Humidity And Bland Aerosol Flashcards
Indications for humidification
Humidification of dry medical gases
Over come humidity decir created by bypassed UAW
Managing hypothermia
Treatment of cold air induced Bronchospasm
Indications for cool aerosol
Treat upper airway inflammation from
Croup, epiglottis, post-extubation
Induce sputum
Hazards of lack of humidity and heat
Hypothermia
Inspissated secretions
Impaired mucociliary function
Destruction of AW epithelium
Mucus plugs & atelectasis
Evaporation occurs in
Non-heated and heated humidifiers
Condensation occurs in
Ventilator and aerosol tubing as source gas moves toward patient
Signs and symptoms of inadequate humidification
Atelectasis
Dry, nonproductive cough
increased RAW
Increased incidents of infections
Increased WOB
Substernal pain
Thick,dehydrated secretions
Goal of humidification
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
Humidifier
Adds molecular water to gas
Nebulizer
Small water particles (aerosol) dispersed into gas for evaporation
Aerosol
Suspended particle of a substance in a gas
Principles governing humidification
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
Bubble humidifier (active)
Most common (unheated)
15 to 20 mg/L absolute humidity
Pressure pop-off (2 psig)
Pass-over humidifier (active)
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
Vaporizers
Heat water to the point of expansion of gas ( room humidifier )
Passive humidifiers
Heat & moisture exchanger - HME ( aka artificial nose)
Provides at least 30 mg/L water vapor -70% efficient
3 types: condenser , hygroscopic and hydrophobic
Simple condenser humidifiers
Condenser element with high thermal conductivity
50% efficiency
Hygroscopic condenser humidifier
Condenser element with low thermal conductivity and hygroscopic salt
70% efficiency ( 40mg/L exhaled , 27 mg/L returned)
May return more heat
Hydrophobic condenser humidifier
Water repellent Elmer
Large surface and low thermal conductivity
70% efficiency
ISO
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
Contraindications for HME use
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
Heating systems -types
Hot plate -at base
Wraparound -surrounds humidifier
Yolk or collar-between reservoir and outlet
Immersion type - in reservoir
Heated wire systems
Servo-controlled monitor
Monitors temperature near AW and adjusts heat applied appropriately
Has overheat alarm
Heating systems
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
Hazards - heated humidity/ HME
Electrical shock
Hypothermia
Hyperthermia
Thermal injury to airway
Burns to patient or circuit meltdown
Under hydration and secretion impaction
Inadvertent overfilling
Bland aerosol therapy
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
Indications for cool bland aerosol therapy
Upper AW edema
LTB/croup
Subglottic edema
Post extubation edema
Post op management of UAW
Sputum induction
Indications for heated aerosol
Bypassed UAW
Management of hypothermia
Hazards of bland aerosol
Wheezing (Bronchospasm)
History of airway hypersensitivity
Nosocomical infections
Over hydration
Patient discomfort
Caregiver Infection
