Question 1

A patient receiving bilevel ventilation develops a small leak at the interface. What action should the therapist take at this time?

Accepted Answer

Most bilevel ventilators available for commercial use are adept at delivering sufficient flow to reach the targeted level of inspiratory pressure. These devices also have a flow compensation feature that ensures that small leaks around the interface or through the mouth do not seriously impair performance. However, the capacity of NIV devices to compensate for severe leaks is limited, and the result is a greater patient/ventilation asynchrony, cited as a common reason for NIV failure in the acute setting.

Question 2

When considering NPAV devices, what is considered the most beneficial effect over NIV?

Accepted Answer

The advantage of these devices is a beneficial effect on cardiac filling pressures and volumes, a benefit found even in healthy individuals.

Question 3

A patient receiving PAV is noticed to increase breathing effort. Which parameters will the ventilator modify to respond to this patient's increased respiratory demand?
I. Increase flow
II. Increase tidal volume
III. Increase pressure
IV. Increase CPAP

Accepted Answer

Unlike PSV, which uses a preset inspiratory pressure, PAV provides inspiratory flow and pressure in proportion to the patient's spontaneous breathing effort as determined by instantaneous feedback from an in-line pneumotachometer.

Question 4

What is the clinical significance of the IPAP-EPAP gradient in bilevel NIV?

Accepted Answer

The IPAP should be set above the expiratory positive airway pressure (EPAP) to raise the child's tidal volume, "unload" the respiratory muscles, and decrease respiratory distress. The differential between the IPAP and EPAP adjustment determines the tidal volume.

Question 5

What is considered the most successful therapeutic condition where NIV can be used in children?

Accepted Answer

Perhaps the most successful experience with NIV as a rescue therapy is its use in acute exacerbations of hypercarbic respiratory failure in children with chronic neuromuscular disorders.

Question 6

Which of the following NIV interfaces should the therapist consider when a child complains of discomfort with a nasal mask?
I. Oronasal mask
II. Nasal plugs
III. Helmet
IV. Nasal pillows

Accepted Answer

Nasal plugs or pillows can be substituted for nasal masks in children who complain of discomfort with the nasal mask. Nasal plugs or pillows are not used as often because most children eventually adapt to the nasal mask very well. They may have some role in teenagers because they place no pressure on the face and do not interfere with vision.

Question 7

What level of IPAP is typically sufficient to achieve the goals of NIV in pediatric patients?

Accepted Answer

In day-to-day clinical practice, an IPAP setting between 8 and 12 cm H₂O is typically sufficient to achieve the goals of NIV in pediatric patients.

Question 8

When should NIV be selected over CPAP in children with OSA?

Accepted Answer

Although there are no clear guidelines, selection of NIV over CPAP in children with OSA is typically made in OSAs complicated by alveolar hypoventilation and hypercarbia.

Question 9

How should a volume-regulated ventilator for NIV be adjusted to deliver the appropriate tidal volume (VT) to a pediatric patient?

Accepted Answer

To appropriately adjust a volume-controlled ventilator for NIV, the delivered tidal volume should be approximately twice that of the child's physiologic tidal volume to accommodate the dead space of the nasopharynx and conducting airways.

Question 10

Which of the following restrictive disorders are likely to respond to both to NIV and CPAP in children?
I. Atelectasis
II. ARDS
III. Pneumonia
IV. Morbid obesity

Accepted Answer

Children with restrictive lung disorders (including atelectasis, pneumonia, and neuromuscular weakness) and morbid obesity typically present with hypoxemia and a reduction in functional residual capacity. Both NIV and CPAP are effective in this setting to restore end-expiratory volume.

Question 11

When a bilevel ventilator is used in the spontaneous/timed mode, at what point does the ventilator employ the timed feature?

Accepted Answer

Most bilevel pressure-targeted ventilators suitable for NIV feature CPAP, spontaneous, timed, and spontaneous/timed operating modes. In the spontaneous/timed mode, the flow-trigger feature is activated. The ventilator responds to a threshold level of inspiratory flow or to a change in volume that is initiated by the patient's spontaneous respiratory effort. At the inspiratory flow threshold, the ventilator delivers additional gas flow to reach the preset inspiratory positive airway pressure (IPAP). Exhalation occurs after the inspiratory flow peaks and then decreases to a threshold level. The ventilator triggers in the timed mode only in the event of prolonged apnea.

Question 12

HFNC has been ordered for a newborn at a rate of 2 L/minutes. What is the approximate nasopharyngeal pressure at this setting?

Accepted Answer

In a study of infants with bronchiolitis, nasopharyngeal pressures increased linearly (0.45 cm H₂O for each 1 L/minutes increase) with HFNC rates up to 6 L/minutes.

Question 13

What is the most effective way for the therapist to promote effective triggering and prevent asynchrony with NIV?

Accepted Answer

The best way for the practicing therapist to promote effective triggering and prevent asynchrony with NIV is to minimize leaks around the mask interface. In the presence of a significant leak, the inspiratory pressure target is never reached, resulting in a long inflation time as the unit delivers massive amounts of inspiratory flow in an attempt to attain the preset inspiratory pressure.

Question 14

In what particular setting has long-term use of NIV on children with cystic fibrosis been successful?

Accepted Answer

In children with advanced cystic fibrosis lung disease, long-term NIV has been successful as a bridge to lung transplantation.

Question 15

When NIV is used to ventilate pediatric patients, which operating mode of ventilation is generally used?

Accepted Answer

Pediatric patients are typically managed with NIV in the spontaneous/timed mode. The chief advantage of this mode is patient comfort.

Question 16

What is the most common complication associated with NIV among pediatric patients?

Accepted Answer

The most common minor complication reported is skin irritation due to the nasal mask (48%), leading to skin necrosis in up to 8%.

Question 17

Which of the following bilevel ventilator settings influences upper airway stability?

Accepted Answer

The EPAP adjustment with NIV primarily determines the end-expiratory lung volume and maintains the stability of the upper airway. In a typical pediatric application of NIV, EPAP levels of 6 to 8 cm H₂O are effective in improving oxygenation and preventing obstructive apnea. Most children, regardless of the setting or indication, poorly tolerate EPAP levels above 10 cm H₂O.

Question 18

What are the primary objectives of noninvasive ventilation (NIV)?
I. To increase the likelihood of successful weaning from mechanical ventilation
II. To improve respiratory gas exchange
III. To decrease the patient's work of breathing
IV. To reduce the risk of ventilator-associated pneumonia

Accepted Answer

The primary objectives of NIV in children with acute respiratory distress are to decrease the work of breathing and improve respiratory gas exchange. These objectives are outlined in Box 16-2 in the textbook.

Question 19

What effect should the therapist expect to observe after successful initiation of continuous positive airway pressure (CPAP) on a neonate who has a restrictive lung disorder?

Accepted Answer

An appropriate level of CPAP must increase end-expiratory lung volume (functional residual capacity) and thereby improve oxygenation. CPAP therapy may or may not improve tidal volume and alveolar ventilation. In children and neonates with restrictive respiratory dysfunction and decreased lung compliance, CPAP therapy can raise tidal volume.

Question 20

A child with a chronic disorder complicated by alveolar hypoventilation is placed on intermittent NIV at night. What is the primary goal of this therapy?

Accepted Answer

NIV is offered to patients with chronic hypoventilation disorders as a clinical benefit used at night to reduce the severity of daytime symptoms associated with chronic hypercarbia-headache and fatigue.

Quiz 16: Noninvasive Mechanical Ventilation of the Infant and Child