Module 4: Non-invasive Respiratory Support

Question 1

What are 4 goals of respiratory support?

Answer 1

• to achieve and maintain adequate pulmonary gas exchange
• to minimize the risk of lung injury
• to reduce patient work of breathing (WOB)
• to optimize patient comfort

Question 2

What are the effects of non-invasive respiratory support (NIRS)? (4)

Answer 2

Decreased intrapulmonary shunting (ventilation/perfusion miss match).

Increased compliance and functional residual capacity and prevention of atelectasis

Recruits additional alveoli and splints the airways

Improved oxygenation

Decreased thoracoabdominal asynchrony

Decreased obstructive and mixed apnea

Conservation of surfactant

Improved lung growth

Question 3

What are the mechanism of non invasive respiratory support (NIRS)?

Answer 3

Recruits additional alveoli, decreases pulmonary vascular resistance

Decreases pulmonary vascular resistance

Splints the airways and diaphragm, stabilizes chest wall

Supports and slows respiratory rate

Recruits alveoli, improves pulmonary blood flow, improves oxygenation

Stretches lung tissue

Question 4

What does infants need to be suitable for NIRS?

Answer 4

• respiratory drive is intact,
• but who have difficulty with maintaining ventilation due to stiff lungs (RDS, atelectasis, BPD) or energy-related issues

Question 5

What conditions where non invasive respiratory support (NIRS) is contraindicated (5)?

Answer 5

Respiratory failure defined as pH < 7.25, pCO2 > 60 (acidosis and hypercapnia)

Congenital malformations of the upper airway (T-E fistula, E.g. choanal atresia, cleft palate)

Congenital diaphragmatic hernia, bowel obstruction, omphalocele, or gastroschisis

Severe cardiovascular instability

Poor respiratory drive

Question 6

What does CPAP stand for?

Answer 6

Continuous Positive Airway Pressure

Question 7

What is CPAP?

Answer 7

CPAP applies positive pressure to the airways of the spontaneously breathing infant during inhalation and expiration.

CPAP is a form of respiratory support that provides a small amount of continuous flow, or a constant pressure, to the lungs.

This small amount of pressure works to keep the alveoli open at the end of expiration, maintaining lung volumes and assisting in alveolar recruitment.

Question 8

Are neonates nose or mouth breathers?

Answer 8

• neonates are preferential nose breathers,
• which easily facilitates the application of nasal CPAP.

Question 9

How is CPAP given to neonates?

Answer 9

• This is accomplished by affixing nasal prongs or fitting a nasal mask to the infant.
• The device provides heated and humidified continuous flow from a circuit connected to a continuous gas source, mechanical ventilator designed for neonates, or a suitably equipped multipurpose ventilator - set in Non-Invasive Ventilation CPAP mode.

Question 10

What happens when CPAP maintain expiratory pressure (3)?

Answer 10

• in an increase in functional residual capacity (FRC) and
• improvement in lung compliance, and
• decreased airway resistance in the infant with unstable lung mechanics.
• This allows a greater tidal volume with subsequent reduction in the work of breathing and stabilization of minute ventilation.

Question 11

What is MAP?

Answer 11

• mean airway pressure (MAP)
• the average pressure in the lungs during one complete breath, including inspiration and expiration

Question 12

What are the 4 necessary parts to any CPAP system?

Answer 12

• A source of flow to create positive pressure
• The interface component that connects the CPAP to the neonate (prongs or mask)
• The driving force or method of positive pressure generation in the CPAP circuit, which includes the flow meter as an oxygen source and a blender or a ventilator to determine fraction of inspired oxygen (FiO2)
• The humidity and heating system.

Question 13

What are 3 ways CPAP can be delivered?

Answer 13

• by nasal ET tube placed no deeper than the nasopharynx,
• nasal prongs, or
• a tight-fitting mask.

Question 14

What are the 3 main types of CPAP?

Answer 14

• continuous flow CPAP,
• Variable Flow CPAP, and
• Bubble CPAP

Question 15

What are two ways to supply positive airway pressure to neonate in respiratory distress?

Answer 15

• constant airway pressure
• variable airway pressure

Question 16

What is constant airway pressure?

Answer 16

• airway pressure is achieved when a continuous flow creates the pressure determined by the CPAP setting on the respiratory device being used.
• The amount of flow will create the continuous positive pressure generated and applied to the lungs

Question 17

What are the two ways nasal cannula supply positive pressure?

Answer 17

• low flow nasal cannula (LFNC)
• Fisher & Paykel OptiV-Flow Jr. : Heated and humidified high flow nasal cannula is a simple, noninvasive method of oxygen delivery that can produce positive pressure in a premature infant. This device requires a 50% leak around the prongs to allow for C02 clearance.

Question 18

What are 3 things the level of pressure generated by nasal prongs depends on?

Answer 18

• flow rate,
• the type of cannula used, and the
• infant respiratory pattern (RR, TV).

Question 19

What are two concerns regarding use of OptiV-Flow Jr.?

Answer 19

inability to:
- adequately monitor the pressure level delivered
- achieving adequate humidity

Question 20

What is bubble CPAP?

Answer 20

A type of continuous flow CPAP that delivers PEEP through nasal prongs or mask interface attached to a circuit with a gas source delivering flow of 6-10 liters per minute on the inspiratory side of the circuit, and the submersion of the expiratory tubing under a designated water level (5-8 cm).

The distance from the surface of the water to the tip of the submerged tube creates the CPAP pressure delivered to the infant.

One centimeter submersed equals one centimeter of water of CPAP.

The “bubbling” of this modality creates chest wall vibration similar to that of high-frequency ventilation that may increase gas exchange, although more studies are needed to support this idea.

Question 21

What are the advantages and disadvantages of bubble CPAP?

Answer 21

Advantages:
- simple, inexpensive (compared to ventilators or other machines)

Disadvantages:
- no audible pressure disconnect alarm, and no audible warning when there are leaks in the system (If the system is not bubbling, there is no PEEP being delivered.

Question 22

What is variable flow CPAP?

Answer 22

• Variable Flow CPAP and ventilators on a NIV mode are methods used to assist spontaneous breathing infants.
• It is a form of nasal intermittent positive pressure ventilation (N-IPPV).
• The kinetic energy created by the inspiratory flow is converted to pressure creating the CPAP supplied to the patient.

Question 23

What are the common methods of delivering variable flow CPAP?

Answer 23

• by nasal prongs and mask.

**These methods are usually interchanged throughout the day to avoid areas of pressure or redness on the infant’s nose or lip.

Question 24

Does flow nasal CPAP device lead to greater lung recruitment?

Answer 24

yes
**although a nasal cannula is able to recruit lung volume, it does so at the cost of increased respiratory effort and Fio2

Question 25

What is a bi-nasal jet nozzle?

Answer 25

The amount of CPAP delivered with variable flow devices is changed by varying the amount of gas flow. A variable flow device incorporates a flow driver that varies the flow by what is called a bi-nasal jet nozzle The generator utilizes the fluidic flip mechanism which causes the direction of the gas on inspiration to be directed through the prongs to the infant and upon exhalation the gas is directed away from the prongs into the expiratory limb reducing the work of breathing. On inspiration the jet nozzle sends a set constant flow of gas down the inspiratory side of the circuit towards the nasal cavity assisting with inspiration. On expiration the anatomy of the nasal cavity causes the exhaled turbulent flow of gas to flip over to the exhalation side of the circuit so that the infant does not have to exhale against the continuous flow travelling through the inspiratory side of the circuit. This allows the infant to spontaneously breathe with less work of breathing on exhalation.

Question 26

What is biphasic mode?

Answer 26

- This mode provides bi-levels of continuous positive airway pressures. - It will provide a baseline pressure, (usually PEEP 5-7 cmH20), along with a timed pressure rise to a higher pressure, (usually 7-9 cmH20).

Question 27

What is a "sigh" in regards to biphasic mode?

Answer 27

- The shift from the lower pressure to the higher pressure level is a 'sigh'. - The number of times it cycles between the baseline and ‘sigh’ level is determined by the respiratory rate that is set (usually 20-30 bpm). - The time for which the higher pressure level is applied is determined by the set Ti (inspiratory time).

Question 28

What does it mean by biphasic mode doesn't synchronize with infant RR?

Answer 28

- The infant will breathe spontaneously at which ever pressure the device has cycled to. - When the gas flow rate is altered, the delivered pressure will change, and the infant will determine their own respiratory rate.

Question 29

What does the following setting mean? lower pressure level = 5 higher pressure level = 7 Ti= 1 sec Rate 10 /min

Answer 29

- The baby will get a CPAP of 5 cm H2O continuously but with intermittent increase of the pressure level to 7 cm H2O lasting for one second. - These increased levels of pressure will occur at a rate of 10 per minute.

Question 30

What is the goal of biphasic mode CPAP?

Answer 30

- this mode of CPAP is to provide a bit more support (sighs), to assist in opening up the alveoli (recruitment). - The Biphasic mode provides bi-level nasal CPAP for the spontaneously breathing neonate through the delivery of sighs above a baseline CPAP pressure.

Question 31

What is biphasic triggered mode?

Answer 31

This mode is exactly the same as the Pressure Assist mode in that it has two CPAP levels (lower level PEEP 5-7 and higher level/sigh PEEP 7-9). The only difference with this mode is that the increased CPAP level (CPAP 7-8) is given every time the infant triggers a breath - therefore synchronizing the increased PEEP (support) with the infant’s breath. This is done by placing an abdominal sensor on the infant. **This mode also contains a backup rate in case the infant is apneic.

Question 32

What does NIPPV stand for?

Answer 32

Nasal Intermittent Positive Pressure Ventilation

Question 33

What does NIPPV use to provide breaths?

Answer 33

- NIPPV most commonly uses a ventilator to provide intermittent breaths at peak inspiratory pressures and rates similar to those used for mechanical ventilation. - NIPPV augments continuous positive airway pressure (CPAP) with superimposed ventilator breathes to a set peak pressure (typically 15 to 22 cmH2O). - NIPPV may be delivered by mask or nasal prongs.

Question 34

What are the benefits of NIPPV?

Answer 34

useful method of augmenting the beneficial effects of NCPAP in preterm infants with apnea that is frequent or severe. Its use appears to reduce the frequency of apneas more effectively than NCPAP. NIPPV also reduces the incidence of extubation failure and the need for re-intubation within 48 hours to one week more effectively than NCPAP alone.

Question 35

What are some complications of Non-invasive respiratory support (4)

Answer 35

Nasal septal irritation and necrosis Gastric distension Pneumothorax Increased intracranial pressure Difficulty keeping prongs in place Over handling Increased noise Over distension of the lungs (inadvertent PEEP) Mucous obstruction of the airway

Question 36

What 3 signs that NIRS is effective?

Answer 36

- decreased WOB, - decrease frequency of apneas and bradycardias - improvements in oxygenation saturation and blood gas values.

Question 37

How can CPAP cause pulmonary over-distension?

Answer 37

- Choosing a CPAP level that is too large may inadvertently hyperinflate the lungs. - The hyperinflated lungs may act as a taponade on the heart and surrounding vasculature resulting in decreased venous return, thus affecting the pulmonary blood flow and cardiac output. - Over-distension can also place infants at increased risk of pneumothorax. - Aggressive use of CPAP can lead to pulmonary over-distention, which can further result in decreased pulmonary blood flow and even decreased cardiac output.

Question 38

How does CPAP cause abdominal distension?

Answer 38

- The air flow from the CPAP that is delivered to the infant can be swallowed causing gastric distension and elevation of the diaphragm, which makes lung expansion more difficult.

Question 39

Why is tube to open barrel for infants on CPAP?

Answer 39

- Be cognizant that the infant receiving CPAP therapy may needs their gastric tube to open barrel as they may have an accumulation of air in their stomach. - Recall that gas will travel from an area of high pressure to low pressure. Leaving the gastric tube open to the atmosphere may allow for this excess air to be released from the stomach and prevent some CPAP-induced distension. - Infants receiving nasal CPAP should have an orogastric tube (instead of nasogastric) for feeding and/or prevention of distension. - This will prevent additional pressure to the already sensitive nasal region and reduce problems with creating a seal when adjusting CPAP interface.

Question 40

What are 5 things a nurse check in regards to the machine when providing NIRS?

Answer 40

- Correct level of CPAP is being delivered - Correct level of O2 is being delivered (If needed) - Ensure correct amount of humidification is being provided - Ensure circuit tubing is not kinked or pulling on baby’s interface (minimize torque) - Position circuit down from the baby.

Question 41

What 2 should be re-evaluated if infant is struggling to maintain airway due to thick secretions?

Answer 41

- temperature and humidity level on the CPAP device. - The frequency of suctioning is individual to the infant.

Question 42

What are 5 feeding considerations for infants on NIRS?

Answer 42

- During this time, it is important to maintain an IV line, not only to provide nutrition, but also to provide an access line for medications in an emergency. - An orogastric (OGT) tube will be used to start feeds. - Breast or bottle feeding is not recommended for infants who require non-invasive respiratory support, as this will further increase their WOB and possibly lead to decompensation. - There is also a risk of reflux and micro-aspiration when infants on non-invasive respiratory support are orally fed. - Furthermore, keeping orogastric tubes open to air between feedings is important in prevention of abdominal distension associated with CPAP.

Question 43

What are 3 DSC for infant receiving NIRS?

Answer 43

- cuddling with parents, - swaddling, and - offering a pacifier to ease this discomfort - to ensure best practice and optimal developmentally supportive care is provided.