Deck 18: Administration of Gas Mixtures

Question 1

Which of the following medications contributes to an increased right-to-left intrapulmonary shunting?

A)Dobutamine
B)Dopamine
C)Prostacyclin
D)Prostaglandin A

Answer 1

C
The intravenous vasodilators nitroprusside and prostacyclin will relax pulmonary vasculature globally,reducing pulmonary vascular resistance,but will also increase pulmonary blood flow past nonfunctioning alveoli and intrapulmonary right-to-left shunt.

Question 2

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 4 hours 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

Answer 2

D
Studies have suggested that optimal dosing is usually in the 20- to 30-ppm range.Some infants will not respond positively.The Neonatal Inhaled Nitric Oxide Study (NINOS)trial indicated that only 6% of nonresponders will demonstrate a positive response when given NO at 80 ppm.Typically,a response would be seen almost immediately;however,it is recommended that the time allotted for determining an infant's response last no longer than 4 hours to limit the exposure to NO.

Question 3

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

Answer 3

C
Decreasing the NO or oxygen concentration is usually not an option;therefore,to reduce NO₂ delivery to the patient,reduce the duration of contact between NO and oxygen.Two methods accomplish this: (1)increase the inspiratory flow or (2)add the NO as close to the patient as possible.Each of these methods has practical limitations.Increasing the ventilator flow will reduce the time of contact between NO and oxygen before reaching the patient,but it may also affect inspiratory time,tidal volume,mean airway pressure,and so on.

Question 4

Although very small amounts of NO₂ are present at the bedside,which health care workers need to exert special precautions to minimize exposure to NO₂?

A)Nurses in the NICU
B)Air transport team members
C)Ground transport team members
D)Respiratory therapists in the NICU

Question 5

During the administration of aerosol therapy,how does a heliox mixture compare with an air-oxygen mixture as a carrier gas?

A)Less aerosol is deposited with heliox.
B)More aerosol is deposited with heliox.
C)The two gas mixtures are equally efficient.
D)Definitive data are not available.

Question 6

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?

A)Close-fitting nonrebreathing mask
B)Close-fitting partial rebreathing mask
C)Nasal cannula
D)High flow nasal cannula

Question 7

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.

Question 8

Which of the following parameters of mechanical ventilation are affected negatively by the use of heliox?

A)PEEP
B)Plateau pressure
C)Peak pressure
D)Volume

Question 9

What is the purpose of administering helium-oxygen gas mixtures to patients?

A)To reduce the work of breathing
B)To improve gas exchange
C)To increase the functional residual capacity
D)To improve pulmonary compliance

Question 10

The respiratory therapist has initiated iNO at 20 ppm for an infant with pulmonary hypertension.After 2 hours a blood gas test reveals a 10% improvement in SaO₂.What should the therapist do?

A)Keep iNO at 20 ppm and wait at least 2 hours before considering any change.
B)Increase iNO to 30 ppm and keep the same Fio₂.
C)Keep iNO at 20 ppm and wean the Fio₂ by 10%.
D)Increase iNO to 30 ppm with no changes in Fio₂.

Question 11

Vascular smooth muscle is largely dependent on which of the following
Intracellular ions?

A)Na+
B)K+
C)Ca²+
D)Mg²+

Question 12

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.

Question 13

What is the potential benefit of adding heliox to patients who have status asthmaticus while undergoing mechanical ventilation?

A)To improve pulmonary compliance
B)To reverse bronchospasm
C)To minimize air trapping
D)To facilitate the removal of tracheobronchial secretions

Question 14

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?

A)5.5 L/minute
B)10 L/minute
C)12.5 L/minute
D)18 L/minute

Question 15

What is the primary physiologic activity of inhaled nitric oxide?

A)Bronchodilation
B)Pulmonary vasodilation
C)Systemic vasodilation
D)Cerebral vasodilation

Question 16

An infant has been receiving iNO for the last 3 days.Which important level should be monitored when ordering a co-oximetry?

A)Methemoglobin
B)Carboxyhemoglobin
C)Reduced hemoglobin
D)Oxyhemoglobin

Question 17

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

Question 18

An infant on high-flow nasal cannula also requires administration of albuterol every 6 hours.The flow of the cannula was adjusted from 4 to 5 liters per minute.How could this affect the aerosol delivery to this infant?

A)It will be unchanged.
B)It will decrease.
C)It will increase.
D)It will increase only if the infant's respiratory rate increases.

Question 19

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.

Question 20

Inhaled NO has been administered to an infant for nearly 4 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.

Question 21

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

Question 22

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?

A)Change heliox to 100% helium
B)Administer nitrogen
C)Administer inhaled anesthetics
D)Add iNO

Question 23

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

Question 24

Which of the following inhaled anesthetics should the therapist recommend to administer via a face mask to a conscious,spontaneously breathing pediatric patient who has status asthmaticus?

A)Isoflurane
B)Enflurane
C)Sevoflurane
D)Halothane