RCP 100 Ch 6: Gas Laws

• Physics helps understanding respiratory care equipment

States of Matter

• Three primary states of matter are solids, liquids, and gases.
• Examples of states of matter are air, water, and food, with water being common among all.
• Water can exist as gas when heated, liquid in a cup, or solid when frozen while the particles remain unchanged.

Solids

• Solids maintain their shape due to strong mutual attractive forces, known as van der Waals force.
• Solids have a high degree of internal order.
• Solids have fixed volume and shape.
• Solids exhibit a strong mutual attractive force between atoms.
• In solids, molecules have very little distance to travel before collision, and this motion is referred to as a "jiggle".

Liquids

• Liquids can move more freely and take the shape of a container, and they can flow.
• Liquids are similar to solids where they are dense and cannot be compressed easily.
• Liquids have a fixed volume, but adapt to the shape of their container.
• Atoms in liquids exhibit less mutual attraction compared to solids, but they determine shape through internal and external forces.

Gases

• Molecular attractive forces in gases are weak, allowing them to move freely and rapidly, without boundaries.
• Gases can be compressed or expanded and have flow.
• Gases don't have a fixed volume or shape; they have weak attractive forces.
• Gas molecules move randomly and rapidly, colliding frequently.

Impact of Heat

• Gases have a weaker bond and can move around more freely.
• Applying heat to a gas molecule causes expansion, similar to breathing, where warm mucus membranes heat the gas inhaled, leading to the volume breathed in increasing.
• Charles Law involves a constant pressure (barometric pressure), and when the gas is inhaled, the temperature increases, the volume is increasing.

Internal Energy of Matter

• All matter produces energy, with potential and kinetic being key.
• Kinetic energy refers to movement or motion.
• The body uses energy all day, used for everything from movement to cellular functions, muscles for breathing, and cardiac muscles.
• Stretching and releasing a rubber band relates to how lungs expand and snap back during breathing, and how the heart's contractility force relies on a greater stretch.

Internal Energy Types

• Atoms in all matter are in constant motion at normal temperature.
• This motion constitutes internal energy.
• Potential energy is the energy of position, involving attractive forces between molecules.
• Potential Energy is weak in gas states and makes up most of internal energy in solids and liquids.
• Kinetic energy is the energy of motion.
• Kinetic energy makes up most of gases' internal energy.

Laws of Thermodynamics

• Thermodynamics refers to the study of properties of matter at various temperatures.
• Thermodynamics refers to the kinetics (speed) of reactions of matter at various temperatures.

Heat Transfer

• Heat transfer happens when two objects of different temperatures are close together, heat moves from hotter to cooler until both are equal.
• Heat transfer can occur in four ways: conduction, convection, radiation, and evaporation/condensation.

Conduction

• Heat transfers through direct contact (transferring heat through matter.
• How well heat transfers depends on the number and force of the collisions of the molecule
• Best with solids
• Metals feel cold due to their higher thermal conductivity, enabling them to absorb heat quickly from the skin.

Convection

• Convection occurs via the mixing of fluid molecules at varying temperatures, heat is transferred through gas or liquid by the movement of hotter material into a cooler zone.
• Convection requires direct contact.
• Convection happens mainly in liquids and gases.
• Forced air heating applies this principle.

Radiation

• Radiation occurs without direct contact between objects
• Example: the sun warming the earth, or electrical stove burner
• Radiant heat energy keeps newborns warm because they lose body heat quickly due to the brown fat cells absence

Evaporation and Condensation

• Vaporization involves a change of state from liquid to gas.
• Evaporation is a vaporization form where heat taken from liquid's surrounding air cools.
• Exercising involves evaporation to cool the skin.
• Condensation is the opposite of evaporation, where gas becomes a liquid.
• Effective ventilation involves a balance between evaporation and condensation to make sure that the airway mucosa does not get dried out and irritated.
• Isothermic saturation boundary causes gas heats in the airway causing condensation and is rebreathed to maintain airway moisture..

Condenser Humidifier

• Hydroscopic condenser humidifier exemplifies condensation and evaporation.
• It functions as an artificial nose.
• Water-absorbent material enclosed absorbs heat and moisture from exhaled gas during exhalation, saving it for next inspiration.
• Upon inspiration, the humidifier adds captured heat and moisture to inhaled gas, decreasing heat and moisture concentration.

Temperature

• Temperature is the amount of heat or thermal energy in a system
• Can be measured in Fahrenheit (°F), Celsius (°C), or Kelvin (K).
• Kelvin Scales are used in Charles Law

Temperature Scales

• Celsius to Fahrenheit Formula: F = 32 + (C * 1.8), OR use F = (9/5 x C) + 32.
• Fahrenheit to Celsius Formula: C = (F - 32) / 1.8, OR use C = 5/9 x (F - 32).
• Convert Celsius to Kelvin Formula: K = C + 273
• Convert Kelvin to Celsius Formula: C = K - 273

Change of State

• When a solid is heated, its molecular kinetic energy increases.
• This increase in the internal energy increases molecular vibrations.
• If heat is applied the vibration weaken internal forces
• If molecules break free from the rigid state, the solid changes into a liquid.
• Liquid-solid phase changes consist of melting (changeover from a solid to liquid state) and freezing

Freezing

• Freezing is the opposite of melting.
• Freezing requires externally applied energy.
• Energy required for freezing is the same energy required to melt it.

Sublimation

• Sublimation is the transition from solid to vapor without becoming liquid in an intermediary form
• Sublimation occurs because vapor pressure is low (e.g., dry ice).

Properties of Liquids

• Liquids take form of and exert pressure varying with depth and density.
• Variations in liquid pressure creates buoyancy
• Archimedes' principle explains how objects float.
• The principle of buoyancy is used in respiratory care to keep the solid particles from being suspended in gases during aerosol treatments.
• A hydrometer is used to measure the specific gravity of liquids in healthcare.

Pressure

• Pressure depends on height and weight density.
• Pascal's principle states that a confined liquid transmits pressure equally.

Buoyancy

• Buoyancy occurs because pressure below submerged object surpasses pressure above it.
• Specific gravity is a ratio of a fluids density when being compared to the fluid density to the reference (water)

Viscosity

• Viscosity is a force opposing fluid's flow.
• Blood has a viscosity five times greater than water.
• Viscosity relates to the internal friction of fluid and occurs regardless of density.
• Blood has a higher viscosity of five, for the blood being able to travel at its rate there take more energy
• Higher temperatures weakens forces between molecules
• Higher temp = lower viscosity

Cohesion

• The meniscus is a Concave pattern that demonstrates when water is being measured,
• Adhesive forces are attractive forces between two different kinds of molecules.
• Cohesive forces are attractive forces between two similar molecules

Water Vs. Mercury

• Water beaker demonstrates the meniscus in is a concave pattern, adhesion forces have to greater than cohesion
• Mercury in the beaker is stronger and its meniscus is convex

Surface Tension

• Surface tension is a force exerted by like molecules at the surface of a liquid.
• inward forces impact molecules on the surface.
• This imbalance causes the surface area film to contract into the curvature shape (meniscus)
• Water on the surface is why we get droplets

Law of Laplace

• Laplaces's law state that pressure varies directly with surface tension
• High surface tension creates higher pressures that help to keep airways open.
• High surface tension can collapse the alveoli, such as in ARDS because the body cannot deliver enough surfactant
• Surfactant may be given to newborns to open open airways with normal pressures.

Capillary Action

• Capillary action is a phenomenon where liquid moves upwards in a small tube against gravity with adhesive and surface tension forces.
• It enables blood samples in capillary tubes, gas humidifiers, and surgical dressings.
• Surface tension maintains smallest possible liquid gas point whole and the strength is dependent on the liquid amount
• Concave meniscus and a larger area enables more liquid intake for small tube action

Liquid- Vaporization Change

• There are two Vaporization Types
• Boiling
• Evaporation
• Boiling is where temperature is at boiling point with vapor exceeding atmospheric point and liquid molecules have kinetic energy to get in atmosphere
• High ambient pressure impacts the water molecules' pressure
• Gas cannot easily leave with atmospheric

Water Vapor Pressure

• When using pressure cooker it creates the increased pressure
• PaCO2 and PH₂O create °37
• C
• 47mmHG
• Alveolar Air Equation determines whether a patient oxygen making it a vs it to be

Humidity

• Absolute humidity (AH) is the measure content of water vapor and its A.K.A water content
• Humidity is dependent on the weather elements

Relative Humidity

• Relative Humidity is when a gas is expressed to have a percent of capacity and the vapor will cause that
• RH (Content (AH) / Saturated capacity) x 100

Properties of Gases

• Gas molecules travel at very high velocities, colliding often, as stated by kinetic theory.
• Velocity goes with Temperature
• Cooling the gas results is the kinetic energy decreases and pressure decreases
• One gram atomic of a substance will count 6.023 = 1 mole

Density

• The relationship of the molecule and the particle close together
• Oxygen can move easier if the is a helim mix with the oxygen, because there is an airway obstruction
• To deliver it you MUST mix with the gases

Diffusion in Lungs

• Diffusion is the movement of HIGH molecules to LOW
• O2 in alveoli to bloods
• This works if the lungs are typically healthy

Gas Pressure

• Exerted by gas whether in or blood tension is when measuring liquid and oxygen can be found dissolved or attached
• Molecule with solid for gas
• PSI (pounds per square inch)
• mm Hg (millimeters of mercury)
• READ torr
• Pressure decrease with high altitude
• cmH2O (centimeters of water pressure)
• kPa (kilopascals)

Gas Laws (Boyle's Law)

• Boyle's Law: pressure decreases, volume increases and is at a constant temperature.
• Cuff pressure will lose at high altitude
• Boyle also explained the human breathing through our diaphragm decreasing our pressure to flow

Dalton's Law

• Dalton's law describes the relationship among partial pressures and the total pressure in a gas mix. 21 %

• 21% will then be exerted (if oxygen)

• Mix must be the same

• nitrogen, argon, water, and carbon

hyperbaric

• Hyperbaric pressure
• Pressuring above atmosphere at sea level and under water 66atm and 2280 mmHG

Solubility of Gases

• Gases has laws with (henry laws) by what the temperature
• Volume with gas dissolution that dissolves

Henry and graham law

• Solubity of gases in liquids, with an increase the solubility decreases with the warmer to molecules escaping pressure and partial pressuring the molecule faster

Critical Temp and pressure

• Every liquid has tempreture and the kinetic is more power so it cannot be in liquid form
• The pressure that is needed for them has a temperature such as 02 which at the point the liquid has been completely liquefied

Fluid Dynamics

• Study with fluids with fluid hydrodynamics that can gas and blood fluid
• Force for liquid and the resistance will stop flow inside
• greater means smaller more of a pressure drop

Fluid Flow

• Fluid can be
• laminar discrete cylnder moving in streams
• turbulent lost pressure irregular fluid molecules

Fluid dynamics Cont.

• Nasal passage will increase flow which
• When flow for tubes is increase

Fluid dynamics

• With an increase of fluid velocity
• The lower the speed faster

Entrainment

• Entrainment depends with entrain device
• volume higher mean fio2 lower