Where is the Isothermic Saturation Boundary (ISB)?
1. The person breathes cold, dry air.
2. Airway is bypassed (artificial airways)
3. Minute Ventilation is higher than normal.
T: 37 Degrees C
AH: 43.9 mg/L
RH at body temp & expressed as a %.
1. Temp: Higher temp of gas; the more water it can hold.
2. Surface Area: Effects rate of evap.
3. Time of contact: Evap. increases as contact time increases.
4. Thermal Mass: greater water in humidifier, the greater the thermal mass & capacity to hold & transfer heat to theraputic gas.
4. Active HME
1. Simple Reservoir
Separates water from gas by means of hydrophobic membrane.
Advantages over bubble humid:
1. Maintains sat at high flows
2. Adds little or no flow resistance to spontaneous breathing circuits
3. Do not generate any aerosols that can spread infection
1. Simple condenser
3. Hydrophobic condenser
HMEs add 30-90 mL of dead space; prevent nosocomial infections; and Ventilator Acquired Pneumonia (VAP).
Absorbs expired heat & moisture & releases it into inspired gas; consists of supply units with microprocessor, H2O pump and humidication device
What is a HME booster?
When do you add heat to humidfiers?
1. hotplate element at base of humidifier.
2. wrap around type
3. yolk or collar element
4. immersion type heater
5. heated wire
1. large water reservoir
2. gravity feed system
1. avoids need for constant checking and manual refilling
2. floatation valve control can be used to maintain humidfier reservoir fluid volume
1. poses risk to pts and caregivers
2. can waste a lot of water
3. can occlude gas flow through circuit.
4. can be aspirated
problem can be minimized with use of water traps and heat circuit by positioning circuit to drain away from pts in checking humidifier and neb often
1. water in circuit can be source of bacterial colonization.
2. minimizing condensation is helpful to reduce risk of colonization.
3. Wick or membrane type passover prevent formation of bacteria carrying aresols
4. frequently changing circuit is not needed to reduce chance of nosocomial infection
how does large volume jet nebulizers work?
1. aerosal mask
2. face tent
3. T-tube (briggs)
4. Tracheostomy mask
1. heat retention
2. CO2 build-up intense: high flows of fresh O2 circulating continuosly help wash out Co2 and reduce heat buildup
1. cross contamination and infection: adhere to infection control guidelines.
2. enviornmental exposures: follow CDC and prevention standards and airborne precautions
3. inadequate mix productions: check electrical supply, carrier gas flowing through device, amplitude control and couplant chamber
4. overhydration: prevention by careful patient selection and monitoring is the key
5. bronchospasm: treatment must be stopped immediately and provide oxygen
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