Spirometry - Ahmed Sohail.ppt

Spirometry
By: Ahmed Sohail Kothawala

Spirometry - Introduction
• SPIROMETRY:- It is a method of assessing lung function by measuring
the total volume of air the patient can expel from the lungs after a
maximal inhalation.
-Simple method for studying pulmonary ventilation
• SPIROMETER:- Instrument used to perform spirometry.
• SPIROGRAM: It is the graphical representation of changes in lung
volume under different conditions of breathing
-Pulmonary volume and capacities vary according to height, age sex
and physical training
 All volumes and capacities
 Increase in males
 Decrease with age
 Increase with height
 Increase in athletes and physically active individuals

Functioning of the Spirometer
A typical basic spirometer consists of a drum inverted over a
chamber of water, with the drum counterbalanced by a weight. In
the drum is a breathing gas, usually air or oxygen; a tube connects
the mouth with the gas chamber. When one breathes into and out
of the chamber, the drum rises and falls, and an appropriate
recording is made on a moving sheet of paper.

Why Perform Spirometry?
• Determine your lung capacity
• Measure airflow obstruction to help make a definitive diagnosis
of COPD
• Confirm presence of airway obstruction
• Assess severity of airflow obstruction in COPD
• Decide how likely it is that inhaled medications may help with
your syntoms
• Monitor disease progression in COPD
• Assess one aspect of response to therapy
• Perform pre-operative assessment

How to perform spirometry?
• For this test, you'll sit in front of a machine and be fitted
with a mouthpiece.
• It's important that the mouthpiece fits snugly so that all the
air you breathe into the machine.
• You'll also wear a nose clip to keep you from breathing air
out through your nose.
• The patient is then instructed to inhale as much as possible
and exhale rapidly & forcefully for as long as flow can be
maintained. The patient should exhale for atleast 6 seconds

PULMONARY VOLUMES
 TIDAL VOLUME :
 Volume of air inspired
or expired with each
normal breath
• Value 500ml (0.5 L)
 INSPIRATORY
RESERVE VOLUME:
 Max extra volume of
air that can be inspired
over normal tidal
volume.
• Value 3000ml (2.5-
3 L) Spirogram

PULMONARY VOLUMES
 EXPIRATORY
RESERVE VOLUME:
 Max extra volume of
air that can be expired
forcefully after the
normal tidal expiration
• Value 1100ml.
 RESIDUAL VOLUME:
 Vol of air remaining l
in the lungs after the
most forceful
expiration
• Value 1200ml. Spirogram

PULMONARY CAPACITIES
 INSPIRATORY
CAPACITY:
 It is the max amount
of air that a person
can breath in.
 Tidal vol +insp res vol
 500+3000=3500ml.
 FUNCTIONAL
RESIDUAL CAPACITY
(FRC):
 Amount of air that
remains in the lung
after normal tidal
expiration
 ERV+RV
 1100+1200=2300ml.
Spirogram

PULMONARY CAPACITIES
•VITAL CAPACITY :
 Max vol of air expired
after max insp
 IRV+TV+ERV
 3000+500+1100
 4600ml (4.5-5L)
 TOTAL LUNG
CAPACITY:-
 Max vol to which the
lungs can be expanded
 IRV+TV+ERV+RV
 3000+500+1100+1200
 5800ml Spirogram

DYNAMIC FUNCTION TEST
 Forced Vital Capacity (FVC)
 Max vol of air expired forcefully and rapidly (as hard and
as far as possible) after a full inspiration.
 Forced Expiratory Volume in first sec
 it is the volume of air expired in the first sec during the
FVC maneuver
 FEV1/FVC
 Imp in differentiating obstructive and restrictive lung
diseases.

Obstructive & Restrictive Lung
Diseases
 Obstructive Airways Disease –
where your ability to breathe out quickly is affected by
narrowing of the airways, but the amount of air you can hold
in your lungs is normal.
 Examples: Asthma, COPD, Emphysema, Cystic Fibrosis
 Restrictive Lung Disease –
where the amount of air you can breathe in is reduced
because your lungs are unable to fully expand (such as in
pulmonary fibrosis)
 Examples: Obesity, Pleural effusion, Myasthenia Gravis

Obstructive Pattern VS
Restrictive Pattern
 Obstructive
 TLC Normal
 Normal or slight decreased
FVC
 Decreased FEV1
 FEV1/ FVC < 70% of
predicted
 Restrictive
 TLC Decreased
 FVC decreased
 Normal or slight decreased
FEV1
 FEV1/ FVC > 70% of
predicted

Disadvantages of Spirometry
 Feel Dizzy
 Feel lightheaded
 Feel tired
 coughing

Spirometry - Ahmed Sohail.ppt

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