spirometry Flashcards
Maximal filling of the lungs is determined by ?
- balance between the maximum inspiratory effort
- the force of recoil of the lungs. (the higher the elasticity, the more the recoil, the harder it is to fill up!
difference btw obstructive and restrictive
and how FRC changes in them?
what happens to the lung’s size in obstructive? explain
fa takhayalay kl mara u …
breath normally, exhale zag
breath normally, exhale zag,
breath normally exhale zag
eventually kl hal air is gunna get trapped in ur lungs!>> we yseer 7ail kbeer!
Explain obstructive and restrictive patterns seen on spirometry
Explain and carry out simple spirometry
The movement of air during breathing can be measured by Spirometry.
Lung volumes and capacities can be measured from a spirometry tracing.
Procedure:
- The procedure is performed sitting in a chair or standing.
- A soft nose clip is worn during the procedure so that breathing is
- through the mouth, rather than the nose.
- A sterile mouthpiece attached to the spirometer is used for breathing.
- With the mouth forming a tight seal around the mouthpiece, the patient is instructed to perform various breathing manoeuvres by inhaling and exhaling.
- After a few cycles of quiet inspiration and expiration a FVC is performed. by taking max inspiration then breathing out as hard and fast as possible, (similar to a vigorous attempt to blow out all the candles on a birthday cake).
what r Lung capacities
Lung capacities are defined relative to fixed points in the breathing cycle.
These are maximum inspiration, maximum expiration, and the end of a quiet expiration.
Identify ‘Tidal volume’, Inspiratory reserve volume’, Expiratory reserve volume’, Residual volume’ ‘Inspiratory Capacity’, ‘Functional Residual Capacity’, ‘Vital Capacity’ and Total lung volume on a spirometry tracing.
Describe the time-volume graph.
- explain what is forced vital capacity (FVC)
- forced expiratory volume in the first second (FEV 1.0)
- FEV1/FVC ratio
time- volume graphs
in normal respiration, obstructive airways disease & restrictive lung disease.
L vs S
Explain flow- volume loops and how they are affected by airway obstruction and restrictive disease
what is (PEFR)?
At the start of expiration, when the lungs are expanded, and the airways are stretched open, the expiratory flow is at its MAX>>
Peak Expiratory Flow Rate (PEFR)
Sketch the expiratory part of the flow- volume loop for a patient with asthma before and after bronchodilators
when does ‘scalloping’ of the flow-volume curve occur?
Interpret data and tracings obtained from spirometry and apply this information in the diagnosis of respiratory disease
why do we have residual volume
We cannot empty our lungs completely, so even after a forced expiration a residual volume will remain.
usually 1.1 liters!
what is Vital capacity?
why can it be reduced?
Max amount of expired air after first being inspired to the max!
cuz lungs either r not:
- filled normally in inspiration
- emptied normally in expiration,
- or both.
how do we measure RV?
the Helium dilution test.
- 1st let person breath out as much as possible so we r left with RV
- then let person breath the He in and out
- the helium will move into lungs and be diluted there> let this work until equilibream is reached!
- the degree of dilution of the concentration in the spirometry, we can estimate the unknown volume of lung!
how do we measure Dead space
Nitrogen washout method.
how do we measure Gas diffusing capacity of the lung?
he ‘diffusion conductance’ is the resistance to diffusion across the alveolar membrane, and is estimated by the carbon monoxide transfer factor (TLCO)
label defects in each
hint: first one normal
how do the modern spirometers calculate the predicted normal FVC and FEV1 for the patient?
based on age, gender, height and ethnicity.
obstructive vs restrictive time volume loop
