Health Information Organizations (HIO) began in the late 1990s.

In your own words, describe HIOs and their purposes, and how this organization might affect your current or future career.

Chapter 04 – Principles of Infection Prevention and Control

Kacmarek et al.: Egan’s Fundamentals of Respiratory Care, 11th Edition

MULTIPLE CHOICE

1. Approximately what percent of hospitalized patients develop a health care–associated infection?

a. 1%
b. 4%
c. 10%
d. 25%

ANS: B

Patients are at risk for developing infections during their hospital stay. A recent study estimated that 4% of hospitalized patients in the United States develop a health care–associated infection.

DIF: Recall REF: p. 60 OBJ: 1

2. Which of the following is considered the primary source of infection in the health care setting?

a. Medical equipment
b. Humans
c. Food and water
d. Carpet

ANS: B

Humans (patients, personnel, or visitors) are the primary sources for infectious agents in the health care setting.

DIF: Recall REF: p. 60 OBJ: 1

3. How do endotracheal tubes increase the risk of infection?

a. By increasing bleeding risks
b. Providing surfaces for biofilms to develop
c. By reducing neutrophil effectiveness
d. By increasing mucociliary escalator clearance

ANS: B

Endotracheal tubes allow pathogens to increase the risk of infection by impeding local host defenses and providing biofilms that may facilitate adherence of pathogens.

DIF: Application REF: p. 60 OBJ: 5

4. Which of the following factors increase the risk of surgical patients for developing postoperative pneumonia?

1. Obesity

2. Prolonged intubation

3. History of smoking

4. Elderly

a. 1 and 3 only
b. 2 and 4 only
c. 2, 3, and 4 only
d. 1, 2, 3, and 4

ANS: D

Patients at highest risk include elderly persons, the severely obese, those with chronic obstructive pulmonary disease (COPD) or a history of smoking, and those having an artificial airway in place for long periods. Strong cough mechanism actually helps to prevent atelectasis and pneumonia.

DIF: Recall REF: p. 60 OBJ: 4

5. What is the most common route of pathogen transmission in the hospital setting?

a. Indirect contact
b. Droplet transmission
c. Airborne transmission
d. Surgical transmission

ANS: A

Indirect contact transmission is the most frequent mode of transmission in the health care environment.

DIF: Recall REF: p. 61 OBJ: 3

6. Which of the following is an example of indirect contact transmission involving fomites?

a. Use of a sterile needle on a pneumonia patient
b. Use of a dirty laryngoscope blade on another patient
c. Drinking tap water
d. Inhaling tuberculosis pathogens in the emergency department

ANS: B

Instruments that have been inadequately cleaned between patients before disinfection or sterilization are an example of indirect contact transmission involving fomites.

DIF: Application REF: p. 62 OBJ: 3

7. If you are caring for a patient who is suspected of having SARS, at what distance from the patient is it recommended to wear an effective filtration mask?

a. 6 ft
b. 10 ft
c. 12 ft
d. 15 ft

ANS: A

Current HICPAC guidelines state it may be prudent to don a mask when within 6 ft of the patient or upon entry into the room of a patient who is on droplet isolation.

DIF: Application REF: p. 62 OBJ: 9

8. Which of the following diseases are transmitted primarily by airborne transmission?

1. Tuberculosis

2. Measles

3. Smallpox

4. Viral hemorrhagic fever

a. 1, 2, and 3 only
b. 1 and 4 only
c. 2, 3, and 4 only
d. 1, 2, 3, and 4

ANS: A

The pathogens transmitted by the airborne route include Mycobacterium tuberculosis, varicella-zoster virus (chickenpox), and rubeola virus (measles). Airborne transmission of variola (smallpox) has been documented and airborne transmission of SARS, monkeypox, and the viral hemorrhagic fever virus has been reported, although not proved conclusively.

DIF: Recall REF: p. 62 OBJ: 3

9. What techniques are used by most hospitals to reduce host susceptibility to infection?

a. Immunization
b. Blood testing
c. Surveillance
d. Having patients wear N95 mask

ANS: D

Hospital efforts to decrease host susceptibility focus mainly on employee immunization and chemoprophylaxis.

DIF: Recall REF: p. 64 OBJ: 6

10. What vaccination does OSHA require hospital employers to provide?

a. Tuberculosis
b. Smallpox
c. Hepatitis B
d. Streptococcus pneumoniae

ANS: C

OSHA mandates that employers offer hepatitis B vaccination.

DIF: Recall REF: p. 62 OBJ: 6

11. What is the first step in equipment processing for reuse on another patient?

a. Drying the equipment
b. Cleaning the equipment
c. Disinfecting the equipment
d. Sterilizing the equipment

ANS: B

Cleaning is the first step in all equipment processing.

DIF: Recall REF: p. 63 OBJ: 8

12. Which of the following statements is NOT true regarding the use of soaps to clean equipment?

a. Soaps act by lowering the surface tension.
b. Soaps work poorly in hard water.
c. Soaps have good bactericidal activity.
d. Soaps can help remove organic material.

ANS: C

Soaps act by lowering surface tension and forming an emulsion with organic matter. Unfortunately, soaps have little bactericidal activity and work poorly in hard water. A detergent refers to a substance (usually a chemical agent but sometimes a physical one) applied to inanimate objects that destroys disease-causing pathogens but not spores.

DIF: Application REF: p. 63 OBJ: 7

13. What should be used to wipe down the surface of devices that cannot be immersed in water?

a. 70% ethyl alcohol
b. Warm soapy water
c. Strong detergent
d. Bleach

ANS: A

The surface of the device should be disinfected using a 70% ethyl alcohol solution or the equivalent.

DIF: Recall REF: p. 70 OBJ: 7

14. Which of the following organisms is NOT destroyed by a disinfection agent?

a. Gram-negative cocci
b. Bacterial spores
c. Gram-positive rods
d. Viruses

ANS: B

Disinfection describes a process that destroys the vegetative form of all pathogenic organisms on an inanimate object except bacterial spores.

DIF: Recall REF: p. 70 OBJ: 7

15. What solution should be used to disinfect the surfaces of the room of a patient who was infected with C. difficile?

a. 70% ethyl alcohol
b. 5.25% sodium hypochlorite
c. 1% sodium benzoate
d. 5% iodine solution

ANS: B

Because C. difficile may form spores that are resistant to commonly used surface disinfectants, the CDC recommends the use of 1:10 dilution of 5.25% sodium hypochlorite (household bleach) and water for routine environmental disinfection in the rooms of patients with C. difficile.

DIF: Recall REF: p. 73 OBJ: 7

16. Which of the following statements is false regarding the use of alcohol disinfectants?

a. Their activity drops when diluted below 50% concentration.
b. Alcohols are good for surface cleaning of stethoscope bells and diaphragms.
c. They can damage rubber tubing.
d. They are considered sporicidal.

ANS: D

Alcohol disinfectants in the health care setting refer to either ethyl alcohol or isopropyl alcohol. Neither is considered a high-level disinfectant as a single agent, they are not sporicidal, and they do not penetrate protein-rich materials. Their activity drops when diluted below 50% concentration. Alcohols are inactivated by protein and can damage rubber, plastics, and the shellac mounting of lensed instruments. Alcohol wipes are a good choice for disinfecting small surfaces, such as medication vial tops. Alcohols are also useful as surface disinfectants for stethoscopes, ventilators, and manual ventilation bags.

DIF: Recall REF: p. 73 OBJ: 7

17. Which of the following characteristics is false for iodophors as disinfectants?

a. Water soluble
b. Nonstaining
c. Less irritating to tissue
d. Bacteriostatic

ANS: D

Unlike iodine tinctures, iodophors are water soluble, nonstaining, and less irritating to tissue. Iodophors are bactericidal, virucidal, and tuberculocidal.

DIF: Recall REF: p. 73 OBJ: 7

18. Which of the following statements is false regarding the use of glutaraldehyde?

a. It is a true sterilizing agent when used properly.
b. It can retain activity up to 90 days once activated.
c. It is used for disinfection on surfaces due to cost.
d. It can cause significant tissue inflammation in workers who use it.

ANS: B

Glutaraldehyde (saturated dialdehyde) is a commonly used high-level disinfectant/sterilant. When aqueous solutions of 2% glutaraldehyde are alkalized (“activated”) to a pH between 7.5 and 8.5, glutaraldehyde can kill vegetative bacteria, M. tuberculosis, fungi, viruses, and spores in less than 10 min (see Table 4-3). This sporicidal activity qualifies glutaraldehyde as a true sterilizing agent.

DIF: Recall REF: p. 74 OBJ: 7

19. What is the recommended dilution level of bleach according to the CDC for cleaning up blood spills?

a. 1:1
b. 1:5
c. 1:10
d. 1:20

ANS: C

The CDC recommends a 1:10 dilution of bleach (or an Environmental Protection Agency [EPA]-registered disinfectant) to disinfect blood spills.

DIF: Recall REF: pp. 77-78 OBJ: 7

20. What is the most common, efficient, and easiest sterilization method?

a. ETO
b. Flash sterilization
c. Steam sterilization
d. Use of hydrochlorofluorocarbon

ANS: C

Moist heat in the form of steam under pressure is the most common, efficient, and easiest sterilization method.

DIF: Recall REF: p. 71 OBJ: 7

21. Which of the following statements is false regarding the use of ETO for sterilization?

a. It is harmless to rubber and plastics.
b. It will penetrate prewrapping.
c. Acute exposure is of little consequence.
d. It is useful for equipment that cannot be autoclaved.

ANS: C

Unfortunately, acute exposure to ETO gas can cause airway inflammation, nausea, diarrhea, headache, dizziness, and even convulsions.

DIF: Recall REF: pp. 70-72 OBJ: 7

22. Which of the following is the most common source of patient infections?

a. Large volume nebulizers
b. Small volume nebulizers
c. Internal circuits of a ventilator
d. Oxygen therapy devices

ANS: A

Large volume nebulizers are the worst offenders.

DIF: Recall REF: p. 73 OBJ: 4

23. Which of the following steps for disinfection of a bronchoscope is false?

a. The first step is cleaning the scope.
b. Disinfection is done by immersion in a liquid disinfectant.
c. The device is stored lying flat to promote drying.
d. Drying techniques can include forced air.

ANS: C

Store in a manner so that the bronchoscope is vertical to prevent recontamination and facilitate drying.

DIF: Recall REF: p. 72 OBJ: 7

24. Which of the following organisms has/have been associated with health care–associated infections in patients using a poorly disinfected bronchoscope?

1. M. tuberculosis

2. Pseudomonas aeruginosa

3. Klebsiella

a. 1 and 3 only
b. 2 and 3only
c. 2 only
d. 1, 2, and 3

ANS: A

Health care–associated infections associated with bronchoscopes have been most commonly reported with M. tuberculosis, nontuberculosis mycobacterium, and P. aeruginosa.

DIF: Recall REF: p. 79 OBJ: 4 | 5

25. Which of the following statements is/are true regarding the use of disposable respiratory care equipment?

1. Recent research supports their use as a cost-effective measure.

2. Many quality issues exist.

3. Reusing the equipment is often done.

a. 1 and 3 only
b. 2 and 3only
c. 2 only
d. 1, 2, and 3

ANS: D

Three major issues are involved in using disposables: cost, quality, and reuse.

DIF: Recall REF: p. 80 OBJ: 8

26. Which of the following are categories under Expanded Precautions?

1. Contact Precautions

2. Droplet Precautions

3. Standard Precautions

4. Airborne Infection Isolation

a. 1 and 2 only
b. 1, 2, and 4 only
c. 2, 3, and 4 only
d. 1, 2, 3, and 4

ANS: B

There are four categories of Expanded Precautions: Contact Precautions, Droplet Precautions, Airborne Infection Isolation, and Protective Environment.

DIF: Recall REF: p. 69 OBJ: 8

27. What is the minimum recommended time for handwashing in the health care environment?

a. 5 sec
b. 15 sec
c. 30 sec
d. 60 sec

ANS: B

Hand hygiene includes handwashing with both plain or antiseptic-containing soap and water for at least 15 sec.

DIF: Recall REF: p. 63 OBJ: 6

28. Which of the following diseases is transmitted through direct contact?

a. HIV
b. Pertussis
c. Hepatitis B
d. Hepatitis C

ANS: A

The only one of those diseases that is transmitted through direct contact is HIV. Hepatitis B and C are both indirect contact, and pertussis is through droplet transmission.

DIF: Recall REF: p. 61 OBJ: 4

29. Which of the following diseases travels through droplet mode?

a. Influenza
b. Rickettsia
c. Malaria
d. Lyme disease

ANS: A

Influenza travels through droplet mode. Rickettsia, Lyme disease, and malaria are vector-borne.

DIF: Recall REF: p. 61 OBJ: 4

30. What is included in a Prevention Bundle?

1. The use of multiple evidence-based best practices to prevent device-related infection.

2. Recent research supports the use of cost-effective measurements.

3. An ongoing process of monitoring patients and personnel for the acquisition of infection in the health care setting.

4. Using prophylactic antibiotic therapy on all hospitalized patients.

a. 1 and 2 only
b. 1, 2, and 3 only
c. 2, 3, and 4 only
d. 1, 2, 3, and 4

ANS: B

Prevention Bundle is the use of multiple evidence-based best practices to prevent device-related infection.

DIF: Recall REF: p. 62 OBJ: 6

31. Small volume nebulizers produce bacterial aerosols that have been commonly associated with which of the following diseases?

a. Pseudomonas aeruginosa
b. Measles
c. Small pox
d. Nosocomial pneumonia

ANS: D

Small volume nebulizers produce bacterial aerosols that have been associated with nosocomial pneumonia.

DIF: Application REF: p. 73 OBJ: 5

32. What is the purpose of an inspiratory HEPA filter in a ventilator circuit?

a. The purpose is to serve as a heated thermistor that prevents condensation from forming in the circuits.
b. It prevents pathogens from being expelled into the surroundings.
c. When placed between the ventilator and the circuit, it can eliminate bacteria.
d. None of the above.

ANS: C

The purpose of an inspiratory HEPA filter, when it is placed between the ventilator and the external circuit, is to eliminate bacteria from the driving gas and prevent retrograde contamination back into the ventilator.

DIF: Application REF: p. 73 OBJ: 8

33. The unit residence asked you to reduce the risk of contamination caused by condensation in the circuit of a mechanically ventilated patient. Which of the following would help to reduce or eliminate condensation in this patient’s circuit?

a. Using a heat and moisture exchange (HME)
b. By draining the circuit on a daily basis
c. By not using any form of heater at all
d. By lowering the temperature in the heater

ANS: A

By replacing an active humidification system by a passive humidification one (HME), there will be less condensation in the circuit because no water is being used to heat and moisten the air, but instead the patient’s own body heat is used. Draining the circuit daily, not using heat, or lowering the heater temperature is not acceptable and may place the patient at risk of infection caused by inspissated secretions among other consequences.

DIF: Analysis REF: p. 73 OBJ: 6

34. Which of the following is the simplest level of infection control based on the recognition that all blood, body fluids, secretions, and excretions may contain transmissible infections agents?

a. Contact Precautions
b. Droplet Precautions
c. Standard Precautions

d. Airborne Infection Isolation

ANS: C

The term Standard Precautions refers to the simplest level of infection control based on the recognition that all blood, body fluids, secretions, and excretions (with the exception of sweat) may contain transmissible infectious agents.

DIF: Recall REF: p. 63 OBJ: 8

Chapter 38 – Humidity and Bland Aerosol Therapy

Kacmarek et al.: Egan’s Fundamentals of Respiratory Care, 11th Edition

MULTIPLE CHOICE

1. What is the point in the respiratory track where inspired gas reaches body temperature, ambient pressure, saturated (BTPS) conditions?

a. Point of thermal equilibrium
b. Hygroscopic saturation boundary
c. Thermal inversion boundary
d. Isothermic saturation boundary

ANS: D

As inspired gas moves into the lungs, it achieves BTPS conditions (body temperature, 37° C; barometric pressure; saturated with water vapor [100% relative humidity at 37° C]). This point, normally approximately 5 cm below the carina, is called the isothermic saturation boundary.

DIF: Recall REF: p. 821 OBJ: 1

2. Which of the following is false about the isothermic saturation boundary (ISB)?

a. Below the ISB, temperature and relative humidity remain constant.
b. Above the ISB, temperature and humidity increase during exhalation.
c. The ISB is normally located just below the larynx (vocal cords).
d. Above the ISB, temperature and humidity decrease during inspiration.

ANS: C

This point, normally approximately 5 cm below the carina, is called the isothermic saturation boundary (ISB). Above the ISB, temperature and humidity decrease during inspiration and increase during exhalation.

DIF: Recall REF: p. 821 OBJ: 1

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

a. 1 and 2 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2, and 3

ANS: D

The ISB shifts distally when a person breathes through the mouth rather than the nose; when he or she breathes cold, dry air; when the upper airway is bypassed (breathing through an artificial tracheal airway); or when the minute ventilation is higher than normal.

DIF: Recall REF: p. 821 OBJ: 1

4. What is the primary goal of humidity therapy?

a. Decrease airway reactivity to cold.
b. Maintain normal physiologic conditions.
c. Deliver drugs to the airway.
d. Reduce upper airway inflammation.

ANS: B

The primary goal of humidification is to maintain normal physiological conditions in the lower airways.

DIF: Recall REF: p. 821 OBJ: 3

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

a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: B

See Box 38-1.

DIF: Recall REF: p. 821 OBJ: 2

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

a. 1 and 2 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2, and 3

ANS: D

Administration of dry medical gases at flows greater than 4 L/min to the upper airway causes immediate heat and water loss and, if prolonged, causes structural damage to the epithelium.

DIF: Recall REF: p. 821 OBJ: 2

7. Inhalation of dry gases can do which of the following?

1. Increase viscosity of secretions.

2. Impair mucociliary motility.

3. Increase airway irritability.

a. 1 and 2 only
b. 3 only
c. 1 and 3 only
d. 1, 2, and 3

ANS: D

As the airway is exposed to relatively cold, dry air, ciliary motility is reduced, airways become more irritable, mucous production increases, and pulmonary secretions become inspissated (thickened due to dehydration).

DIF: Recall REF: p. 821 OBJ: 2

8. Which of the following inspired conditions should be maintained when delivering medical gases to the nose or mouth?

a. 50% relative humidity (RH) at 20° to 22° C
b. 100% RH at 20° to 22° C
c. 80% RH at 28° to 32° C
d. 100% RH at 32° to 35° C

ANS: A

See Table 38-1.

DIF: Recall REF: p. 821 OBJ: 3

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?

a. 50% relative humidity (RH) at 20° to 22° C
b. 100% RH at 20° to 22° C
c. 95% RH at 29° to 32° C
d. 100% RH at 32° to 35° C

ANS: C

See Table 38-1.

DIF: Recall REF: p. 822 OBJ: 3

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?

a. 50% relative humidity (RH) at 20° to 22° C
b. 100% RH at 37° to 42° C
c. 95% RH at 29° to 32° C
d. 100% RH at 32° to 35° C

ANS: D

See Table 38-1.

DIF: Recall REF: p. 822 OBJ: 3

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

a. 2, 3, and 4 only
b. 1, 2, and 3 only
c. 1, 2, 3, and 4
d. 2 and 3 only

ANS: C

The delivery of cool humidified gas is used to treat upper airway inflammation resulting from croup, epiglottitis, and postextubation edema.

DIF: Recall REF: p. 822 OBJ: 3

12. What device adds molecular water to gas?

a. Agitator
b. Humidifier
c. Nebulizer
d. Atomizer

ANS: B

A humidifier is a device that adds molecular water to gas.

DIF: Recall REF: p. 822 OBJ: 4

13. Factors affecting a humidifier’s performance include which of the following?

1. Surface area

2. Temperature

3. Time of contact

4. Outlet size

a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: B

The following four variables affect the quality of a humidifier’s performance: (1) temperature, (2) surface area, (3) time of contact, and (4) thermal mass.

DIF: Recall REF: p. 823 OBJ: 5

14. What is the most important factor determining a humidifier’s performance?

a. Surface area
b. Temperature
c. Time of contact
d. Gas flow

ANS: B

Temperature is an important factor affecting humidifier performance.

DIF: Recall REF: p. 823 OBJ: 5

15. The greater the temperature of the gas, the:

a. more water vapor it can hold.
b. less water vapor it can hold.
c. less efficient the humidifier is.
d. more water vapor is lost.

ANS: A

The greater the temperature of a gas, the more water vapor it can hold (increased capacity).

DIF: Recall REF: p. 823 OBJ: 5

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?

a. Approximately 100%
b. Approximately 60%
c. Approximately 40%
d. Approximately 20%

ANS: D

Although the humidifier fully saturates the gas, the low operating temperature limits total water vapor capacity to approximately 9.4 mg/L water vapor, equivalent to approximately 21% of body humidity.

DIF: Recall REF: p. 823 OBJ: 6

17. What is the simplest way to increase the humidity output of a humidifier?

a. Increase the time that the gas and the water are in contact.
b. Increase the surface area between the water and the gas.
c. Decrease the water vapor pressure of the gas.
d. Increase the temperature of either the water or the gas.

ANS: D

Simply heating the humidifier to 40° C (Figure 38-3, right) increases its output to 51 mg/L, which is more than adequate to meet BTPS conditions.

DIF: Recall REF: p. 823 OBJ: 6

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

a. 2, 3, and 4 only
b. 1, 2, and 3 only
c. 3, 4, and 5 only
d. 1, 2, 3, 4, and 5

ANS: D

See Box 38-3.

DIF: Recall REF: p. 822 OBJ: 2

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.

a. 1 and 3 only
b. 1, 2, and 4 only
c. 3 and 4 only
d. 1, 2, 3, and 4

ANS: B

In passover and wick-type humidifiers, the flow rate of gas through the humidifier is inversely related to contact time, with high flow rates reducing the time available for evaporation to occur.

DIF: Recall REF: p. 824 OBJ: 6

20. Which of the following types of humidifiers are used in clinical practice?

1. Heat and moisture exchanger

2. Passover humidifier

3. Bubble humidifier

a. 1 and 2 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2, and 3

ANS: D

Active humidifiers typically include (1) bubble humidifiers, (2) passover humidifiers, (3) nebulizers of bland aerosols, and (4) vaporizers. Passive humidifiers refer to typical heat and moisture exchangers (HMEs).

DIF: Recall REF: p. 824 OBJ: 6

21. Simple unheated bubble humidifiers are commonly used to humidify gases with what type of systems?

a. Mechanical ventilation
b. Oronasal O2 delivery
c. Tracheal O2 airway
d. Aerosol drug delivery

ANS: B

Unheated bubble humidifiers are commonly used with oronasal O2 delivery systems (see Chapter 41) to raise the water vapor content of the gas to ambient levels.

DIF: Recall REF: p. 824 OBJ: 6

22. What is the goal of using an unheated bubble humidifier with oronasal O2 delivery systems?

a. Raise the humidity of the gas to ambient levels.
b. Fully saturate the inspired gas to body temperature, ambient pressure, saturated (BTPS) conditions.
c. Cool the gas down to below room temperature.
d. Fully saturate the inspired gas to ambient temperature, ambient pressure, saturated (ATPS) conditions.

ANS: A

Unheated bubble humidifiers are commonly used with oronasal O2 delivery systems (see Chapter 41) the goal is to raise the water vapor content of the gas to ambient levels.

DIF: Recall REF: p. 824 OBJ: 6

23. What is the typical water vapor output of an unheated bubble humidifier?

a. 5 to 10 mg/L
b. 10 to 15 mg/L
c. 15 to 20 mg/L
d. 20 to 25 mg/L

ANS: C

As indicated in Table 38-2, unheated bubble humidifiers can provide absolute humidity levels between approximately 15 and 20 mg/L.

DIF: Recall REF: p. 825 OBJ: 6

24. Increasing the flow through an unheated bubble humidifier has which of the following effects?

a. Decreasing the water vapor content
b. Decreasing the relative humidity
c. Increasing the water vapor content
d. Increasing the relative humidity

ANS: A

As gas flow increases, these devices become less efficient as the reservoir cools and contact time is reduced.

DIF: Recall REF: p. 824 OBJ: 6

25. Unheated bubble humidifiers are of limited effectiveness at flows above which of the following?

a. 4 L/min
b. 6 L/min
c. 8 L/min
d. 10 L/min

ANS: D

Unheated bubble humidifiers are of limited effectiveness at flow rates higher than 10 L/min.

DIF: Recall REF: p. 824 OBJ: 6

26. Why should you not heat the reservoirs of a bubble humidifier used with an oronasal O2 delivery system?

a. Condensate will obstruct the delivery tubing.
b. Heating will melt the reservoir or cause a fire.
c. Heating will absorb the extra water vapor.
d. Heating will cause too much aerosol impaction.

ANS: A

Heating the reservoirs of these units can increase humidity content but is not recommended because the resulting condensate tends to obstruct the small-bore delivery tubing to which they connect.

DIF: Recall REF: p. 825 OBJ: 6

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.

a. 1 and 2 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2, and 3

ANS: A

The relief valve on a bubble humidifier serves to warn of flow-path obstruction and to prevent bursting of the humidifier bottle.

DIF: Recall REF: p. 825 OBJ: 6

28. To protect against obstructed or kinked tubing, simple bubble humidifiers incorporate which of the following?

a. HEPA outlet filter
b. Pressure relief valve
c. Automatic hygrometer
d. Electronic alarm system

ANS: B

Bubble humidifiers incorporate a simple pressure-relief valve or pop-off.

DIF: Recall REF: p. 825 OBJ: 6

29. The typical pressure pop-off incorporated into most simple bubble humidifiers releases pressure above which of the following?

a. 760 mm Hg
b. 10 cm H2O
c. 250 kPa
d. 2 psig

ANS: D

Typically, the pop-off is either a gravity or spring-loaded valve that releases pressures above 2 psig.

DIF: Recall REF: p. 825 OBJ: 6

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?

a. Malfunctioning humidifier
b. Normal, leak-free system
c. Malfunctioning flowmeter
d. Leak in the delivery tubing

ANS: B

If the system is obstructed at or near the patient interface and the pop-off sounds, the system is leak free.

DIF: Recall REF: p. 825 OBJ: 6

31. At high flow rates, what do some bubble humidifiers produce?

a. Additional heat
b. Microorganisms
c. Low pressures
d. Aerosol particles

ANS: D

At high flow rates, bubble humidifiers can produce aerosols.

DIF: Recall REF: p. 825 OBJ: 6

32. What are some types of passover humidifiers?

1. Simple reservoir

2. Membrane

3. Wick

a. 1 and 2 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2, and 3

ANS: D

There are three common types of passover humidifiers: (1) the simple reservoir type, (2) the wick type, and (3) the membrane type.

DIF: Recall REF: p. 825 OBJ: 6

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?

a. Bubble
b. Wick
c. Cascade
d. Hygroscopic

ANS: B

Typically a wick is placed upright with the gravity-dependent end in a heated water reservoir.

DIF: Recall REF: p. 825 OBJ: 6

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.

a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: B

A membrane-type humidifier separates the water from the gas stream by means of a hydrophobic membrane (Figure 38-3). Water vapor molecules can easily pass through this membrane, but liquid water (and pathogens) cannot. As with the wick-type humidifier, bubbling does not occur. Moreover, if a membrane-type humidifier were to be inspected while it was in use, no liquid water would be seen in the humidifier chamber.

DIF: Recall REF: p. 824 OBJ: 6

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.

a. 1 and 3 only
b. 1, 2, and 3 only
c. 2 and 4 only
d. 1, 3, and 4 only

ANS: D

Compared with bubble humidifiers, passover humidifiers offer several advantages. First, unlike bubble devices, they can maintain saturation at high flow rates. Second, they add little or no flow resistance to spontaneous breathing circuits. Third, they do not generate any aerosols and thus pose a minimal risk for spreading infection.

DIF: Recall REF: p. 825 OBJ: 6

36. Which type of humidifier “traps” the patient’s body heat and expire water vapor to raise the humidity of inspired gas?

a. Membrane
b. Bubble
c. Heat and moisture exchanger
d. Passover

ANS: C

Like the nose, a heat and moisture exchanger captures exhaled heat and moisture and uses it to heat and humidify the next inspiration.

DIF: Recall REF: p. 825 OBJ: 6

37. Heat and moisture exchangers (HMEs) are mainly used to do what?

a. Warm and humid gases delivered to the trachea via ventilator circuits.
b. Humidify therapeutic gases delivered at high flows to the lower airway.
c. Provide extra humidity for a patient with thick or retained secretions.
d. Warm and humid dry therapeutic gases delivered to the upper airway.

ANS: A

Traditionally, HME use has been limited to providing humidification to patients receiving invasive ventilatory support via endotracheal or tracheostomy tubes.

DIF: Recall REF: p. 825 OBJ: 3

38. Which of the following are types of heat and moisture exchangers (HMEs)?

1. Simple condenser

2. Hygroscopic condenser

3. Hydrophobic condenser

a. 1 and 2 only
b. 2 and 3 only
c. 1, 2, and 3
d. 3 only

ANS: C

There are three basic types of HMEs: (1) simple condenser humidifiers, (2) hygroscopic condenser humidifiers, and (3) hydrophobic condenser humidifiers.

DIF: Recall REF: p. 826 OBJ: 6

39. Which of the following best describes the performance of a typical hygroscopic condenser HME?

a. 40 mg/L water vapor exhaled; 27 mg/L returned
b. 40 mg/L water vapor exhaled; 20 mg/L returned
c. 27 mg/L water vapor exhaled; 40 mg/L returned
d. 44 mg/L water vapor exhaled; 37 mg/L returned

ANS: A

These devices typically achieve approximately 70% efficiency (40 mg/L exhaled, 27 mg/L returned).

DIF: Recall REF: p. 826 OBJ: 6

40. A heat and moisture exchanger has an efficiency rating of 80%. What does this mean?

a. Of the exhaled water vapor, 80% returns to the patient on inspiration.
b. The inspired temperature is 80% of the expired temperature.
c. Of the exhaled water vapor, 20% returns to the patient on inspiration.
d. The device provides 80% relative humidity at body temperature.

ANS: A

These devices typically achieve approximately 70% efficiency (40 mg/L exhaled, 27 mg/L returned).

DIF: Analysis REF: p. 826 OBJ: 6

41. An ideal heat and moisture exchanger (HME) should have an efficiency rating of at least which of the following?

a. 30%
b. 50%
c. 70%
d. 90%

ANS: C

The ideal HME should operate at 70% efficiency or better.

DIF: Recall REF: p. 826 OBJ: 6

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

a. 1 and 3 only
b. 2, 3, and 4 only
c. 2 and 4 only
d. 1, 2, 3, and 4

ANS: A

The ideal HME should operate at 70% efficiency or better (providing at least 30 mg/L water vapor); use standard connections; have a low compliance; and add minimal weight, dead space, and flow resistance to a breathing circuit.

DIF: Recall REF: p. 826 OBJ: 6

43. Which of the following statements is false of heat and moisture exchangers (HMEs)?

a. Moisture output falls at high volumes and rates of breathing.
b. High inspiratory flows and high FiO2 values can decrease HME efficiency.
c. In-use HMEs have little effect on flow resistance to breathing.
d. HMEs reduce bacterial colonization of ventilator circuits.

ANS: C

As shown in Table 38-3, the moisture output of HMEs tends to fall at high volumes and rates of breathing. In addition, high inspiratory flows and high FiO2 levels can decrease HME efficiency. Flow resistance through the HME also is important. When an HME is dry, resistance across most devices is minimal. However, because of water absorption, HME flow resistance increases after several hours’ use. For some patients, the increased resistance imposed by the HME may not be well tolerated, particularly if the underlying lung disease already causes increased work of breathing. Because HMEs eliminate the problem of breathing-circuit condensation, many consider these devices (especially hydrophobic filter HMEs) to be helpful in preventing nosocomial infections.

DIF: Recall REF: p. 826 OBJ: 6

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

a. 1 and 2 only
b. 2 and 3 only
c. 2 only
d. 3 only

ANS: A

Heated humidifiers are used mainly for patients with bypassed upper airways and/or for those receiving mechanical ventilatory support.

DIF: Application REF: p. 828 OBJ: 6

45. A patient receiving nasal O2 at 3 L/min complains of nasal dryness and irritation. Which of the following actions would be appropriate?

a. Recommending that the flow be decreased to 2 L/min
b. Adding a humidifier to the delivery system
c. Recommending that the flow be increased to 4 L/min
d. Switching to a simple mask at 3 L/min

ANS: B

For the occasional patient who complains of nasal dryness or irritation when receiving low-flow O2, a humidifier should be added to the delivery system.

DIF: Application REF: p. 839 OBJ: 15

46. Which of the following is false about a simple heated humidifier (one that does not incorporate a servo-control mechanism)?

a. The controller regulates the heating element’s electric power.
b. The controller monitors the temperature of the heating element.
c. The controller varies current to achieve a set airway temperature.
d. The patient’s airway does affect the controller.

ANS: D

Humidifier heating systems also have a controller that regulates the element’s electric power. In the simplest systems, the controller monitors the heating element, varying the delivered current to match either a preset or an adjustable temperature. In these systems, the patient’s airway temperature has no effect on the controller.

DIF: Recall REF: p. 828 OBJ: 6

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.

a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: D

Conversely, a servo-controlled heating system monitors temperature at or near the patient’s airway using a thermistor probe. The controller then adjusts heater power to achieve the desired airway temperature. Both types of controller units usually incorporate alarms and alarm-activated heater shutdown. Box 38-4 outlines key features of modern heated humidification systems.

DIF: Recall REF: p. 828 OBJ: 6

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?

a. 25° C
b. 30° C
c. 35° C
d. 40° C

ANS: D

See Box 38-5.

DIF: Recall REF: p. 829 OBJ: 6

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.

a. 1 and 2 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2, and 3

ANS: A

See Box 38-5.

DIF: Recall REF: p. 829 OBJ: 6

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.

a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: B

See Box 38-5.

DIF: Recall REF: p. 829 OBJ: 6

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?

a. 2° C
b. 4° C
c. 6° C
d. 8° C

ANS: A

See Box 38-5.

DIF: Recall REF: p. 829 OBJ: 6

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

a. 2 and 4 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 1, 2, 3, and 4

ANS: D

See Box 38-5.

DIF: Recall REF: p. 829 OBJ: 6

53. Where should you place the thermistor probe for a servo-controlled heated humidifier being used on a patient receiving mechanical ventilation?

a. In the expiratory limb of the circuit, near but not at the “wye”
b. In the inspiratory limb of the circuit, as close to the “wye” as possible
c. In the expiratory limb of the circuit, as close to the “wye” as possible
d. In the inspiratory limb of the circuit, near but not at the “wye”

ANS: D

See Rule of Thumb p. 827.

DIF: Recall REF: p. 828 OBJ: 7

54. When using a servo-controlled heated humidifier to deliver gas to an infant, the thermistor probe should be placed where?

a. Inside the circuit, outside the incubator, or away from the radiant warmer
b. Outside the circuit, inside the incubator, or away from the radiant warmer
c. Inside the circuit, inside the incubator, or away from the radiant warmer
d. Outside the circuit, outside the incubator, or away from the radiant warmer

ANS: A

Place heated humidifier thermistor probes in the inspiratory limb of a ventilator circuit far enough from the patient Y adaptor to ensure that warm exhaled gas does not fool the controller system. Never place a thermistor probe in an isolette or a radiant warmer, where the probe is warmed externally and the humidifier is fooled into shutting down, reducing the humidity available to the patient.

REF: p. 828 OBJ: 8

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

a. 1 and 2 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2, and 3

ANS: D

Unfortunately, the use of manually refilled reservoirs requires a momentary interruption of humidifier operation and mechanical ventilation. Moreover, because the system must be “opened” for refilling, cross contamination can occur. Water levels in manually filled systems are constantly changing, so that changes in the humidifier fill volume alter the gas compression factor and thus the delivered volume during mechanical ventilation.

DIF: Recall REF: p. 828 OBJ: 7

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

a. 2 and 3 only
b. 1 and 2 only
c. 1, 2, and 3
d. 1 and 3 only

ANS: C

The simplest type of automatic feed system is the level-compensated reservoir (Figure 38-7). In these systems, an external reservoir is aligned horizontally with the humidifier, maintaining relatively consistent water levels between the reservoir and the humidifier chamber. In flotation-type systems, a float rises and falls with the water level. As the water level falls below a preset value, the float opens the feed valve; as the water rises back to the set fill level, the float closes the feed valve. An optical sensor can also be used to sense water level, driving a solenoid valve to allow refilling of the humidifier reservoir.

DIF: Recall REF: p. 829 OBJ: 7

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

a. 1 and 3 only
b. 1, 2, and 3 only
c. 4 only
d. 1, 2, and 4 only

ANS: D

The AARC has published Clinical Practice Guideline: Humidification During Mechanical Ventilation. Excerpts appear on p. 831.

DIF: Recall REF: p. 831 OBJ: 7

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

a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: B

The AARC has published Clinical Practice Guideline: Humidification During Mechanical Ventilation. Excerpts are in CPG 38-1.

DIF: Recall REF: p. 831 OBJ: 7

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

a. 1 and 3 only
b. 2, and 3 only
c. 3 and 4 only
d. 1, 2, and 4 only

ANS: D

The AARC has published Clinical Practice Guideline: Humidification During Mechanical Ventilation. Excerpts are in CPG 38-1.

DIF: Recall REF: p. 831 OBJ: 7

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?

a. The inspiratory flow setting of the ventilator should be increased.
b. The HME must be removed from the circuit during MDI use.
c. The VT setting of the ventilator should be decreased.
d. A heated humidifier should replace the HME when using the MDI.

ANS: B

The AARC has published Clinical Practice Guideline: Humidification During Mechanical Ventilation. Excerpts are in CPG 38-1.

DIF: Recall REF: p. 831 OBJ: 7

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?

a. Increase the hygroscopic condenser humidifier temperature.
b. Reassess the patient’s secretions over the next 24 to 48 hr.
c. Replace the hygroscopic condenser humidifier with a new one.
d. Switch the patient to a large-volume heated humidifier.

ANS: D

The AARC has published Clinical Practice Guideline: Humidification During Mechanical Ventilation. Excerpts are in CPG 38-1.

DIF: Application REF: p. 831 OBJ: 7

62. How often should heat and moisture exchangers be inspected and replaced?

a. At least every shift
b. When contaminated by secretions
c. At least every day
d. When condensate is visible

ANS: B

The AARC has published Clinical Practice Guideline: Humidification During Mechanical Ventilation. Excerpts are in CPG 38-1.

DIF: Recall REF: p. 831 OBJ: 7

63. During routine use on an intubated patient, a heated humidifier should deliver inspired gas at which of the following?

a. Temperature of 33 ± 2° C, with a minimum of 30 mg/L of water vapor
b. Temperature of 37 ± 2° C, with a minimum of 44 mg/L of water vapor
c. Temperature of 20 ± 2° C, with a minimum of 10 mg/L of water vapor
d. Temperature of 30 ± 2° C, with a minimum of 24 mg/L of water vapor

ANS: A

The AARC has published Clinical Practice Guideline: Humidification During Mechanical Ventilation. Excerpts are in CPG 38-1.

DIF: Recall REF: p. 831 OBJ: 8

64. Which of the following are the proper temperature alarm settings for a heated humidifier used during mechanical ventilation?

High      Low

a. 35° C   32° C
b. 37° C   30° C
c. 39° C   33° C
d. 35° C   30° C

ANS: B

The AARC has published Clinical Practice Guideline: Humidification During Mechanical Ventilation. Excerpts are in CPG 38-1.

DIF: Recall REF: p. 831 OBJ: 8

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

a. 2 and 4 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 1, 2, 3, and 4

ANS: D

Factors influencing the amount of condensation include (1) the temperature difference across the system (humidifier to airway), (2) the ambient temperature, (3) the gas flow, (4) the set airway temperature, and (5) the length, diameter, and thermal mass of the breathing circuit.

DIF: Recall REF: p. 832 OBJ: 9

66. Which of the following is false about heated humidifier condensate?

a. It can block or obstruct the delivery circuit.
b. It must be treated as contaminated waste.
c. It requires that circuits be drained frequently.
d. It poses minimal infection risk.

ANS: D

Condensation can disrupt or occlude gas flow through the circuit, potentially altering FiO2 and/or ventilator function. Moreover, condensate can work its way toward the patient and be aspirated. For these reasons, circuits must be positioned to drain condensate away from the patient and must be checked often, and excess condensate must be drained from heated humidifier breathing circuits on a regular basis. Typically, patients contaminate ventilator circuits within hours, and condensate is colonized with bacteria and thus poses an infection risk. To avoid problems in this area, health care personnel should treat all breathing-circuit condensate as infectious waste.

DIF: Recall REF: p. 832 OBJ: 9

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

a. 1 and 2 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2, and 3

ANS: A

See Rule of Thumb p. 832.

DIF: Recall REF: p. 832 OBJ: 9

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

a. 1, 2, and 3
b. 2 and 3 only
c. 1 and 2 only
d. 1 and 3 only

ANS: C

One common method is to place water traps at low points in the circuit (both the inspiratory and expiratory limbs of ventilator circuits). The most common approach uses wire heating elements inserted into the ventilator circuit.

DIF: Recall REF: p. 832 OBJ: 9

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?

a. In the expiratory limb only, at a high point in the circuit.
b. In both the expiratory and inspiratory limbs, at high points in the circuit.
c. In the expiratory limb only, at a low point in the circuit.
d. In both the expiratory and inspiratory limbs, at low points in the circuit.

ANS: D

One common method is to place water traps at low points in the circuit (both the inspiratory and expiratory limbs of ventilator circuits).

DIF: Recall REF: p. 832 OBJ: 9

70. When using nebulizers, where should you place them to minimize risk of contamination?

a. In the inspiratory limb only, at a high point in the circuit
b. In both the expiratory and inspiratory limbs, at high points in the circuit
c. In the expiratory limb only, at a low point in the circuit
d. In both the expiratory and inspiratory limbs, at low points in the circuit

ANS: A

To minimize this risk, place nebulizers in a superior position, so that any condensate travels downstream from the nebulizer.

DIF: Recall REF: p. 832 OBJ: 9

71. Which of the following are true when heated-wire circuits are used with heated humidifiers except:

a. the humidifier operates at a higher temperature.
b. there is less condensate and a reduced need for drainage.
c. cost savings (less water and staff time) are realized.
d. there is less infection risk for both patient and caregivers.

ANS: A

When heated-wire circuits are used, the humidifier heats gas to a lower temperature (32° to 40° C) than it does with conventional circuits (45° to 50° C). The reduction in condensate in the tubing results in less water use, reduced need for drainage, and less infection risk for both patient and health care workers.

DIF: Recall REF: p. 833 OBJ: 9

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

a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: B

It is now known that frequent ventilator-circuit changes actually increase the risk of nosocomial pneumonia.

DIF: Recall REF: p. 833 OBJ: 9

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?

a. Observing no visible condensate anywhere in the delivery tubing
b. Confirming an airway temperature between 32° and 35° C
c. Observing a few drops of condensate at or near the patient’s airway
d. Observing condensate over the full length of the delivery tubing

ANS: C

To ensure that the inspired gas is being properly conditioned, clinicians should always adjust the temperature differential to the point that a few drops of condensation form near the patient “wye.” Lacking direct measurement of humidity, observation of this minimal condensate is the most reliable indicator that the gas is fully saturated at the specified temperature.

DIF: Recall REF: p. 834 OBJ: 9

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?

a. The gas at the airway is fully saturated.
b. The temperature setting of the heater is too high.
c. The airway temperature exceeds the dew point.
d. The temperature setting of the heater is too low.

ANS: A

To ensure that the inspired gas is being properly conditioned, clinicians should always adjust the temperature differential to the point that a few drops of condensation form near the patient “wye.” Lacking direct measurement of humidity, observation of this minimal condensate is the most reliable indicator that the gas is fully saturated at the specified temperature.

DIF: Application REF: p. 834 OBJ: 9

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?

a. Less than 25%
b. 25% to 90%
c. 90% to 100%
d. Less than 100%

ANS: D

If condensate cannot be seen, there is no way of knowing the level of relative humidity without direct measurement—it could be anywhere between 99% and 0%.

DIF: Application REF: p. 834 OBJ: 8

76. When is a heat and moisture exchanger (HME) performing well?

a. Condensate appears in the attached flex tube.
b. No condensate is visible on the filter or insert.
c. The HME temperature is at least 40° C.
d. Condensate is visible on the filter or insert.

ANS: A

Lacking direct measurement of humidity, observation of this minimal condensate is the most reliable indicator that the gas is fully saturated at the specified temperature.

DIF: Recall REF: p. 834 OBJ: 9

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

a. 1, 2, and 3
b. 2 and 3 only
c. 1 and 2 only
d. 1 and 3 only

ANS: A

The AARC has published Clinical Practice Guideline: Bland Aerosol Administration. Excerpts are in CPG 38-2.

DIF: Recall REF: p. 835 OBJ: 10

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

a. 1, 2, and 3
b. 2 only
c. 1 and 2 only
d. 1 and 3 only

ANS: B

The AARC has published Clinical Practice Guideline: Bland Aerosol Administration. Excerpts are in CPG 38-2.

DIF: Recall REF: p. 835 OBJ: 10

79. Hazards and complications of bland aerosol therapy include which of the following?

1. Bronchospasm

2. Overhydration

3. Infection

4. Hemoconcentration

a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: B

The AARC has published Clinical Practice Guideline: Bland Aerosol Administration. Excerpts are in CPG 38-2.

DIF: Recall REF: p. 835 OBJ: 13

80. Which of the following indicate a potential need for administration of a water or isotonic saline aerosol?

a. Stridor or brassy, crouplike cough

b. Evidence of increased volume of secretions

c. Hoarseness after extubation

d. Patient discomfort after bronchoscopy

a. 1 and 3 only
b. 1, 3, and 4 only
c. 2 and 4 only
d. 2, 3, and 4 only

ANS: B

The AARC has published Clinical Practice Guideline: Bland Aerosol Administration. Excerpts are in CPG 38-2.

The presence of one or more of the following may be an use indication for administration of a water or isotonic or hypotonic saline aerosol:

• Stridor

• Brassy, crouplike cough

• Hoarseness after extubation

• Diagnosis of laryngotracheobronchitis or croup

• History of upper airway irritation and increased work of breathing (e.g., smoke inhalation)

• Patient discomfort associated with airway instrumentation or insult

• Bypassed upper airway

• Need for sputum induction (e.g., Pneumocystis pneumonia or tuberculosis) is an indication for administration of hypertonic saline aerosol.

DIF: Recall REF: p. 835 OBJ: 13

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

a. 1, 2, and 3
b. 2 and 3 only
c. 1 and 2 only
d. 1 and 3 only

ANS: D

The AARC has published Clinical Practice Guideline: Bland Aerosol Administration. Excerpts are in CPG 38-2.

DIF: Application REF: p. 835 OBJ: 13

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

a. 1, 2, and 3 only
b. 1, 2, 3, and 4
c. 3 and 4 only
d. 1, 2, and 4 only

ANS: B

The AARC has published Clinical Practice Guideline: Bland Aerosol Administration. Excerpts are in CPG 38-2.

DIF: Recall REF: p. 835 OBJ: 13

83. What is the most common device used to generate bland aerosols?

a. Small-volume jet nebulizer
b. Ultrasonic nebulizer
c. Large-volume jet nebulizer
d. Spinning disk nebulizer

ANS: C

The large-volume jet nebulizer is the most common device used to generate bland aerosols.

DIF: Recall REF: p. 835 OBJ: 11

84. Which of the following are true regarding large-volume jet nebulizers?

a. A variable air-entrainment port allows air mixing and different FiO2 values.

b. Liquid particles are generated by mechanical vibration energy.

c. They are pneumatically powered and attach directly to a flowmeter.

d. Baffling causes impaction or removal of large, unstable particles.

a. 1 and 3 only
b. 1, 2, and 3 only
c. 2 and 4 only
d. 1, 3, and 4 only

ANS: D

As depicted in Figure 38-13, these devices are pneumatically powered, attaching directly to a flowmeter and compressed gas source. Liquid particle aerosols are generated by passing gas at a high velocity through a small “jet” orifice. The resulting low pressure at the jet draws fluid from the reservoir up to the top of a siphon tube, where it is sheared off and shattered into liquid particles. The large, unstable particles fall out of suspension or impact on the internal surfaces of the device, including the fluid surface (baffling). The remaining small particles leave the nebulizer through the outlet port, carried in the gas stream. A variable air-entrainment port allows air mixing to increase flow rates and to alter FiO2 levels.

DIF: Recall REF: p. 836 OBJ: 11

85. What is the total water output of unheated large-volume jet nebulizers?

a. 10 to 16 mg H2O/L
b. 16 to 25 mg H2O/L
c. 26 to 35 mg H2O/L
d. 33 to 55 mg H2O/L

ANS: C

Depending on the design, input flow, and air-entrainment setting, the total water output of unheated large-volume jet nebulizers varies between 26 and 35 mg H2O/L.

DIF: Recall REF: p. 836 OBJ: 11

86. What is the total water output of heated large-volume jet nebulizers?

a. 16 to 25 mg H2O/L
b. 26 to 35 mg H2O/L
c. 33 to 55 mg H2O/L
d. 56 to 75 mg H2O/L

ANS: C

When heated, output increases to between 33 and 55 mg H2O/L, mainly because of increased vapor capacity.

DIF: Recall REF: p. 836 OBJ: 11

87. Which of the following nebulizers uses a piezoelectric transducer to generate liquid particle aerosols?

a. Hydrodynamic nebulizer
b. Ultrasonic nebulizer
c. Jet nebulizer
d. Centrifugal nebulizer

ANS: B

An ultrasonic nebulizer is an electrically powered device that uses a piezoelectric crystal to generate aerosol.

DIF: Recall REF: p. 836 OBJ: 12

88. Which of the following principles is used by the ultrasonic nebulizer to produce aerosol droplets?

a. Evaporative cooling
b. Mechanical baffling
c. Fractional distillation
d. High-frequency vibrations

ANS: D

This crystal transducer converts radio waves into high-frequency mechanical vibrations (sound).

DIF: Recall REF: p. 836 OBJ: 12

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

a. 1, 3, and 4 only
b. 2, 3, 4, and 5 only
c. 1, 2, 3, 4, and 5
d. 3, 4, and 5 only

ANS: B

See Figure 38-15.

DIF: Recall REF: p. 836 OBJ: 12

90. The particle size produced by an ultrasonic nebulizer depends mainly on which of the following?

a. Blower (fan) speed
b. Signal amplitude
c. Signal frequency
d. Chamber baffling

ANS: C

The frequency at which the crystal vibrates, preset by the manufacturer, determines aerosol particle size.

DIF: Recall REF: p. 836 OBJ: 12

91. Which of the following mean mass aerodynamic diameter (MMAD) aerosol suspensions is produced by an ultrasonic nebulizer operated at 1.25 MHz?

a. 1 to 2 µm
b. 6 to 10 µm
c. 4 to 6 µm
d. Less than 1 µm

ANS: C

A nebulizer operating at 1.25 MHz produces an aerosol with an MMAD of between 4 and 6 µm.

DIF: Recall REF: p. 836 OBJ: 12

92. The aerosol output (in mg/L) of an ultrasonic nebulizer depends mainly on which of the following?

a. Signal amplitude
b. Chamber baffling
c. Source current
d. Signal frequency

ANS: A

Amplitude affects water output.

DIF: Recall REF: p. 836 OBJ: 12

93. To produce the highest possible density aerosol from an ultrasonic nebulizer, how would you set the controls?

a. Amplitude low, flow rate high
b. Amplitude high, flow rate low
c. Amplitude low, flow rate low
d. Amplitude high, flow rate high

ANS: B

See Rule of Thumb p. 837.

DIF: Recall REF: p. 837 OBJ: 12

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

a. 1, 2, and 3
b. 2 and 3 only
c. 2 only
d. 3 only

ANS: D

Exceptions include the use of the USN for sputum induction where the high output (1 to 5 ml/min) and aerosol density seems to yield higher quantity and quality of sputum specimens for analysis, but at some cost increased airway reactivity.

DIF: Application REF: p. 837 OBJ: 12

95. How often would you recommend that a home care patient disinfect a home ultrasonic room humidifier?

a. Per manufacturer’s specifications or at least every day
b. Per manufacturer’s specifications or at least every 3 days
c. Per manufacturer’s specifications or at least every 6 days
d. Per manufacturer’s specifications or at least every 2 weeks

ANS: C

In the absence of a manufacturer’s recommendation, these units should undergo appropriate disinfection at least every 6 days.

DIF: Application REF: p. 837 OBJ: 13

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

a. 2 and 4 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: A

Airway appliances used to deliver bland aerosol therapy include the aerosol mask, face tent, T tube, and tracheostomy mask.

DIF: Application REF: p. 837 OBJ: 12

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

a. 2 and 4 only
b. 1, 2, and 3 only
c. 1 and 3 only
d. 2, 3, and 4 only

ANS: C

The T tube is used for patients who are orally or nasally intubated or who have a tracheostomy. The tracheostomy mask is used solely for patients who have a tracheostomy.

DIF: Application REF: p. 837 OBJ: 12

98. Which of the following devices would you recommend to administer bland water aerosol to an infant or small child?

a. Face tent
b. Croup tents
c. T tube
d. Aerosol mask

ANS: A

Infants and small children may not readily tolerate direct airway appliances such as masks, so enclosures such as mist tents and aerosol hoods are used to deliver bland aerosol therapy to these patients.

DIF: Application REF: p. 837 OBJ: 12

99. What are some problems common to mist tents?

1. Heat retention

2. CO2 buildup

3. Hypothermia

a. 1, 2, and 3
b. 1 and 2 only
c. 2 and 3 only
d. 1 and 3 only

ANS: B

Any body enclosure poses two problems: CO2 build-up and heat retention.

DIF: Recall REF: p. 838 OBJ: 13

100. All mist tents prevent CO2 build-up by what process?

a. Recirculating the gas
b. Providing high gas flows
c. Using CO2 absorbers
d. Cooling the gas

ANS: B

CO2 build-up can be reduced by providing sufficiently high gas flow rates.

DIF: Recall REF: p. 838 OBJ: 13

101. Which of the following measures can help to ensure a good sputum sample?

a. Using an ultrasonic nebulizer instead of a jet nebulizer
b. Using a 5% saline solution instead of a 3% concentration
c. Having the patient rinse the mouth or blow the nose before induction
d. Using the lowest possible aerosol density (high flow and low output)

ANS: C

To ensure a good sputum sample, every effort must be made to separate saliva from true respiratory tract secretions. In some cases, protocols include having patients brush their teeth and tongue surface thoroughly and rinse their mouths before sputum induction.

DIF: Recall REF: p. 838 OBJ: 14

102. For what should sputum collected by aerosol therapy induction be inspected?

1. Color

2. Volume

3. Odor

4. Consistency

a. 2 and 4 only
b. 1, 2, and 3 only
c. 1 and 3 only
d. 1, 2, 3, and 4

ANS: D

See Box 38-5.

DIF: Recall REF: p. 838 OBJ: 14

103. To minimize problems with environmental safety when aerosol therapy is prescribed for immunosuppressed patients or those with tuberculosis, what precautions should you follow?

1. Those for tuberculosis exposure

2. Centers for Disease Control and Prevention (CDC) standards and contact precautions

3. CDC standards and airborne precautions

a. 1, 2, and 3
b. 1 and 2 only
c. 2 and 3 only
d. 1 and 3 only

ANS: A

To minimize problems in this area, all clinicians should strictly follow CDC standards and airborne precautions, including those specified for control of exposure to tuberculosis.

DIF: Application REF: p. 839 OBJ: 13

104. Causes of inadequate mist production with pneumatically powered jet nebulizers include which of the following?

1. Inadequate input flow

2. Siphon tube obstruction

3. Jet orifice misalignment

4. Tripped circuit breaker

a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: B

With pneumatically powered jet nebulizers, poor mist production can be caused by inadequate input flow of driving gas, siphon tube obstruction, or jet orifice misalignment.

DIF: Recall REF: p. 839 OBJ: 13

105. An ultrasonic nebulizer is not putting out any mist. After confirming (1) good electrical power supply (cord, plug, and circuit breakers are in good working order), (2) carrier gas is actually flowing through the device, and (3) the output control is set at maximum, what should you do?

a. Take the unit out of service and send it to engineering for repair.
b. Inspect the couplant chamber to confirm cleanliness and fill level.
c. Disassemble the radiofrequency generator and test for electrical leakage.
d. Hook it up the chamber inlet to a flowmeter set at 10 L/min or higher.

ANS: B

If there is still no visible mist output, the clinician should inspect the couplant chamber to confirm proper fill level and the absence of any visible dirt or debris.

DIF: Application REF: p. 839 OBJ: 13

106. The risk of overhydration with continuous delivery of bland water aerosols is greatest among which patient group?

1. Patients with fluid or electrolyte imbalances

2. Patients with fever and infection

3. Infants and small children

a. 1, 2, and 3
b. 1 and 2 only
c. 2 and 3 only
d. 1 and 3 only

ANS: D

The risk of overhydration is highest for infants, small children, and those with preexisting fluid or electrolyte imbalances.

DIF: Recall REF: p. 839 OBJ: 13

107. After administering a 30-min bland water aerosol treatment to a dehydrated elderly patient with chronic bronchitis, you note increased wheezing and a general decrease in the intensity of breath sounds. Which of the following has probably occurred?

a. Reactive bronchospasm has occurred and worsened airway obstruction.
b. Inspissated secretions have swollen and worsened airway obstruction.
c. Nothing; this is a normal response to bland aerosol therapy.
d. The patient is developing atelectasis due to overhydration.

ANS: B

In addition to overhydration of the patient, inspissated pulmonary secretions also can swell after high-density aerosol therapy, worsening airway obstruction.

DIF: Analysis REF: p. 839 OBJ: 13

108. A patient with chronic obstructive pulmonary disease (COPD) is receiving heated water aerosol treatments through a jet nebulizer four times daily as a supplement to other bronchial hygiene measures designed to aid in mobilizing retained secretions. After each session, you notice the presence of moderate wheezing. Which of the following recommendations would you make to the physician?

a. Discontinue the heated water aerosol treatments.
b. Consider prior treatment with a bronchodilator.
c. Switch to a higher-density aerosol (e.g., ultrasonic).
d. Discontinue the other bronchial hygiene measures.

ANS: B

If the physician still requests bland aerosol therapy for such a patient, pretreatment with a bronchodilator may be needed.

DIF: Application REF: p. 839 OBJ: 15

109. A neonatologist is concerned about the possibility of hearing damage occurring to a premature infant receiving bland water aerosol delivered via air-entrainment nebulizers inside an incubator or isolette. Which of the following would you recommend as the best way to overcome this problem?

a. Use a heated passover humidifier instead.
b. Use an ultrasonic nebulizer system instead.
c. Place sound baffles in the aerosol tubing.
d. Place earplugs in the infant’s outer ears.

ANS: A

The best way to avoid this problem and further minimize infection risks is to use heated passover humidification instead of nebulization.

DIF: Application REF: p. 839 OBJ: 15

110. Key considerations in selecting or recommending humidity or bland aerosol therapy for a patient include which of the following?

1. Required gas flow

2. Presence of an artificial tracheal airway

3. Character of pulmonary secretions

4. Need for or duration of mechanical ventilation

5. Presence of heat and moisture exchanger (HME) contraindications

a. 2, 3, and 4 only
b. 1, 2, and 3 only
c. 3, 4, and 5 only
d. 1, 2, 3, 4, and 5

ANS: D

Key considerations include (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.

DIF: Recall REF: p. 839 OBJ: 15

111. In general, to deliver O2 to the upper airway, a bubble humidifier is required only when the gas flow exceeds which of the following?

a. 1 L/min
b. 2 L/min
c. 3 L/min
d. 4 L/min

ANS: D

Regarding delivery of O2 to the upper airway, the American College of Chest Physicians advises against using a bubble humidifier at flow rates of 4 L/min or less.

DIF: Recall REF: p. 839 OBJ: 15

 
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