Respiratory 10 & 11 Flashcards
What two additional tests can be done with Spirometry?
- Forced Expiratory Volume in 1 sec (FEV1)
* Forced Vital Capacity (FVC)
What is asked of the patients when performing a FEV1 and FVC?
The patron makes a maximal inspiration and then you ask the patient after the maximal inspiration to make an exploratory effort to exhale as much as they can as fast as they can
How is the Forced Vital Capacity different from Vital Capacity?
Forced expiratory volume describes how much of the vital capacity volume that can be expelled in one second
What is the Forced Expiration (FEV1) like in a healthy patient?
A healthy person can normally expel most of the air from their lungs in one second
What is the Forced Vital Capacity (FVC)?
The total amount of air that is blown out in one breath after max inspiration as fast as possible
What is the equation for Vital Capacity?
TV + IRV + ERV = Vital Capacity
What does the Ration FEV1/FVC represent?
The proportion of air that is blown out in one second
What do patients with obstructive disease have a difficulty doing?
Exhaling all the air from the lungs
In what diseases is the obstructive pattern typical?
- Bronchial asthma
- COPD
- Cystic fibrosis
How is the FEV volume affected in obstructive lung diseases?
The FEV1 is greatly reduced
How is expiration affected by people with obstructive lung diseases?
Expiration is much slower
How is FVC affected in the obstructive pattern?
It can be normal or reduced
What is that ratio FEV1/FVC like in the obstructive pattern?
It is lower, typically <0.7
Which agonists reduce bronchospasm in people with asthma?
Beta 2 adrenergic agonists
What occurs in people with the restrictive pattern?
They have a reduced ability to fill their lungs with air
What are restrictive lung patterns usually due to?
Conditions that cause stiffness of the lungs, or chest wall and muscles
How are FEV1 and FVC affected by restrictive pattern diseases?
FEV1 and FVC are reduced
How is the ratio of FEV1/FVC affected by the restrictive pattern?
FEV1/FVC is almost normal
Which diseases exhibit the restrictive pattern?
- Lung fibrosis
- Neuromuscular diseases (ALS, muscular dystrophy)
- Scarring of the lung tissue
What method can measure functional residual capacity?
The helium dilution method
What is the functional Residual Capacity?
The amount of air that is in the lungs at the end of a normal expiration
How does the Helium dilution test work?
- A participant is asked to breathe in in a out a mixture of helium and oxygen with a known concentration
- We let the patient do this until their is an equilibrium between the stuff that is breathed in and out
What does V2 represent in the Helium test?
The total residual volume
What is the equation used in the Helium Dilution test?
V2 + V1 (C1- C2) / (C2)
What are Static properties of the lung?
Mechanical properties that are present in the lungs and occuring when no air is flowing
What are the Static properties mostly correlated with?
Maintenance of lung volume
What are the Static properties of the lung?
- Intrapleural pressure
- Transpulmonary pressure
- Static compliance of the lung
- Surface tension of the lung
What are Dynamic properties of the lung?
Mechanical properties when the lungs are changing volume and air is flowing in and out
What are the Dynamic properties necessary for?
Permitting airflow
What are the dynamic properties of the lungs?
- Alveolar pressure
- Dynamic lung compliance
- Airway and tissue resistance
What is Ventilation?
The exchange of air between the atmosphere and the alveoli
What is Bulk flow?
When gas moves from high pressure to low pressure
What does Boyle’s law state?
For a fixed amount of an ideal gas kept at a fixed temperature, P and V are inversely proportional (when one increases the other one decreases)
What is the equation for boyle’s law?
P1V1 = P2V2
What is flow generated by in the lungs?
A difference in pressure between the atmospheric pressure and alveolar pressure
What is the equation of flow?
F = ∆P/R
What is the Pleura?
A thin double layered envelope that encases the lung
What does the Visceral Pleura cover?
The external surface of the lung
What does the Parietal Pleura cover?
The Thoracic wall and superior face of the diaphragm
What does the Intrapleural fluid cover?
It reduces friction of lung against thoracic wall during breathing
What do the the lungs have a tendency to do?
The lungs have a tendency to collapse due to elastic recoil
What does the Chest wall have a natural tendency to do?
It has a natural tendency to expand
