Term
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Definition
*water that is present in a gas mixture as vapor
*Exerts water vapor pressure
*temp important. Increase temp of a gas means the gas can hold more water vapor |
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Term
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Definition
water changes from liquid to a vapor
Requires heat energy that comes from surroundings |
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Term
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Definition
*type of vaporization
*heat is taken from the air surrounding the liquid thereby cooling the air
*ex: sweating |
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Term
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Definition
*heat increases kinetic energy and more molecules escape the surface
*temperature of a gas affects both capacity to hold molecular water and water vapor pressure |
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Term
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Definition
Content of water present in a given volume of gas
*measured with a hygrometer
*at 37° C absolute humidity (content) is 43.9 mg/L and water vapor pressure is 46.9 torr |
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Term
| Factors affecting the rate of evaporation and resulting absolute humidity |
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Definition
*temp: high temp= high rate of evaporation
*pressure = indirect relationship with the rate of evaporation
*surface area = more= more evaporation
*time= time the gas is exposed will increase its humidity |
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Term
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Definition
Measured water vapor content divided by the saturated capacity of the gas at a given temp.
*need to know saturated capacity |
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Term
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Definition
| Heat, humidify, filter inspired gas |
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Term
| Isothermal saturation boundary |
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Definition
Inspired gas conditions reach 100% relative humidity at body temp
*5cm below carina |
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Term
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Definition
*mouth breathing
*bypassing the upper airway
*higher than normal minute ventilation |
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Term
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Definition
| Difference between the amount of water vapor inspired and the water vapor content contained in the gas in the lungs |
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Term
| Indications for humidity therapy |
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Definition
1. Humidifying dry medical gases
2. overcoming humidity deficit created when upper airway is bypassed
3. Managing hypothermia
4. treatment of bronchospasm caused by cold air
5. thickened secretions |
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Term
| Humidifying dry medical gases |
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Definition
*shift isb
*airway dysfunction |
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Term
| Overcoming humidity deficit |
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Definition
*created when upper airway is bypassed
*airway damage can occur |
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Term
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Definition
Controversial
Other methods used |
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Term
| How will a pt present if they need humidification therapy |
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Definition
*atelectasis
*dry, nonproductive cough
*increased airway resistance
*increased incidences of infection
*substernal pains
*thick, dehydrated secretions |
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Term
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Definition
| Minimize humidity deficit |
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Term
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Definition
*passover:
Wick
membrane
advt: no resistance, do not generate aerosols, reduce risk of infection
*bubble
Bubble & bubble diffuser |
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Term
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Definition
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Term
| Types of hme: simple condenser humidifier |
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Definition
*high thermal conductivity
*capture about 50% of pts exhaled moisture |
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Term
| Types of hme: hygroscopic condenser humidifier |
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Definition
*lower thermal conductivity with hygroscopic salt
*70% efficiency |
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Term
| Types of hme: hydrophobic condenser humidifier |
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Definition
*condenser is a water repellent
*large surface area
*70% efficiency
*bacterial filter |
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Term
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Definition
*operate at 70% efficiency providing at least 30 mg/L water vapor
*have low compliance
*add minimal weight, dead space and flow resistance to a breathing circuit |
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Term
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Definition
*factors can decrease efficiency
*increased surface area |
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Term
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Definition
*hot plate
*wrap around
*yolk or collar
*immersion
*heated wire |
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Term
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Definition
*control and monitor the temperature of the gas
*constant temperature is delivered
*servo controlled |
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Term
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Definition
*no lodd or interruption in ventilation
*constant water level
*avoid the need for constant checking |
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Term
| Problems associated with heated humidifier systems |
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Definition
*condensation
*disruption of gas flow to pt
*contamination |
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