Question 1

The therapist is treating a very irritable young child with upper airway obstruction. Which oxygen device will be the most appropriate to administer the greatest concentration of helium?&#10;A) Close-fitting nonrebreathing mask&#10;B) Close-fitting partial rebreathing mask&#10;C) Nasal cannula&#10;D) High-flow nasal cannula

Accepted Answer

Spontaneously breathing patients with upper or lower airway obstruction can be given heliox via mask. Because the goal of heliox therapy is to reduce the density of the inspired gas, it is important to deliver the greatest concentration of helium. Therefore, the patient must be able to tolerate the lowest possible fractional concentration of inspired oxygen (FiO₂), and room air entrainment must be minimized, resulting in a higher fractional concentration of inspired helium (FiHe). Nasal cannulas (with the exception of high-flow nasal cannulas) and simple masks allow far too much room air entrainment, thereby diluting the helium concentration. Therefore, a close-fitting nonrebreathing mask should be used. This limitation makes the treatment of young patients difficult. Children in distress may not tolerate the tightly fitting mask required to minimize air entrainment.

Question 2

The therapist is using an oxygen flowmeter to deliver an 80:20 heliox mixture to a patient. The reading on the flowmeter is 10 L/minute. What is the actual flow received by the patient?&#10;A) 5.5 L/minute&#10;B) 10 L/minute&#10;C) 12.5 L/minute&#10;D) 18 L/minute

Accepted Answer

An 80:20 heliox mixture is 1.8 times more diffusible than oxygen. To correct for the difference in gas density, the indicated flow on the flowmeter is multiplied by 1.8. A 70:30 heliox mixture is 1.6 times more diffusible than oxygen. To obtain the accurate flow rate for this mixture, the indicated flow is multiplied by 1.6.

Question 3

After increasing the inspiratory flow of the ventilator to decrease the generation of NO₂, the therapist notices many changes in the ventilator parameters. The therapist adds the NO into the inspiratory limb of the ventilator circuit close to the patient. What will be a limitation of the procedure?

A) A larger number of oxygen radicals are produced at this position.
B) Adding NO too close to the patient reduces proper mixing, which is necessary to ensure accurate NO measurement.
C) Adding NO in this position of the circuit is contraindicated.
D) The contact time between NO and O₂ is too long to be clinically useful.

B
Adding NO into the inspiratory limb of the ventilator circuit close to the patient will reduce contact time, but it also creates monitoring difficulties. The practitioner must allow an adequate distance for proper mixing to ensure accurate NO measurement.

Accepted Answer

Adding NO into the inspiratory limb of the ventilator circuit close to the patient will reduce contact time, but it also creates monitoring difficulties. The practitioner must allow an adequate distance for proper mixing to ensure accurate NO measurement.

Question 4

How should the NO₂ alarm be set on the delivery system? A) At 2 ppm B) At 4 ppm C) At 6 ppm D) At 8 ppm

Accepted Answer

It is suggested that the high NO₂ alarm be set at 2 ppm on the delivery system to prevent toxic gas exposure to the lungs.

Question 5

Which of the following substances prevents the release of Ca²⁺ from the sarcoplasmic reticulum? A) Intracellular cGMP B) EDRF C) cGMP-dependent kinase D) Calmodulin

Accepted Answer

In the body, the process of smooth muscle relaxation uses cyclic guanosine monophosphate (cGMP) to reduce Ca²⁺ levels. In smooth muscle cells, cGMP activates cGMP-dependent kinase, preventing the release of Ca²⁺ from the sarcoplasmic reticulum, resulting in smooth muscle relaxation. In the early 1980s, researchers reported a potent smooth muscle-relaxing agent, endothelium-derived relaxing factor (EDRF), now understood to be endogenous nitric oxide.

Question 6

What is the purpose of administering helium-oxygen gas mixtures to patients?&#10;A) To reduce the work of breathing&#10;B) To improve gas exchange&#10;C) To increase the functional residual capacity&#10;D) To improve pulmonary compliance

Accepted Answer

It is important to note that helium is not used to treat the underlying cause of increased airway resistance but rather to decrease the work of breathing until more definitive therapies are effective. When helium is combined with oxygen, the resulting gas mixture density is one third that of air.

Question 7

What is the product of the reaction between oxygen and nitric oxide? A) Oxygen radicals. B) N₂O. C) NO₂. D) The two molecules do not react with each other.

Accepted Answer

When combined with oxygen, NO produces NO₂, a toxic gas. Although rare, the patient as well as health care providers can be adversely affected. Factors influencing NO₂ production are oxygen concentration, NO concentration, and time of contact between NO and oxygen.

Question 8

The therapist is evaluating a small tachypneic infant receiving heliox mixture 70:30 through an infant hood. Although the SpO₂ has improved, the child shows signs of worsening work of breathing. What is the most probable mechanism to explain this situation?

A) The FiHe is too low in a 70:30 mixture to change work of breathing in this infant.
B) The flow going through the infant hood is inadequate.
C) A greater concentration of helium is present at the top of the hood and away from the infant's nose and mouth.
D) The infant is breathing too fast; thus heliox is not reaching the airways.

Accepted Answer

Stillwell and colleagues investigated the use of heliox mixtures delivered through an infant hood. Not surprisingly, they found a greater concentration of helium at the top of the hood (due to its lower gas density), away from the infant's nose and mouth. This resulted in a lower FiHe and therefore a denser gas being delivered to the infant.

Question 9

What is the potential benefit of adding heliox to patients who have status asthmaticus while undergoing mechanical ventilation?&#10;A) To improve pulmonary compliance&#10;B) To reverse bronchospasm&#10;C) To minimize air trapping&#10;D) To facilitate the removal of tracheobronchial secretions

Accepted Answer

The use of heliox mixtures has been advocated to minimize air trapping and hemodynamic compromise and to reduce peak inspiratory pressures.

Question 10

Vascular smooth muscle is largely dependent on which of the following intracellular ions? A) Na⁺ B) K⁺ C) Ca²⁺ D) Mg²⁺

Accepted Answer

Current understanding suggests that vascular smooth muscle is largely dependent on intracellular calcium ion (Ca²⁺) concentration. Smooth muscle tissue comprises bundles of myofibrils, threadlike contractile fibers encased by the sarcoplasmic reticulum, a network of tubes or channels that store Ca²⁺.

Question 11

The respiratory therapist has initiated nitric oxide for an infant with severe refractory hypoxemia. The initial dose was 20 ppm and titrated up to 30 ppm for the last 1 hour due to lack of response. However, there still is no response. What should the therapist do?

A) Increase iNO to 40 ppm
B) Increase iNO to 60 ppm
C) Increase iNO to 80 ppm
D) Discontinue iNO and consider a different therapeutic intervention

Accepted Answer

The answer of The respiratory therapist has initiated nitric oxide...

Question 12

A patient who has been admitted with status asthmaticus is receiving beta adrenergics every 2 hours and heliox with very limited response. What should the therapist suggest at this time?&#10;A) Change heliox to 100% helium.&#10;B) Administer nitrogen.&#10;C) Administer inhaled anesthetics.&#10;D) Add iNO.

Accepted Answer

The answer of A patient who has been admitted with...

Question 13

The therapist taking care of an infant on iNO observes that the NO₂ levels have been increasing. In order to correct the situation, he increases the inspiratory flow of the ventilator. What will be some of the limitations associated with this change?
I) It reduces time of contact between NO and O₂.
II) It affects the mean airway pressure because it changes the inspiratory time.
III) It may increase the delivered tidal volume.
IV) It reduces the mean airway pressure and increases the inspiratory time.

A) I only
B) II and IV only
C) I, II, and III only
D) II, III, and IV only

Accepted Answer

The answer of The therapist taking care of an infant...

Question 14

Which of the following parameters of mechanical ventilation is affected negatively by the use of heliox?&#10;A) PEEP&#10;B) Plateau pressure&#10;C) Peak pressure&#10;D) Volume

Accepted Answer

The answer of Which of the following parameters of mechanical...

Question 15

Which of the following medications contributes to an increased right-to-left intrapulmonary shunting?&#10;A) Dobutamine&#10;B) Dopamine&#10;C) Prostacyclin&#10;D) Prostaglandin A

Accepted Answer

The answer of Which of the following medications contributes to...

Question 16

The respiratory therapist has initiated nitric oxide for an infant with severe refractory hypoxemia. The initial dose was 20 ppm and titrated up to 30 ppm for the last 1 hour due to lack of response. However, there still is no response. What should the therapist do?

A) Increase iNO to 40 ppm
B) Increase iNO to 60 ppm
C) Increase iNO to 80 ppm
D) Discontinue iNO and consider a different therapeutic intervention

Accepted Answer

The answer of The respiratory therapist has initiated iNO at...

Question 17

The therapist is performing a routine assessment and ventilator check on a patient who is receiving heliox near the wye adapter of the ventilator circuit. He notices a serious discrepancy between the set tidal and the exhaled volume. What should the therapist do to correct this situation?

A) Administer heliox through the heliox-approved inlet of the mechanical ventilator.
B) Add a 16-inch piece of corrugated tubing between the wye adapter and the place on the inspiratory limb where heliox is administered.
C) Reduce the liter flow on the heliox.
D) Adjust ventilator settings to compensate for the lower viscosity of heliox.

Accepted Answer

The answer of The therapist is performing a routine assessment...

Question 18

Inhaled NO has been administered to an infant for nearly 2 hours. The respiratory therapist notices suboptimal response and suggests HFOV. What is the principle behind the potential benefit of adding this ventilatory modality to this infant?

A) HFOV improves ventilation and reduces the formation of NO₂.
B) Lung volumes are optimized with HFOV and further enhance the effects of iNO.
C) The high frequency accelerates the diffusion of NO through the alveolar surface.
D) HFOV reduces the need for higher doses of iNO.

Accepted Answer

The answer of Inhaled NO has been administered to an...

Question 19

An infant has been receiving iNO for the last 3 days. Which important level should be monitored when ordering a co-oximetry?&#10;A) Methemoglobin&#10;B) Carboxyhemoglobin&#10;C) Reduced hemoglobin&#10;D) Oxyhemoglobin

Accepted Answer

The answer of An infant has been receiving iNO for...

Question 20

What is the primary physiologic activity of inhaled nitric oxide?&#10;A) Bronchodilation&#10;B) Pulmonary vasodilation&#10;C) Systemic vasodilation&#10;D) Cerebral vasodilation

Accepted Answer

The answer of What is the primary physiologic activity of...

Question 21

Which of the following inhaled anesthetic gases has/have demonstrated the possibility to treat status asthmaticus?
I) Halothane
II) Thromboxane
III) Isoflurane
IV) Sevoflurane

A) II only
B) I, II, and III only
C) I, III, and IV only
D) II, III, and IV only

Accepted Answer

The answer of Which of the following inhaled anesthetics should...

Question 22

Which of the following inhaled anesthetic gases has/have demonstrated the possibility to treat status asthmaticus?
I) Halothane
II) Thromboxane
III) Isoflurane
IV) Sevoflurane

A) II only
B) I, II, and III only
C) I, III, and IV only
D) II, III, and IV only

Accepted Answer

The answer of Which of the following inhaled anesthetic gases...

Deck 18: Administration of Gas Mixtures