Humidity, Aerosal Therapy, Nebs, and Enclosures Flashcards

1
Q

Heat Moisture Exchange principles

A

primary function of the upper respiratory tract is to heat, filter, and humidify gas. Nose is better at conditioning gas than mouth

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2
Q

Gas arriving in the lungs at body temp has what percentage of relative humidity?

A

100%

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3
Q

Definition of humidity

A

water vapor in a gaseous state; exerts a partial pressure

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4
Q

Partial pressure exerted by what is dependent on what?

A

temperature and relative humidity

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5
Q

BTPS conditions

A

temp: 37 C/98.6 F; 44mg/L absolute humidity; 47 mmHg (partial pressure); 100% relative humidity

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6
Q

Definition of saturation

A

the max amount of humidity a gas can carry at a given temp; also its capicity

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7
Q

If you allow a gas to cool you get what?

A

rainout or condensation

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8
Q

Warm gas has more what than a cold gas?

A

capacity

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9
Q

Absolute humidity definition

A

actual amount of water vapor in a gas, expressed as weight/unit volume

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10
Q

Relative humidity definition

A

a ratio or percentage of the actual water vapor content of a gas compared to the amount it could hold if it were saturated

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11
Q

RH equation

A

content/capacity X 100

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12
Q

Body Humidity definition

A

also called percent body humidity. It expresses how much water vapor is in inspired gas compared to BTPS air

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13
Q

Humidity deficit definition

A

the (absolute) different b/w alveolar water vapor content and the water vapor content of inspired air. It is the amount of water vapor that must be supplied by the mucosa

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14
Q

What is the purpose of a humidifier?

A

to condition inspired gas by inc. water vapor content. Thereby preventing drying of mucosa.

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15
Q

Room temperature humidifiers can be used when?

A

by patients with a normal upper airway. For example a nasal cannula >4LMP

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16
Q

What damage can dry gases cause?

A

mucosal damage, cellular damage, chronic inflammation, increased sputum viscosity

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17
Q

What are some signs and symptoms of inadequate airway humidification?

A

atelectasis, dry cough, inc.airway resistance, inc. WOB, inc.incidence of infection, substernal pain (chest pain), thick secretions

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18
Q

What are some type of patients that have special humidification needs?

A

infants/peds, asthmatics, upper airway inflammation, hypothermia, bypassed airway

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19
Q

What temperature of the gas can cause airway burns?

A

> 44 C

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20
Q

Factors affecting efficiency of a humidifier are what?

A

time (how long the water and gas are in contact with each other), surface area, temperature

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21
Q

Bubbler humidifier

A

unheated- use small bore oxygen supply tubing, 20-40% BH, low risk of bacterial infection, bubbles tend to cool water during use, more efficient at lower flows (<5LMP), Heated- use large bore corrugated tubing

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22
Q

Heated bubbler- high flow

A

one brand name is Cascade, up to 100 LMP, high efficiency, can provide 100% BH, temperature range 24-49 C (75-120 F)

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23
Q

Heated wick-high flow

A

wick absorbs water increasing surface area. acts like a home thermostat, Concha Therm II is the most common brand, heated wire circuit (optional), auto feed water, 100% BH, servo controlled temperature

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24
Q

Passover

A

heated, high flow, 100% BH, servo controlled temperature, examples Isolettes, Fisher&Paykel models, and Emerson mech. vents

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25
Q

HME

A

heat moisture exchangers (nose, artificial nose), exhaled heat and moisture retained in device, best suited for short term patients or daytime use on ventilator dependent patients, efficiency dependent on temperature and humidity of gas, flowrates, surface area of unit, and thermal conductivity of housing

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26
Q

Types of HME

A

Simple (paper, plastic, metal, 50% efficiency) Hygroscopic (paper, wool, foam+salts, 70% efficiency) Hydrophobic (paper, foam, slightly more than 70% efficiency)

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27
Q

Contraindications to HME

A

thick secretions, temperature less than 32 C, minute ventilation >10LPM, exhaled Vt less than 70% of inspiratory Vt

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28
Q

Vapor Phase humidification

A

Brand: Vapotherm, newer brand is Precision Flow, main use is high flow nasal cannula, also used for masks and trach collars,95-100% BH at 33-40 C

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29
Q

What cartridge and flows is acceptable for an adult?

A

High flow cartridge with flows 8-40 LPM

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30
Q

What cartridge and flows are acceptable for a peds patient?

A

High flow cartridge with flows 8-20 LPM

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31
Q

What cartridge and flows are acceptable for infants

A

Low flow cartridge with flows 1-8 LPM

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32
Q

Optiflow

A

high flow heated nasal cannula, flow rates up to 60LPM for adults

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33
Q

Capillary Force Vaporization

A

capillary action draws water into a heated disk. water is vaporized under pressure. Can be used with high flow cannula or for mech. vents

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34
Q

Most pneumatic nebs operate on what two principles?

A

Bernoulli and Venturi

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35
Q

SVN

A

small volume neb, usually holds 5-30mL, intermittent use(10-20 minutes with meds), output 1-2 mL/min, usual flowrates 6-8 LMP, particle size is inversely proportional to flowrate, inc. residual volume

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36
Q

LVN

A

large volume neb, used for few hours to days, most common for bland aerosol delivery, noisy with high flowrates and low FiO2, heated but not servo controlled

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37
Q

When would you need to use double nebs?

A

greater than 50%

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38
Q

What is an immersion heater

A

it goes directly into water, possible contamination if not cleaned ofter

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39
Q

Babbington or Hydrosphere

A

hollow sphere bathed in liquid, can entrain room air, used in oxygen tents, no longer produced

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40
Q

SPAG

A

small particle aerosol generator, designed to be used with Ribravirin, used for infection with RSV (viral), drying chamber, high cost of meds, takes 3 days for meds to work, use full isolation gear when unit is running

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41
Q

Centrifugal

A

AKA spinning disk, commonly used as room humidifer, best to use distilled water, produces mist, needs regular cleaning

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42
Q

Ultrasonic

A

frequency determines particle size, high output 6ml/min, very dense aerosol produced, commonly used for sputum inductions, med delivery, and room humidification, breaks easy, low residual volume

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43
Q

Vibrating mesh nebs

A

newest, push liquid through a aperture or mesh producing aerosol passive devices (mesh does not move) and active devicescan be used continuously or intermintley, very popular in PEDS, very low residual volumes, expensive

44
Q

aerosol definition

A

liquid or solid particles suspended in a carrier gas. Can be seen as a mist or a spray

45
Q

particle size for vibrating mesh nebs

A

3-6 microns

46
Q

particle size for SPAG

A

1-3 microns

47
Q

particle size for Babbington or Hydrosphere

A

2-5 microns

48
Q

particle size for LVN

A

1-5 microns

49
Q

particle size for SVN

A

1-5 microns

50
Q

atomization definition

A

production of an aerosol with a large range of particle sizes

51
Q

Atomizer definition

A

a device used to produce an aerosol with a large range of particle sizes

52
Q

Nebulization definition

A

production of an aerosol with the use of a baffle which creates a more consistent particle size

53
Q

Nebulizer definition

A

a device used to produce an aerosol with a consistent particle size

54
Q

Baffle definition

A

a mechanical means of reducing the average particle size by removing the larger particles from the gas prior to reaching the patient

55
Q

What are some factors that affect the delivery of aerosol particles?

A

stability, penetration, deposition, gravity, kinetic activiy, inertial impact, physical nature of particles, and size of particles, and ventilatory pattern

56
Q

Stability definition

A

the ability of an aerosol to remain in suspension over time

57
Q

What is the most stable size of particles?

A

.25-0.7 microns (so stable they are likely to be exhaled)

58
Q

Penetration definition

A

the maximum depth that suspended particles are carried into the pulmonary tree (bronchi)

59
Q

Deposition definition

A

the point at which an aerosol impacts on airway surfaces or “rains-out”

60
Q

Gravity does what to the particles?

A

particles with a larger mass deposit sooner than particles with less mass.

61
Q

Kinetic activity

A

affects particles < 3 microns. Random motion of particles causes them to impact on airway surfaces. Inc # particles = inc. collision = inc aggregation of particles = inc deposition

62
Q

Inertial impact definition

A

particles have greater mass than air molecules. when there is a change in direction of gas flow, inertia causes particles to impact on airways. Most common for larger particles with greater mass

63
Q

Physical nature of particles definition

A

(chemical properties) aerosol particles can change in size and shape as they are inhaled, depending on their chemical process. This process is called aging

64
Q

What is the particle size that falls into the therapeutic range

A

1-5 microns

65
Q

Particle size >100 deposition site

A

Does not enter respiratory tract

66
Q

Particle size 5-100 deposition site

A

mouth, nose, and upper airways

67
Q

Particle size 2-5 deposition site

A

bronchi and bronchioles

68
Q

Particle size 0.5-2 deposition site

A

can enter alveoli

69
Q

Particle size < 0.5 deposition site

A

stable and tend to not become deposited

70
Q

Ventilatory pattern

A

encourage mouth breathing and normal inspiratory flow rates for aerosolized meds. Technique is not important when aerosol is being used for humidification purposes

71
Q

Distilled definition

A

no minerals in water

72
Q

Sterile definition

A

no pathogens present

73
Q

Saline definition

A

NaCl varying in amounts

74
Q

Normal saline definition

A

Same NaCl content as body tissue (0.9%)

75
Q

Half normal saline

A

0.45% NaCl

76
Q

Hydroscopic definition

A

absorb water and increase in size

77
Q

Isotonic definition

A

also called normal saline

78
Q

Hypertonic definition

A

high salt content, tend to absorb water

79
Q

Hypotonic definition

A

lower salt content than body fluids, tends to evaporate, especially as temp increase

80
Q

Bland aerosols definition

A

aerosol fluid that has no therapeutic qualities. Used for humdification

81
Q

What are the indications for use of aerosols?

A

to provide humidification of inspired gases, to deliver meds, to aid in secretion clearance, and to treat upper airways inflammation

82
Q

What are some complications and hazards to aerosols?

A

drug reactions, bronchospasm, swelling of dried secretions, fluid overload, infection and cross contamination, sound levels, potential airway burns, eye irritation, and exposure to second hand aerosol drugs

83
Q

what year were oxygen tents developed?

A

1920s

84
Q

What 3 things does oxygenation depend on when using an enclosure?

A

volume of enclosure, flowrate entering it, and the amount of seal

85
Q

CAM tent

A

Child/Adult Mist tent, has refrigeration unit which provides a continuous cool temp to the back panel, provides 40% oxygen with flow rates of 7-15 plus air entrainment from LVN. Does NOT recirculate oxygen

86
Q

Croupette

A

provides recirculation of oxygen, getting approx. 50% oxygen at max. (21-50%) Flowrates 8-10 LMP, uses ice to cool.

87
Q

Advantages to Oxygen tents

A

lots of humidity (main benefit), good for patient not tolerating mask

88
Q

Disadvantages to tents

A

difficult to maintain FIO2, heat built up in tent, very wet, messy to set up and D/C, difficult to clean, possible suffocation, isolation (psychological)

89
Q

Temperature for tents

A

canopy traps heat, try to maintain normal body temp, usually with a cool mist

90
Q

Incubators

A

Brand: Isolettes, began use in 1857, primary goal is to maintain patients temp by providing a warm enviroment.

91
Q

How can you provide a set temperature to a patient in an incubator?

A

attach a skin probe, or with a set temp, thermometer, and manual regulation

92
Q

Oxygen level provided by an incubator?

A

21-40%

93
Q

If greater than 40% is needed while in an incubator what do you need to use?

A

you can add a hood, nasal cannula

94
Q

Hoods

A

usually firm plastic and or plexiglass. Can be disposable or non disposable

95
Q

Minimum flow for a hood

A

7 LPM

96
Q

Oxygen level provided by a hood?

A

21-100% possible

97
Q

What are hoods used for?

A

to prevent heat loss in newborns and small infants and prevent hearing damage. Use heated humidification

98
Q

Hoods are usually used for what ages?

A

6 months or less

99
Q

What cant you use with a hood?

A

a nebulizer because we want to limit bacteria and noise

100
Q

Huts

A

flexible plastic sided huts for larger infants and children

101
Q

Minimum flow for a hut?

A

10-12LPM

102
Q

Oxygen level provided by a hut?

A

21-40% Need to keep closed to maintain FIO2

103
Q

Huts are usually used for what ages?

A

6-24 months (sometimes 36 months)

104
Q

What do you have to use for a hut?

A

cool mist neb

105
Q

XL hut

A

sometimes called King Tut Hut. LMP >15

106
Q

Isothermal boundary definition

A

Point at which inspired gases reach BTPS in airways. About 5 cm above carina