問題一覧
1
What is the point in the respiratory track where inspired gas reaches body temperature, ambient pressure, saturated (BTPS) conditions?
Isothermic saturation boundary
2
Which of the following is false about the isothermic saturation boundary (ISB)?
The ISB is normally located just below the larynx (vocal cords).
3
Which of the following factors cause the isothermic saturation boundary (ISB) to shift farther down into the airways?
1. Decreased ambient temperature
2. Increased tidal volume (VT)
3. Endotracheal intubation
1, 2, and 3
4
What is the primary goal of humidity therapy?
Maintain normal physiologic conditions.
5
Indications for warming inspired gases include which of the following?
1. Treating a patient whose airways are reactive to cold
2. Providing humidification when the upper airway is bypassed
3. Treating a patient with a low body temperature (hypothermia)
4. Reducing upper airway inflammation or swelling
1, 2, and 3 only
6
Administration of dry gases at flows exceeding 4 L/min can cause which of the following?
1. Structural damage
2. Heat loss
3. Water loss
1, 2, and 3
7
Inhalation of dry gases can do which of the following?
1. Increase viscosity of secretions.
2. Impair mucociliary motility.
3. Increase airway irritability.
1, 2, and 3
8
Which of the following inspired conditions should be maintained when delivering medical gases to the nose or mouth?
50% relative humidity (RH) at 20° to 22° C
9
Which of the following inspired conditions should be maintained when delivering medical gases to the hypopharynx, as when administering oxygen (O2) by nasal catheter?
95% RH at 29° to 32° C
10
Which of the following inspired conditions should be maintained when delivering medical gases directly into the trachea through an endotracheal tube or a tracheotomy tube?
100% RH at 32° to 35° C
11
Clinical indications for delivering cool humidified gas include which of the following?
1. Postextubation edema
2. Upper airway inflammation
3. Croup (laryngotracheal bronchitis)
4. Epiglottitis
1, 2, 3, and 4
12
What device adds molecular water to gas?
Humidifier
13
Factors affecting a humidifier’s performance include which of the following?
1. Surface area
2. Temperature
3. Time of contact
4. Outlet size
1, 2, and 3 only
14
What is the most important factor determining a humidifier’s performance?
Temperature
15
The greater the temperature of the gas, the:
more water vapor it can hold.
16
Gas leaving an unheated humidifier at 10° C and 100% relative humidity (absolute humidity = 9.4 mg/L) would provide what relative humidity at body temperature?
Approximately 20%
17
What is the simplest way to increase the humidity output of a humidifier?
Increase the temperature of either the water or the gas.
18
Which of the following are clinical signs and symptoms of inadequate airway humidification?
1. Atelectasis
2. Dry cough
3. Increased airway resistance
4. Increased incidence of infection
5. Increased work of breathing
1, 2, 3, 4, and 5
19
Which of the following are true about humidification and contact time?
1. The longer a gas is exposed to water, the greater is the amount of evaporation.
2. The rate of gas flow through a humidifier determines contact time.
3. Low flows decrease and high flows increase relative humidity output.
4. Bubble humidifier contact time depends on the water column depth.
1, 2, and 4 only
20
Which of the following types of humidifiers are used in clinical practice?
1. Heat and moisture exchanger
2. Passover humidifier
3. Bubble humidifier
1, 2, and 3
21
Simple unheated bubble humidifiers are commonly used to humidify gases with what type of systems?
Oronasal O2 delivery
22
What is the goal of using an unheated bubble humidifier with oronasal O2 delivery systems?
Raise the humidity of the gas to ambient levels.
23
What is the typical water vapor output of an unheated bubble humidifier?
15 to 20 mg/L
24
Increasing the flow through an unheated bubble humidifier has which of the following effects?
Decreasing the water vapor content
25
Unheated bubble humidifiers are of limited effectiveness at flows above which of the following?
10 L/min
26
Why should you not heat the reservoirs of a bubble humidifier used with an oronasal O2 delivery system?
Condensate will obstruct the delivery tubing.
27
The relief valve on a bubble humidifier serves which of the following functions?
1. It indicates when flow has been interrupted.
2. It protects the device from pressure damage.
3. It warns you when the water level is low.
1 and 2 only
28
To protect against obstructed or kinked tubing, simple bubble humidifiers incorporate which of the following?
Pressure relief valve
29
The typical pressure pop-off incorporated into most simple bubble humidifiers releases pressure above which of the following?
2 psig
30
When checking an O2 delivery system that incorporates a bubble humidifier running at 6 L/min, you occlude the delivery tubing, and the humidifier pressure relief immediately pops off. What does this indicate?
Normal, leak-free system
31
At high flow rates, what do some bubble humidifiers produce?
Aerosol particles
32
What are some types of passover humidifiers?
1. Simple reservoir
2. Membrane
3. Wick
1, 2, and 3
33
A design that increases surface area and enhances evaporation by incorporating an absorbent material partially submerged in a water reservoir that is surrounded by a heating element best describes what type of humidifier?
Wick
34
Which of the following are true regarding a membrane-type humidifier?
1. Water and gas are separated by a hydrophobic membrane.
2. The membrane is permeable to water vapor but not to liquid water.
3. As with other passover humidifiers, there is no bubbling action.
4. A small layer of liquid water remains on both sides of the membrane.
1, 2, and 3 only
35
Advantages of passover humidifiers include which of the following?
1. They add minimal flow resistance to breathing circuits.
2. They do not require heating to maintain body temperature, ambient pressure, saturated (BTPS) conditions.
3. They do not generate any bacteria-spreading microaerosol.
4. They can maintain water vapor saturation at high flows.
1, 3, and 4 only
36
Which type of humidifier “traps” the patient’s body heat and expire water vapor to raise the humidity of inspired gas?
Heat and moisture exchanger
37
Heat and moisture exchangers (HMEs) are mainly used to do what?
Warm and humid gases delivered to the trachea via ventilator circuits.
38
Which of the following are types of heat and moisture exchangers (HMEs)?
1. Simple condenser
2. Hygroscopic condenser
3. Hydrophobic condenser
1, 2, and 3
39
Which of the following best describes the performance of a typical hygroscopic condenser HME?
40 mg/L water vapor exhaled; 27 mg/L returned
40
A heat and moisture exchanger has an efficiency rating of 80%. What does this mean?
Of the exhaled water vapor, 80% returns to the patient on inspiration.
41
An ideal heat and moisture exchanger (HME) should have an efficiency rating of at least which of the following?
70%
42
Which of the following are features of an ideal heat and moisture exchanger (HME)?
1. High compliance
2. Minimal dead space
3. 70% or higher efficiency
4. Minimal flow resistance
1 and 3 only
43
Which of the following statements is false of heat and moisture exchangers (HMEs)?
In-use HMEs have little effect on flow resistance to breathing.
44
For which of the following patients would you select a heated humidifier?
1. Patient receiving O2 through a bypassed upper airway
2. Patient receiving long-term mechanical ventilation
3. Patient receiving O2 through an oronasal mask
1 and 2 only
45
A patient receiving nasal O2 at 3 L/min complains of nasal dryness and irritation. Which of the following actions would be appropriate?
Adding a humidifier to the delivery system
46
Which of the following is false about a simple heated humidifier (one that does not incorporate a servo-control mechanism)?
The patient’s airway does affect the controller.
47
Characteristics of a servo-controlled heated humidifier include which of the following?
1. Monitors heater temperature.
2. Adjusts heater power automatically.
3. Provides automatic heater shutdown.
4. Includes temperature safety alarms.
2, 3, and 4 only
48
A heated humidifier should trigger both auditory and visual alarms and interrupt power to the heater when the delivered temperature exceeds which of the following?
40° C
49
What should happen when the remote temperature sensor of a heated humidifier becomes disconnected or fails?
1. Power to the heater should be interrupted.
2. Auditory and visual alarms should trigger.
3. The unit’s outlet valve should lock closed.
1 and 2 only
50
Conditions that can cause temperature “overshoot” with servo-controlled heated humidifiers include which of the following?
1. The unit is allowed to warm up without flow.
2. Flow is decreased during normal operation.
3. The airway temperature probe becomes dislodged.
4. The unit reservoir is refilled with sterile water.
1, 2, and 3 only
51
The temperature of gas delivered to a patient’s airway by a servo-controlled heated humidifier should not vary by more than how much?
2° C
52
Which of the following are necessary features to look for in selecting a heated humidifier?
1. Water level readily visible
2. Over-temperature protection
3. Auditory and visual alarms
4. Minimal temperature overshoot
1, 2, 3, and 4
53
Where should you place the thermistor probe for a servo-controlled heated humidifier being used on a patient receiving mechanical ventilation?
In the inspiratory limb of the circuit, near but not at the “wye”
54
When using a servo-controlled heated humidifier to deliver gas to an infant, the thermistor probe should be placed where?
Inside the circuit, outside the incubator, or away from the radiant warmer
55
What are some potential problems with manually refilled heated humidifier reservoirs?
1. Cross contamination and infection
2. Variable compliance or delivered volume
3. Delivery of dry and/or hot gases
1, 2, and 3
56
Which of the following automatic feed systems are used to regulate water levels when using a humidifier with a continuous feed system?
1. Leveling reservoirs
2. Flotation controls
3. Optical sensors
1, 2, and 3
57
Which of the following are contraindications for heat and moisture exchangers?
1. Presence of thick, copious, or bloody secretions
2. Presence of a large leak around artificial airway
3. When a patient is suffering from hyperpyrexia
4. When a patient’s minute ventilation exceeds 10 L/min
1, 2, and 4 only
58
Which of the following are potential hazards of using heat and moisture exchangers?
1. Failure of low-pressure alarms to detect disconnection
2. Underhydration or impaction of secretions
3. Hypoventilation due to increased dead space
4. Unintended tracheal lavage from condensate
1, 2, and 3 only
59
Which of the following are potential hazards of using a heated humidifier during mechanical ventilation?
1. Aerosolization of condensate during disconnection
2. Underhydration or impaction of secretions
3. Hypoventilation due to increased dead space
4. Unintended tracheal lavage from condensate
1, 2, and 4 only
60
A patient receiving ventilatory support is being provided with humidification using a heat and moisture exchanger (HME). A physician orders a bronchodilator drug administered through a metered dose inhaler (MDI) via the ventilator circuit. Which of the following must be performed to ensure delivery of the drug to the patient?
The HME must be removed from the circuit during MDI use.
61
A patient has been supported by a mechanical ventilator using a heat and moisture exchanger for the last 3 days. Suctioning reveals an increase in the amount and tenacity of secretions. Which of the following actions is indicated?
Switch the patient to a large-volume heated humidifier.
62
How often should heat and moisture exchangers be inspected and replaced?
When contaminated by secretions
63
During routine use on an intubated patient, a heated humidifier should deliver inspired gas at which of the following?
Temperature of 33 ± 2° C, with a minimum of 30 mg/L of water vapor
64
Which of the following are the proper temperature alarm settings for a heated humidifier used during mechanical ventilation?
37° C 30° C
65
The amount of condensation occurring in a heated, humidified gas delivery system depends on which of the following?
1. Length, diameter, and mass of the circuit
2. Temperature differential along the circuit
3. Ambient temperature
4. Rate of gas flow through the circuit
1, 2, 3, and 4
66
Which of the following is false about heated humidifier condensate?
It poses minimal infection risk.
67
Which of the following barrier precautions should be used when heated humidifier circuits are changed or removed?
1. Wearing gloves
2. Wearing goggles
3. 5-min hand scrub
1 and 2 only
68
Which of the following are acceptable means to help minimize the problems caused by condensation in heated humidifier circuits?
1. Installing water traps in the circuit
2. Using a heated-wire circuit
3. Setting heater temperature to 25° to 28° C
1 and 2 only
69
When using water traps to help minimize the problems caused by condensation in a heated-humidifier ventilator circuit, where would you place the traps?
In both the expiratory and inspiratory limbs, at low points in the circuit.
70
When using nebulizers, where should you place them to minimize risk of contamination?
In the inspiratory limb only, at a high point in the circuit
71
Which of the following are true when heated-wire circuits are used with heated humidifiers except:
the humidifier operates at a higher temperature.
72
Which of the following reduce the risk of nosocomial infection when using heated humidification systems?
1. Use of wick or membrane humidifiers
2. Use of heated-wire delivery circuits
3. High humidifier reservoir temperatures
4. Frequent changing of delivery circuits
1, 2, and 3 only
73
What is the most reliable indicator that the gas delivered by a servo-controlled heated-wire humidifier system is fully saturated at the airway?
Observing a few drops of condensate at or near the patient’s airway
74
In checking a servo-controlled heated-wire humidifier system, you notice that a few drops of condensate tend to form but only near the patient’s airway. Based on this observation, what can you conclude?
The gas at the airway is fully saturated.
75
When checking a patient attached to a servo-controlled heated-wire humidifier breathing circuit, you notice no visible condensate anywhere in the tubing. Based on this observation, you can conclude that the relative humidity of the delivered gas is which of the following?
Less than 100%
76
When is a heat and moisture exchanger (HME) performing well?
Condensate appears in the attached flex tube.
77
For which of the following patients might you recommend bland aerosol therapy administration?
1. Patient with upper airway edema
2. Patient with a bypassed upper airway
3. Patient who must provide a sputum specimen
1, 2, and 3
78
For which of the following patients would you recommend bland aerosol therapy administration?
1. Patient with a history of airway hyperresponsiveness
2. Patient with a bypassed upper airway
3. Patient with active bronchoconstriction
2 only
79
Hazards and complications of bland aerosol therapy include which of the following?
1. Bronchospasm
2. Overhydration
3. Infection
4. Hemoconcentration
1, 2, and 3 only
80
Which of the following indicate a potential need for administration of a water or isotonic saline aerosol?
Evidence of increased volume of secretions
81
For which of the following patients might you recommend administration of a hypertonic saline aerosol?
1. Acquired immune deficiency syndrome (AIDS) patient with severe pneumonia symptoms
2. Patient with a bypassed upper airway
3. Patient suspected of having tuberculosis
1 and 3 only
82
Which of the following would indicate that administration of a bland water aerosol to a patient with postextubation upper airway edema was having the desired effect?
1. Decreased work of breathing
2. Improved vital signs
3. Decreased stridor or dyspnea
4. Improved O2 saturation
1, 2, 3, and 4
83
What is the most common device used to generate bland aerosols?
Large-volume jet nebulizer
84
Which of the following are true regarding large-volume jet nebulizers?
1. A variable air-entrainment port allows air mixing and different FiO2 values.
2. Liquid particles are generated by mechanical vibration energy.
3. They are pneumatically powered and attach directly to a flowmeter.
4. Baffling causes impaction or removal of large, unstable particles.
1, 3, and 4 only
85
What is the total water output of unheated large-volume jet nebulizers?
26 to 35 mg H2O/L
86
What is the total water output of heated large-volume jet nebulizers?
33 to 55 mg H2O/L
87
Which of the following nebulizers uses a piezoelectric transducer to generate liquid particle aerosols?
Ultrasonic nebulizer
88
Which of the following principles is used by the ultrasonic nebulizer to produce aerosol droplets?
High-frequency vibrations
89
Which of the following are components of an ultrasonic nebulizer?
1. Air-entrainment orifice
2. Radiofrequency generator
3. Nebulizer chamber
4. Piezoelectric transducer
5. Blower or fan
2, 3, 4, and 5 only
90
The particle size produced by an ultrasonic nebulizer depends mainly on which of the following?
Signal frequency
91
Which of the following mean mass aerodynamic diameter (MMAD) aerosol suspensions is produced by an ultrasonic nebulizer operated at 1.25 MHz?
4 to 6 μm
92
The aerosol output (in mg/L) of an ultrasonic nebulizer depends mainly on which of the following?
Signal amplitude
93
To produce the highest possible density aerosol from an ultrasonic nebulizer, how would you set the controls?
Amplitude high, flow rate low
94
For which of the following patients might you recommend bland aerosol therapy via an ultrasonic nebulizer (USN)?
1. Patient with upper airway edema
2. Patient with a bypassed upper airway
3. Patient who must provide a sputum specimen
3 only
95
How often would you recommend that a home care patient disinfect a home ultrasonic room humidifier?
Per manufacturer’s specifications or at least every 6 days
96
A physician orders bland water aerosol administration to a patient with an intact upper airway. Which of the following airway appliances could you use to meet this goal?
1. Simple O2 mask
2. Face tent
3. T tube
4. Aerosol mask
2 and 4 only
97
A physician orders bland water aerosol administration to a patient with a tracheostomy. Which of the following airway devices could you use to meet this goal?
1. Tracheostomy mask
2. Face tent
3. T tube
4. Aerosol mask
1 and 3 only
98
Which of the following devices would you recommend to administer bland water aerosol to an infant or small child?
Face tent
99
What are some problems common to mist tents?
1. Heat retention
2. CO2 buildup
3. Hypothermia
1 and 2 only
100
All mist tents prevent CO2 build-up by what process?
Providing high gas flows
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47問 • 2年前問題一覧
1
What is the point in the respiratory track where inspired gas reaches body temperature, ambient pressure, saturated (BTPS) conditions?
Isothermic saturation boundary
2
Which of the following is false about the isothermic saturation boundary (ISB)?
The ISB is normally located just below the larynx (vocal cords).
3
Which of the following factors cause the isothermic saturation boundary (ISB) to shift farther down into the airways?
1. Decreased ambient temperature
2. Increased tidal volume (VT)
3. Endotracheal intubation
1, 2, and 3
4
What is the primary goal of humidity therapy?
Maintain normal physiologic conditions.
5
Indications for warming inspired gases include which of the following?
1. Treating a patient whose airways are reactive to cold
2. Providing humidification when the upper airway is bypassed
3. Treating a patient with a low body temperature (hypothermia)
4. Reducing upper airway inflammation or swelling
1, 2, and 3 only
6
Administration of dry gases at flows exceeding 4 L/min can cause which of the following?
1. Structural damage
2. Heat loss
3. Water loss
1, 2, and 3
7
Inhalation of dry gases can do which of the following?
1. Increase viscosity of secretions.
2. Impair mucociliary motility.
3. Increase airway irritability.
1, 2, and 3
8
Which of the following inspired conditions should be maintained when delivering medical gases to the nose or mouth?
50% relative humidity (RH) at 20° to 22° C
9
Which of the following inspired conditions should be maintained when delivering medical gases to the hypopharynx, as when administering oxygen (O2) by nasal catheter?
95% RH at 29° to 32° C
10
Which of the following inspired conditions should be maintained when delivering medical gases directly into the trachea through an endotracheal tube or a tracheotomy tube?
100% RH at 32° to 35° C
11
Clinical indications for delivering cool humidified gas include which of the following?
1. Postextubation edema
2. Upper airway inflammation
3. Croup (laryngotracheal bronchitis)
4. Epiglottitis
1, 2, 3, and 4
12
What device adds molecular water to gas?
Humidifier
13
Factors affecting a humidifier’s performance include which of the following?
1. Surface area
2. Temperature
3. Time of contact
4. Outlet size
1, 2, and 3 only
14
What is the most important factor determining a humidifier’s performance?
Temperature
15
The greater the temperature of the gas, the:
more water vapor it can hold.
16
Gas leaving an unheated humidifier at 10° C and 100% relative humidity (absolute humidity = 9.4 mg/L) would provide what relative humidity at body temperature?
Approximately 20%
17
What is the simplest way to increase the humidity output of a humidifier?
Increase the temperature of either the water or the gas.
18
Which of the following are clinical signs and symptoms of inadequate airway humidification?
1. Atelectasis
2. Dry cough
3. Increased airway resistance
4. Increased incidence of infection
5. Increased work of breathing
1, 2, 3, 4, and 5
19
Which of the following are true about humidification and contact time?
1. The longer a gas is exposed to water, the greater is the amount of evaporation.
2. The rate of gas flow through a humidifier determines contact time.
3. Low flows decrease and high flows increase relative humidity output.
4. Bubble humidifier contact time depends on the water column depth.
1, 2, and 4 only
20
Which of the following types of humidifiers are used in clinical practice?
1. Heat and moisture exchanger
2. Passover humidifier
3. Bubble humidifier
1, 2, and 3
21
Simple unheated bubble humidifiers are commonly used to humidify gases with what type of systems?
Oronasal O2 delivery
22
What is the goal of using an unheated bubble humidifier with oronasal O2 delivery systems?
Raise the humidity of the gas to ambient levels.
23
What is the typical water vapor output of an unheated bubble humidifier?
15 to 20 mg/L
24
Increasing the flow through an unheated bubble humidifier has which of the following effects?
Decreasing the water vapor content
25
Unheated bubble humidifiers are of limited effectiveness at flows above which of the following?
10 L/min
26
Why should you not heat the reservoirs of a bubble humidifier used with an oronasal O2 delivery system?
Condensate will obstruct the delivery tubing.
27
The relief valve on a bubble humidifier serves which of the following functions?
1. It indicates when flow has been interrupted.
2. It protects the device from pressure damage.
3. It warns you when the water level is low.
1 and 2 only
28
To protect against obstructed or kinked tubing, simple bubble humidifiers incorporate which of the following?
Pressure relief valve
29
The typical pressure pop-off incorporated into most simple bubble humidifiers releases pressure above which of the following?
2 psig
30
When checking an O2 delivery system that incorporates a bubble humidifier running at 6 L/min, you occlude the delivery tubing, and the humidifier pressure relief immediately pops off. What does this indicate?
Normal, leak-free system
31
At high flow rates, what do some bubble humidifiers produce?
Aerosol particles
32
What are some types of passover humidifiers?
1. Simple reservoir
2. Membrane
3. Wick
1, 2, and 3
33
A design that increases surface area and enhances evaporation by incorporating an absorbent material partially submerged in a water reservoir that is surrounded by a heating element best describes what type of humidifier?
Wick
34
Which of the following are true regarding a membrane-type humidifier?
1. Water and gas are separated by a hydrophobic membrane.
2. The membrane is permeable to water vapor but not to liquid water.
3. As with other passover humidifiers, there is no bubbling action.
4. A small layer of liquid water remains on both sides of the membrane.
1, 2, and 3 only
35
Advantages of passover humidifiers include which of the following?
1. They add minimal flow resistance to breathing circuits.
2. They do not require heating to maintain body temperature, ambient pressure, saturated (BTPS) conditions.
3. They do not generate any bacteria-spreading microaerosol.
4. They can maintain water vapor saturation at high flows.
1, 3, and 4 only
36
Which type of humidifier “traps” the patient’s body heat and expire water vapor to raise the humidity of inspired gas?
Heat and moisture exchanger
37
Heat and moisture exchangers (HMEs) are mainly used to do what?
Warm and humid gases delivered to the trachea via ventilator circuits.
38
Which of the following are types of heat and moisture exchangers (HMEs)?
1. Simple condenser
2. Hygroscopic condenser
3. Hydrophobic condenser
1, 2, and 3
39
Which of the following best describes the performance of a typical hygroscopic condenser HME?
40 mg/L water vapor exhaled; 27 mg/L returned
40
A heat and moisture exchanger has an efficiency rating of 80%. What does this mean?
Of the exhaled water vapor, 80% returns to the patient on inspiration.
41
An ideal heat and moisture exchanger (HME) should have an efficiency rating of at least which of the following?
70%
42
Which of the following are features of an ideal heat and moisture exchanger (HME)?
1. High compliance
2. Minimal dead space
3. 70% or higher efficiency
4. Minimal flow resistance
1 and 3 only
43
Which of the following statements is false of heat and moisture exchangers (HMEs)?
In-use HMEs have little effect on flow resistance to breathing.
44
For which of the following patients would you select a heated humidifier?
1. Patient receiving O2 through a bypassed upper airway
2. Patient receiving long-term mechanical ventilation
3. Patient receiving O2 through an oronasal mask
1 and 2 only
45
A patient receiving nasal O2 at 3 L/min complains of nasal dryness and irritation. Which of the following actions would be appropriate?
Adding a humidifier to the delivery system
46
Which of the following is false about a simple heated humidifier (one that does not incorporate a servo-control mechanism)?
The patient’s airway does affect the controller.
47
Characteristics of a servo-controlled heated humidifier include which of the following?
1. Monitors heater temperature.
2. Adjusts heater power automatically.
3. Provides automatic heater shutdown.
4. Includes temperature safety alarms.
2, 3, and 4 only
48
A heated humidifier should trigger both auditory and visual alarms and interrupt power to the heater when the delivered temperature exceeds which of the following?
40° C
49
What should happen when the remote temperature sensor of a heated humidifier becomes disconnected or fails?
1. Power to the heater should be interrupted.
2. Auditory and visual alarms should trigger.
3. The unit’s outlet valve should lock closed.
1 and 2 only
50
Conditions that can cause temperature “overshoot” with servo-controlled heated humidifiers include which of the following?
1. The unit is allowed to warm up without flow.
2. Flow is decreased during normal operation.
3. The airway temperature probe becomes dislodged.
4. The unit reservoir is refilled with sterile water.
1, 2, and 3 only
51
The temperature of gas delivered to a patient’s airway by a servo-controlled heated humidifier should not vary by more than how much?
2° C
52
Which of the following are necessary features to look for in selecting a heated humidifier?
1. Water level readily visible
2. Over-temperature protection
3. Auditory and visual alarms
4. Minimal temperature overshoot
1, 2, 3, and 4
53
Where should you place the thermistor probe for a servo-controlled heated humidifier being used on a patient receiving mechanical ventilation?
In the inspiratory limb of the circuit, near but not at the “wye”
54
When using a servo-controlled heated humidifier to deliver gas to an infant, the thermistor probe should be placed where?
Inside the circuit, outside the incubator, or away from the radiant warmer
55
What are some potential problems with manually refilled heated humidifier reservoirs?
1. Cross contamination and infection
2. Variable compliance or delivered volume
3. Delivery of dry and/or hot gases
1, 2, and 3
56
Which of the following automatic feed systems are used to regulate water levels when using a humidifier with a continuous feed system?
1. Leveling reservoirs
2. Flotation controls
3. Optical sensors
1, 2, and 3
57
Which of the following are contraindications for heat and moisture exchangers?
1. Presence of thick, copious, or bloody secretions
2. Presence of a large leak around artificial airway
3. When a patient is suffering from hyperpyrexia
4. When a patient’s minute ventilation exceeds 10 L/min
1, 2, and 4 only
58
Which of the following are potential hazards of using heat and moisture exchangers?
1. Failure of low-pressure alarms to detect disconnection
2. Underhydration or impaction of secretions
3. Hypoventilation due to increased dead space
4. Unintended tracheal lavage from condensate
1, 2, and 3 only
59
Which of the following are potential hazards of using a heated humidifier during mechanical ventilation?
1. Aerosolization of condensate during disconnection
2. Underhydration or impaction of secretions
3. Hypoventilation due to increased dead space
4. Unintended tracheal lavage from condensate
1, 2, and 4 only
60
A patient receiving ventilatory support is being provided with humidification using a heat and moisture exchanger (HME). A physician orders a bronchodilator drug administered through a metered dose inhaler (MDI) via the ventilator circuit. Which of the following must be performed to ensure delivery of the drug to the patient?
The HME must be removed from the circuit during MDI use.
61
A patient has been supported by a mechanical ventilator using a heat and moisture exchanger for the last 3 days. Suctioning reveals an increase in the amount and tenacity of secretions. Which of the following actions is indicated?
Switch the patient to a large-volume heated humidifier.
62
How often should heat and moisture exchangers be inspected and replaced?
When contaminated by secretions
63
During routine use on an intubated patient, a heated humidifier should deliver inspired gas at which of the following?
Temperature of 33 ± 2° C, with a minimum of 30 mg/L of water vapor
64
Which of the following are the proper temperature alarm settings for a heated humidifier used during mechanical ventilation?
37° C 30° C
65
The amount of condensation occurring in a heated, humidified gas delivery system depends on which of the following?
1. Length, diameter, and mass of the circuit
2. Temperature differential along the circuit
3. Ambient temperature
4. Rate of gas flow through the circuit
1, 2, 3, and 4
66
Which of the following is false about heated humidifier condensate?
It poses minimal infection risk.
67
Which of the following barrier precautions should be used when heated humidifier circuits are changed or removed?
1. Wearing gloves
2. Wearing goggles
3. 5-min hand scrub
1 and 2 only
68
Which of the following are acceptable means to help minimize the problems caused by condensation in heated humidifier circuits?
1. Installing water traps in the circuit
2. Using a heated-wire circuit
3. Setting heater temperature to 25° to 28° C
1 and 2 only
69
When using water traps to help minimize the problems caused by condensation in a heated-humidifier ventilator circuit, where would you place the traps?
In both the expiratory and inspiratory limbs, at low points in the circuit.
70
When using nebulizers, where should you place them to minimize risk of contamination?
In the inspiratory limb only, at a high point in the circuit
71
Which of the following are true when heated-wire circuits are used with heated humidifiers except:
the humidifier operates at a higher temperature.
72
Which of the following reduce the risk of nosocomial infection when using heated humidification systems?
1. Use of wick or membrane humidifiers
2. Use of heated-wire delivery circuits
3. High humidifier reservoir temperatures
4. Frequent changing of delivery circuits
1, 2, and 3 only
73
What is the most reliable indicator that the gas delivered by a servo-controlled heated-wire humidifier system is fully saturated at the airway?
Observing a few drops of condensate at or near the patient’s airway
74
In checking a servo-controlled heated-wire humidifier system, you notice that a few drops of condensate tend to form but only near the patient’s airway. Based on this observation, what can you conclude?
The gas at the airway is fully saturated.
75
When checking a patient attached to a servo-controlled heated-wire humidifier breathing circuit, you notice no visible condensate anywhere in the tubing. Based on this observation, you can conclude that the relative humidity of the delivered gas is which of the following?
Less than 100%
76
When is a heat and moisture exchanger (HME) performing well?
Condensate appears in the attached flex tube.
77
For which of the following patients might you recommend bland aerosol therapy administration?
1. Patient with upper airway edema
2. Patient with a bypassed upper airway
3. Patient who must provide a sputum specimen
1, 2, and 3
78
For which of the following patients would you recommend bland aerosol therapy administration?
1. Patient with a history of airway hyperresponsiveness
2. Patient with a bypassed upper airway
3. Patient with active bronchoconstriction
2 only
79
Hazards and complications of bland aerosol therapy include which of the following?
1. Bronchospasm
2. Overhydration
3. Infection
4. Hemoconcentration
1, 2, and 3 only
80
Which of the following indicate a potential need for administration of a water or isotonic saline aerosol?
Evidence of increased volume of secretions
81
For which of the following patients might you recommend administration of a hypertonic saline aerosol?
1. Acquired immune deficiency syndrome (AIDS) patient with severe pneumonia symptoms
2. Patient with a bypassed upper airway
3. Patient suspected of having tuberculosis
1 and 3 only
82
Which of the following would indicate that administration of a bland water aerosol to a patient with postextubation upper airway edema was having the desired effect?
1. Decreased work of breathing
2. Improved vital signs
3. Decreased stridor or dyspnea
4. Improved O2 saturation
1, 2, 3, and 4
83
What is the most common device used to generate bland aerosols?
Large-volume jet nebulizer
84
Which of the following are true regarding large-volume jet nebulizers?
1. A variable air-entrainment port allows air mixing and different FiO2 values.
2. Liquid particles are generated by mechanical vibration energy.
3. They are pneumatically powered and attach directly to a flowmeter.
4. Baffling causes impaction or removal of large, unstable particles.
1, 3, and 4 only
85
What is the total water output of unheated large-volume jet nebulizers?
26 to 35 mg H2O/L
86
What is the total water output of heated large-volume jet nebulizers?
33 to 55 mg H2O/L
87
Which of the following nebulizers uses a piezoelectric transducer to generate liquid particle aerosols?
Ultrasonic nebulizer
88
Which of the following principles is used by the ultrasonic nebulizer to produce aerosol droplets?
High-frequency vibrations
89
Which of the following are components of an ultrasonic nebulizer?
1. Air-entrainment orifice
2. Radiofrequency generator
3. Nebulizer chamber
4. Piezoelectric transducer
5. Blower or fan
2, 3, 4, and 5 only
90
The particle size produced by an ultrasonic nebulizer depends mainly on which of the following?
Signal frequency
91
Which of the following mean mass aerodynamic diameter (MMAD) aerosol suspensions is produced by an ultrasonic nebulizer operated at 1.25 MHz?
4 to 6 μm
92
The aerosol output (in mg/L) of an ultrasonic nebulizer depends mainly on which of the following?
Signal amplitude
93
To produce the highest possible density aerosol from an ultrasonic nebulizer, how would you set the controls?
Amplitude high, flow rate low
94
For which of the following patients might you recommend bland aerosol therapy via an ultrasonic nebulizer (USN)?
1. Patient with upper airway edema
2. Patient with a bypassed upper airway
3. Patient who must provide a sputum specimen
3 only
95
How often would you recommend that a home care patient disinfect a home ultrasonic room humidifier?
Per manufacturer’s specifications or at least every 6 days
96
A physician orders bland water aerosol administration to a patient with an intact upper airway. Which of the following airway appliances could you use to meet this goal?
1. Simple O2 mask
2. Face tent
3. T tube
4. Aerosol mask
2 and 4 only
97
A physician orders bland water aerosol administration to a patient with a tracheostomy. Which of the following airway devices could you use to meet this goal?
1. Tracheostomy mask
2. Face tent
3. T tube
4. Aerosol mask
1 and 3 only
98
Which of the following devices would you recommend to administer bland water aerosol to an infant or small child?
Face tent
99
What are some problems common to mist tents?
1. Heat retention
2. CO2 buildup
3. Hypothermia
1 and 2 only
100
All mist tents prevent CO2 build-up by what process?
Providing high gas flows