Humidity And Bland Aerosol

Question 1

Indications for humidification

Answer 1

Humidification of dry medical gases

Over come humidity decir created by bypassed UAW

Managing hypothermia

Treatment of cold air induced Bronchospasm

Question 2

Indications for cool aerosol

Answer 2

Treat upper airway inflammation from
Croup, epiglottis, post-extubation

Induce sputum

Question 3

Hazards of lack of humidity and heat

Answer 3

Hypothermia

Inspissated secretions

Impaired mucociliary function

Destruction of AW epithelium

Mucus plugs & atelectasis

Question 4

Evaporation occurs in

Answer 4

Non-heated and heated humidifiers

Question 5

Condensation occurs in

Answer 5

Ventilator and aerosol tubing as source gas moves toward patient

Question 6

Signs and symptoms of inadequate humidification

Answer 6

Atelectasis

Dry, nonproductive cough

increased RAW

Increased incidents of infections

Increased WOB

Substernal pain

Thick,dehydrated secretions

Question 7

Goal of humidification

Answer 7

Provide 100% for patients of bypassed UAW

Minimize humidity deficit while breathing dry medical gas

In low flow systems humidity provides comfort - not needed under 4lpm

Question 8

Humidifier

Answer 8

Adds molecular water to gas

Question 9

Nebulizer

Answer 9

Small water particles (aerosol) dispersed into gas for evaporation

Question 10

Aerosol

Answer 10

Suspended particle of a substance in a gas

Question 11

Principles governing humidification

Answer 11

Temperature.
—most important
—higher temp. Gas holds more water (capacity)
—heated humidifiers outperform unheated

Surface Area.
—large water reservoir
—bubbles-smaller bubbles –> greater surface area

Contact time. - More time more evaporation

Thermal mass. - greater amount of H2O increased capacity for evaporation

Question 12

Bubble humidifier (active)

Answer 12

Most common (unheated)
15 to 20 mg/L absolute humidity
Pressure pop-off (2 psig)

Question 13

Pass-over humidifier (active)

Answer 13

Reservoir:
directs gas over surface of water

Wick:
absorbent material to increase the surface area for dry gas to interface with heated water

Membrane:
Separates gas by placement of hydrophobic membrane. Water vapor mass passes thru easily while liquid water & pathogens cannot

Advantages = maintains saturation of gas at high flow rates , adds small amount to circuit and decreases risk of infection

Question 14

Vaporizers

Answer 14

Heat water to the point of expansion of gas ( room humidifier )

Question 15

Passive humidifiers

Answer 15

Heat & moisture exchanger - HME ( aka artificial nose)

Provides at least 30 mg/L water vapor -70% efficient

3 types: condenser , hygroscopic and hydrophobic

Question 16

Simple condenser humidifiers

Answer 16

Condenser element with high thermal conductivity

50% efficiency

Question 17

Hygroscopic condenser humidifier

Answer 17

Condenser element with low thermal conductivity and hygroscopic salt

70% efficiency ( 40mg/L exhaled , 27 mg/L returned)

May return more heat

Question 18

Hydrophobic condenser humidifier

Answer 18

Water repellent Elmer

Large surface and low thermal conductivity

70% efficiency

Question 19

ISO

Answer 19

Operates at 70% efficiency or better (30 mg/L)

Low compliance

Standard connections 15/22mm

Adds minimal weight , dead space , flow resistance to breathing circuit

Simple-safe , no heat used , portable , low cost , no extra water or electricity

Question 20

Contraindications for HME use

Answer 20

Thick, copious or bloody secretions

Hypothermia <32C

Expired VT less <70% of delivered VT

HME must be removed from patient circuit during aerosol treatments when Nebulizer is placed in the patient circuit

May be contraindicated in patients with high spontaneous minute volumes > 10 L/min

Question 21

Heating systems -types

Answer 21

Hot plate -at base

Wraparound -surrounds humidifier

Yolk or collar-between reservoir and outlet

Immersion type - in reservoir

Heated wire systems

Question 22

Servo-controlled monitor

Answer 22

Monitors temperature near AW and adjusts heat applied appropriately

Has overheat alarm

Question 23

Heating systems

Answer 23

Should not exceed body temp

For bypassed UAW temp must be set at 33 C at least

Must have audible/visual alarms

Water level must be visible

Internal compliance must be low and stable

Question 24

Hazards - heated humidity/ HME

Answer 24

Electrical shock

Hypothermia

Hyperthermia

Thermal injury to airway

Burns to patient or circuit meltdown

Under hydration and secretion impaction

Inadvertent overfilling

Question 25

Bland aerosol therapy

Answer 25

Larger particle size than humidity

Uses baffle to reduce particle size

Delivers sterile water , NSS, hypotonic or hypertonic saline solution

May accompany O2

Frequently implicated in nosocomial infections -water droplet can carry bacteria

LVN - most common

Ultrasonic Nebulizer

Question 26

Indications for cool bland aerosol therapy

Answer 26

Upper AW edema
LTB/croup
Subglottic edema
Post extubation edema
Post op management of UAW
Sputum induction

Question 27

Indications for heated aerosol

Answer 27

Bypassed UAW
Management of hypothermia

Question 28

Hazards of bland aerosol

Answer 28

Wheezing (Bronchospasm)

History of airway hypersensitivity

Nosocomical infections

Over hydration

Patient discomfort

Caregiver Infection