lecture 34 spirometry Flashcards
What is the definition of recoil?
the ability to return to resting volume once stretched
what does lung recoil mean?
inward force produced by the elastic properties of the alveoli; acts to collapse the lung
what does chest wall recoil mean?
(PCWR) outward force produced by the chest wall
what is PIP?
intrapleural pressure
this is the pressure within the pleural cavity
- this is between the visceral layer connected to lung and chest wall parietal layer
The opposing recoil forces of the chest wall and the lung create a negative subatmospheric PIP
what condition has air in the pleural space?
pneumothorax..
can be caused by punctured chest wall or lung. the pressure is moving towards 0 and the lung collapses as it wants to
What occurs in a a closed pneumothorax?
air enters the pleural space from a punctured lung
what occurs in an open pneumothorax?
air enters into pleural space from chest wall
what occurs in a tension pnemothorax?
it causes a shift in the mediastinum and compromises hemodynamic stability.. great vessels are kinked
-can be spontaneous or traumatic
a patient does a pulmonary test with emphysema what are his results?
decreased FEV1/FVC
emphysema is an obstructive lung disease, their lungs are more compliant, more air in lung than normal
increased TLC
increased FRC
increased RV
what test measures lung volumes?
spirometry
what is tidal volume? (TV)
the volume of air inhaled or exhaled with each normal breath
what is Inspiratory Reserve Volume? (IRV)
the volume of air that can be inhaled at the end of a normal tidal inspiration
What is Expiratory Reserve Volume ( ERV)?
the volume of air within the lungs that can be exhaled after the end of a tidal exhalation
what is Residual Volume (RV)?
the air remaining in the lungs after a maximal expiration ( this volume of gas cannot be expelled, and cannot be measured by spirometry because it doesn’t come out)
What is functional residual capacity? (FRC)
the total volume of air remaining in the lungs at the end of a tidal exhalation, spirometer doesn’t work
ERV+RV
what is total lung capacity (TLC)?
the volume of air in the lungs at the end of maximal inspiration
this is measured by adding IRV TV ERV RV
spirometry will not work
What is vital capacity? (VC)
the volume of air exhaled from maximal inspiration to maximal exhalation; maximum expiration.
when done with force this volume is termed forced vital capacity (FVC) ( tells you about lung status function)
this is the sum of IRV TV and ERV
what is forced expiratory volume in 1 second?
the forced volume of air exhaled in the first second of FVC test (FEV1)
What is IC?
inspiratory capacity it is IRV+TV which means inspiratory reserve volume + tidal volume
LOOK AT 12
what are obstructive long disease?
expiratory flow rate is significantly decreased resulting n decreased FEV1/FVC ratio
both FEV and FVC is decreased
emphysema/is compliant lung recoil is lost its hard to breath out
asthma is also one, narrow airways
what is restrictive disorder?
Lung inflation is decreased, inspiration is screwed. decreased FEV1 and FVC.
the FEV1/FVC ratio is normal or increased…
force vital capacity is less
pulmonary fibrosis/less compliant
infant respiratory distressed
or fractures rib
on a spirometer test/graph what occurs at time 0? how does the spirometer work?
it is the total lung capacity
then once inspired completely, the FVC test is expire forcefully until you can’t anymore… that time is measured. then the volume of air expired is also measured. look at pic! the fvc was marked with an X slide 15
low ratio of FEV1/ FVC means obstructive
high ratio= restrictive
what is FEF 25-75?
Forced expiratory flow (FEF).
represents the expiratory flow over the middle half of the FVC ( between 25-75)
sometimes FEV1/FVC cannot see early airflow obstruction but FEF can see it
FEV1/FVC ratio in restrictive disease can remain what?
normal because of proportional decrease
history and presentation is important
see pic slide 17
FEV1/FVC ratio in obstructive disease lung disease
FEV1 is smaller compared to FVC, so ratio is decreased
see pic
slide 18
In obstructive disease total lung capacity is ______
increased
in restrictive disease total lung capacity is___
decreased
in obstructive disease residual volume is______
increased
in restrictive disease residual volume is______
decreased
in obstructive disease functional residual capacity is ?
FRC
increased
in restrictive disease functional residual capacity is ?
decreased
what is the ratio of FEV1/FVC for obstructive disease?
<0.8
what is the ratio of FEV1/FVC for restrictive disease?
> 0.8
what is a genetic risk factor for emphysema?
Alpha 1 antitrypsin
what are signs of air trapping? what disease has this?
prolonged expiratory phase, barrel chest, flat diaphragm
emphysema
remember this is disentegration of the lung’s elastic framework and destruction of alveolar walls
what test can measure residual volume (RV)?
helium dilution technique, can only measure for people without obstructive disease
what test can measure residual volume with an obstructive disease?
plethysmograph
Boyles law is used to estimate the lung volume
