Ventilation Flashcards
What does ventilation refer to?
The amount of air entering and leaving the lungs per minute.
What is alveolar ventilation?
The amount of air exchanging with blood - Air actually getting to the alveoli
How is CO2 concentration in alveolar gas related to ventilation?
They are inversely related.
What is anatomic dead space?
The amount of a breath not reaching alveoli
What is the physiologic dead space?
The amount of a breath not exchanging with blood (measured by ratio of CO2 in expired air vs. arteries)
What regions of the lung are ventilated better?
The lower regions are ventilated better than the upper regions.
What does ventilation describe?
How gas (oxygen) gets to the alveoli
What is one of four general causes of reduced oxygen in the blood (hypoxia)?
A reduction in ventilation
What are six things that can cause a reduction in ventilation?
- Drugs (opiates)
- Brain damage
- Breathholding
- Pneumothorax
- Nerve damage
- Muscle damage
What is Tidal Volume? What is it’s average value?
The amount of air inspired and expired in routine breathing.
About 500 ml.
What is total lung volume usually about?
4000 mL
What is total lung capacity usually about?
7000 mL
What is vital capacity? What is it’s value?
The maximum volume of air that can be exhaled after a maximum inspiration. [The largest breath you can take!]
About 6000 mL.
What is residual volume? What is it’s value?
The amount remaining in the lungs after a maximal expiration.
About 1500 mL.
What is Functional Residual Capacity? What is it’s value?
The amount remaining in the lungs after a typical exhalation.
About 2500 mL.
How can you measure Functional Residual Capacity?
You can’t measure this directly, BUT you can calculate it!
What can you measure/calculate with the Gas Dilution Technique?
- Functional residual volumes
- Tidal volumes
- Vital Capacity
What other technique can be used to measure Lung Volume?
Plethysmograph
How does a plethysmograph measure?
It measures pressure in a box of fixed volume surrounding an individual.
-You have to measure change in pressure in the mouth along with change in volume in the box.
What two equations should you know with the plethysmograph?
- P1V1 = P2V2
2. Change in volume = V2-V1
What is Total Ventilation?
The amount of air entering and leaving the lung each minute.
How is Total Ventilation usually calculated? What is it’s usual value?
Volume*bpm = Total Ventilation
500 mL*15bpm = 7500 mL/min