1Lung function test

Module 4

Training of Inhalation Therapy

& Pediatric Asthma Management

Departemen IKA FKUI-RSCM

Respiration Oxygen is a vital need for organism

Human takes O2 from environment

respiration: the process of gas exchange between an organism and its environment

absorption of O2 and the excretion of CO2

respiration:

gas exchange in the lung (external respiration)

the transport of gases in the circulatory system,

gas exchange in the tissues (internal respiration)

Respiration 2 organ systems: respiratory &

cardiovascular

three fundamental mechanisms of gas transport :

1.ventilation, the atmosphere the alveoli

2.diffusion, the alveoli pulmonary capillary blood

3.circulation, pulmonary capillary blood tissue cells

Pulmonary function measurementsIn broader meaning, clinical & lab settings:

quantitative evaluation of several physiologic components of respiration:

lung volumes and capacities,

respiratory ventilation focus of discussion

pulmonary circulation,

ventilation-perfusion ratio,

diffusion,

arterial blood gases measurements, and

mechanics of breathing

What exactly are PFTs?

The term encompasses a wide variety of objective methods to assess lung function. (Remember that the primary function is gas exchange).

Examples of PFT equipments, include: Spirometry

Lung volumes by helium dilution or body plethysmography

Blood gases

Exercise tests

Diffusing capacity

Bronchial challenge testing

Pulse oximetry

Respiratory ventilation inspiration: an amount of air volume flows into

the lung through the airways

expiration: the same volume of air flows out of the lung

ventilation consists of two main components, volume (or capacity) and flow

restrictive disorders: disturb the lung expansion / lung volumes

obstructive disorders: disturb the flow

both restrictive and obstructive disorders will disturb the ventilation

Lung volumes & capacitiesLUNG VOLUMESTidal volume (TV)Inspiratory reserve volume (IRV)Expiratory reserve volume (ERV) Residual volume (RV)

LUNG CAPACITIESTotal lung capacity(TLC =VC + RV).

Vital capacityVC = IRV + TV + ERV).

Inspiratory capacity (IC=TV + IRV).

Functional residual cap (FRC = ERV + RV).

Spirometry

Spirometry is a medical test that measures the volume of air an individual inhales or exhales as a function of time. (ATS, 1994)

Spirometry

measurement of the movement of air into and out of the lungs during various breathing maneuvers, using a spirometer

spirogram: curves depict the results

old days: mechanics spirometer; limited parameters; volume associated spirogram (FEV)

nowadays: electronic spirometer, equipped with computer, monitor, printer etc

1 parameter: FLOW; calculated derived to others parameters

Indications of PFTDiagnostic

To evaluate respiratory associated symptoms, signs, and abnormal lab tests Symptoms: cough, dyspnea, wheezing, orthopnea, or

chest pain

Signs: wheezing, cyanosis, chest deformity, exercise limitation, hyperventilation

Abnormal tests: hypoxemia, hypercapnia, polycythemia

Abnormal chest X-ray: atelectasis, bronchiectasis

To measure the effect of disease on pulmonary

To assess preoperative risk

To assess prognosis

Indications of PFTMonitoring

To assess effectiveness of therapeutic therapy Bronchodilator therapy

Inhaled steroid

To provide information on the course of diseases affecting lung function Respiratory disease: obstructive airways disease,

interstitial lung disease

Neuromuscular disease: Guillain-Barre syndrome, Spinal muscular atrophy

Thalassemia

To detect adverse reactions to drugs

Public health: Epidemiologic surveys

Applicability spirometry in children

UK (London)

2-5 years old, 75 % acceptable & reproducibleAurora P. Am J Respir Crit Care Med 2004;169:1152-9.

US (Indiana)

3-6 years old, 82,6% acceptable & reproducibleEigen H. Am J Respir Crit Care Med 2001;163:619-23.

Germany

2-5 years old, 69,6% successful with SPIROGAMEVilozni D. Am J Respir Crit Care Med 2001;164:2200-5.

HOW OLD INDONESIAN CHILDRENCAN PERFORM IT CORRECTLY ?

6 years old?

Spirometry in children the biggest obstacle: it needs their cooperation

and effort

each portion of the maneuvers should be carefully explained at an age appropriate level

the childs participation should be elicited in a playful rather than challenging fashion

satisfactory performance can generally achieved in 6-year-old child (elementary school)

although some 10-year-old children continue to have difficulty

Pediatric Considerations

Ability to perform spirometry depend on developmental age of child, personality, and interest of the child.

Patients need a calm, relaxed environment and good coaching. Patience is the key.

Even with the best of environments and coaching, a child may not be able to perform spirometry. (And that is OK.)

Spirometry clinical diagnostic purposes:

1. vital capacity VC

2. maximal voluntary ventilation MVV

3. forced (expiratory) vital capacity FVC

the third is the most frequent used

FVC spirogram: parameters associated with volume of the lung and flow in the airways

Kinds of Spirometry Maneuver

1. Vital Capacity (VC) maneuver

TV maneuver is the core of VC maneuver.

Basic movement : inspiration and expiration as natural as possible, with regular rhythm and same depth.

Next is maximal inspiration continued by relax and not in a hurry maximal expiration.

Difficult for children

2. Maximal Voluntary Ventilation (MVV) maneuver- achieved by cumulating the maximal ventilation

volume of fast and deep breathing during 12 seconds.

- principle by performing forceful inspiration and expiration in a given time.

- For children it is tiring enough; to repeat this, the child needs to take a rest for a while

Difficult for children

Forced vital capacity (FVC) maneuvers

also called Forced Expiratory Volume (FEV)

measure the speed of expired airflow and duration of expiration

maximal inspiration followed by expiration as fast and as powerful as possible until all air in the lung has expired out

gives enough data, relatively easy to perform, and more suitable for children

done 3 times, to choose the best of three

Steps of FVC maneuvers

1. Patient in standing or sitting position, standing is better

2. Apply the nose clamp

3. Put the mouth piece of sensor to patients mouth

4. Patient makes a deep maximal inspiration

5. Afterward, patient makes forceful expiration as fast as possible, and as long as possible

Spirogram of Volume-time curve

and Flow-volume curve

6 Sec

6L/S

0 Sec

6L/S

Illustration of Curve Score & Obstruction Index

Pulmonary function testing

not as a primary diagnostic tool but as a yardstick by which either previous or subsequent assessment measured

to evaluate and monitor diseases that affect lung function,

to evaluate disability or impairment, and

surveys in epidemiology

Interpretation of PFT

the first step in interpreting spirometry is to assess and comment on test quality

variability is greater in spirometry -inconsistency effort - especially in children

represent adequate effort by the patient, reproducible, and contain no artifact that would alter the test results

if the requirements for quality are not met, test should be interpreted with caution

Interpretation of PFT

comparing values measured in patients with reference value related with sex, age, and body height

using index and ratio of parameters from the same person

many diagrams of combinations of several parameters can be used.

20 1 53 4 86 7 9 100

1

2

3

4

5

6

Time (seconds)

V

o

l

u

m

e

(

l

i

t

e

r

s

)

FEV1

VC

B

Normal time-volume curve

3 4 5 621

Inhalation

F

l

o

w

(

l

i

t

e

r

s

p

e

r

s

e

c

o

n

d

)

Volume (liters)

FEV1

Peak expiratory flow

Exhalation

VC-8

-6

-4

-2

0

2

4

6

8

10

12Normal flow-volume curve

What do we measure ?What do we measure ?What do we measure ?What do we measure ?

FVC

FEV1

FEV1/FVC

FEF50

FEF25-75

Interpretation of PFT

Two basic types of lung dysfunction can be defined by spirometry: restrictivedisorders and obstructive disorders

Restrictive disorders: lung volumes are small

the volume component of ventilation is less than it should be

the value of FVC is less than predicted

Interpretation of PFT

Obstructive disorders: the airways are narrower than it should be

the flow component of ventilation is disturbed

the primary criterion for airflow obstruction is a reduced FEV1 and Vdotvalues

Vital capacity may also reduced in the presence of airflow obstruction

Characteristic Patterns of Obstructive

and Restrictive Lung diseases

Obstruction Restriction

FVC Normal or

FEV1 Normal or

FEV1/FVC

FEF25-75 Normal, , or

START

FEV1/FVC70%

FEV1 > 80%

FEV1 60-

Fl

o

w

i

n

l

i

t

e

r

s

/

s

e

c

4

6

8

10

0

2

4

2

8

6

21 43 65

Inspiration

expiration

Vol in liters

A

BC

NORMAL

RESTRICTIVE

OBSTRUCTIVE

Obstructive diseases

Asthma

Emphysema/ hyperinflation

Chronic bronchitis

Restrictive Diseases

Pneumonia

Pulmonary TB

Interstitial fibrosis

Pulmonary edema

Pleural effusion

Peritonitis

Ascites

Myasthenia gravis

V50.FEV1

FVC

PEF V25.

Base line

2 agonist +ipratropium

Pentagonal

Bronchial Provocation Test

Measure bronchial hyperresponsiveness

Constructing stimulus-response curve

To measure changes in airway caliber following provocation FEV1

The provocative concentration reduces FEV1 by 20% from baseline (PC20 or PD20) index of responsiveness

Reversibility Test

Diagnostic help in demonstrating reversible airflow obstruction only if the baseline 80% of predicted

Lung function measurement at baseline

Bronchodilator as nebulization (usually albuterol in a dose of 2.5 or 5.0 mg by nebulization)

Reassess 15 to 60 minutes after drug delivery

Resume

Lung has a pivotal role in human life, which is gas exchange process

The direct role of the lung is to provide adequate ventilation

Two main components are volume and flow

Many disease and disorders can cause lung dysfunction, either disturb the volume or the flow, or both; can detected by spirometry

Spirometry is the measurement of the movement of air into and out of the lungs during various breathing maneuvers

41

Thanks for

your attention