Mechanism of Breathing/Compliance Flashcards
Which muscles could be used during inspiration?
Diaphragm
External Intercostals
Which muscles are used during quiet expiration?
NONE!
Active expiration: muscles in abdominal wall, scalenes, etc.
Categorize each of the following as either obstructive/ restrictive:
- Asthma
- Bronchitis
- Pulmonary fibrosis
- Emphysema
- obstructive
- obstructive
- restrictive
- obstructive
T/ F: patients with obstructive lung diseases breath at higher lung volumes
True
List the four steps of inspiration
- Contraction of inspiratory muscles
- Inflation of chest cavity
- Inflation of lung
- Inward airflow
Point to where a healthy person and a person with obstructive disease would be on this curve
What is the intrapleural pressure in relation to the lung pressure?
Its more negative
- It creates a vacuum that helps pull out lungs with expanding chest cavity
- It not more negative = pneumothorax
Why is the intrapleural pressure negative?
See image:
- Lung is trying to move in to its equilibrium position
- Chest wall is trying to move out to equilibrium position
- OPPOSING FORCES GENERATE A VACUUM
What are the normal values of Pip (intrapleural pressure) at the end of inspiration? Expiration?
- 30 cm-H2O at end of inspiration
- 5 cm-H2O at end of expiration
Draw the curves on this line of inspiration and then expiration
What is the elastic recoil pressure?
The tendency for the lung to try to return to its intrinsic equilibrium position producing a pressure
Define compliance
Measure of how easily an applied pressure induces a volume change
- Measure of rigidity
How do you calculate transpulmonary pressure (PTP)?
PTP= P(lung)– P(IP)
- Difference between inside and outside of lung
At what transpulmonary pressure is there the highest degree of compliance?
- 15 cm-H20
- Or the middle of the curve when the slope is highest
What is hysteresis?
=How the compliance curve looks depends on whether you are in inspiration or expiration
- *Lower compliance when inspiring*
Give an example for a disease that increases & decreases compliance
- Emphysema: increased compliance
- Pulmonary fibrosis: decreased compliance
For the following two diseases, will inspiration or expiration be most affected?
- Emphysema
- Pulmonary fibrosis
Emphysema: problems with expiration
Pulmonary fibrosis: problems with inspiration
Which disease is represented by the following curve?
Emphysema
What can cause a reduction in chest wall compliance?
Causes of reduced chest wall compliance
- Old age
- Obesity
- Scar tissue
What effect will decreased lung compliance on the Volume/ pressure curve?
- Decreased volumes at a given pressure
- Decreased tidal volume
- same compliance
