Spirometry and peak flow metry in bronchial asthma

WORLD ASTHMA DAY 2012
 YOU CAN CONTROL YOUR ASTHMA
world asthma week 2012
drpankajyadav05@gmail.com
Department of paediatrics FEHRC

SPIROMETRY AND PEAK FLOMETRY
IN
BRONCHIAL ASTHMA
Presented by
Dr. PANKAJYADAV

 SPIROMETRY IS A PULMONARY FUNCTIONTESTTHAT
MEASURESTHE VOLUME OF AIR AN INDIVIDUAL
INHALES OR EXHALES AS A FUNCTION OF TIME.
 SPIROMETRY MEASURES HOW MUCH AND HOW
QUICKLYAIR CAN BE EXPELLED FOLLOWING A DEEP
BREATH.
 FLOW , ORTHE RATE ATWHICHVOLUME IS CHANGING
ASA FUNCTION OFTIME, CAN ALSO BE MEASURED
WITH SPIROMETRY.
WHAT IS SPIROMETRY ?

 EARLIEST SPIROMETRIC MEASUREMENT OF LUNG
VOLUMES AND ITS EXPIRABLE COMPONENTS WAS
DONE BY HUTCHINSON IN 1846
 EQUIPMENT FORTESTING CHILDREN SHOULD BE
CAPABLE OF MEASURING SMALLVOLUMES AND LOW
FLOWS
 CAN BE PERFORMED BYTHE AGE OF 3YEARS

SPIROMETER

Method – how to perform
1. 4 normal breaths
2. Inhale as deeply as
possible
3. Exhale to normal depth
4. 3 normal breaths
5. Exhale as much as
possible
6. 3 normal breaths
7. Inhale as much as possible
8. Exhale as fast and
completely as possible
9. 4 normal breaths

 VOLUME OF GAS EXPIRED AND RATE AT
WHICH THEY ARE EXPIRED ARE MEASURED
 PERMITS ASSESSMENT OF THOSE VOLUMES
WHICH CAN BE VOLUNTARILY EXCHANGED
 ALL THE COMPONENTS OF TOTAL LUNG
CAPACITY EXCEPT RV, FRC, AND TLC CAN BE
MEASURED

INTERPRETATION DEPENDS ON
SOME FACTORS
 Normal values vary and depend on:
 Height
 Age
 Gender
 Ethnicity

REFERENCE STANDARDS
 PULMONARY FUNCTION
MEASUREMENTS ON CHILDREN
WITHOUT RESPIRATORY DISEASE FOR
COMPARISION
 TELL HOW LUNG FUNCTION SHOULD
CHANGE OVER TIME WITH NORMAL
GROWTH
 GROWTH RELATED CHANGES IN PFT
CORELATE BEST WITH HEIGHT world asthma week 2012

SPECIAL CONSIDERATION IN PAEDIATRIC
PATIENT
 ABILITY TO PERFORM SPIROMETRY
DEPENDS ON DEVELOPMENTAL AGE OF
CHILD , PERSONALITY, AND INTEREST OF
THE CHILD.
 PATIENT NEED A CALM , RELAXED
ENVIRONMENT AND GOOD COACHING,
PATIENCE IS THE KEY.
 EVEN WITH BEST ENVIRONMENT AND
COACHING, A CHILD MAY NOT BE ABLE
TO PERFORM SPIROMETRY. world asthma week 2012

SPIROMETRY IN ASTHMA
ASPECTS OF LUNG FUNCTION MEASURED BY
SPIROMETRY IN DETERMINING SEVERITY
AND CONTROL OF ASTHMA :-
 FORCED VITAL CAPACITY –TOTAL AMOUNT
OF AIR FORCEFULLY EXHALED AFTER
MAXIMAL INSPIRATION
 FORCED EXPIRATORY VOLUME AT ONE
SECOND- AMOUNT OF AIR FORCEFULLY
EXHALED AT ONE SECOND
Department of paediatrics FEHRCworld asthma week 2012 drpankajyadav05@gmail.com

FEV1 / FVC RATIO
 FEV1 / FVC IN NORMAL INDIVIDUALS –
APPROX 85%
 RESTRICTIVE LUNG DISEASE – AIRFLOW IS
REDUCED IN PROPORTION TO REDUCTION
IN LUNG VOLUME - FEV1 / FVC > 80%
 OBSTRUCTIVE LUNG DISEASE – AIRFLOW IS
REDUCED MORE THAN LUNG VOLUME -
FEV1 / FVC IS REDUCED

A NORMAL FLOW
VOLUME LOOP
HAS A RAPID
PEAK EXPIRATORY
FLOW RATE WITH
A GRADUAL
DECLINE IN FLOW
BACKTO ZERO.

OBSTRUCTIVE LUNG DISEASE
 Obstructive lung
disease changes the
appearance of the flow
volume curve
 As with a normal
curve, there is a rapid
peak expiratory
flow, but the curve
descends more quickly
than normal and takes
on a concave shape

Normal Obstruction

The shape of the flow
volume loop is relatively
unaffected in restrictive
disease, but the overall
size of the curve will
appear smaller when
compared to normals on
the same scale.

INTERPRETATION OF THE VALUES
FVC
Interpretation of % predicted:
 80-120% Normal
 70-79% Mild
 50%-69% Moderate
 <49% Severe

INTERPRETATION
 FEV1 > 80%
 FEV1 60 – 79%
 FEV1 40 – 59%
 FEV1 <40%
 NORMAL
 MILD
 MODERATE
 SEVERE

INTERPRETATION OF VALUES
 FEF 25-75%
 Interpretation of %
predicted:
 >79% Normal
 60-79% Mild
obstruction
 40-59% Moderate
obstruction
 <40% Severe
obstruction
 FEV1/FVC
 Interpretation of
absolute value:
 80 or higher Normal
 79 or lower Abnormal

 IF STILL IN DOUBT OF PATIENT HAVING
ASTHMA, REPEAT THE TEST AFTER
SHORT ACTING BRONCHODILATOR LIKE
SALBUTAMOL
 IMPROVEMENT IN FEV1 OF 12% OR
MORE CONFIRMS DIAGNOSIS

ROLE OF SPIROMETRY IN ASTHMA
 HELPS TO MAKE DIAGNOSIS
 ASSESS DEGREE OF AIRFLOW OBSTRUCTION
 TO PREDICT WHETHER OBSTRUCTION IS
REVERSIBLE
 AIDS IN MANAGEMENT OF ASTHMA
 TO MONITOR PROGRESSION OF DISEASEworld asthma week 2012

PEAK FLOW METRY
 MEASURES PEAK EXPIRATORY FLOW
RATE (PEFR)
 DETECTS OBSTRUCTION IN LARGE
CENTRAL AIRWAYS ONLY
 NOT RECOMMENDED FOR ALL
PATIENTS, USED ONLY IN THOSE WITH
MODERATE TO SEVERE ASTHMA

INTERPRETATION
 PEF COMPARED TO PATIENT’S OWN
PREVIOUS BEST MEASUREMENTS USING
HIS OWN PEAK FLOW METER
 IMPROVEMENT OF 60L/MIN OR >20% OF
PRE BRONCHODILATOR PEF
OR
DIURNAL VARIATION OF >20%

SUMMARY
 Spirometry is a reproducible and inexpensive
tool in the management of asthma
 Spirometry is useful in the diagnosis of
asthma (demonstrations of reversibility)
 Spirometry measures both large and small
airways function and can be used to monitor
patients world asthma week 2012

THANK YOU

Spirometry and peak flow metry in bronchial asthma

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