PULMONARY FUNCTION TESTS PLAY A VERY IMPORTANT ROLE IN ESTIMATING THE FUNCTION OF LUNGS ESPECIALLY IN ASTHAMA AND COPD, One of the frequent reasons patients see their primary care physicians is for the symptom of dyspnea. Among the objective tests to quantify this symptom is the pulmonary function test

1. PULMONARY
FUNCTION
TEST
Guided by:
Dr S.P. Srinivas Nayak,
Assistant Professor,
SUCP, HYD
Presented By: ISMAT BANO, PharmD
Sultan Ul Uloom College of Pharmacy
Hyderabad, India

2. One of the frequent reasons patients see
their primary care physicians is for the
symptom of dyspnea. Among the
objective tests to quantify this symptom
is the pulmonary function test, which
includes several different studies:
spirometry with flow-volume loop, lung
volumes, and diffusing capacity of lung
for carbon monoxide. The results may
indicate both respiratory and no
respiratory disorders, including helping in
the diagnosis of cardiac or
neuromuscular diseases.

3. An objective way to differentiate between the
multiple causes of dyspnea (a highly
subjective symptom) is to order a pulmonary
function test (PFT), which assists in the
identification and quantification of respiratory
system abnormalities.
• PFTs can help diagnose:
• Asthma
• Allergies
• chronic bronchitis
• respiratory infections

4. • lung fibrosis
• bronchiectasis, a condition in which the airways in the lungs stretch and widen
• COPD, which used to be called emphysema
• asbestosis, a condition caused by exposure to asbestos
• sarcoidosis, an inflammation of your lungs, liver, lymph nodes, eyes, skin, or other tissues
• scleroderma, a disease that affects your connective tissue
• pulmonary tumour
• lung cancer

5. PFT can be done with 2 methods.
These 2 methods may be used
together or separately:
Spirometry: A spirometer is a device
with a mouthpiece hooked up to a
small electronic machine.
Plethysmography: You sit or stand
inside an air-tight box that looks
like a short, square telephone
booth to do the tests.

6. Spirometry procedure
A spirometry test usually takes about 15 minutes and generally happens in your
doctor’s office. Here’s what happens during a spirometry procedure:
1. You’ll be seated in a chair in an exam room
at your doctor’s office. Your doctor or a
nurse places a clip on your nose to keep
both nostrils closed. They also place a cup-
like breathing mask around your mouth.
2. Your doctor or nurse next instructs you to
take a deep breath in, hold your breath for a
few seconds, and then exhale as hard as
you can into the breathing mask.

7. • You’ll repeat this test at least three times to make sure that your
results are consistent. Your doctor or nurse may have you
repeat the test more times if there is a lot of variation between
your test results. They’ll take the highest value from three close
test readings and use it as your final result.

8. Test
• Spirometry is effort dependent. The subject must understand that they need to
give maximum effort. 15% greater volume can be achieved with good
coaching. The subject should assume the correct posture: seated, feet flat on
floor with head slightly elevated, looking ahead and chin pointed forward.
• Ask the subject to attach a nose clip
• Tell the subject that they will need to fill their
lungs, then to blow out as hard and fast as they
can and to keep blowing until you tell them to
stop Instruct the subject to take a very deep
breath in, filling their lungs completely Then to
insert the BVF in their mouth (as shown) and
blow out as hard and as fast as they can
without any hesitation Instruct the subject to
keep blowing until they have completely
emptied their lungs

9. • The subject may feel like they cannot breathe out any longer, but
keep encouraging them, the flow head will detect very low air
flow. (In obstructive lung disease the expiration could be 20
seconds or more)
•
• Ensure that the subject keeps their back straight throughout the
manoeuvre Instruct the subject to take the mouthpiece out of
their mouth and relax.
• Review the spirometry manoeuvre and inform the subject if they
are doing well or advise them on how to improve their technique.
• It is important to allow adequate rest times between the
manoeuvres as this could affect the maximum effort of the
subject

10. POST TEST
• The acceptable blows should be reviewed as a session, comparing the curves to
determine if they are repeatable.
• Have 3 acceptable tests been performed
• The two highest accepted FEV1 values should be within 0.15L (150ml) of each other
• The two highest accepted FVC values should be within 0.15L (150ml) of each other
Graph 1: Example of a good spirometry session

11. One of the primary spirometry measurements is FVC, which is the greatest total
amount of air you can forcefully breathe out after breathing in as deeply as
possible. If your FVC is lower than normal, something is restricting your
breathing.
Normal or abnormal results are evaluated differently between adults and
children:
For children ages 5 to
18:
For adults:
FVC MEASUREMENT

12. FEV1 measurement
The second key spirometry measurement is
forced expiratory volume (FEV1). This is the
amount of air you can force out of your lungs
in one second. It can help your doctor
evaluate the severity of your breathing
problems. A lower-than-normal FEV1 reading
shows you might have a significant breathing
obstruction.
FEV1/FVC ratio The FEV1/FVC ratio is a number that
represents the percentage of your lung capacity you’re
able to exhale in one second. The higher the percentage
derived from your FEV1/FVC ratio, in the absence of
restrictive lung disease that causes a normal or elevated
FEV1/FVC ratio, the healthier your lungs are. A low
ration suggests that something is blocking your airways:

13. Spirometry graph
Spirometry produces a graph that shows your flow of air over time. If your lungs are
healthy, your FVC and FEV1 scores are plotted on a graph that could look
something like this:
If your lungs were obstructed in some way,
your graph might instead look like this:

14. A, Normal. B, Moderate obstruction with “scooping.” C, Severe obstruction

15. D, Moderate restriction. E, Severe restriction. F, Variable extrathoracic
obstruction with flattening of the inspiratory portion of the flow-volume loop
(granulomatosis with polyangiitis).

16. G, Variable intrathoracic obstruction with flattening of the expiratory portion of the flow-
volume loop (relapsing polychondritis). H, Fixed obstruction with flattening of both portions
of the flow-volume loop (tracheal stenosis). I, Weak effort (myopathy). J, Normal but with a
prominent tracheal plateau.

17. The abnormal results of spirometry separate into 2 large
classes of disorders: obstructive and restrictive.
Spirometry is essential for the diagnosis of obstructive
processes including chronic obstructive pulmonary disease
(COPD) and asthma.
In obstructive disorders, the FEV1/FVC ratio is reduced.
The severity of obstruction is quantified by the degree of
reduction in FEV1 (expressed as a percentage of the
predicted normal value), which is derived from a reference
population of normal individuals and calculated using
height, age, sex, and ethnicity or race .

19. Once the ventilatory pattern is
identified, the severity of the disease
must be determined. The American
Thoracic Society has developed a
scale to rate the severity of disease
based on predicted FEV1 and TLC.
The final step in interpreting
spirometry is to determine if
additional testing is needed to further
define the abnormality detected by
spirometry. Measurement of static
lung volumes, including FRC, is
required to make a definitive
diagnosis of restrictive lung disease.

20. • PFT measures:
• Tidal volume (VT). This is the amount of air inhaled or exhaled during normal breathing.
• Minute volume (MV). This is the total amount of air exhaled per minute.
• Vital capacity (VC). This is the total volume of air that can be exhaled after inhaling as
much as you can.
• Functional residual capacity (FRC). This is the amount of air left in lungs after exhaling
normally.
• Residual volume. This is the amount of air left in the lungs after exhaling as much as you
can.
• Total lung capacity. This is the total volume of the lungs when filled with as much air as
possible.
• Forced vital capacity (FVC). This is the amount of air exhaled forcefully and quickly after
inhaling as much as you can.
• Forced expiratory volume (FEV). This is the amount of air expired during the first,
second, and third seconds of the FVC test.
• Forced expiratory flow (FEF). This is the average rate of flow during the middle half of
the FVC test.
• Peak expiratory flow rate (PEFR). This is the fastest rate that you can force air out of

22. Following spirometry, Static lung volume (SLV) was
measured via body plethysmography, using the
preferred and alternate methods in random order.
Lung plethysmography is also called pulmonary
or body plethysmography. It helps doctors
assess the condition of people with lung
disease, which can occur with a decrease in
total lung capacity (TLC).
Although spirometry is the standard way to
measure lung volumes, lung plethysmography
is more accurate. Measurements from this test
are based on Boyle’s Law, a scientific principle
that describes the relationship between the
pressure and volume of a gas. This law says
that if temperature remains the same, you can
use measurements of the volume of a gas to
find out its pressure and vice versa.
PLETHYSMOGRAPHY

23. You’ll sit or stand in a small, airtight chamber that is
partially or completely see-through and may
resemble a phone booth. Babies may have a special
type of test that allows them to lay down.
They’ll put clips on your nose to shut off air to your
nostrils.
They’ll ask you to breathe or pant against a
mouthpiece when it’s both opened and closed.
This will provide your doctor with important
measurements, including:
•TLC
•The amount of air left in your lungs when you
breathe out normally, which is called functional
residual capacity (FRC)
•How much air is left when you breathe out as much
as possible, or residual capacity (RC)

24. • As your chest moves while you breathe or pant, it changes the pressure and
amount of air in the chamber. Your breathing also changes the pressure against
the mouthpiece. From these changes, your doctor can get an accurate measure
of TLC, FRC, and RC.
• Normal values depend on a combination of many factors, such as:
• Age
• Height
• ethnic background
• Sex
• A normal value for you may be different than a normal value for someone else.

25. Measurement of Lung Volumes
• Measurement of lung volumes with a body plethysmograph (body box)
uses Boyle's gas law, which states that pressure multiplied by volume is
constant (at a constant temperature).
• The subject sits in an airtight box (Fig. 21-3) and breathes through a
mouthpiece that is connected to a flow sensor (pneumotach).
• The subject then makes panting respiratory effort against a closed
mouthpiece.
• During the expiratory phase of the maneuver, the gas in the lung
becomes compressed, lung volume decreases, and the pressure inside
the box falls because the gas volume in the box increases.
• By knowing the volume of the box and measuring the change in
pressure of the box at the mouth, the change in volume of the lung can
be calculated.

26. Pressure–volume loop obtained from a
person seated in a body plethysmograph.
Pressure at the mouth represents alveolar
pressure; pressure in the box represents
thoracic gas volume. After the shutter has
closed at end-expiration (Pm, V), the
subject attempts to inspire. Pm falls, and
the pressure in the box increases. This
increase in box pressure is calibrated in
terms of an equivalent volume change.
The new position of the trace at the end of
the inspiratory effort is (Pm + ΔPm, V +
ΔV). The slope of the loop depends on the
volume of gas in the lungs when the
shutter is closed (FRC).

27. At the end of a quiet expiration, the shutter is closed and the patient is instructed to
pant gently against it.
The panting movements cause both mouth pressure and box pressure to change.
With each inspiratory effort, as mouth pressure falls and gas in the lungs is rarefied,
lung volume increases. Because the plethysmograph is a closed box, the increase
in lung volume produces a corresponding increase in box pressure.
With each expiratory effort, as lung volume decreases, box pressure falls. Because
the shutter is closed while the measurements are made, mouth pressure equals
alveolar pressure (PA).
These oscillations in mouth pressure and box pressure or lung volume appear on
the oscilloscope as a closed loop.
Measurement of the slope of this loop is used to determine the volume of gas in the
lungs at the time of shutter closure – that is, TGV or VTG.
When the occlusion occurs at resting, end-expiratory lung volume, the
measurement yields FRC.

28. Applying Boyle’s law to the plethysmographic determination of
lung volume,
In the pressure
plethysmograph, ΔV is
sensed as a change in
pressure within the
box, and ΔP is
determined from the
change in mouth
pressure during
breathing efforts
against the closed
shutter.

29. Rearranging the equation and solving for V yield
Therefore, the only unknown in this equation is V, which can be
calculated by incorporating values for barometric pressure and the
inverse of the slope of the plot of mouth pressure versus box pressure
(ΔP/ΔV).

30. In reality airway resistance is finite, thereby causing a nonzero pressure
gradient. Airflow always tends to reduce pressure differences until
equilibrium is reached. During inspiration, however, the continuing
inspiratory movement of the thorax ensures that its volume excursion is
slightly ahead of the equilibrating mass flow. When the thoracic, i.e. lung
volume ceases to increase, alveolar and box pressure will rapidly reach
equilibrium. As long as air is flowing, however, the increase in lung
volume is slightly greater than the volume of air that has passed through
the airways into the lung. This small difference represents a lag in mass
flow during the breathing cycle and is called “shift volume”.
The shift volume provides the link to the box pressure that is at the heart
of body plethysmography and allows the determination of two primary
measures: thoracic gas volume and specific airway resistance.

31. the shift volume in the box is the mirror image of the shift volume of
the lung. This is the consequence of the fact that the box is
hermetically sealed and has stable walls. Therefore, any change in
lung volume must be equivalent to an opposite change in the free
volume of the box outside the body, independent of the fact whether
pressure equilibration has been achieved or not.
The patient, seated in the body plethysmograph, pants at a rate of about
two breaths per second while airflow is measured using a
pneumotachograph. During inspiration and expiration, gas in the alveoli
is alternately rarefied and compressed, causing changes in pressure
within the sealed plethysmograph. The relationship between
plethysmograph pressure and airflow during the panting maneuver is
displayed on the X and Y axes of an oscilloscope.

32. Plot of airflow versus body plethysmograph
pressure (Pbx). The slope of this curve, in the
range of 0 to 0.5 L/s of inspiratory flow,
divided into the slope of the loop obtained
when the shutter is closed provides a
measure of airway resistance (Raw).
While the panting continues, a shutter at the
airway opening is closed so that airflow is
transiently interrupted. Using the technique
employed in the determination of FRC,
changes in pressure in the plethysmograph
(equivalent to changes in lung volume) and at
the mouth are displayed on the X and Y axes,
respectively, of the oscilloscope. However,
since airflow is zero while the shutter is
closed, the pressure at the mouth equals
alveolar pressure (Pao = PA).

33. The question arises how to assess the change in alveolar pressure. This is
determined by measuring the pressure generated at the mouth during
respiratory efforts, while the airflow is blocked. The zero-flow condition implies
mouth pressure to be equal to alveolar pressure, because occurrence of a
pressure gradient and occurrence of airflow are necessarily linked to each
other. To achieve this condition, a shutter is used that prevents air from
entering or leaving the lung (occlusion pressure maneuver). Normal
inspiratory and expiratory efforts against the closed shutter lead to
decompression and compression of the air in the lung.

34. This relationship bears information on lung volume.
When moving a plunger a certain distance (volume
difference) in a short versus a long cylinder of given
cross section, pressure change will be greater in the
short cylinder.
Translated to the lung: the larger the lung volume for a
given shift volume, the smaller the pressure change.
Conversely, the greater the pressure change, the
smaller the lung volume must be relative to the shift
volume.
Therefore, in a large lung the occlusion pressure curve
will be more flat, and in a small lung more steep.

35. After the first occlusion maneuver, patients should continue to breathe
normally until they have recovered from potential changes in FRC
subsequent to the maneuver.
It is strongly recommended to perform at least one further occlusion
maneuver. The values should be within 10% of each other. Depending on
their difference, the operator can decide whether further measurements are
necessary.
In general, three or more measurements are recommended, of which at
least two should be within 10% of each other. The median of the
reproducible values is taken as final value.
Since the maneuver might be perceived as exhausting by the patient, it
should not be repeated more often than needed to obtain a reliable value.
The occlusion maneuver is the part of body plethysmography which is most
prone to artifacts of different kind leading to erroneous conclusions.

36. Schematic representation of the
apparatus used to perform the
occluded inspiratory effort
maneuver. A selective inspiratory
occlusion was performed during
expiration by means of the
inspiratory pneumatic shutter.
Consequently, patients were
allowed to exhale freely, after
which they were encouraged to
perform a maximum inspiration
against the occluded airway. The
expiratory shutter was kept open
during the maneuver.

37. If possible, the patient should perform a maximal
expiration to determine expiratory reserve volume (ERV)
without potential for intermediate shifts in FRC.
This should be followed by a maximal inspiration to
determine inspiratory vital capacity (IVC).
Residual volume (RV) can then be calculated as FRC
minus ERV.
Probably the best choice is to take median FRC and
maximum ERV for this.
Next, total lung capacity (TLC) is computed as the sum of
RV and the maximal IVC from all satisfactory respiratory
maneuvers.

38. The present analysis aims to demonstrate that body
plethysmography is a technically demanding,
physiologically nontrivial, highly informative, non invasive
method to obtain information on airway obstruction and
lung volumes that is not available through spirometer. It
normally takes no more than a few minutes to get reliable
values.
Importantly, the examination requires only a minimum of
cooperation and in most cases is less bothersome for the
patient than spirometry

39. . Moreover, in contrast to
spirometry, it is an examination
under physiological conditions,
as the measurements are
performed during quiet
breathing.
Therefore, body
plethysmography is an important,
unique method for assessing the
functional state of the airways.
The method appears to be of
particular value for characterizing
the multiple, heterogeneous
alterations occurring in patients
with COPD. It also offers
potential for further exploration
and development.

40. Lung plethysmography is done for the following reasons:
• Help diagnose restrictive lung disease, which is a type of disease that restricts lung
expansion.
• Evaluate obstructive lung diseases, such as bullous emphysema and cystic fibrosis
• follow the course of a disease and its response to treatment
• measure your resistance to airflow
• Measure your response to bronchodilator medications
• assess whether your lung capacity will be affected by such treatments as
methacholine, histamine, or isocapnic hyperventilation

41. PFT IN CLINICAL PHARMACY
Spirometry has evolved from testing performed
in a pulmonary function laboratory under the
direction of a pulmonologist to testing
performed in primary care or outpatient settings
including community pharmacies.
This paradigm shift in outpatient testing has
primarily occurred due to advances in
spirometry technology. Spirometry technology
has advanced to include portable handheld
devices requiring minimal calibration or quality
control to perform accurate testing.

42. Due to these advances, a major concern is that the quality of testing
performed outside of a pulmonary function laboratory may be
substandard and not meet rigorous standards set forth by
international clinical practice guidelines.
Traditionally, primary care physicians utilize office staff including
medical assistants or registered nurses to perform office testing.
Inadequate training or limited time in performing testing by the
office staff may result in suboptimal quality testing.
Testing of poor quality can lead to false-positive interpretations and
prescription of unnecessary respiratory medications, which may lead
to serious adverse effects.

43. The practice and scope of pharmacy services may
vary internationally. In the United States, the scope
of practice is established by state legislatures and
regulated by each state board of pharmacy.
At present, 47 states and the District of Columbia
(Washington, D.C.), pharmacists are authorized into
collaborative practice agreements with a physician
or designated prescriber, which results in the
expanding of clinical services.
However, since there are no restrictions on who can
perform spirometry, pharmacists have an opportunity
to expand this service and incorporate this into
collaborative practice agreements with physicians.

44. • Pharmacists have demonstrated their value in optimizing pharmaceutical care for patients
with respiratory diseases including chronic obstructive pulmonary disease (COPD) and
asthma.
• Data have shown that pharmacists improve medication adherence, knowledge of disease,
and reduction in hospital admission rates, and patients were more satisfied with the quality
of their care.
• In addition, pharmacists have also introduced spirometry testing as a service in a limited
number of clinical studies in the care of COPD and asthma patients.
• Pharmacists trained in performing quality spirometry can offer a number of advantages
including better convenience for the patient, early identification of airflow limitations,
expedite physician prescribing inhaled respiratory medications, and teaching patients the
proper use of respiratory delivery devices.
• Pharmacists working in collaboration with the prescribing physician can perform spirometry
testing within the community pharmacy or within the physician's office.

45. ABNORMAL PULMONARY
FUNCTIONS AND PFT IN COVID-19
PATIENTSRecent studies reveal that the lung is the organ most
affected by COVID-19, with pathologies that include
diffuse alveolar epithelium destruction, capillary
damage/bleeding, hyaline membrane formation,
alveolar septal fibrous proliferation, and pulmonary
consolidation.
Previous studies have demonstrated that recovered
patients with coronavirus pneumonia can be left with
damaged lungs.
Impaired lung function was common and could last for
months or even years.

46. According to the WHO interim guidance and the guidance from China, disease
severity was categorised as;
• mild illness (mild symptoms without radiographic appearance of
pneumonia),
• pneumonia (having symptoms and the radiographic evidence of pneumonia,
with no requirement for supplemental oxygen),
• severe pneumonia (having pneumonia, including one of the following:
respiratory rate >30 breaths·min−1; severe respiratory distress; or oxygen
saturation measured by pulse oximetry (SpO2) ≤93% on room air at rest),
• critical cases (e.g. respiratory failure requiring mechanical ventilation, septic
shock, other organ failure occurrence or admission into the intensive care
unit).

47. One-hundred and ten discharged cases were recruited, which included 24 cases of mild
illness, 67 cases of pneumonia and 19 cases of severe pneumonia.
The mean age of these cases was 49.1 years and fifty-five of them were females.
Forty-four (40%) patients had at least one underlying comorbidity, of which 23.6% had
hypertension and 8.2% had diabetes.
Only 3 patients (2.7%) were reported having chronic respiratory diseases (one patient
with asthma, one with chronic bronchitis and one with bronchiectasis).
DLCO% in 51 cases (47.2%), total lung capacity (TLC)% in 27 (25.0%), forced expiratory
volume in the first second (FEV1)% in 15 (13.6%), forced vital capacity (FVC) % in 10
(9.1%), FEV1/FVC in 5 (4.5%), and small airway function in 8 (7.3%).

48. • A significant difference in impaired diffusing-capacity among the different groups of
severity, which accounted for
• 30.4% in mild illness,
• 42.4% in pneumonia and
• 84.2% in severe pneumonia, respectively(p<0.05).
This trend of the gradual decrease in level of DLCO among patients was identical with
the varying degree of severity.
For about half (25/51) of the DLCO-impaired patients, the DLCO corrected for alveolar
volume (DLCO/VA) was still within the normal range, which might indicate that DLCO
decrease was more than the DLCO/VA in recovered subjects.
The value ofTLC % predicted in severe pneumonia cases was much less than that of
pneumonia or mild illness, suggesting higher impairment of lung volume in severe
cases.
There was no significant difference among the discharged survivors with different
severity in regard to other ventilator defects (e.g. FEV1, FVC, FEV1/FVC).

52. • In conclusion, the study firstly reveals that, in discharged survivors with
COVID-19, impairment of diffusion capacity is the most common
abnormality of lung function followed by restrictive ventilatory defect,
which are both associated with the severity of the disease.
• Pulmonary function test (not only spirometry, but also diffusion
capacity) should be considered to performed in routine clinical follow-up
for certain recovered survivors, especially in severe cases.
• Subsequent pulmonary rehabilitation might be considered as an
optional strategy.
• Long-term studies are needed to address whether these deficits are
persistent.

53. THANK YOU.