RESP CARE PROCED 3111 SECTION 1

Gases move from ____ pressure to ____ pressure, based on the pressure gradient (delta P), and takes the path with the ____ amount of resistance

high to low; least

What causes gas pressure?

Molecules colliding with walls of their container and each other

Pascal's law states that pressure is:

Exerted equally in all directions of its container

According to the Kinetic Theory of Gases, what describes molecular movement?

Molecular collisions are elastic (don't transfer energy) and molecules are always randomly moving

Which principle describes how gas velocity affects lateral wall pressure?

Bernoulli's principle. as velocity of a gas increases, lateral wall pressure decreases

What determines whether gas flow is laminar or turbulent?

Reynold's number

A Reynold's number of over 2000 indicates that flow is:

Turbulent, erratic

What happens when gas velocity increases through a tube?

Lateral wall pressure decreases

What is the Venturi Principle primarily used for?

Increasing total air flow by entraining ambient air

What occurs when head pressure reaches 1.893x atmospheric pressure?

Flow becomes choked and can no longer increase

What does FiO2 represent?

Fraction of inspired oxygen

What measurement device uses a mercury column to measure atmospheric pressure?

Barometer

What measurement device consists of a hollow coiled metal tube with an elliptical cross section, and is commonly found on medical gas tanks?

Bourdon gauge

True or False: Velocity describes movement at ONE specific point, meanwhile Rate of Flow describes movement in an ENTIRE system

True

True or False: A smaller opening of a tube = smaller velocity

False

True or False: Velocity (rate of flow) depends on size of opening (resistance)

True

Pressure A is +3 and Pressure B is +7. What is the pressure gradient, and which way will the gradient travel?

4, toward Pressure A

Viscous shearing describes:

a high velocity jet injected into a quiescent (stationary) gas

Decreasing the radius of a tube increases velocity, thus ________ lateral wall pressure

decreasing

Refer to note's page on Venturi's principle. Describe why the FiO2 starts at 100% but is less than 100% after air is entrained into the tube.

The 100% FiO2 mixes with the ambient air (21% O2) after it is entrained and becomes a diluted mixture of air once it reaches the patient

Refer to note's page on Venturi's Principle cont. Describe why back pressure will result in an higher FiO2, even after air is entrained

Back pressure increases lateral wall pressure, causing less air entrainment. Thus, total flow is lower and FiO2 will be higher.

Nebulizers become choked at ____ psi driving Pressure

26

Ducted ejectors are similar to Venturi, except:

tube diameter does not change, and the purpose is to maintain high velocity