Pulm Physiology Flashcards
Ventilation
Amount of air moving into or out of the lungs in a given time.
Exchange of gases between the atmosphere and the alveoli.
How does air move into and out of the lungs?
By bulk flow from areas of high pressure to areas of low pressure.
**Move based on pressure changes.
How do you calculate flow?
F= deltaP/R
What are the conditions at steady state?
O2 UPTAKE= O2 CONSUMPTION
CO2 PRODUCTION= CO2 EXCRETION
Total Lung Capacity (TLC)
TLC= VC + RV= ~6-7L
**Spirometry cannot be used to measure this because spirometry cannot be used to measure residual volume.
Vital Capacity
amount of air in a normal breath
Residual Volume
amount of air remaining in lungs at max expiration
**Cannot be measured via spirometry.
Functional Residual Capacity
amount of air in lungs after normal expiration.
FRC= ERV + RV= ~2.5 L
**measured by helium dilution (cannot dissolve in blood) or body plethysmograph
Forced Vital Capacity
amount of air exhaled during a forceful expiration
TV + IRV + ERV= ~5L
Inspiratory Reserve Volume
additional amount of air that can enter during forced inspiration
~3L
Expiratory Reserve Volume
difference between tidal end volume and forceful expiration end volume
~1L
Forced Expiratory Volume in 1sec
maximal inspiration and then forced expiration
**normal is 80% of FVC
Peak Flow Meter
measures maximal flow of expiration (how forcefully you expire)
Lung volumes seen in patients with obstructive lung disease?
FEV1 values less than 70% of FVC
- *Difficult to rapidly expire when there i an airway obstruction.
- *EX. asthma, emphysema, chronic bronchitis
Lung volumes seen in patients with restrictive lung disease?
Reduced FVC but may have a normal FEV1 to FVC ratio.
- *Reduced expansion of the lung parenchyma.
- *EX. obesity, pulmonary fibrosis, weakness of the inspiratory muscles, neuromuscular disorder
