Physics Laws Flashcards
Identify the law:
The total pressure of a mixture is equal to the sum of the partial pressures exerted by each gas in the mixture
Dalton’s Law
Calculate P3:
Ptotal= 100 mmHg
P1= 20 mmHg
P2= 20 mmHg
P3= x mmHg
x= 60 mmHg
Calculate Ptotal:
P1= 30 mmHg
P2= 40 mmHg
P3= 50 mmHg
Ptotal= 120 mmHg
At sea level, the agent monitor measures the end-tidal isoflurane as 8 mmHg. Convert this to volumes percent.
1%
At sea level, the agent monitor measures the end-tidal sevoflurane as 2%. What is the partial pressure of sevoflurane in the exhaled tidal volume?
15.2 mmHg
Identify the law:
At a constant temperature, the amount of gas that dissolves in a solution is directly proportional to the partial pressure of that gas over the solution. –> The higher the gas pressure, the more it will dissolve into a liquid (at a constant temperature)
Henry’s Law
How does partial pressure affect solubility?
Directly proportional (Henry’s Law)
How does temperature affect solubility?
Inversely proportional (Henry’s Law)
Identify the law application:
Anesthetic emergence is prolonged in the hypothermic patient.
Henry’s Law
What is the oxygen solubility coefficient?
0.003 mL/dL/mmHg
What is the carbon dioxide solubility coefficient?
0.067 mL/dL/mmHg
How is dissolved oxygen in the blood calculated?
By multiplying the PaO2 by 0.003 mL/dL/mmHg (the solubility coefficient)
Henry’s Law
How is dissolved CO2 in the blood calculated?
By multiplying the PaCO2 by 0.067 mL/dL/mmHg (the solubility coefficient)
Henry’s Law
What is the formula for oxygen delivery?
DO2 = CO x [(1.34 x Hgb x SpO2) + (PaO2 x 0.003)] x 10
Identify the law:
The rate of transfer of a gas through a tissue medium is directly proportional to the partial pressure difference (driving force), diffusion coefficient (solubility), and membrane surface area. The rate of transfer is inversely proportional to the membrane thickness and molecular weight.
Fick’s Law
Identify the law application:
Diffusion hypoxia
Fick’s Law
Identify the law application:
A patient with severe COPD has reduced alveolar surface area and therefore has a slower rate of inhalation induction
Fick’s Law
Identify the law application:
Calculation of cardiac output
Fick’s Law
Identify the law application:
Drug transfer across the placenta
Fick’s Law
Identify the law:
The molecular weight of a gas determines how fast it can diffuse through a membrane.
The rate of diffusion of a gas is inversely proportional to the square root of the gas’s molecular weight.
Smaller molecules diffuse through a membrane faster than larger molecules
Graham’s Law
Identify the law application:
Second gas effect
Graham’s Law
Identify the law application:
Pneumatic bellows used for positive pressure ventilation
Boyle’s Law
Identify the law application:
Diaphragm contraction increases tidal volume
Boyle’s Law
Identify the law application:
LMA cuff ruptures when placed in than autoclave
Charles’s Law