Ventilation - L3 Flashcards
2 types of respiratory diseases?
Obstructive and restrictive
What is pulmonary minute ventilation?
It is the total volume of air entering and leaving
respiratory system each minute
What is minute ventilation formula?
= VT (Tidal Volume) x Respiratory Rate
What is normal respiration rate?
12 breaths per minute
What is normal VT?
500 mL
What is normal minute ventilation?
500 mL x 12 breaths/min = 6000 mL/min
Which is more important alveolar ventilation or pulmonary ventilation?
Alveolar ventilation is more important than pulmonary ventilation
What is alveolar ventilation?
It is the volume of air exchanged between the atmosphere and the alveoli per minute
What is less alveolar ventilation or pulmonary ventilation?
Alveolar ventilation is less than pulmonary ventilation due to anatomic dead space
Alveolar ventilation formula?
Alveolar ventilation = (tidal volume – dead space) x
respiratory rate = (500-150 mL/br) x 12 br/min =
4200ml/min
is resistance of airways smaller or bigger in smaller ones?
resistance is smallest in smallest airways
What is there to match airflow to blood flow?
There are local controls
Which area is greater - blood flow (perfusion) or airflow (ventilation)?
The area in which blood flow - perfusion is greater than airflow - ventilation
What happens in obstructive respiratory diseases (3) and give some examples of the diseases:
- Airway narrowing
- Increased airway resistance
- Reduced flow during expiration
Examples: emphysema, chronic bronchitis, asthma.
What happens in restrictive respiratory diseases (3) and give an example of the diseases:
- Reduced compliance
- Scar tissue formation
- Fibrosis
Example: pulmonary fibrosis
What are some other conditions? 4
Diseases impairing diffusion of O2 and CO2
Neuromuscular disorders
Inadequate perfusion
Ventilation-perfusion imbalances
What is FEV 1.0?
Forced expired volume in 1 second
FVC - what does it stand for?
Forced vital capacity
FEV 1.0 / FVC?
Disease index i.e. <80%
Local controls which increase CO2 in area of small airflow what happens?
Causes relaxation of local airway smooth muscle
This causes dilation of local airways
This decreases airway resistance
Thus increases airflow
Local controls which decrease O2 in area of small airflow what happens?
There is an increase in contraction of local pulmonary arteriolar smooth muscle
This causes constriction of local blood vessels
This increases vascular resistance
Thus decreasing blood flow
If the local controls act to balance by decreasing CO2 in the lung area what happens?
This increases contraction of local airway smooth muscle and constricts local airways which increases airway resistance and decreases airflow
If the local controls act to balance by increasing O2 in the lung area what happens?
By increasing oxygen, this relaxes the local pulmonary arteriolar smooth muscle which dilates local blood vessels and decreases vascular resistance which thus increases blood flow
Obstructive disorders - type 1 what happens to the airway?
Airway is hyper reactive and there is reversible airway narrowing
Obstructive disorders - type 1 what happens to the mucous?
Mucous thickening
Obstructive disorders - type 1 what are the causes? 5
- Allergens, pollens, animal fur, dusts
- Smoking, smog & airborne pollutants
- Changes in air temperature, humidity, pressure
- Exercise
- Emotional stress, anxiety
Obstructive disorders - type 1 what is the treatment?
Bronchodilators, anti-inflammatory, O2
What is the most common childhood respiratory disease?
Obstructive - Type 1
What happens to smooth muscle in obstructive type 1 disorders? what about when it is severe?
Smooth muscle constriction by spasms in small airways
When severe, the narrowing can be lethal
What happens to the airway wall and mucous in obstructive type 2 disorders?
Inflammation of airway walls and excessive mucous production
* Airway narrowing and coughing (but cough cannot get rid of mucous)
Is obstructive type 2 disorders reversible / irreversible?
Reversible
Causes of obstructive type 2 disorders? 4
- Bacterial & viral infections
- Smoking
- Airborne pollutants
- Chronic irritation (eg: miners)
Are obstructive type 3 disorders reversible / irreversible?
Irreversible
What happens to alveolar walls in obstructive type 3 disorders?
Destruction of alveolar walls (collapsing of small airways)
Causes of obstructive type 3 disorders? 4
- Smoking induced inflammation
- Cilia destruction, tar accumulation
- Airborne contaminants
- Genetic: lack of α anti-trypsin production
Where does enlargement of air spaces in obstructive type 3 disorders take place?
Primarily distal to terminal bronchioles
What does increased lung compliance in obstructive type 3 disorders take place via? 3
- Destruction of elastic fibres
- Excessive release of enzymes: trypsin
- Macrophages secrete α anti-trypsin to inhibit trypsin (but with chronic irritation, trypsin can break alveolar walls) - Reduced elastic recoil of the lung
Causes of restrictive respiratory disorders type 1?
o No known cause in 2/3 of all cases
o Asbestos fibre breathing (can also cause lung cancer)
o Inflammation
o Scar tissue formation
What happens to elasticity in restrictive 1 disorders?
There is reduced elasticty
What does restrictive 1 disorders result from?
Results from over 130 disorders
What happens to the work of breathing in restrictive 1 disorders?
Increased
What happens to compliance of lung and chest wall in restrictive 1 disorders?
Reduced
What is the name for restrictive 1 disorders?
Diffuse Interstitial Lung Disease (DILL)
What type of patients does restrictive 1 diseases take place in?
Slim patients
Disease characteristics of obstructive for:
a. Total Lung capacity
b. Residual volume
c. FVC
d. Functional residual capacity
e. inspiratory capacity
f. FEV 1.0
g. FEV 1.0 / FVC
a. Normal or higher
b. very increased/higher
c. decreased
d. increased
e. decreased
f. very decreased
g. < 80%
Disease characteristics of restrictive for:
a. Total Lung capacity
b. Residual volume
c. FVC
d. Functional residual capacity
e. inspiratory capacity
f. FEV 1.0
g. FEV 1.0 / FVC
a. Decreased
b. Normal or decreased
c. decreased
d. normal or decreased
e. very decreased
f. normal decreased
g. normal or increased
