Deck 41: Medical Gas Therapy

Question 1

A patient with chronic hypercapnia placed on an FiO₂ of 0.6 starts hypoventilating. What is a possible cause of this phenomenon?

A) Decreased cardiac output
B) O₂ toxicity
C) O₂-induced hypoventilation
D) Absorption atelectasis

Answer 1

C
Explanation: When breathing moderate to high O₂ concentrations, COPD patients with chronic hypercapnia may tend to ventilate less.

Question 2

Specific clinical objectives of oxygen (O₂) therapy include which of the following?
1) Decrease the symptoms caused by chronic hypoxemia.
2) Decrease the workload hypoxemia imposes on the heart and lungs.
3) Correct documented arterial hypoxemia.
4) Correct documented respiratory acidosis.

A)2 and 4 only
B)3 and 4 only
C)1 and 3 only
D)1, 2, and 3 only

Answer 2

D

Question 3

A patient breathing 100% O₂ for 24 hr or longer would most likely exhibit which of the following?
1) Decreased DLCO
2) Decreased C_L
3) Increased PAO₂ - PaO₂
4) Decreased VC

A)2 and 4 only
B)1, 2, and 3 only
C)3 and 4 only
D)1, 2, 3, and 4

Answer 3

D

Question 4

Retinopathy of prematurity (ROP) is a potentially serious management problem mainly in the care of whom?

A) Premature or low-birth-weight infants
B) Cystic fibrosis patients
C) Children with asthma
D) Patients with acute respiratory distress syndrome (ARDS)

Question 5

Which of the following factors should be used in properly selecting an O₂ delivery device?
1) Knowledge of general performance of the device
2) Physician's preference
3) Individual capabilities of the equipment

A)2 and 3 only
B)1 and 2 only
C)1, 2, and 3
D)1 and 3 only

Question 6

Which of the following are true about absorption atelectasis?
1) It can occur only when breathing supplemental O₂.
2) Its risk is increased in patients breathing at low tidal volumes (V_T values).
3) Its risk is decreased through the natural "sigh" mechanism.
4) It results in an increase in the physiologic shunt fraction.

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 7

You set up an Oxy-Hood with an FiO₂ of 0.5 for a newborn infant. What is the maximum time that should pass before assessing this patient's PaO₂ or SaO₂?

A) 1 hr
B) 2 hr
C) 8 hr
D) 12 hr

Question 8

Properly applied O₂ therapy can decrease which of the following?
1) Ventilatory demand
2) Work of breathing
3) Cardiac output

A)2 and 3 only
B)1 and 2 only
C)1, 2, and 3
D)1 and 3 only

Question 9

Benefits of properly applied O₂ therapy in patients with chronic hypoxemia include which of the following?
1) Reversal of pulmonary vasoconstriction
2) Relief of pulmonary hypertension
3) Decreased right ventricular workload
4) Improved pulmonary vital capacity

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 10

You start a chronic obstructive pulmonary disease (COPD) patient on a nasal O₂ cannula at 2 L/min. What is the maximum time that should pass before assessing this patient's PaO₂ or SaO₂?

A) 2 hr
B) 8 hr
C) 12 hr
D) 72 hr

Question 11

Which of the following is consistent with the radiographic appearance after prolonged exposure to O₂?

A) Air bronchograms
B) Pulmonary abscess
C) Patchy infiltrates
D) Pneumothorax

Question 12

Which of the following typically occurs first when monitoring the earliest physiologic response to breathing 100% O₂?

A) Substernal chest pain
B) Decreased using capacity (DLCO)
C) Decreased lung compliance (C_L)
D) Decreased vital capacity (VC)

Question 13

Which of the following would indicate a need for O₂ therapy for an adult or a child?
1) SaO₂ less than 90%
2) PaCO₂ greater than 45 mm Hg
3) PaO₂ less than 60 mm Hg

A)2 and 3 only
B)1 and 2 only
C)1, 2, and 3
D)1 and 3 only

Question 14

Which of the following signs and symptoms are associated with the presence of hypoxemia?
1) Tachypnea
2) Tachycardia
3) Cyanosis
4) Bradycardia

A)2 and 3 only
B)1 and 2 only
C)1, 2, and 3 only
D)1 and 4 only

Question 15

What is/are the primary organ system(s) affected by O₂ toxicity?
1) Central nervous system (CNS)
2) Lungs
3) Kidneys

A)1 only
B)1 and 3 only
C)1 and 2 only
D)1, 2, and 3

Question 16

A physician places a patient in respiratory failure on 100% O₂. To avoid the hazards of O₂ toxicity, you would recommend that every effort is made to reduce this FiO₂ to less than 50% within what timeframe?

A) 8 hr
B) 24 hr
C) 48 hr
D) 5 days

Question 17

To minimize the risk of retinopathy of prematurity (ROP), the American Academy of Pediatrics recommends keeping the PaO₂ below what level?

A) 60 mm Hg
B) 70 mm Hg
C) 80 mm Hg
D) 90 mm Hg

Question 18

Some strategies for minimizing the risk of fire hazard with O₂ therapy include which of the following?
1) Using the lowest effective FiO₂
2) Properly educating patients and caregivers
3) Avoiding aluminum regulators and other high-risk devices
4) Mixing the oxygen with carbon dioxide.

A)1 and 3 only
B)1, 2, and 3 only
C)2 and 4 only
D)1, 2, 3, and 4

Question 19

According to AARC clinical practice guidelines, what is the minimum frequency for checking the functioning of an O₂ delivery system?

A) Every 4 hr
B) Every 8 hr
C) Every 24 hr
D) Every 48 hr

Question 20

When determining a need for O₂ therapy, the respiratory therapist should assess which of the following?
1) Neurologic status
2) Pulmonary status
3) Cardiac status

A)1 and 2 only
B)2 and 3 only
C)1 and 3 only
D)1, 2, and 3

Question 21

Which of the following are advantages of the nasal cannula as a low-flow O₂ delivery system?
1) Stability
2) Low cost
3) Easy application
4) Disposability

A)2 and 4 only
B)1, 2, and 4 only
C)2, 3, and 4 only
D)1, 2, 3, and 4

Question 22

You enter the room of a patient who is receiving nasal O₂ through a bubble humidifier at 5 L/min. You immediately notice that the humidifier pressure relief is popping off. Which of the following actions would be most appropriate in this situation?

A) Check and tighten all connections.
B) Replace the humidifier with a new one.
C) Look for crimped or twisted delivery tubing.
D) Decrease the flow rate to 2 L/min.

Question 23

A cooperative and alert postoperative patient who is able to eat requires a continuous but low FiO₂. Precise FiO₂ concentrations are not needed. Which of the following devices would best achieve this end?

A) Simple O₂ mask
B) Air-entrainment mask
C) Nasal cannula
D) Nonrebreathing mask

Question 24

Which of the following factors will decrease the FiO₂ delivered by a low-flow O₂ system?
1) Short inspiratory time
2) Fast rate of breathing
3) Lower O₂ input
4) Large minute ventilation

A)2 and 4 only
B)1, 2, and 3 only
C)3 and 4 only
D)1, 2, 3, and 4

Question 25

Which of the following is considered an advantage of the transtracheal catheter?

A) It does not provide any economic benefit compared with the nasal cannula.
B) It decreases the anatomic reservoir.
C) It requires 40% to 60% less O₂ flow than the nasal cannula.
D) It requires higher flows than the nasal cannula.

Question 26

What is the minimum flow setting for a simple mask applied to an adult?

A) 3 L/min
B) 5 L/min
C) 8 L/min
D) 10 L/min

Question 27

A true high-flow O₂ delivery system should provide at least what flow?

A) 60 L/min
B) 50 L/min
C) 40 L/min
D) 30 L/min

Question 28

A physician orders supplemental O₂ for a patient through a nasal cannula at a flow of 12 L/min. When you ask what the goal is, the physician states that the patient should receive approximately 60% O₂. Which of the following should you recommend?

A) The O₂ should be given through a reservoir mask at 10 L/min.
B) The cannula flow should be set to 15 instead of 12 L/min.
C) The O₂ should be given through a simple mask set at 5 to 12 L/min.
D) The O₂ should be given through a simple mask set at 12 to 15 L/min.

Question 29

Which of the following is false about the simple O₂ mask?

A) It has no valving system or reservoir bag.
B) It can easily deliver high FiO₂ values (>0.6 to 0.7).
C) It requires a minimal input flow of 5 L/min.
D) It generally functions as a variable-performance system.

Question 30

Which of the following is true about reservoir cannulas?

A) They reduce O₂ use as much as 200%.
B) During exercise, they do not reduce O₂ use.
C) Humidification is absolutely necessary.
D) Nasal anatomy and breathing pattern can affect performance of the device.

Question 31

Which of the following statements are true about low-flow O₂ delivery systems?
1) The greater the patient's inspiratory flow, the greater is the FiO₂.
2) All low-flow devices provide variable O₂ concentrations.
3) The O₂ provided by a low-flow device is diluted with air.
4) The patient's flow usually exceeds that from a low-flow device.

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 32

A 27-year-old woman received from the emergency department is on a nasal cannula at 5 L/min. Approximately what FiO₂ is this patient receiving?

A) 28%
B) 32%
C) 35%
D) 40%

Question 33

Some of the major disadvantages of the transtracheal catheter are which of the following?
1) Infection
2) Mucus plugging
3) Excessive oxygen use
4) Lost tract or insertion opening

A)1 and 3 only
B)1, 2, and 4 only
C)3 and 4 only
D)2, 3, and 4 only

Question 34

A well-fitted nonrebreathing mask, adjusted so that the patient's inhalation does not deflate the bag (flows approximately 10 L/min), should provide inspired O₂ concentrations in what range?

A) 55% to 70%
B) 45% to 60%
C) 75% to 90%
D) 70% to 85%

Question 35

To ensure a stable FiO₂ under varying patient demands, what must an O₂ delivery system do?

A) It must have a reservoir system at least equal to the V_T.
B) It must provide all the gas needed by the patient during inspiration.
C) It must maintain flows that are at least equal to the patient's peak flows.
D) It must be able to deliver any O₂ concentration from 21% to 100%.

Question 36

A 52-year-old man is admitted to the hospital emergency department with a primary complaint of severe radiating chest pain and signs of central cyanosis. The attending asks for your advice on selecting a device that provides a moderate FiO₂ for this patient. Which of the following would you recommend?

A) Simple O₂ mask at 8 L/min
B) Air-entrainment mask at 40% O₂
C) Nasal cannula at 5 L/min
D) Nonrebreathing mask at 10 L/min

Question 37

Disadvantages of standard O₂ masks include which of the following?
1) Being difficult to apply to patients.
2) Patient discomfort (straps and heat).
3) Increasing the risk of aspiration.
4) Must be removed for eating.

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 38

A patient is receiving O₂ through a nonrebreathing mask set at 8 L/min. You notice that the mask's reservoir bag collapses completely before the end of each inspiration. Which of the following actions is appropriate in this case?

A) Change to a partial rebreather.
B) Decrease the liter flow.
C) Increase the liter flow.
D) Change to a simple mask.

Question 39

A physician orders 2 L/min O₂ through a simple mask to a 33-year-old postoperative woman with moderate hypoxemia breathing room air (PaO₂ = 52 mm Hg). What would be the correct action at this time?

A) Carry out the physician's prescription exactly as written.
B) Recommend that the mask be changed to a cannula at 2 L/min.
C) Recommend a flow of at least 5 L/min to washout carbon dioxide (CO₂).
D) Do not apply the O₂ until the medical director has been contacted.

Question 40

You must deliver the highest possible FiO₂ to a 67-year-old man with pulmonary edema breathing at a rate of 35/min. Which of the following O₂ delivery systems would be most appropriate?

A) Nonrebreathing mask at 12 to 15 L/min
B) Simple mask at 12 to 15 L/min
C) Partial rebreathing mask at 12 to 15 L/min
D) Aerosol mask with nebulizer set to 100%

Question 41

A physician requests that you provide a patient with exactly 40% O₂ at a flow of 60 L/min. Lacking a blender, you must manually mix air and O₂ to achieve the desired mixture at the prescribed flow. Which of the following air and O₂ flows would you select? Air (L/min) O₂ (L/min)

A) 45 15
B) 15 45
C) 40 20
D) 20 40

Question 42

What temperature is required to maintain a neutral thermal environment (NTE) in an Oxy-Hood for infants weighing 2500 g or more?

A) 25° C
B) 30° C
C) 35° C
D) 40° C

Question 43

A physician orders 40% O₂ through an air-entrainment nebulizer for a patient with a minute volume of 12 L/min. What is the minimum nebulizer input flow required to ensure the prescribed FiO₂?

A) 8 L/min
B) 10 L/min
C) 12 L/min
D) 14 L/min

Question 44

Which of the following are true about air-entrainment systems?
1) Their FiO₂ values are directly proportional to their total flow.
2) They can provide variable FiO₂ values under some clinical conditions.
3) They always deliver O₂ concentrations less than 100%.
4) They yield a set FiO₂ only if their flow exceeds the patient's.

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 45

A physician wants a stable FiO₂ of 0.5 for a newborn infant with severe hypoxemia. Which of the following systems would you select?

A) O₂ hood with blender and heated humidifier
B) Pediatric ("croup") tent with O₂ input of 8 L/min
C) O₂ hood with blender and unheated humidifier
D) Infant incubator with O₂ input of 10 L/min

Question 46

To confirm proper operation of an O₂ blending system, what should you do?
1) Test low-pressure alarms and bypass systems.
2) Analyze FiO₂ at 0.21, 1.00, and prescribed level.
3) Confirm air and O₂ inlet pressures.

A)1 and 2 only
B)2 and 3 only
C)1 and 3 only
D)1, 2, and 3

Question 47

You design an air-entrainment system that mixes air with O₂ at a fixed ratio of 1:7. Approximately what O₂ concentration will this device provide?

A) 33%
B) 40%
C) 80%
D) 90%

Question 48

An O₂ delivery device takes separate pressurized air and O₂ sources as input, then mixes these gases through a precision valve. What does this describe?

A) O₂ blending system
B) Reservoir system
C) Air-entrainment system
D) Low-flow system

Question 49

What is the upper limit of O₂ concentrations available through tents?

A) 60% to 70%
B) 50% to 60%
C) 40% to 50%
D) 30% to 40%

Question 50

To ensure the prescribed FiO₂ for a patient receiving 65% O₂, you apply a closed reservoir delivery system with a one-way expiratory valve. What other component must be included in this system to ensure a fail-safe operation?

A) Water trap
B) High-pressure alarm
C) Emergency inlet valve
D) Low-pressure alarm

Question 51

In giving O₂ to an infant through a hood, which of the following are correct?
1) A neutral thermal environment should be maintained.
2) Gases should be directed away from the infant's face.
3) High input flow (>10 to 15 L/min) should be avoided.
4) A minimum flow of 7 L/min must be maintained.

A)1, 2, and 3 only
B)2 and 4 only
C)2, 3, and 4 only
D)1, 2, 3, and 4

Question 52

Directing a cool O₂ mixture to an infant in an Oxy-Hood can result in which of the following?
1) Increased O₂ consumption
2) Increased convective heat loss
3) Apnea (cessation of breathing)

A)1 and 2 only
B)2 and 3 only
C)1 and 3 only
D)1, 2, and 3

Question 53

Which of the following factors determine the actual O₂ provided by an air-entrainment system?
1) O₂ input flow to the jet
2) Air-to-O₂ ratio of the device
3) Resistance downstream from the jet

A)2 and 3 only
B)1 and 2 only
C)1, 2, and 3
D)1 and 3 only

Question 54

Which of the following are components of a typical O₂ blender?
1) Precision metering device or mixture control
2) Audible dual low-pressure alarm system
3) Pressure regulating and equalizing valves
4) Variable-size air-entrainment port

A)2 and 4 only
B)1, 2, and 3 only
C)3 and 4 only
D)1, 3, and 4 only

Question 55

Which of the following alternatives may increase the FiO₂ capabilities of air-entrainment nebulizers?
1) Add open reservoir to expiratory side of T tube.
2) Connect together two or more nebulizers.
3) Use a commercial dual-flow system.
4) Add open reservoir to inspiratory side of T tube.

A)1 and 2 only
B)1, 2, and 3 only
C)1 and 4 only
D)1, 2, 3, and 4

Question 56

You note that the air intake ports surrounding the jet of a 35% air-entrainment mask are partially obstructed by the patient's bedding. Which of the following would you expect?
1) Decrease in the device's total output flow
2) Increase in the percent O₂ delivered by the device
3) Change in the FiO₂ received by the patient

A)1 and 2 only
B)2 and 3 only
C)1 and 3 only
D)1, 2, and 3

Question 57

A 45-year-old patient with congestive heart failure is receiving O₂ through a 35% air-entrainment mask. With an O₂ input of 6 L/min, what is the total output gas flow?

A) 16 L/min
B) 24 L/min
C) 28 L/min
D) 36 L/min

Question 58

What is the problem with input flows greater than 10 to 15 L/min in an infant Oxy-Hood?

A) Production of harmful noise levels
B) Difficulty in maintaining adequate humidification
C) Difficulty in maintaining stable high FiO₂ values
D) Increased likelihood of cold stress

Question 59

You connect an intubated patient to an air-entrainment nebulizer system through a T tube set at 60% with an input flow of 15 L/min. Toward the middle of inspiration, you observe that mist stops exiting from the open end of the T tube. What does this indicate?

A) Flow is adequate to meet patient needs.
B) Patient has a low inspiratory flow rate.
C) Flowmeter must be calibrated.
D) Patient is not receiving 60% O₂.

Question 60

What is the maximum FiO₂ expected to be delivered by most air-entrainment masks?

A) 30%
B) 40%
C) 50%
D) 60%

Question 61

Physiologic effects of inhaled nitric oxide (NO) include which of the following?
1) Recruitment of collapsed alveoli
2) Improved blood flow to ventilated alveoli
3) Decreased pulmonary vascular resistance
4) Reduced intrapulmonary shunting

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 62

Which of the following would indicate adequate oxygenation for adult patients with chronic lung disease and an accompanying acute-on-chronic hypoxemia?
1) SaO₂ of 90% or higher
2) PaO₂ of 50 to 60 mm Hg
3) SaO₂ of 85% to 90%

A)1 and 2 only
B)2 and 3 only
C)1 and 3 only
D)1, 2, and 3

Question 63

Which of the following conditions can be treated with hyperbaric oxygen (HBO) therapy?
1) Carbon monoxide poisoning
2) Septic shock
3) Air embolism
4) Clostridial gangrene

A)1 and 2 only
B)1, 3, and 4 only
C)3 and 4 only
D)1, 2, 3, and 4

Question 64

At what level of carboxyhemoglobin saturation is hyperbaric oxygen (HBO) therapy indicated for an adult patient?

A) Greater than 10%
B) Greater than 15%
C) Greater than 20%
D) Greater than 25%

Question 65

During hyperbaric oxygen (HBO) therapy at 3 ATA, what is the approximate half-life of blood carboxyhemoglobin?

A) 23 min
B) 80 min
C) 5 hr
D) 24 hr

Question 66

Which of the following is false about multiplace hyperbaric oxygenation chambers?

A) The chamber normally is filled with 100% O₂.
B) Air locks allow entry and egress of caregivers.
C) Pressures of 6 ATA or more can be applied.
D) Care is provided directly within the chamber.

Question 67

What are some key patient considerations in selecting O₂ therapy equipment?
1) Type of airway (natural or artificial)
2) Severity and cause of the hypoxemia
3) Age group (infant, child, adult)
4) Stability of the minute ventilation

A)2 and 4 only
B)1, 2, and 3 only
C)3 and 4 only
D)1, 2, 3, and 4

Question 68

An infant requires both a precise high FiO₂ and maintenance of a neutral thermal environment. Which of the following systems can best achieve these goals?
1) Oxy-Hood or warmed O₂ blending system without incubator
2) Heated incubator with automatic O₂ controlling system
3) Heated incubator with Oxy-Hood or O₂ blending system

A)1 and 2 only
B)2 and 3 only
C)1 and 3 only
D)1, 2, and 3

Question 69

Primary safety concerns in the application of hyperbaric oxygenation include which of the following?
1) Sudden decompression
2) Electrical fires
3) CO₂ accumulation

A)1 and 2 only
B)2 and 3 only
C)1 and 3 only
D)1, 2, and 3

Question 70

During hyperbaric oxygen therapy at 3 ATA, plasma contains about how much dissolved O₂?

A) 1 ml/dl
B) 3 ml/dl
C) 5 ml/dl
D) 7 ml/dl

Question 71

Criteria for initiating hyperbaric oxygen (HBO) therapy on an adult patient suspected of suffering from acute carbon monoxide poisoning include which of the following?
1) History of unconsciousness
2) Carboxyhemoglobin saturation less than 20%
3) Presence of neurologic abnormality
4) Presence of cardiac instability

A)2 and 3 only
B)1, 3, and 4 only
C)3 and 4 only
D)1, 2, 3, and 4

Question 72

In which of the following procedures is air embolism a potential complication?
1) Central line placement
2) Lung biopsy
3) Hemodialysis

A)1 and 2 only
B)2 and 3 only
C)1 and 3 only
D)1, 2, and 3

Question 73

What does 1 atmospheric pressure absolute (ATA) equal?
1) 101 kPa
2) 50 psi
3) 760 mm Hg

A)1 and 2 only
B)2 and 3 only
C)1 and 3 only
D)1, 2, and 3

Question 74

In which of the following clinical situations would you recommend hyperbaric oxygen (HBO) therapy, if available?
1) Carbon monoxide poisoning
2) Respiratory or cardiac arrest
3) Severe trauma
4) Cyanide poisoning

A)1 and 4 only
B)2 and 3 only
C)1, 2, 3, and 4
D)1, 2, and 4 only

Question 75

Physiologic effects of hyperbaric oxygen (HBO) therapy include all of the following except:

A) neovascularization.
B) bubble reduction.
C) enhanced immune function.
D) systemic vasodilation.

Question 76

What is the level of SpO₂ typically associated with discontinuation of O₂ therapy?

A) 88%
B) 90%
C) 92%
D) 94%

Question 77

What is the most common complication of hyperbaric oxygen therapy?

A) Air embolism
B) Pneumothorax
C) Ear or sinus barotrauma
D) Seizures or convulsions

Question 78

A patient receiving 3 L/min O₂ through a nasal cannula has a measured SpO₂ of 93% and no clinical signs of hypoxemia. At this point, what should you recommend?

A) Decreasing the flow to 2 L/min and rechecking the SpO₂
B) Maintaining the therapy as is and rechecking the SpO₂ on the next shift
C) Increasing the flow to 4 L/min and rechecking the SpO₂
D) Discontinuing the O₂ therapy

Question 79

At an FiO₂ of 1, what is the approximate half-life of blood carboxyhemoglobin?

A) 20 min
B) 80 min
C) 3 hr
D) 5 hr

Question 80

A variant of a common low-flow, nasal O₂ delivery device that is capable of providing both high humidity and a high FiO₂ is known as which of the following?

A) High-flow nasal cannula
B) Transtracheal catheter
C) Nasal catheter
D) Demand-flow oxygen