Emergency medicine

1. Spirometry
Dr Rahul
Junior resident
KGMU
Lucknow

2. Overview
1. Introduction
2. Lung Volumes and Capacities
3. Types of spirometer
4. Spirometric curves
5. Indications & contraindications of spirometry
6. Complications of spirometry
7. Technique
8. Bronchodilator Responsiveness testing

3. SPIROMETRY
• Spirometry is a physiological test that measures how an
individual inhales/exhales volumes of air over a period of
time.
• Most commonly used pulmonary function test.
• It can measures various volumes and capacities except
residual volume, functional residual capacity and total
lung capacity.

4. HISTORY
In mid 1800s, John Hutchinson, a surgeon, recognised that vital
capacity is a powerful indicator of longevity. He invented the
spirometer and called the vital capacity ‘the capacity to live’.
John Hutchinson developed a simple spirometer based on water seal
principle that measured the maximum volume of air which can move in
and out of lung, vital capacity.

5. Lung volumes &
Capacities

6. Lung volumes:
• Static lung volumes: Lung volumes that are not affected
by the rate of air movement in and out of the lungs are
termed as Static lung volumes. VT (tidal volume), IRV
(inspiratory reserve volume), ERV (expiratory reserve
volume), IC (inspiratory capacity) and VC (vital capacity).
• Dynamic lung volumes: Lung volumes that depend upon
the rate at which air flows out of the lungs are termed
dynamic lung volumes. Forced Vital Capacity (FVC) and
Forced Expiratory Volume in 1st second (FEV1).

7. Definitions
• The Terms: “Volume” and “Capacity”
• The term “volume” refers to the lung volumes that can’t be broken down into smaller
components (RV, VT and IRV etc).
• The “capacity” refers to the lung volumes that can be broken down into other smaller
components (IC, FVC and VC etc)
e.g: IC = IRV + VT
FRC = ERV + RV
• Tidal Volume (VT):The volume of air that we normally inhale or exhale while at rest.
• Residual Volume (RV): The volume of air that remains in the lungs at the end of a maximal
exhalation.
• Expiratory Reserve Volume (ERV): The maximum volume of air that can be exhaled at the
end of a tidal exhalation

8. Lung Volumes
1.Tidal Volume (TV): volume of air inhaled or exhaled with each breath during normal quiet
breathing (6‐8 ml/kg) (500 ml)
2.Inspiratory Reserve Volume (IRV): The maximum volume of air that can be inhaled after normal
tidal inspiration. (3000 ml)
3.Expiratory Reserve Volume (ERV): The maximum volume of air that can be exhaled after
normal tidal expiration. (1500 ml)
4.Residual Volume (RV): Volume of air remaining in lungs after maximium exhalation (20‐25
ml/kg) 1200 ml. It can not be measured by spirometry .

9. 1.Vital Capacity (VC): The maximum volume of air exhaled after maximal deep inspiration.
(60‐70 ml/kg= 5000ml= (TLC-RV)
2.Inspiratory Capacity (IC): The maximum volume of air inspired after normal tidal expiration.
(=IRV+ TV= 2400‐3800ml).
3.Expiratory Capacity (EC): The maximum volume of air expired after the normal tidal
inspiration. (TV+ ERV).
4.Functional Residual Capacity (FRC): Volume of air remain in lung after normal tidal expiration.
(RV+ERV)= 2500-3000ml
5.Total Lung Capacity (TLC): Sum of all volume compartments or volume of air in lungs after
maximum inspiration (4‐6 L).
Lung capacities

11. Types of spirometers- Volume/ flow
• Volume Displacement Spirometers- These record the amount
of air exhaled or inhaled within a certain time (older version)
• Flow sensing Spirometers-These measure how fast the air
flows in or out as the volume of air inhaled or exhaled increases
(newer version)
Johns DP, Pierce R. Pocket guide to Spirometry. McGraw Hill Australia, 2003

12. Features of Volume
Spirometers
• Calibration check are easy to perform. They hold their calibration
much better than flow spirometers.
• Many can produce flow/volume curves and loops, with addition of
potentiometer or digital encoder with a PC.
• Meet ATS standards easily.
• Most are heavy, cumbersome to move

13. Flow Spirometers
• Measure Flow vs. Volume
"Y" axis - Flow Rate in l/sec
"X" axis - Volume in liters.
• Slow & hesitant starts,
cough and artifacts are
easily detected.

14. Volumes/ Flows measured by spirometry
• Forced Vital capacity (FVC)
• Forced Expiratory volume in 1 second (FEV1)
• FEV1/ FVC
• PEFR
• FEF25-75%
• MVV

15. FORCED VITAL CAPACITY (FVC)-
• Maximum volume of air that can be breathed out as forcefully and rapidly as
possible following a maximum inspiration.
• Indirectly reflects flow resistance property of airways.
FORCED EXPIRATORY VOLUME IN 1 SEC (FEV1)-
• Maximum volume of air which can be exhaled forcibly out in 1 second after
deep full inspiration.
• The volume expired in the first second during FVC maneuver.
• MEASURES the severity of the airway obstruction.

16. Types of spirometry tracings-
V-T and F-V curves

17. Volume Time Curve (Spirogram)
• It shows the amount of air expired from the lungs
as a function to time.
• The normal volume time curve has a rapid up
slope and approaches a plateau soon after
exhalation.
• The maximum volume attained represents the
forced vital capacity (FVC).
• The volume attained after one second represents
the forced expiratory volume (FEV1).

19. Flow Volume Loop- Inspiratory / Expiratory limbs
• Graphic illustration of a patient’s spirometry efforts.
• Continuous loop from inspiration to expiration.
• A Expiratory flow volume loop has a rapid peak
expiratory flow rate (termed as ‘peak of the curve’).
The expiratory flow rate then falls and the tracing
moves downward to meet the volume axis. It is
termed ‘the slope of the curve.
• The inspiratory portion of the loop is a deep curve
plotted on the negative portion of the flow axis. It
indicates upper airway disease.
• The overall shape of the flow volume loop is
important in interpreting spirometry results.
Peak
Slope

21. PEFR- Peak expiratory flow rate
This is the maximum flow of air achieve during a forceful exhalation, measured in
litres per second. It is effort dependent and occur in early part of forceful exhalation.
.
Test Values In Spirometry
Burrows, B., 1975. Pulmonary Terms and Symbols. Chest, 67(5), pp.583-
593.

22. FEF25-75% or 25-50%- Forced expiratory flow 25-75% or 25-50%
This is the average flow of air during the middle portion of the FVC manoeuver ( also
sometimes referred to as MMEF , for maximal mid-expiratory flow). May reflect effort
independent expiration and the status of small airways. (<2mm in diameter)
FIF 25-75% or 25-50%- Forced inspiratory flow 25-75% or 25-50%
This is similar to FEF 25-75% or 25-50% except the measurement is taken during inspiration.
Important in extra thoracic disease.

23. Concept of FEV3 and FEV6
• Measurement of the forced expiratory volume in 3 s (FEV3)
may better reflect small airway obstruction compared with
FEV1.
• Reductions in FEV3/FVC have been associated with early air
trapping, hyperinflation, and reduced diffusing capacity of the
lung for carbon monoxide (Dlco)

24. Diagnostic
• To evaluate symptoms, signs or abnormal laboratory tests.
• To measure the effect of disease on pulmonary function
• To assess pre-operative risk
• To assess prognosis.
Indications of spirometry

25. Monitoring
• To assess therapeutic intervention.
• To describe the course of diseases that affect lung function.
• To monitor for adverse reactions to drugs with known pulmonary
toxicity

26. Contraindications of spirometry
Due to increase in myocardial demand or change in blood pressure
• Acute MI within 1 wk
• Systemic hypotension or severe hypertension
• Significant atrial/ventricular arrhythmia
• Non-compensated heart failure
• Uncontrolled pulmonary hypertension
• Acute cor pulmonale
• Clinically unstable pulmonary embolism
• History of syncope related to forced expiration/cough

27. Due to increase in intra-cranial/ intra-ocular pressure
Cerebral aneurysm
Brain surgery within 4 wk
Recent concussion with continuing symptoms
Eye surgery within 1 wk
Due to increase in sinus and middle and middle ear pressure
Sinus or middle ear surgery or infection within 1 wk
Due to increase in intrathoracic and intraabdominal pressure
Presence of pneumothorax
Thoracic/abdominal surgery within 4 wk
Late term pregnancy
Infection control issues
Active or suspected transmissible respiratory or systemic infection like TB

28. • Syncope
• headache
• Chest pain
• Paroxysmal coughing
• Nosocomial infection
• Oxygen desaturation due to interruption of O2
• Bronchospasm
Complications of spirometry

29. Procedure for recording
FVC

30. Pre-test requirements
• The subject should be seated for approximately 5 minutes prior to the
tests and should remain seated throughout the investigations
• Record the subject’s age, height and gender for calculation of the
reference values
• If dentures: use them

31. Activities to be avoided
before PFT
• No smoking for 1 hour
• No intoxicants within 8 hours
• No vigorous exercise for 1 hour
• No tight clothes

32. Bronchodilator Medication Withholding Time
SABA ( albuterol or salbutamol) 4-6 h
SAMA ( ipratropium) 12 h
LABA ( formoterol or salmeterol) 24 h
Ultra- LABA ( indacaterol, vilanterol) 36 h
LAMA ( tiotropium, umeclidinium,
glycopyronium)
36- 48 h
Bronchodilator Withholding Times

33. Patient Details
• Enter:
• Demographic profile
• Age
• Height
• Smoking status
• Ethnicity

34. FVC Manoeuvre
FVC maneuver: 4 phases
-Maximal inspiration
-Blast” of expiration
-Continued complete expiration for
a maximum of 15 seconds
-Inspiration at maximal flow back to
maximum lung volume
• Preceding inspiration should be
rapid and any pause at full
inspiration be minimal (<2 s)

35. Open Circuit Method
• Have subject assume correct posture and attach nose clip
• Inhale completely and rapidly with a pause of 1 s at TLC. Place
mouthpiece in mouth and close lips around it.
• Exhale maximally until no more air can be expelled

36. Closed Circuit Method
• Attach nose clip; place mouthpiece in mouth and close lips around
it; and breathe normally
• Inhale completely and rapidly to TLC
• Exhale maximally until no more air can be expelled

37. End of Forced Expiration indicators (EOFE)
-Earlier called end of test (EOT) criteria
-Must achieve one of these End of Forced Exhalation (EOFE)
indicators:
• Expiratory plateau (<0.025 L change in the last 1 s of
expiration): most important
• Expiratory time >15 s

38. Criteria for Acceptability
1. Maximum inspiratory effort should be done before exhalation.
1. No hesitation on start and rapid rise of curve until peak flow is reached.
1. Maximum effort to be maintained throughout procedure with no sudden cessation of
flow and reversal of flow.
1. No cough (especially in early part of the curve)
1. No leak of air outside mouthpiece of spirometre.
1. Must achieve one of these 3 EOFE (End of forced expiration) indicators :
a. Expiratory plateau (<25ml in last 1 sec of expiration)
a. Expiratory time >15 sec
a. FVC within repeatability tolerance of or is greater than the largest prior observed
fvc.

39. Good end of the test :
• Plateau of VT curve of at least 1 second, i.e. volume is not changing
with time indicating that the patient is approaching or has reached
the residual volume (RV)
• Reasonable duration of effort.

40. Features of the ideal FV and VT curves:
• The ideal FV curve should have the following
features:
• Good start with sharp and rounded PEF.
• Smooth continuous decline free from artifacts.
• Good termination with a small upward concavity at or
near the 0 flow.
• The ideal VT curve should either have a plateau for 1
second

41. • Blunt peak (Sand mound):
indicates inadequate effort. (Fig.
1).
• Notch: A notch in the initial part
indicates a cough or hesitant start
(Fig. 2).
• Delayed peak: The curve starts
from zero, but the peak is delayed
(Fig. 3).
Abnormal Patterns in Peak
Fig.1 Fig.2
Fig. 3

42. • Steep Curve: In restrictive lung diseases, curve is steep and
straight (Fig. 1)
• Rat tail appearance: characteristics of obstructive airways,
airflow starts with a peak, but flow rapidly declines due to
airway collapse resulting in shift of upward concavity
proximally and a long plateau. (Fig.2)
• Notches on slope: Coughing in the later part of the slope
does not affect the results (Fig. 3). Hence no need of
repeating the test.
• Abrupt termination of the slope: Patients stops expiration
before complete exhalation. The test should be repeated as
spirometric parameters will show a typical restrictive
defect.
Abnormal patterns in slope
Fig.1 Fig.2
Fig.3
Fig.4

44. Selecting Parameters for
Reporting
• Largest FVC and FEV1 from acceptable maneuvers should be
reported even if these come from different curves.
• Curve with largest FVC is to be taken for display

45. Reference Values:
• The values for spirometric measurements have a wide range of
normal in the normal subjects. These values depend on certain
variables:
• Sex (Men have bigger lungs than women)
• Age (The spirometric values drop with age)
• Height (Tall people have bigger lungs. If it is difficult to measure the
height, as in kyphoscoliosis, then the arm span can be measured instead.
• Race (Caucasians have relatively bigger lungs than those of African and
Asian descent)

46. Measuring bronchodilator responsiveness of
Airflow Obstruction
• Spirometry is performed before and 15 minutes
after administering bronchodialator
• 400 μg salbutamol via a metered-dose inhaler and
spacer
• Patient should stop any β2-agonist for 6 hr, long-
acting bronchodilator for 12 hr, ultra long acting β2-
agonist and theophyllins for 24 hr

47. Interpretation: Points to Remember
• Check for calibration
• Always check shape of curve: acceptable or not
• Check for repeatability of results
• Choose correct normal reference values
• Always do clinical correlation
• Borderline values: report with caution