Term
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Definition
| involves applying water vapor and sometimes heat to the inspired gas |
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Definition
| actual mass or content of water in a measured volume of air |
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Term
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Definition
| difference in water vapor content between saturated gas conditions present in the lungs |
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Definition
| temperature where water vapor condenses back to its liquid form |
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Definition
| device that adds molecular water to gas |
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Term
| decribe: Normal Physiologic Process of Airway Humidification |
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Definition
| (1) ambient air inspired thru nose is warmed to 34 |
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Term
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Definition
Body, Temperature, Pressure, Standard
- When gas moves into the lungs, it acheives BTPS |
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Term
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Definition
Isothermic Saturation Boundary is located 5 cm below the carina.
Point where inspired gas becomes fully saturated to 100% relative humidity at body temperature and remains constant (BTPS) |
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Term
| 3 clinical situations that causes ISB distal shift |
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Definition
*note: a distal shift indicates humidity therapy
1. cold, dry air
2. bypassed upper airway
3. increased minute ventilation |
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Term
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Definition
To maintain normal physiological conditions in the lower airways
Assures normal function of mucociliary transport |
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Term
| Primary indications for humidity therapy |
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Definition
1. Humidifying dry medical gases
2. Overcoming the humidity deficit when the upper airways is bypassed |
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Term
| Secondary indications for humidity therapy |
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Definition
1. Managing hypothermia
2. Treating bronchospasm caused by cold air |
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| 7 clinical signs and symptoms of inadequate airway humidification |
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Definition
1 Atelectasis
2 Dry, nonproductive cough
3 Increased airway resistance
4 Increased incidence of infection
5 Increased work of breathing
6 Substernal pain
7 Thick, dehydrated secretions |
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Term
| 3 variablees that affect the efficiency of a humidifier |
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Definition
1. Temperature - The > the temp. of gas, the more water vapor it can hold.
2. Surface Area - The > the SA between water and gas, the more evaporation will occur.
3.Contact Time - the longer the gas remains in contact with water, the > the amount of evaporation |
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Term
| 3 methods to increase surface area |
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Definition
| 3 methods to incr. SA: a) bubble diffusion b) aerosol c) wick technologies |
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Term
| 2 types of low flow humidifiers |
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Definition
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| 3 types of high flow humidifiers |
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Definition
1. bubble
2. passover
3. heat-moisture exchanger |
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Term
| describe: function, indications, contraindications, hazards of all types of humidifiers |
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Definition
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Term
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Definition
| change of state from gas to liquid, as with water vapor condensation |
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Term
| Factors that affect condensation in respiratory therapy devices |
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Definition
Temperature difference across the system
Ambient temperature
Gas flow
Set airway temp
Length, diameter and mass of tubing |
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Term
| How to assess the need for humidification |
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Definition
| (1) gas flow, (2) presence or absence of an artificial tracheal airway, (3) character of the pulmonary secretions, (4) need for and expected duration of mechanical ventilation, and (5) contraindications to using an HME. |
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Term
| Based on a given scenario, choose the best humidifier device for that patient |
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Definition
| verify against flowchart 796 |
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Term
| Common problems with low-flow humidification systems |
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Definition
| poor mist production can be caused by inadequate input flow of driving gas, siphon tube obstruction, or jet orifice misalignment. |
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Term
| Performance criteria for heated humidifiers |
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Definition
They need to provide at least 30 mg/L water vapor
Use standard connects
Low compliance
Minimal weight
Low dead space
Low flow resistance |
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Term
| State the RH provided by a bubble humidifier |
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Definition
| At room temperature, 10 mg/L absolute humidity corresponds to approximately 80% relative humidity but only approximately 25% body humidity |
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Term
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Definition
| (1) simple condenser humidifiers, (2) hygroscopic condenser humidifiers, and (3) hydrophobic condenser humidifiers. |
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Term
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Definition
The typical HME is a passive humidifier, capturing both heat and moisture from expired gas and returning up to 70% of both to the patient during the next inspiration.
*Note: aka the artificial nose |
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Term
| 9 contraindications to the use of an HME |
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Definition
1. Increased volume of secretions
2. Thick, dehydrated secretions
3. Hypothermia
4. Large tidal volumes (>700 ml)
5. Small tidal volume (VT) with large-rebreathed-volume heat and moisture exchanger (HME) (i.e., HME volume > 30% of VT)
6. Uncuffed endotracheal tubes
7. Large leak around an endotracheal tube, such as might occur with a large bronchopleurocutaneous fistula or leaking endotracheal tube cuff
8. Exhaled VT < 70% of inhaled VT
9. HME cannot be placed between nebulizer and airway during aerosol therapy.
10. HME cannot be used with heated humidification. |
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