physics of oxygen therapy

Question 1

what is pressure ?

Answer 1

some force applied over some area.

gases or liquid particles collide to the surface creating a force which equals pressure

Question 2

barometric pressure

Answer 2

pressure that is at atmospheric level
is basically the weight of air above us
atm ussually is at 760mmHg

Question 3

conversion- 1 atm is equal to

Answer 3

760 mmHg
1034 cmH20
101.3 kpa
14.7 psi

Question 4

dalton’s law

Answer 4

In a mixed gas, each gas has a partial pressure it exerts
this partial pressure is equal to the pressure the gas would exert if it existed alone and occupied the same volume as the mixture.
the total pressure of the mix gas is equal to the sum of it’s partial pressure.

Question 5

why is the Partial pressure of oxygen lower in the alveoli ?

Answer 5

is lower due to a number of reasons

• water vapor ( creates its own partial pressure)
• incomplete pulmonary gas exchange
• addition of CO2 and removal of O2 from the alveoli
• when you give a person oxygen therapy you are increasing the partial pressure of 02 which increases tension in the alveoli.

Question 6

normal alveolar oxygen tension

Answer 6

is 100 mmHg

too little means collapse too much can damage elasticity of alveoli

Question 7

define volume

Answer 7

volume is the amount of space an object or substance occupies. usually measure in L for RTs

Question 8

kinetic energy q

Answer 8

energy created by motion

gas molecules are always in motion and therefore have kinetic energy

Question 9

factors that can increase evaporation

Answer 9

• large surface area ( spill of a liquid)
• kinetic energy ( creates heat)
• decrease in pressure above or around the liquid (think of a pot lid containing that liquid inside)

Question 10

factors that liquid needs to overcome in order to become a gas

Answer 10

The attraction of the molecules for each other

The pressure of the gas above the liquid

Question 11

critical temperature

Answer 11

The temperature at which a gas cannot be converted back to a liquid no matter how much pressure is exerted on it

Question 12

critical pressure

Answer 12

The pressure that must be applied to a substance at its critical temperature to maintain equilibrium between the liquid and gas phases
In other words, the pressure where evaporation and condensation occur at equal rates