Pulm Phys & Pharm Flashcards
Alveolar pressure is the
Pressure inside of the lung
Intrapleural pressure is the
Pressure outside of the lung
Transpulmonary pressure (TPP)
The difference between:
Alveolar pressure - Intrapleural pressure
diffusion of CO2 vs O2
CO2 diffuses 20X faster than O2
Alveolar Surface tension for SPHERICAL SHAPE Equation?
Tension = Pressure x radius /2
What law describes alveolar surface tension?
Law of Laplace
What law describes the diffusion of a gas through a membrane?
Graham’s law
What law describes the greater the pressure difference (gradient), the greater the rate of diffusion?
Henry’s Law
What law describes the rate of diffusion of (O2, N2, CO2) is proportional to the partial pressure caused by each gas alone?
Dalton’s Law
What law describes lung compliance?
Boyle’s Law
-change in volume / change in pressure
V/Q ratios of upper vs lower areas of the lungs?
Upper areas of the lung have better ventilation in relation to perfusion = higher V/Q ratio
Lower levels of the lung have better perfusion than ventilation = lower V/Q
Ratio of change in volume to change in pressure
Compliance
Max pressure during the inspiratory phase time
Peak Pressure
ratio of change in driving pressure to change in flow rate
Resistance
energy expended to move gas in and out
Work of breathing
best vent settings to prevent barotrauma?
PC-VG
PS
Mechanisms of Gas exchange (3)
ventilation
perfusion
diffusion
Oxygen Content (CaO2)
= [Hb x 1.34 x Sao2%] x [Pao2 x 0.003]
Diffusion of gas is determined by: (4)
- Membrane thickness: thicker the membrane, slower the diffusion
- Surface area of the membrane: SA of lungs is massive
- Diffusion coefficient of the gas in the substance of the membrane
- the pressure difference between the two sides of the membrane.
Total body oxygen delivery is the product of?
- O2 content or arterial blood (CaO2) and
- rate of delivery of blood to the tissues (CO)
DO= CO X CaO2
CaO2= Hgb X 1.39 X SaO2 + (0.0031 X PaO2)
Define: CaO2
CaO2: oxygen content of arterial blood
Define: SaO2
SaO2: arterial oxygen saturation
Define: PaO2
PaO2: partial pressure of oxygen in arterial blood
Define the constant: 1.39
- 39
- the amount of oxygen (mL) bound to each gram (g) of hemoglobin
- (varies between 1.34-1.39)
- 1.39 mL O2 per g of Hb