Exam 3: 13 Mar Flashcards
What is the significance of flow volume loops in pulmonary function tests?
They help assess maximal peak expiratory force and airway collapse.
What is forced vital capacity?
The maximum amount of air that can be forcibly exhaled after taking the deepest breath possible.
How does airway collapse affect expiratory flow rate?
It reduces the expiratory flow rate due to obstruction.
What is the relationship between lung volume and airway resistance?
Lower lung volume increases airway resistance.
True or False: In restrictive lung diseases, peak expiratory flow rate is typically higher.
False
What pressures are involved in normal expiration?
Pleural pressure and elastic recoil pressure.
What happens to airway pressure during forced expiration?
It increases significantly due to applied force.
What is the role of pleural pressure in preventing airway collapse?
Negative pleural pressure helps keep the airways open.
Fill in the blank: The _______ is essential for maintaining airflow through the lungs.
pressure gradient
What can cause small airway collapse?
High surrounding pressure compared to small airway pressure.
What is meant by ‘airway traction’?
The support provided by elastic tissue to keep small airways open.
How does emphysema affect elastic recoil in the lungs?
It reduces elastic recoil due to loss of elastic tissue.
What is a common example of fixed intra or extra thoracic obstruction?
An endotracheal tube.
True or False: A smaller diameter endotracheal tube increases airflow resistance.
True
What is the relationship between elastic recoil and lung compliance?
Less elastic recoil leads to increased lung compliance.
What is the effect of low lung volume on small airways?
It narrows small airways, increasing the risk of collapse.
How does the structure of upper respiratory tract airways differ from small airways?
Upper airways are supported by cartilage, while small airways are not.
What happens to the pressure gradient as you move away from the alveoli during expiration?
The pressure gradient decreases.
What happens during passive expiration?
Air is pushed out of the lungs by elastic recoil.
Fill in the blank: The pressure inside the small airways must be _______ than the surrounding pressure to prevent collapse.
greater
What is the impact of airway obstruction on flow volume loops?
It alters the shape of the loops, indicating resistance.
What condition often leads to the loss of elastic tissue in the lungs?
Emphysema.
What is the primary factor that influences airway collapse in small airways?
The balance between internal airway pressure and external environmental pressure.
How does a healthy lung maintain airway patency?
Through sufficient elastic tissue and pressure gradients.
What happens when a smaller diameter tube is placed in the trachea?
Higher resistance to air flow
Causes difficulty in both inspiration and expiration.
What does obstruction in the flow volume loop typically affect?
Limits both inspiration and expiration
It cuts off the expired portion of the flow volume loops.
What is an example of a fixed obstruction in the respiratory system?
Endotracheal tube
It obstructs airflow throughout the respiratory cycle.
What characterizes a variable intrathoracic obstruction?
Affects only expiration
It is not present throughout the entire respiratory cycle.
In the context of variable intrathoracic obstruction, what happens during forced expiration?
Airway collapse can occur due to positive pressure
This can happen if elastic recoil is not normal.
What condition can cause variable intrathoracic obstruction?
Emphysema or asthma
These conditions typically involve small airway collapse.
What is a variable extra thoracic obstruction?
Obstruction outside the chest that affects inspiration
It can cause airway collapse due to negative pressure.
What can lead to variable extra thoracic obstruction?
Paralyzed vocal cords or missing cartilage
These conditions may prevent normal airway support.
What is the normal FEV1/FVC ratio in healthy individuals?
Approximately 80%
This ratio indicates normal lung function.
What does FEV1 stand for?
Forced expiratory volume in one second
It measures the amount of air expelled in the first second of a forced exhalation.
What does FVC stand for?
Forced vital capacity
It represents the total amount of air that can be forcibly exhaled.
What occurs if the FEV1/FVC ratio is lower than 80%?
Indicates a potential respiratory problem
It suggests possible obstruction or restriction in lung function.
What is the significance of measuring lung volumes over time during a forced expiratory maneuver?
It helps assess how quickly air can be expelled from the lungs
Typically shows how lung volume decreases during expiration.
What is a characteristic finding in restrictive lung disease?
Low vital capacity
The FEV1 may also be low, but the ratio can be normal.
What does a low FEV1 in conjunction with a low FVC suggest?
Restrictive lung disease
It indicates a proportionate decrease in both volumes.
What might a significantly low FEV1/FVC ratio indicate?
Obstructive lung disease
This suggests a problem with airflow, often seen in conditions like COPD.
What happens to airway pressure during inspiration with variable extra thoracic obstruction?
Internal airway pressure becomes negative
This can cause collapse of the airway if not supported.
What does a low force vital capacity indicate?
Restrictive lung disease
A low force vital capacity suggests that the lungs cannot expand fully, often seen in conditions like restrictive lung disease.
What is the significance of the FEV1 to FVC ratio?
Indicates obstructive or restrictive lung disease
A ratio less than 70% usually indicates an obstructive problem, while a higher ratio may suggest restrictive lung disease.
What does a flattened expiratory curve suggest?
Obstructive lung disease
A hallmark shape change in the flow-volume loop indicates issues with airflow, typical of obstructive lung diseases.
How can bronchodilator response help in diagnosing lung conditions?
Indicates airway reactivity
If a bronchodilator improves FEV1, it suggests asthma; if not, it may indicate emphysema or another irreversible obstructive condition.
What does an increased residual volume indicate?
Obstructive lung disease
An increase in residual volume relative to total lung capacity can help differentiate between types of obstructive lung diseases.
What is the purpose of the carbon monoxide diffusion test?
Measures surface area available for gas exchange
This test assesses how well oxygen and carbon dioxide can transfer between the alveoli and blood.
What is the procedure for measuring closing capacity?
Monitor nitrogen concentration during expiration
The patient exhales to residual volume, then inhales 100% oxygen and exhales again to measure nitrogen levels.
What happens to nitrogen concentration during a vital capacity maneuver with 100% oxygen?
Dilution of nitrogen occurs
The nitrogen previously in the lungs gets diluted as oxygen is inhaled, affecting nitrogen concentration in expired air.
How does lung volume affect nitrogen dilution?
Base of the lung dilutes nitrogen more than the apex
The base of the lung, being less full, allows for more dilution of nitrogen when inhaling oxygen.
What is indicated by the first phase of the nitrogen expiration maneuver?
Expiring dead space air
This phase includes air that was not involved in gas exchange, primarily from the trachea and bronchi.
Fill in the blank: A FEV1/FVC ratio of less than ___ is typically considered a problem in pulmonary function testing.
70
This threshold is used to distinguish between normal and obstructive lung function.
What is the expected outcome in a patient with advanced emphysema during a forced expiration test?
Prolonged expiration time with low FEV1
Patients may struggle to empty their lungs due to loss of elastic recoil, leading to a characteristic prolonged expiration.
True or False: A normal FEV1 suggests healthy lung function.
True
A normal FEV1 indicates that the patient can exhale a sufficient volume of air in one second, suggesting no significant obstructive disease.
What are the three main types of lung diseases indicated by pulmonary function tests?
- Obstructive lung disease
- Restrictive lung disease
- Mixed lung disease
These classifications help in diagnosing specific pulmonary conditions based on test results.
What is the first phase of the nitrogen expiration maneuver?
The first phase involves expiring dead space air with no nitrogen content
This phase represents the anatomical dead space air, approximately 100 cc.
What occurs during phase two of the nitrogen expiration maneuver?
Phase two is a transitional period with mixed anatomical dead space air and alveolar air
This phase correlates with the Fowler test.
What is the primary source of expired air during phase three?
Most expired air during phase three comes from the base of the lung
Initially, the base has a lot of nitrogen dilution due to previous emptying.
What characterizes phase four of the nitrogen expiration maneuver?
Phase four is marked by an abrupt change in expired nitrogen concentration due to small airway collapse
This indicates a shift from air coming from the base to the apex of the lung.
What are the terms used to describe the inflection point between phases three and four?
The terms are closing capacity and closing volume
Closing capacity includes closing volume plus residual volume.
How does aging affect the closing capacity and closing volume?
Closing capacity and closing volume increase with age
This is due to loss of elastic tissue, resulting in earlier small airway collapse.
What happens to residual volume (RV) as a person ages?
Residual volume tends to increase as we age
This is linked to difficulties in emptying parts of the lung.
At what age does small airway collapse begin to occur during normal breathing?
Small airway collapse begins around age 55
This occurs even in individuals who are in perfect health.
What is the impact of small airway collapse on the work of breathing in older adults?
Older adults experience increased work of breathing due to frequent small airway collapse
They have to exert more effort to breathe compared to younger individuals.
True or False: Total lung capacity significantly changes with age.
False
Total lung capacity remains relatively constant as we age.
What is the significance of the nitrogen meter in lung function testing?
The nitrogen meter is used to detect small changes in lung function related to airway behavior
It can help identify respiratory issues before they become serious.
Fill in the blank: The transitional phase in the nitrogen expiration maneuver is similar to the _______.
[Fowler test]
What happens to the proportion of expired air from different lung regions during phase three?
As expiration progresses, the proportion shifts from the base to the apex of the lung
This reflects the emptying pattern of the lungs.
How does the collapse of small airways affect nitrogen concentration in the expired air?
Collapse leads to a decrease in nitrogen concentration in expired air from those alveoli
This results in an abrupt change in the nitrogen concentration curve.
What is Full Body plethysmography?
A pulmonary function test that measures lung volumes and capacities in a sealed chamber
It involves complex equipment and is not commonly visualized.
