Cardiopulmonary FINAL REVIEW

Surface Tension

- Force exerted by like molecules at a liquids surface - The importance of surface tension to any healthcare worker is in cleaning and disinfection. Washing hands with soap and water is a good effective tool to decrease the surface tension of contaminants on the hands. - To the respiratory therapist an increase in surface tension within the alveoli means collapse and atelectasis! A substance called surfactant is normally produced in the lung to help decrease surface tension and open alveoli and may be administered to newborn infants who are born premature with a deficiency in naturally occurring surfactant (helps open the alveoli up / this would be decreasing surface tension). - increasing surface tension would be the alveoli closing

Radiation

- Heat transfer from radiation occurs without direct contact between two substances Sunlight is a form of radiation that is radiated through space to our planet without the aid of fluids or solids. The energy travels through nothingness. The sun heats trillions of miles of space. Conduction is not responsible because there are no solids in space like a spoon touching the planet from space, so it is not conduction. It is not convection, because there are no fluids like air or water is space. EX: baby warner when the baby is first born - radiant heat is transferred to the baby from the lights

Liquid water can easily turn into its gaseous or vapor form. Water vapor content of a gas is important for comfort and airway health. What 3 factors affect the amount and rate of vaporization of water?

1. Temp. 2. Pressure 3. Humidity level in air

Oxygen Concentrators demonstrate which of the gas laws we learned about in this Chapter?

Graham's Law

Temperature Scales

Kelvin Scale Celsius Scale Fahrenheit Scale

nebulizer

generates and disperses particles into the gas stream

Breathing circuits condensate must always be treated as

infectious materials

App. of Poiseulli's Law

- COPD pts with air trapping - pts intubated with too small of a ETT - Bronchodilator Therapy - Heliox Therapy COPD patients experience air-trapping when they exhale due to "floppy" airways. (Over compliant airways). Pursed lipped breathing produces a more laminar flow to help keep airways open longer for more exhalation. Most of the turbulent air-flow is through the mouth and upper airway. As we progress down the airway air flow becomes more laminar in the smaller airways. If the size of an ETT is too small the driving pressure to deliver a mechanical breath through a ventilator increases a patient's WOB. Also the flow greatly decreases which also may contribute to a patient's increase WOB Bronchodilator Therapy causes an increase in the radius of the airway which decreases airway resistance, pressure, and increases a more laminar flow through the lung. Helium is a less dense gas than oxygen and therefore produces a more laminar flow through the airways. In cases of severe airway constriction like we would see in severe asthma, Oxygen combined with Helium will flow in a straighter more laminar flow through constricted airways.

Why should a resp. therapist care about heat transfer?

- Conduction heating takes place in servo controlled heaters in Mechanical Ventilation and heaters for LTA - Convection heating occurs in infant incubators - Radiation heating occurs in infant warmers Evaporation/Condensation occurs is MV circuits, LTA circuits with drain bags to catch condensation in the tubing and in Passover Humidifiers. too cold = secretions and can be hard to remove too hot = potential burns

Your text identifies 6 important problems associated with bland aerosol therapy. For each of these problems, give a possible solution or means of prevention.

- Cross contamination / infection = Guidelines on covering solutions, equipment processing, water should be changed regularly, couplant compartments and nebulizer chambers of USNs disinfected/replaced regularly - Environmental safety = Strictly following the standards and air precautions, also dealing with environmental control of drug aerosols. PPE / Masks - Inadequate mist = Jet nebulizer - unit repair or replacement ... USN - you need to check for carrier gas flowing through device and the amplitude, or output, control is set above min. if still no visible mist output you look at couplant chamber. - Overhydration = Careful patient selection and monitoring can prevent most potential problems with overhydration. Small infants/elderly = high risk ... will hear crackles - Bronchospasm = PT history and diagnosis need to be reviewed ... they need to be continually checked on and reevaluated every 8 hours is this occurs during therapy you would immediately stop the treatment, give O2, and appropriate bronchodilator therapy (albuterol) imitated ASAP. - Noise = Sound should remain below 58 dB to avoid hearing loss ... careful selection of equipment ... best solution is to use heated pass-over humidification instead of nebulization.

O2 Hemoglobin Dissociation Curve

- O2 will either leave hemoglobin easily or stay in the hemoglobin - RIGHT SHIFT ... this can happen when (O2 is unloading quickly to tissue) C - O2 A - cidosis D - PG (chem. in blood that helps O2 leave blood to go to tissue easily) E - xercise T - emperature - this supplies in increase in CO2 which can decrease rate if breathing ... when exercising or running a temp. - LEFT SHIFT ... this can happen when (O2 is NOT unloading from the blood) - this helps if someone falls in frozen water and their temp. decrease then they can be resuscitated later from the O2 being stored in the hemoglobin instead of being unloaded immediately

Why should we care for temp. scale?

- Patient's temperature direct us toward different therapies. Do we need to warm the gases we deliver to give more water vapor to the patient to humidity deficit? Do we need a cool aerosol to reduce inflammation? Increasing the temps of gases and using unfamiliar temperature scales increases the risk of too much heat being delivered to the airway and increases the risk of airway burns and too little temperature to an airway can increase the risk of thick retained secretions and mucus plugging. Ex 1: Hypothermia = prolonged exposure to the cold. The Hypothalamus response is to make the body shiver to generate more heat and vasoconstriction to conserve more heat. Because hypothermia reduces O2 consumption and CO2 production, these patients often present with slow, shallow RR and HR. So in Mechanical Ventilation, adjustments may need to be made to RR and Vt during the period of hypothermia. Cold water drownings have been successfully resuscitated in recent years because of this knowledge. Hypothermia can also interfere with the results of a pulse oximeter if circulation is slowed. Ex 2: Hyperthermia (fever) increases the body's O2 consumption and CO2 production. The body has to increase RR and Vt to match the body's increased metabolism to maintain homeostasis and if that cannot be maintained then respiratory failure happens. Capillary Blood gases and Transcutaneous Blood Gas monitoring are only meaningful if the site of the capillary gas is warmed to 42 degrees which dilates the capillaries to resemble arterial blood in infants. you have to warm the heel to get the blood to flow Respiratory equipment like PFTs and ATPS values and convert them to BTPS to compute lung volumes and flows accurately. - Pulmonary Function Testing (PFTs) - You would be collecting ambient temperature air and the machine changes it to body temperature

Factors Affecting Evaporation

- Temp. - Pressure - Surface Area Temperature is the single most influential factor for evaporation. The warmer the air, the more water vapor it can hold and the faster the rate of evaporation Pressure: where high temperatures increase vaporization, high pressures reduce vaporization. On the other hand low pressures increase vaporization Surface area: the greater the surface area the greater the rate of evaporization. Which humidifier will evaporate quicker the Passover CPAP humidifier or the O2 bubble humidifier?

Why should we care about Viscosity

- The viscosity of fluids is how we determine how to deliver liquids whether it be by medication or bland aerosols. That is how we deliver water vapor by humidity or sterile water by bland aerosol. We may not deliver some medications together in a nebulizer because of the thickness of the different fluids. Antibiotic medication may need to be delivered at higher flow than just bronchodilators. - COPD patients are at higher risk for POLYCYTHEMIA a condition where the red blood cells count is elevated. Polycythemia is a condition where the bone marrow produces an increased # of RBC in response to chronically low blood O2 levels. If this condition exists then patients are at higher risk for clot formation and stroke. Also the heart must use more energy when blood viscosity increases as in Polycythemia. - Pulmonary Emboli for lungs

Viscosity

- Viscosity : the force opposing a fluids flow - Laminar Flow - Shear Rate A fluid's viscosity is directly proportional to the cohesive forces between its molecules. The stronger the cohesive forces , the greater the fluid's viscosity. The greater the viscosity of a liquid the thicker the liquid. Laminar Flow is the pattern by which fluid moves in parallel lines with cohesion developing between the layers Shear rate is the measure of how easily the layers are broken apart.

App. of Henry's Law

- adjustment of O2 levels to augment a feverish or hypothermic pt - correcting ABG values in hyperthermic or hypothermic pt In respiration, CO2 is approx. 20 times more soluble than O2 in the blood. Therefore, O2 is more readily released to the tissues and CO2 binds with the blood to be exhaled out into the air. In conditions like high fever, patient's exhibit less solubility of oxygen and therefore, less healing, and less usable O2 for healing. Conversely patients with very low body temperatures may exhibit more O2 solubility in the blood, but because of the very low body temp, O2 may not metabolize, but stay dissolved in the blood. For optimal metabolism Temperature must be normal 37 degrees Celsius.

Inhalation

- ambient air enters nose - warms to 28.5 C (conviction) - picks up water vapor from moist mucosal lining (evaporation) - cooling mucosal surface to 30.2 C at end

Change of state

- evaporation / vapor and pressure / humidity (what is the diff?) 1. water vapor vs aerosol 2. vapor pressure 3. humidity Water is a good example of evaporation. It rains and fills up a pond, the radiant heat from the sun dries up the pond and saturates the surrounding air. Which in turn creates rain and fills up the pond again. After water is converted to vapor, it acts like any other gas and exerts a pressure. This invisible gas form of water is called water vapor. Whereas the visible particulate water is called an aerosol, or fog Vapor pressures are significant because we use a calculation to determine the Alveolar Oxygen: PAO2 = FiO2 x (Pb -47) - (PACO@ / 0.8) Once oxygen is in the lungs, it is diluted by both water vapor and carbon dioxide. To account for all these factors, the Alveolar Air Equation is used to look at the oxygen at the alveolar level. For example, air that is fully saturated with water vapor at 37 degrees C and 760 mm Hg has a water vapor pressure of 47 mm Hg and an absolute humidity of 44 mg/L. Humidity is water in molecular form. It is also described as the amount of water vapor in the air. Absolute Humidity is actual content (weight) of water in a gas. Expressed as mg/L Relative Humidity is the ratio of water vapor present to its capacity to hold water at a certain temperature. Expressed as a percent. RH is measured by a hygrometer. 100% RH is a fully saturated gas.

Exhalation

- expired gas - transfer heat back to cooler tracheal and nasal mucosa (32.2 C at end) - as saturated gas cools = less water vapor - condensation on mucosal surfaces during exhalation ... water reabsorbed by mucus (rehydration - in cold environments condensate may exceed ability of mucus to reabsorb water = runny nose

Evaporation / Condensation

- is heat taken from the air surrounding a liquid thereby cooling the air. In strenuous exercise, the body produces sweat. The sweat evaporates and so it cools the skin. - Condensation is the opposite of evaporation. A gas turns back into a liquid (cooling) and heat is lost into the surrounding air. - EX: Tubing ... flow of gas coming from device going through condenser then pushed through the circuits which can cause evaporation through person breathing in condensed air ... for this you would use a drain bag

Capillary Action

- is the action of a liquid moving up in a small tube against gravity - EX ... cap. heel stick in infants sterile packing in wounds

Conduction

- is the heat transfer through matter from one particle to another particle. It is the transfer and distribution of heat from atom to atom within a substance. - Ex: a metal spoon in a coffee cup becomes warmer because heat from the coffee is conducted along the spoon. Conduction is most effective in solids, but happens in liquids. - EX: Large Volume Nebulizer - water is drawn up then heated then supplied to the pt

Conviction

- is the transfer of heat by the actual movement of warmed matter. Heat leaves the cup as the currents of steam and air rise. Convection is the transfer of heat energy in a gas or liquid by the movement of currents (it may also happen in solids like sand) The heat moves with the fluid. Ex: Boiling pot of water for pasta. The warmer portions of the water are less dense and therefore, rise. Meanwhile, the cooler portions of the water fall because they are denser. EX: incubator - this is air being pushed into a box so the baby is warmed

Graham's Law of Gaseous Diffusion

- states that the rate of diffusion of a gas is proportional to the square root of its molecular weight - SIMPLY ... molecules move form areas of high concentration to that of lower concentration - according to this principle ... lighter gases will diffuse more rapidly than heavier gases

Dalton's Law

- states the total pressure of a gas mix must equal the sum of the partial pressures for each gas - Room Air 1. N2 = 78% 2. O2 = 21% 3. Other = 1% 760 mmHg or 760 torr N2 = 0.78 x 760 = 592.8 593 mmHg O2 = 0.21 x 760 = 160 mmHg Other = 0.01 x 760 = 7.6 mmHg These added all together = 760

Henry's Law

- the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid - EXAMPLE... a can of carbonated soda. Before the can is opened the gas above the drink is almost pure carbon dioxide at a pressure slightly higher than atmospheric pressure. The drink itself contains dissolved carbon dioxide. When the can is opened, some of the gas escapes giving the characteristic "popping" sound. Now because the partial pressure of carbon dioxide is lower above the liquid, some of the carbon dioxide comes out of the soda as bubbles. If the can of soda is left out in the open, the concentration of carbon dioxide will equilibrate with the room air and the soda is left "flat".

bland aerosol therapy wither sterile water is often used to treat

- upper airway edema - overcome humidity deficit in pt with tracheal airway - help obtain sputum specimens

What factors determine how long till each heat transfer is empty?

1. Temperature - most important 2. Surface area 3. Contact time - Bubbler would have more of this then a Passover

4 Consequences of prolonged inspiration of improperly conditioned gases

1. atelectasis (a complete or partial collapse of the entire lung or area (lobe) of the lung) 2. dry, non-reproductive cough 3. increased airway resistance 4. increased work of breathing

4 factors shift isothermic saturations boundary distally

1. breathing through mouth instead of nose 2. breathing cold dry air 3. upper airway bypassed (artificial tracheal airways) 4. when minute vent. higher than normal

Heat Transfer Occurs 4 Diff. Ways

1. conduction 2. conviction 3. radiation 4. evaporation / condensation

2 indications for humidification

1. dry medical gases 2. overcoming humidity deficit created when UPPER AIRWAY BYPASSED

2 primary problems with tents and body enclosures

1. heat retention 2. CO2 buildup FIRES

Types of heat and moisture exchangers (HMEs)

1. simpler condenser 2. hygroscopic condenser humidifier 3. hydrophobic condenser humidifier

4 variables affect performance of humidifier

1. temp. 2. surface area 3. time if contact 4. thermal mass MOST IMPORTANT - temp.

According to Graham's Law of Diffusion, carbon dioxide is about _______ times higher than that of O2. For this reason hypoxia is ________________ to treat than hypercapnia in presence of airway obstruction.

20 more difficult

gases delivered to trachea should be warmed to

32 C - 35C

Liter flow exceeding what value require humidification?

4 L/min

Hygroscopic condenser humidifier

A low thermal conductivity element is impregnated with hygroscopic salt (calcium or lithium chloride). The salt plus the element capture heat and moisture. During inspiration, the moisture is returned to the gas without cooling. - By using element with low thermal conductivity more heat is retained (this is from the salt - it captures more moisture from expiration. Lower water vapor in inspired gas liberates water molecules directly from hygroscopic salt without cooling. 70% efficiency

LVN jet neb. also controls FiO2, how?

A variable air-entrainment port allows air mixing to increase flow rate and to alter FiO2 levels.

3 risk for heated humidifier

A. airway burns - burns to both patient and caregiver B. hypothermia / hyperthermia C. electrical shock - fire hazards

5 contraindications using HMEs (according to AARC)

A. copious, thick, or bloody secretions B. expired tidal volumes less than 70% of inspired volume C. body temp. below 32 C - hypothermia D. minute volume greater than 10 L/min E. during in line aerosol medication treatments

3 hazards with water that "rain out" ... condenses in humidified breathing circuits

A. increased WOB or vent airway B. aerosolization contaminated condensate during disconnection C. inadvertent tracheal lavage from condensate - water going to the patient (either inhaling of it going on them)

3 primary advantages to passover humidifier over bubble...

A. maintains heat and saturation at higher flow rates B. they add little to no flow resistance to spontaneous breathing circuits C. they do not generate any aerosols and pose minimal risk for spreading infection

7 indications given in the AARC Clinical Practice Guidelines for bland aerosol administration

A. presence of upper airway edema (cool, bland aerosol) - sterile, hypotonic, or hypertonic solution -for fire can use a tent or aerosol mask - FiO2 100% B. bypassed upper airway C. need for sputum specimens - hypertonic saline (3% - 7%) - USN, SVN, LVN (isotonic) D. LTB (croup) - inflammation of the upper airway ... cool aerosol ... face tent/HFNC E. postextubation edema - you would hear stridor ... cool aerosol (aerosol mask/tent) F. postoperative management of upper airway G. subglottic edema

5 factors influence amount of condensation in breathin circuit

A. temp. difference across the system (humidifier to airway) B. ambient temp. C. gas flow D. set airway temp. E. the length, diameter, and thermal mass of the breathing circuit

control determines actual amount of aerosol produced

Amplitude control

Why should we care about Bernoulli Law

An RT should be concerned about the Bernoulli Effect because it influences Fluid Entrainment The most common application of fluid entrainment is the air injector. An air injector is a device used to increase the total flow in a gas stream. Venturi Tubes give greater air entrainment than a simple air injector. They give a constant FiO2 even when Total Flow varies. For this reason it is often used for COPD patients in distress, so we may know precisely how much FiO2 the patient is receiving even when they are distressed and increasing their total flow demands due to increasing WOB One drawback to the Venturi however, is when there is any buildup of pressure downstream from the entrainment port and will decrease gas entrainment. Ex: In an aerosol whose tubing is occluded by water........ The FiO2 raises in the tubing and the patient receives higher than prescribed O2.

Large Volume Nebulizers demonstrate which of the gas laws we have learned about so far?

Bernoulli Law

Boyle's Law

Boyle's law states that the volume in a gas varies indirectly with it pressure simply put ... the more pressure exerted on the lung, the smaller the volumes in the lung

A registered respiratory therapist is performing lung testing on a patient. The patient inhales 1.5 liters from the spirometer. What will happen to the volume of gas inside the patient's lungs? What is the name of the gas law that this addresses?

Charles' Law, the vol. of gas will expand

An oxygen cylinder left in the trunk of a hot car in August will most likely show an increase in pressure within the tank. What is the name of the gas law that this demonstrates?

Gay-Lussac Law

Asthma and the narrowing of the airways due to muscle constriction around the airway and inflammation demonstrate which physical principle of Respiratory Therapy?

Poiseulli's Law

When you start to inhale, your diaphragm drops, and your chest expands. In other words, you increase the size or volume of your chest. What happens to the pressure inside your chest and name the gas law this supports?

Pressure in your chest will decrease

What happens to the temperature when liquid oxygen is converted into gaseous oxygen?

Rapid cooling, drop in temp.

Overcoming resistance from alveolar collapse due to atelectasis demonstrate which physical principle of Respiratory Therapy?

Surface Tension

What is the most significant factor affecting airway resistance?

The diameter of he airway

preset variable determines the size of the aerosol particles generated by a USN

The frequency at which the crystal vibrates (set by manufacturer) determines the size of the aerosol particles; it will be proportional to the signal frequency.

isothermic saturation boundary (ISB)

The point at which inspired gas is fully saturated at body temperature (44 mg/L at 37° C), approximately 5 cm below the carina at the level of the third-generation airways. (decreases during inhalation and increases during exhalation)

14. What safety device is incorporated into the design of a bubble humidifier?

The simple pressure-relief valve or "pop off" ... you will hear a whistle or a pop off sound - this is to prevent bursting of the humidifier bottle.

Active HME

They add humidity, heat, or both to inspired gas by chemical or electrical means. It's based on the hygroscopic HME (absorbs expired heat/moisture releases in inspired gas)

Explain why visible moisture, a mist, comes out when you exhale on a cold day?

Water vapor condenses when the hot exhaled air meets cold room air.

Without humidity, our airways get irritated and mucus gets thick and difficult to expectorate. The actual amount, or weight of water vapor in a gas is called ______________.

absolute humidity

hygrometer

an instrument for measuring the humidity of a specific air or a gas without extracting moisture ... measure temp. and RH

Simple Condenser

contains a condenser element with high thermal conductivity; latter consists of metallic gauze, corrugated metal, or parallel metal tubes. Inspired air cools the condenser element, and expired water vapor condenses directly on the surface and rewarms it. Next inspiration, cool dry air is warmed and humidified as it passes over the condenser element. They can recapture only some 50% of a PT exhaled moisture.

Large volume jet nebulizers are often used to provide moisture to the airway of patients with tracheostomy tubes. When would you use this on a patient who is not intubated?

croup, postextubation edema, after tracheal surgery

2nd Law of Thermodynamics

deals with the natural direction of energy processes. For example, according to this law, heat will flow only from a hotter object to a colder object.

Oxygen normally exists as a gas at sea level. What has to happen to turn gaseous oxygen into liquid oxygen for medical use?

decreases in temp. and increases in pressure (and a storage system)

humidifier

device that adds invisible molecular water to a gas

App. of Graham's Law

diffusion of O2 and CO2 across the AC membrane home O2 concentration work off this principle with molecular sieves

App. of Boyle's Law

for pts with restrictive lung disease the greater the pressure on the lungs the less volume the lungs will hold So patient's with RLD (restrictive lung disease) will show smaller tidal volumes and faster respiratory rates. Also with MV, the way we adjust the ventilators will depend on whether the patient's have low compliant lungs or high compliant lungs - Ex: RLD Vt on MV is 6-8 ml/kg/IBW - COPD Vt on MV is 8-10 ml/kg/IBW Normal MV = 5 - 8 mL Normal RR (f) = 12 - 20 Normal Lungs - Wt = 60 - kg Vt = 8 mL x 60 kg - = 480 mL - MV = 480 mL x 12 = 5760 mL ... 5.8 L

App. of Gay Lussac's Law

gas cylinders have safety relief valves on the stems or yokes of the cylinder to prevent explosion of the cylinder under conditions of high heat or fire pressure within circuits and tubing will increase with the heating systems we use to increase humidity (tubing can be expanded from the heat)

App. of Charles' Law

gas cylinders left in the trunk of a car may explode due to the increase of volume within the tank

What specialized breathing circuit usually circumvents the condensation problem?

heated wire circuits - less chance of "rain out"

App of Laplace's Law

in conditions of atelectasis, volume will go toward the larger alveolus rather than the smaller one Smaller alveoli have greater deflating pressures than a larger alveolus and so deflates more readily Also, the smaller alveolus has a greater surface tension so the air will naturally go to the larger alveolus first which is easier to inflate with less surface tension

Kelvin

is an internationally known metric scale used in almost every country other than the US. It was developed in the 1960's and is used mostly in research and scientific methodology. Zero degrees Kelvin is as close to absolute zero as possible. (The degree at which no kinetic energy is detectable for molecules) The freezing point of water is 273 degrees Kelvin.

Celsius

is one of the most common measurements of temperature in the hospital setting here in the US. Zero degrees Celsius is equal to the freezing point of water.

temperature

is the most important factor affecting humidifier output

Fahrenheit

is the other most coming measurement in the hospital setting ... 32 degrees F is the freezing point of water

Adiabatic Compression of a Gas

is where a gas's heat energy is allowed to rise of fall as it undergoes changes in pressure of volume application: why it is important to "crack" the cylinder? Adiabatic compression of gas can cause rapid increases in temperature when compressing a volume of gas within a tank. This rapid rise in temperature can ignite any combustible material in the system, so it is very important that RT's clear any dust, dirt, or debris from the cylinder yoke prior to pressurizing the tank.

Bubble humidifier added to which O2 system

low flow ... nasal cannula (1/4 - 6 L/min)

At high flows, some bubble humidifiers may produce ________________________, which can carry infectious bacteria.

micro aerosols

Conditioning of inspired gases is done primarily by the

nose

Range for AH delivered by humidifier... amount converted in terms of relative body humidity

output 15 - 20 mg/L RBH = 25%

provides power to operate LVN jet neb.

pneumatically powered from flowmeter or compressed gas

Poiseulli's Law

predicts pressure required to produce a given flow : - laminar flow ... HELIOX (severe airway obstruction) ... listening to BS (if they are breathing through their nose then it is laminar and harder to hear) ... COPD (highly complaint - lungs stretching out - problem is when they are breathing out their airway becomes flopped closed which makes it harder for the lungs to release the air which results in the lungs to collapse down ... releasing trapped air is by breathing through "pursed lips" to have a long, laminar breaths which gives them more time to release air so the lungs to not flop) - turbulent flow ... HFNC (high flow gets more O2 and flow to the lungs and also keeps the airway open longer) transitional flow Laminar Flow is also called streamline flow where fluid flows in parallel layers with no disruptions between layers. At low velocity the fluid flows without lateral mixing and adjacent layers slide past each other like playing cards. (No cross currents) The flow is orderly with all particles moving in the same direction Turbulent flow occurs at higher velocity where chaotic channels lead to lateral mixing of the layers Transitional flow is the mixture of laminar and turbulent flows. An example is an airplane with laminar flow over the wing ending with a turbulent flow at the end of the wing

Joule Thompson Effect

primary method for liquefying O2 : 1. gas as rapidly heated gas expands and cools the energy needed to expand the gas decreases and temp. drops 2. this temp. drop also creates a pressure drop which if large enough will actually liquefy the gas The phenonomen of expansion cooling of a gas is called The Joule Thompson Effect. Under Boyle's Law gases under constant temperature, the volume of a gas varies inversely with its pressure. Under ideal conditions the temperature of a gas should not change with either expansion or contraction of a gas. However, there is something called the Joule Thompson Effect that explains why we are able to change O2 gas from a gas into a liquid.

ALWAYS provide humidification

pts with artificial airways ... endotracheal tubes

As Respiratory Therapists, we compare the weight of water vapor to the amounts it could hold if the gas were fully saturated. This ratio of content to capacity is known as _________________.

relative humidity

Bernoulli Law

simply ... where there is moving air, there is low pressure Bernoulli Effect is when a fluid moves through a tube of uniform diameter, the pressure decreases progressively over the length of the tube. Therefore when a flowing fluid encounters a very narrow passage, its velocity will increase. Aerosol tubing test: The end of the tube is moving in air (Remember moving air, decreasing pressure) Spin the tubing in the air creates a condition where higher pressure wants to move toward low pressure Turbulent air flow through the aerosol tubing creating a whistling sound.

American Standard Safety System (ASSS)

specifications adopted in the US and Canada for threaded high-pressure connections between compressed gas cylinders and their attachments

Charles' Law

states that at constant pressure the volume of a gas will vary directly with temp. simply put ... as temp. rises, so does volume pf a gas and as temp. decreases so will the volume of a gas My car has a sensor in it that tells me when a tire has low pressure. When the seasons change and the weather gets colder, my sensor alerts me when my tires need inflating back to its manufacturer suggested pressure for optimal gas mileage. RESP. THERAPY CARE ... O2 tanks ... if traveling and hot outside then you would keep the cylinder in the car instead of the trunk to prevent it from overheating and result in the cylinder of activation of the pressure relief valve or explode

1st Law of Thermodynamics

states that energy can neither be created nor destroyed. So, any energy a substance gains must equal the energy loss by its surroundings.

Laplace's Law

states that pressure caries directly with the surface tension of the liquid and inversely with its radius simply ... pressure will go toward the path of least resistance

Gay Lussac's Law

states that the pressure of a gas varies directly with changes in the temp.

Inspissated

thickening and dry, owing to dehydration - happens when airway is exposed to cold dry air, ciliary motility is reduced, airway becomes more irritable, mucus production increases, and then pulmonary secretions will become inspissated

Hydrophobic condenser humidifier

use a water-repellent element with a large surface area and low thermal conductivity. During exhalation the condenser temp. increases to ~25C from conduction and latent heat of condensation. On inspiration cool gas and evaporation reduce the condenser down to 10C. this large temp change results in the conservation of more water to be used in humidifying next breath. 70% efficiency - some provide bacterial filtration (reduce pneumonia) unsuitable with limited resp. reserve or those prone to airway blockage/increase artificial airway occlusions

App. of Dalton's Law

why do we need O2 masks if an airplane depressurizes while in flight at 300,00 ft (226 torr) - PiO2 = 0.21 x 226 torr = 47 torr - REMEMBER ... normal value should be 160 torr

The AARC recommends what range of alarm settings for electronically controlled heated humidifiers?

· AARC recommends 33 C, within 2 C, with a min. of 30 mg/L of water vapor · Low setting 30 C and no higher than 35 C

BTPS conditions

•Body temperature at 37º C; barometric pressure; saturated with water vapor [100% relative humidity at 37º C]