Spirometry is the measurement of the flow and volume of air entering and leaving the lungs Test of pulmonary function (PFT) • Indicator of health status or disease • Exercise fitnessRespiratory system is functions include gas exchange , pH regulation, vocalization , and protection from foreign substances.Respiration:Cellular is the cellular mechanism of energy conversionExternal is the exchange of gases between atmosphere and cells, Includes ventilation, gas exchange at lungs and cells, and transport of gases in the blood.
2. Spirometry is the measurement of the flow and
volume of air entering and leaving the lungs
Test of pulmonary function (PFT)
• Indicator of health status or disease
• Exercise fitness
3. Respiratory system is functions include gas exchange ,
pH regulation, vocalization , and protection from
foreign substances.
Respiration:
CellularCellular
is the cellular mechanism of energy conversion
ExternalExternal
is the exchange of gases between atmosphere and
cells, Includes ventilation, gas
exchange at lungs and cells, and transport of gases in
the blood.
4.
5.
6. The process of exchange of air between the lungs
and the ambient air
Airflow in respiratory system is directly proportional
to the pressure gradient and inversely related to
the resistance of the airways.
A single respiratory cycle = inspiration + expiration
7.
8. Lung air pressure < Atmosphere air pressure
Diaphragm & inspiratory muscles contract →
Thoracic cavity expands negative pressure→ →
air flows into lungs
9. Passive process resulting from natural elastic
recoil of the expanded lung walls.
During rapid breathing, internal intercostal and
abdominal muscles contract to help force air out at
a more forceful, rapid rate
10.
11.
12.
13.
14. Age
Body size (height & weight)
Gender
Pulmonary health
Altitude(height)
Irritants
21. Apparatus used to measure static & dynamic lung
volumes/capacities using a closed system
• Registers the amount and rate of air moved into
or out of the lungs
• 2 main types;
1. Volume: records the amount of air exhaled or
inhaled within a certain time*
2. Flow: measures how fast the air flows in or out
as the volume of air inhaled or exhaled
increases
24. Some are portable versions
Leak tests and calibrations are easy to perform
Many can produce flow/volume curves and loops
with the addition of special electronic or
digital circuitry.
Volume spirometers hold their calibration months to
years better than flow spirometers
25. Not practical by hand to determine peak expiratory
flow or instantaneous volumes,
Coughs and submaximal efforts are not as obvious
Some are heavy, cumbersome and may be prone to
fostering mold or bacterial growth if not cleaned
properly
26. Key features
Measure how quickly air flows past a detector and
then derives the volume by electronic means.
Records flow rate at brief intervals (30-300x/sec)
and use data to reconstruct the flow rate at each
point in time and volume (digitization).
Tracings measure flow in relation to volume
27. Computer can produce volume-time
tracings
Tend to be lighter and more portable
Disposable, single-use flow sensors, available on
some floe spirometers eliminate the risk (low)
of cross-contamination.
28. No real-time or hard copy tracings
Reliance on electronic equipment
FEV1.0 cannot be calculated by hand unless the
time is indicated in seconds on a flow-volume
tracing
Some flow spirometers are more difficult to
calibrate and may lose their calibration over time
if not well maintained
29. Test results are not disease specific
May not be sensitive enough to show
abnormalities before extensive and in some
cases irreversible damage has been done
(mostly for restrictive diseases)
∴ Should not be used as the sole screening tool of
a respiratory surveillance program.
31. A reduction of FEV1
In relation to the forced vital capacity will result in a
low FEV1/FVC%
The lower limit of normal for FEV1/FVC is around 70-
75%
The exact limit is dependent on age.
32. Normal or high FEV1/FVC% ratio
Reduction in both FEV1 and FVC
Interstitial lung disease
Respiratory muscle weakness
Thoracic cage deformities such as kypho-scoliosis
33. A combination of both obstruction and restriction
resulting in gas trapping, rather than as a result of
small lungs.
A reduced FVC together with a
low FEV1/FVC% ratio
It is necessary to measure the patient's total lung
capacity to distinguish between these two
possibilities.
34. Severity of Airway Obstruction FEV1 (% of Predicted)
Mild >70
Moderate > 60 and < 70
Moderately severe > 50 and < 60
Severe > 34 and < 50
Very severe < 34
Severity of Chest Restriction* FVC (% of Predicted)
Mild >70 but < LLN
Moderate > 60 and <70
Moderately severe > 50 and < 60
Severe > 34 and < 50
Very severe < 34