Anaecon India - Spirometery

Sarthak JainShailendra SinghANAECON INDIA HEALTHCARE PVT. LTDP-13, M.I.G. FLATS,PRASAD NAGAR, NEW DELHI – 110 005

Spirometry is a method of assessing lung function by measuring the volume of air that the patient is able to expel from the lungs after maximum inspiration.

It is reliable method of differentiating between obstructive airways disorder (COPD, Asthma) and restrictive diseases (Where the size of the lungs is reduced)

Spirometry plays a key role in the diagnosis and assessment of chronic obstructive disease COPD. COPD means airways obstructions which does not change markedly over several month.

Diagnosis - To detect respiratory defects at an early stage

Control - To control respiratory defect or condition.

Classification - Type of the Pulmonary defect.

Selection - For suitability of surgery, Anesthesia, Inhalation therapy, rehabilitation exercise.

Treatment - To give proper treatment. Prognosis - to arrive at an accurate

assessment based on objective data.

FVC – the volume of air that the patient can forcibly exhale in one breath.

FEV 1 - the volume of air that the patient exhale in the first second of expiration.

FEV1/FVC - the ratio of FEV1 to FVC COPD can be diagnosed only if FEV1 less

than 80% predicted and FEV1/FVC less than 70%

-FEV1 (%predicted) – between 60 % to 80%Mild – No abnormal signs, smoker’s cough, Little or no breathlessness.-FEV1 (%predicted) – between 40% to 60%Moderate - Breathlessness ( with or without wheeze), Cough ( with or without sputum), Possible reduction in breath sounds-FEV1 (%predicted) – below 40%Severe – Breathlessness on any exertion/at rest, Lung over inflation usual, cyanosis, peripheral edema and polycythaemia in advance disease.

- SVC – Important test for assessing COPD. VC is often greater than FVC in COPD- FVC – to verify obstructive ( airflow limitation ) and restrictive disorder ( lung volume)- MVV – test for assessing the maximum ventilation capacity.- Bronchodilator – to determine whether airflow

obstruction is reversible. Bronchodilator

increase caliber by relaxing airways

smooth muscle.

Patient : 45 year old women, height 5’3” FEV1 - Reading/predicted value 1.43/2.60 =

55% of predicted value FVC – Reading/predicted value 2.5/3.03 =

82.5% of predicted value FEV1/FVC – Reading/reading 1.43/2.5 x 100%

= 57%

In the PFT Lab the measurement lung volume usually refers to the measurement of total Lung capacity ( TLC ), Residual Volume ( RV), Functional residual capacity ( FRC ), and Vital capacity. These measurements are essential to assess lung function. They are important for the diagnosis of restrictive disorder.

FRC : is most commonly determined with one of three basic technique.

1. Multi breath closed circuit He washout2. Body plethysmograph.3. Multi breath open circuit N2 washout.

Dynamic lung volumes : In which the patient exhales, and occasionally inhales, at a maximum effort.

Static lung volume : Theses are performed without regard to time.

The measurement of obstruction is necessarily made during dynamic tests while restriction is measured by static volumes but can also be deduced from dynamic volume. In other words obstruction is described by reduced flow rates whereas lung volumes describe restriction.

TV

IRV

ERV

FRC

RV

VC

FRC = ERV + RVTLC = ERV + RV + TV + IRV

Spirometry preparation

1. Ambient conditionsfor BTPS correction* inspiratory flows

– Temperature, relative humidity, (ambient pressure)

2. Flow/Volume calibration using a 3 L calibration pump

– 1 to 2 discard strokes– 2 to 6 Calibration strokes

3. Actualisation of ambient data– Alteration of temperature >2 °C– Alteration of humidity >10%

*All flows and volumes are standardized to BTPS, i.e. related to expiratory air.

BTPS = Body Temperature, Pressure, Saturated with water vapour

Only calibrated spirometers can be relied upon!

Calibration of pneumotachographs daily or after replacement!

Cleaning / HygineA lot of patients are afraid of infections – therefore it is

recommended to put on the new mouthpiece in front of the patient!

Alternatively bacteria filters should be used.

Disinfection, purification After each measurement Spirette

Daily pneumotachograph

• Weekly/monthly Components distal of the pneumotachograph

In infectious patients (e.g. MRSA , HIV, hepatitis B, tuberculosis), as well as in patients with immunodeficiency (e.g. chemotherapy, post-transplantation, cystic fibrosis) bacteria filters should always be used. Alternatively the contaminated components have to be disinfected.

Disposable bacteria filter (MicroGard)

Cleaning / Hygine

• Cleaning proteins– in ultrasound bath

• Disinfection with Descogen– In regard to concentration see instruction leaflet

• Neutralisation in warm tap water – For screens, distilled water is recommended

• Drying at room temperature

• Storage in clean and covered receptacles

Cleanliness regulations for contaminated components

Preparation of SpirometryParameters measured in standing position are not better than in sitting position but different !

www.spiro-webCard.de

Head straight or in slight extension

Upright sittingposition

• Sitting position– Upright position – Reference values measured in sitting

position – Parameter values in standing position

are 2-7% increased

• Position of the head– Straight or in slight extension– Flexion or rotation of the head

increase upper airway resistance– Handheld-pneumotachographs –

look out!

• Flexion at forced manoeuvre• Support arm recommended

Quality Check

Partial effort dependent

(determined by the leastic recoil of the lung)

Steepness of the volume acceleration phase can be achieved from every patient independent of disease and degree of disease.

Volume Flow- acceleration limitation End-expiratory phase Effort - dependent

A: Maximal effortB: Submaximal effortC: Low effort

A: Maximal effortB: Exhalation not complete

A: Maximal effortB: Submaximal effort

Flow [L/s]

Volume [L]TLC Effort dependent RV

A

B

C

AB

AB

12

3

Quality Check

Patient should exhale suddenly and forced.

Patient should exhale suddenly and forced

Patient should cough before starting the measurement

Patient should inhale longer and to the maximum

Patient should exhale as long as possible; minimal 6 s

Different reasons; more details in next slight

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Quality Check

IVC = 3% FEV1 = 2%

IVC = 15% FEV1 = 14%

Acceptable repeatability

Insufficient repeatability

Minimum 3 trials Quality check of best 2 trials ERS/ATS

FEV1 & FVC < 150 mL FVC (<1L) < 100mL FEV1 und FVC < 5% PEF < 10%

Interpretation

Restriction Reduction of volumes Tiffeneau-Index

FEV1/IVC > 70%

Obstruction Reduction of flows Tiffeneau-Index

FEV1/IVC < 70%

Differentiation between Restriction and Obstruction!

narrowing of airways

VC

contraction of alveolar tissue

FEV1

Staging Obstructive parameters

I Mild FEV1 > 70% pred.

II Moderate FEV1 60 - 69% pred.

III Moderate severe FEV1 50 - 59% pred.

IV Severe FEV1 35 - 49% pred.

V Very severe FEV1 < 35% pred.

FEV1 / IVC < 5% Percentile of predicted (< 70% pred.)

Recommendations of German „Atemwegsliga“ 2005

Staging of Restrictive parameters

TLC < 5% Percentile of predicted (< 80% pred.)

I Mild IVC > 70% pred.

II Moderate IVC 60 - 69% pred.

III Moderate severe IVC 50 - 59% pred.

IV Severe IVC 35 - 49% pred.

V Very severe IVC < 35% pred.

Recommendations of German „Atemwegsliga“ 2005

Spirometry interpretation

Ratio FEV1/IVC > 70% FEV1 > 80% of predicted

Typical triangel shape Linear decrease of flow

until FVC is reached

Normal case

Upper point of inflection acute-angled

Nearly vertical ascent

Exhalation (FVC) and Inspiration (IVC) nearly identical

Normal Case


Mild obstructiv: - Ratio FEV1/IVC < 70%

- FEV1 > 70% of predicted

Peak-flow mostly diminished.

Expiratory flow/volume loop is concavely shaped.

Vital capacity VC is mostly normal.

E.g.: Asthma or COPD


Moderate to server Case

- Ratio FEV1/IVC < 70% - FEV1 50% to 70% (moderate) - FEV1 < 50% (severe)

Peak-flow diminished.

In case of dynamic hyperinflation also VC is reduced.

E.g.: Exacerbation of asthma, severe COPD


Severe obstructive Case

- ratio FEV1%IVC < 70%- FEV1 dramatically decreased- FVC, IVC usually decreased

Typical expiratory „Knickkurve“As result of an airway collapse at expiration Often in severe emphysema In severe obstruction


Restrictive Case

- FEV1%IVC > 70% - FVC lower 80%- Appearance of a narrowed normal curve- Decrease of FVC is characteristic- Flows may be reduced

Becausse of increased tissue tension it is possible that FEV1%IVC values exceed the normal range


- FEV1 may be > 80% - IVC usually normal

The expiration is less obstructed because the positive pressure inside the airways dilates the stenosis.

Typical for a varible extrathoracic stenosis is the plateau during inspiration. During inspiration the obstruction aggravates because the negative pressure inside the airways narrows the stenosis.

Extrathoracic Case


Intrathoracic Case

- FEV1 diminished- IVC usually normal

Typical for the variable extrathoracic stenosis is the criation of an expiratory plateau

During expiration the obstruction aggravates because the thoracic pressure compresses the airways and therefore narrows the stenosis


Pre - Post Cases

COPD Asthma

FEV1 < 12% FEV1 >= 12%

Health & Medicine

Anaecon India - Spirometery