Spirometry and peak flow metry in bronchial asthma

WORLD ASTHMA DAY 2012

YOU CAN CONTROL YOUR ASTHMA

world asthma week 2012 [email protected]

Department of paediatrics FEHRC

SPIROMETRY AND PEAK FLOMETRY IN BRONCHIAL ASTHMA

Presented by Dr. PANKAJ [email protected]



SPIROMETRY IS A PULMONARY FUNCTION TEST THAT MEASURES THE VOLUME OF AIR AN INDIVIDUAL INHALES OR EXHALES AS A FUNCTION OF TIME.

SPIROMETRY MEASURES HOW MUCH AND HOW QUICKLY AIR CAN BE EXPELLED FOLLOWING A DEEP BREATH.

FLOW , OR THE RATE AT WHICH VOLUME IS CHANGING AS A FUNCTION OF TIME, CAN ALSO BE MEASURED WITH SPIROMETRY. world asthma week 2012

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WHAT IS SPIROMETRY ?

EARLIEST SPIROMETRIC MEASUREMENT OF LUNG VOLUMES AND ITS EXPIRABLE COMPONENTS WAS DONE BY HUTCHINSON IN 1846

EQUIPMENT FOR TESTING CHILDREN SHOULD BE CAPABLE OF MEASURING SMALL VOLUMES AND LOW FLOWS

CAN BE PERFORMED BY THE AGE OF 3 YEARS



SPIROMETER



Method – how to perform

1. 4 normal breaths2. Inhale as deeply as

possible3. Exhale to normal depth4. 3 normal breaths5. Exhale as much as

possible6. 3 normal breaths7. Inhale as much as

possible8. Exhale as fast and

completely as possible9. 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



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 [email protected] Department of paediatrics FEHRC

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

world asthma week 2012


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 REDUCEDworld asthma week 2012

[email protected] Department of paediatrics FEHRC

NORMAL FLOW VOLUME LOOP

A NORMAL FLOW VOLUME LOOP HAS A RAPID PEAK EXPIRATORY FLOW RATE WITH A GRADUAL DECLINE IN FLOW BACK TO 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 shapeworld asthma week 2012

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Normal Obstruction



RESTRICTIVE FLOW VOLUME LOOP

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.world asthma week 2012

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INTERPRETATION OF THE VALUES

FVC Interpretation of %

predicted: 80-120% Normal

70-79% Mild

50%-69% Moderate

<49% Severe world asthma week 2012 [email protected]


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 [email protected]


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%world asthma week 2012

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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



THANK YOU



Spirometry and peak flow metry in bronchial asthma

Health & Medicine

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