Anaecon India - SpirometeryPresentation Transcript
Sarthak Jain Shailendra Singh ANAECON INDIA HEALTHCARE PVT. LTD P-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
-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
Bronchodilator – to determine whether airflow obstruction
is reversible. Bronchodilator increase
caliber by relaxing airways smooth
Patient : 45 year old women, height 5’3”
FEV1 - Reading/predicted value 1.43/2.60 = 55% of
FVC – Reading/predicted value 2.5/3.03 = 82.5% of
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.
Multi breath closed circuit He washout
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 + RV TLC = ERV + RV + TV + IRV
TV – Tidal volume is the volume of air inspired and expired with each breathing during each
breathing. The end of inspiration phase is called end inspiration level and the end of
expiration phase is called the end expiration level.
RV – The maximum volume of air inhaled from the end inspiratory level.
ERV – The maximum volume of air that can be exhaled from the end expiratory level.
RV – The volume of air that remains in the lungs after end of maximum expiration. RV = FRC-ERV
VC – The volume of air that can be exhale after maximum inspiration. ( when this volume is exhaled forcefully, it is called forced vital capacity, and when it is exhaled slowly, it is called SVC.
IC – The volume of air that can be inhaled from the end expiratory level. IC = TV + IRV
FRC – The volume of air remaining in the lungs from the end expiration level. At this point in the ventilation cycle, the elastic force of the chest wall (acting to expand chest) is exactly balanced by the elastic force of the lungs (acting to deflate lungs.)
TLC – The volume of air in lungs after maximum inspiration. It consist of all four volumes RV, TV, ERV and RV and two capacities IC and FRC.
Flow/Volume calibration using a 3 L calibration pump
1 to 2 discard strokes
2 to 6 Calibration strokes
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 = B ody T emperature, P ressure, S aturated with water vapour Only calibrated spirometers can be relied upon! Calibration of pneumotachographs daily or after replacement!
Cleaning / Hygine
A 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.
After each measurement Spirette
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
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 Spirometry Parameters measured in standing position are not better than in sitting position but different ! www.spiro-webCard.de Head straight or in slight extension Upright sitting 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 effort B: Submaximal effort C: Low effort A: Maximal effort B: Exhalation not complete A: Maximal effort B: Submaximal effort 1 2 3 Flow [L/s] Volume [L] TLC Effort dependent RV A B C A B A B
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 www.spiro-webCard.de
Differentiation between Restriction and Obstruction! narrowing of airways VC contraction of alveolar tissue FEV1
Staging Obstructive parameters FEV1 / IVC < 5% Percentile of predicted (< 70% pred.) Recommendations of German „Atemwegsliga“ 2005 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.
Staging of Restrictive parameters TLC < 5% Percentile of predicted (< 80% pred.) Recommendations of German „Atemwegsliga“ 2005 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.
Ratio FEV 1 /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
Spirometry interpretation Mild obstructiv:
- Ratio FEV 1 /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
Spirometry interpretation Moderate to server Case
- Ratio FEV 1 /IVC < 70%
- FEV1 50% to 70% (moderate)
- FEV1 < 50% (severe)
In case of dynamic hyperinflation also VC is reduced.
E.g.: Exacerbation of asthma, severe COPD
Spirometry interpretation Severe obstructive Case
- ratio FEV 1 %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
Spirometry interpretation Restrictive Case
- FEV 1 %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 FEV 1 %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.
Spirometry interpretation 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
Spirometry interpretation Pre - Post Cases COPD Asthma FEV1 < 12% FEV1 >= 12%