<80%
Severity FEV1
Intermittent Normal
Mild persistent ≥ 80%
Moderate persistent 60-80%
Severe persistent ≤ 60%
45.
46. Bronchial provocation test
Useful for diagnosis of asthma in the setting of
normal pulmonary function tests
Common agents:
- Methacholine, Histamine, others
Diagnostic if: ≥20% decrease in FEV1
47. Indications
• History suggestive of
bronchospasm induced by
environmental or occupational
agent in the setting of normal
PFT
• Cough Variant Asthma
Contraindications and
Precautions
• Baseline FEV1/FVC% <70
• Recent upper respiratory tract
infection
• Recent influenza vaccination
• Recent administration of
bronchodilator
• Ingestion of caffeine within 6
h before testing
• Cold-air breathing,
hyperventilation, exercise
within 6 h before testing
• Recent acute myocardial
infarction or cerebrovascular
accident, uncontrolled
hypertension, or known aortic
aneurysm
53. Mixed type
• Low FEV1/ FVC – obstr
• Reduced VC & TLC – restr
• D/D
– Sarcoidosis
– Interstitial fibrosis
– Lobar pneumonia or large pl effusion in COPD
54.
55. Contraindications
• Hemoptysis of unknown origin,
• Pneumothorax,
• Unstable angina pectoris,
• Recent myocardial infarction
• Thoracic aneurysms,
• Abdominal aneurysms,
• Cerebral aneurysmsRecent abdominal or thoracic surgical
procedures
• History of syncope associated with forced exhalation.
• Recent eye surgery (increased intraocular pressure during
forced expiration)
56. Activities that should preferably be
avoided prior to lung function testing
• Smoking within at least 6 h of testing
• Consuming alcohol within 24 h of testing
• Performing vigorous exercise within 30 min of testing
• Wearing clothing that substantially restricts full chest
and abdominal expansion
• Eating a large meal within 2 h of testing
• Short acting B2 agonists & anticholinergics -4 hours
• Long acting B2 agonists – 12 hr
• Oral methylxanthine -12 hours
57. Upper airway obstruction
• Upper airway is the segment
of conducting airways that
extends between the nose
( during nasopharyngeal
breathing) or mouth during
oropharyngeal breathing) and
the carina.
• Fixed obstruction .
• Variable intra-thoracic .
• Variable extra-thoracic.
58. Fixed upper airway
obstruction
• Post-intubation stenosis
• Large Goiters compressing the trachea
• Endotracheal neoplasms
• Stenosis of both main bronchi
• Obstruction of the internal airway
62. Indices that show UAO in
spirometry
• Fixed obstruction:
FEF50%/FIF50%=1
FEV1/FIV1=1
• Variable extra thoracic:
FEF50%/FIF50%>2
FEV1/FIV1>1
• Variable intra thoracic:
FEF50%/FIF50%<1 ( even 0.3)
FEV1/FIV1<1
64. EMPEY index
• It is the ratio of FEV1 to PEF
• The best indicator in large airways obstruction
• Significant value is greater than 8
• The higher the index the more severe the obstruction
• As a clinical screen in the absence of a flow-volume
loop it is a reasonable guide to the presence of UAO
66. • 4 volumes: inspiratory
reserve volume, tidal volume,
expiratory reserve volume,
and residual volume
• 2 or more volumes comprise a
capacity.
• 4 capacites: vital capacity,
inspiratory capacity,
functional residual capacity,
and total lung capacity
67. • Functional Residual
Capacity (FRC):
– Sum of RV and ERV or
the volume of air in the
lungs at end-expiratory
tidal position
– Measured with multiple-
breath closed-circuit
helium dilution, multiple-
breath open-circuit
nitrogen washout, or
body plethysmography
(not by spirometry)
69. Diffusion capacity
• Diffusing capacity of lungs for CO
• Measures ability of lungs to transport inhaled gas from
alveoli to pulmonary capillaries
• Depends on:
- alveolar—capillary membrane
- hemoglobin concentration
- cardiac output
70. Alveolo – capillary membrane
• Gas diffuses across this
alveolar-capillary
barrier.
• This barrier is as thin as
0.3 μm in some places
and has a surface area
of 50-100 square
meters!
75. DLCO - indications
Differentiate asthma from emphysema
Evaluation and severity of restrictive lung disease
Early stages of pulmonary hypertension
• Expensive!
79. Pre-operative Evaluation For Surgery
Other Than Pulmonary Resection
High Risk
Moderate Risk
75%
FEV1
FVC
50%
25%
75%
Low Risk
“Normal risk”
25% 50%
80. Pre-operative Risk Assessment
For Pulmonary Resection Surgery
• Calculate predicted post operative (ppo) FEV1
• For pneumonectomy,
predicted P.O FEV1 = preoperative FEV1 X % perfusion to
remaining lung
(regional quantitative perfusion scans may be used)
• For lobectomy,
Predicted P.O. FEV1 =
preoperative FEV1 X no of lung segments remaing after resection
/total no segments in both lungs
• Using “Rule of Five”
• FEV1 > 1L makes patient suitable for any lung resection
surgery
86. 1. Acceptable exhalation in
children <10
years in spirometry
a. 3 Secs
b. 6 Secs
c. 9 Secs
d. None
87. 2. Flow volume curve shows
a. Poor effort b. bronchial asthma
c. Emphysema d. ILD
88. 3.Conditions that cause isolated
decrease in DLCO
a. Pulmonary
thromboembolism
b. Pulmonary hypertension
c. Vasculitis
d. Scleroderma
e. Early ILD
f. all
89. Case 2
49 y/o Female
Shortness of breath and
nonproductive cough
FEV1/FVC: 85%
FVC: 1.17 L (34%)
FEV1: 1.00 L (37%)
VC: 1.17 L (34%)
a.Pulmonary fibrosis b. Br.asthma
c.COPD C. None