Neonatal pulmonary disorders may require additional respiratory support beyond supplemental oxygen, such as nasal CPAP, HFNC, nasal BiPAP, NIPPV, nHFOV, or even NIV-NAVA.

By Bill Pruitt, MBA, RRT, CPFT, FAARC


Neonates often require support to achieve adequate oxygenation and ventilation due to the premature condition of their lungs. Issues such as apnea of prematurity, persistent pulmonary hypertension of the newborn (PPHN), and respiratory distress syndrome (RDS) are frequently treated with oxygen therapy combined with another application. These additional therapies may include nasal continuous positive airway pressure (nCPAP), high-flow nasal cannula (HFNC), nasal bilevel positive airway pressure (nBiPAP), noninvasive positive pressure ventilation (NIPPV), noninvasive high-frequency oscillatory ventilation (nHFOV), or noninvasive neurally adjusted ventilatory (NIV-NAVA).

Pediatric patients may also need extra support, mainly due to acute situations (ie, trauma, near-drowning, severe infection, post-operative respiratory failure) or chronic conditions such as upper airway obstruction, neuromuscular or musculoskeletal disease, lower respiratory tract diseases, and abnormalities in the control of breathing.1 Most of the same approaches mentioned above are applied in pediatric patients (nCPAP, HFNC, nBiPAP, etc).

Intubation and invasive mechanical ventilation may be considered in cases where a noninvasive approach is failing or is not tolerated, but with invasive ventilation, many areas of risk increase. Complications such as upper airway trauma, laryngeal swelling, post-extubation vocal cord dysfunction, increased use of sedation, ventilator-associated lung injury and pneumonia, longer hospitalization, and nosocomial infection may occur with invasive ventilation. This article will discuss the approaches that provide high-level support with a focus on new technology, best practices, and how they differ or excel compared to the other approaches.

Nasal CPAP (nCPAP)

Respiratory care for neonatal and pediatric patients is driven by the presenting signs and symptoms and, in neonates, linked to gestational age (See Table 1 Classification based on gestational age).2 Most need low flow oxygen therapy at the minimum but when respiratory distress develops (detected by tachypnea, grunting, nasal flaring) nCPAP is often applied.3 Beyond providing supplemental oxygen, nCPAP increases functional residual capacity (FRC) and helps support and recruit alveoli in the face of increased risk of atelectasis due to immature lungs. Additionally, the positive pressure helps support and keep airways open. nCPAP can be provided by three approaches:

  • Fluidic CPAP (or variable flow CPAP) has two flow paths, one for inspiratory flow from the CPAP device, and the other for expiratory flow from the patient. The expiratory path has little to no resistance, so expiration is unimpeded. This approach makes the transition from inspiration to expiration very quick and reduces the work of breathing for premature babies.4
  • Constant flow systems utilize a standard ventilator circuit and includes a continuous bias flow. Many ventilator models can respond to neonates who are in distress by opening a demand valve to provide for higher flow rates in the face of increased demand. One drawback is that in very premature infants, the ventilator demand valve system might not recognize very weak respiratory efforts and not trigger to provide the extra flow.4
  • Bubble CPAP is a system that is the least expensive and calls to mind the positive end expiratory pressure (PEEP) water columns used in early mechanical ventilation in the 1970’s. The circuit has an inspiratory and expiratory heated tubing with inspiratory flow coming from a blender running through a humidifier to the nasal cannula. Expiratory flow passes through a water column, providing expiratory resistance and thus generating PEEP. PEEP is adjusted by the changing the depth of the tubing submersion in the water column. Additionally, the amount of constant flow through the system contributes to the level of PEEP. Pressure is monitored with a pressure manometer. Continuous flow (generally between 4 to 8 LPM) generates bubbling which provides mild oscillations between 5 to 20 Hz on average within the airways.4

Table 1. Classification based on gestational age

Term> 37 Weeks
Late preterm34 weeks to <37 weeks
Moderate preterm32 weeks to < 34 weeks
Very preterm< 32 weeks
Extremely preterm< 28 weeks
Adapted from UpToDate website: Classification of prematurity categorized by birth weight or gestational age. 2023.


High-flow Nasal Cannula (HFNC)

HFNC systems provide heated, fully saturated blended gas with an inspiratory flow ranging from 4 to 8 LPM in neonates. The inspiratory flow is high enough to generate positive airway pressure from about 2 to 5 cmH2O, which increases oxygenation by increasing FRC and recruiting/supporting alveoli. The high inspiratory flow rate washes out nasopharyngeal dead space, thus improving effective alveolar ventilation (shown in a 2020 publication by measuring end-expiratory CO2—or pEECO2). Note in this research project the authors found no significant change in transcutaneous CO2. HFNC has also been shown to reduce respiratory rate in pre-term infants.5 Significant differences in positive airway pressure can occur with an open versus closed mouth (lower when mouth is open), and pressure also drops if the nasal canula gets dislodged. Open versus closed mouth also affects the washout effect, reflected in a lower pEECO2 if the mouth is open.5

HFNC systems are linked to specific humidification devices and cannula that are not interchangeable between different systems. Also, in comparison to nCPAP, the HFNC prongs are shorter and smaller in diameter. In sizing the HFNC, the prongs should take up <50% of the internal diameter of the nares to allow for sufficient leak and to avoid problems with generating excessive pressure in the nasopharynx.4 Several HFNC systems are available on the market, including systems by Dräger, Fisher & Paykel Healthcare, Vapotherm, and Maxtec.

Nasal Bilevel Positive Airway Pressure (nBiPAP)

nBiPAP delivers a set inspiratory pressure airway pressure (iPAP) and a set expiratory (ePAP), thereby providing an inspiratory “boost” in the same manner as a pressure-supported breath on inspiration and a baseline CPAP during the expiratory phase. The augmented inspiratory flow provided by the iPAP increases tidal volume and reduces work of breathing. nBiPAP may be delivered through a single limb or double limb circuit and is provided either by a dedicated BiPAP device, or a critical care ventilator that has the capability of providing the BiPAP mode.

Increased ventilation occurs with an increase in the net difference between the iPAP and the ePAP settings, thus helping remove CO2. A set iPAP of 12 cmH2O and a set ePAP of 5 cmH2O (net change of 7 cmH20) will remove more CO2 than an iPAP/ePAP setting of 10 and 6 cmH2O (net change of 4 cmH2O). The mean airway pressure (MAP) and baseline ePAP support oxygenation by increasing FRC and recruiting/supporting alveoli. The mode can be either synchronized or unsynchronized and the rate usually is set between 10 to 30 breaths/min.

The UpToDate website source on “Respiratory support, oxygen delivery, and oxygen monitoring in the newborn” (last updated August 2022) states that, “Data are insufficient to determine whether bilevel nCPAP provides any advantage over standard CPAP for respiratory support in neonates.”4

Noninvasive Positive Pressure Ventilation (NIPPV)

Noninvasive positive pressure ventilation is often used for acute or impending respiratory failure in neonates and pediatric patients. NIPPV can be set up to either be synchronized with each spontaneous effort or unsynchronized—thus providing a set number of breaths based on the rate (timed breaths). NIPPV often uses a pressure control approach rather than volume control to have more control over potential high pressures that can be seen in volume control. However, volume-targeted ventilation modes are beginning to be used where a targeted tidal volume is set and the ventilator adjusts the peak inspiratory pressure over time to achieve the targeted volume (with limits set in place to avoid high pressures).

NIPPV is contraindicated in cases involving cardiopulmonary arrest, impaired mental status, high risk of aspiration, or in patients who need airway protection (ie, epiglottitis, upper airway edema, burns).6 These cases should be managed by intubation and mechanical ventilation. In addition, NIPPV may not be appropriate in cases involving:

  • Hemodynamic instability with use of vasopressors
  • Upper gastrointestinal bleeding
  • Facial injuries or facial abnormalities that would interfere with a good seal
  • Untreated pneumothorax (however, NIPPV may be used once a chest tube is inserted)6

Often, NIPPV is provided through a nasal or full-face mask, but nasal prongs may also be used as an interface. The nasal applications are most common in infants because they allow access to the face and allow for oral feeding.7 Protection of the skin is important and problems involving skin irritation and breakdown can be reduced/avoided by several actions:

  • use of a hydrocolloid dressing on the nasal bridge,
  • selecting the most appropriate fit for a mask so pressure is more equally distributed
  • use of a mask that includes air or gel cushions
  • use of alternating interfaces if feasible (ie, switching between mask and prongs)6

The interface is often held in place in infants and younger children by using a form-fitting cap with straps connected to the interface.

Settings for NIPPV include FiO2 to target an SaO2 of >92% to 95%. The peak pressure setting is usually between 15 to 22 cmH2O and a suitable baseline PEEP to try and keep the FiO2 <50%.6-7 Compared to HFNC, NIPPV was shown to have a lower work of breathing (WOB) and less thoracoabdominal asynchrony.7 In a recent meta-analysis, NIPPV was found to be superior to CPAP in preventing progression to invasive ventilation and decreasing the incidence of treatment failure (defined as any need for additional support). However, the evidence in these findings were judged to be low to moderate.7

Synchronized NIPPV can be done by either by use of pneumatic capsules to detect abdominal wall movement (Graseby’s capsule) or by flow triggering. However, in cases involving high spontaneous breathing rates, trigger delays and inconsistent trigger response can be a problem.7 Flow triggering is most often used but is not considered completely reliable due to possible leaks at the mouth and nose which effect the sensitivity needed to trigger a breath.7-8 Regardless of these issues, synchronized NIPPV has been found to be superior to non-synchronized NIPPV and nCPAP in reducing the need for intubation, improving successful extubation, and treating apnea of prematurity.7

Noninvasive High-frequency Oscillatory Ventilation (nHFOV)

Noninvasive High-frequency Oscillatory Ventilation is used mainly in the neonatal population and ventilates the lungs using high respiratory rates measured in hertz (Hz). Rates are set in the range of 5 to 8 Hz which is equivalent to 300 to 480 breaths per minute. The tidal volume delivered is very small, sometimes less than the dead space. nHFOV offers several advantages including no need for synchronization, increased removal of CO2, less risk of volutrauma/barotrauma, and increased FRC.8 For a more extensive discussion of HFOV see the booklet produced by Dräger, the manufacturer of the BabyLog ventilator (reference 9).

Settings needed to establish nHFOV include:

  • respiratory rate or frequency (the main determinate of PaCO2)
  • amplitude (which is the primary determinate of tidal volume – initiated & titrated by looking for chest wiggles/vibrations)
  • mean airway pressure (MAP)
  • bias flow (continuous flow running through the circuit – generally starting at 20-35 LPM)
  • inspiratory time (usually starting at 33%)
  • FiO2 (generally set to target a SpO2 of 88 to 92%)10

nHFOV has been a controversial approach to caring for neonates. However, in a recent article on neonatal noninvasive respiratory support, the authors state: “While data from further clinical trials reveal contradicting results, recent meta‐analyses point towards a superiority of nHFOV compared to nCPAP in terms of CO2 clearance, avoidance of MV, and preventing of extubation failure in premature infants.”7

Noninvasive Neurally Adjusted Ventilatory Assist (NIV-NAVA)

Use of NIV-NAVA is becoming more widespread. This approach to ventilation uses a nasogastric tube that senses diaphragmatic electrical activity to provide a trigger for spontaneous breaths. This unique approach enables synchronized breaths and controls the duration of the breath and variation in inspiratory pressure based on the neonate’s diaphragmatic electrical activity.7,11 Currently, Getinge offers NAVA ventilation on its Servo ventilators.

Use of a nasogastric tube to monitor patient effort through electrical activity of the diaphragm (EAdi) has shown that conventional ventilation strategies for triggering resulted in several asynchronous problems which have been classified as major (including ineffective triggering, auto-triggering, and double triggering) or minor (including premature or anticipated cycling, prolonged or delayed cycling, and triggering delay).12 Beyond the use of EAdi to monitor the degree of synchrony, ultrasonic monitoring of the diaphragm is being used in research and may eventually be added to the bedside to detect asynchrony. Asynchronous ventilation increases work of breathing, is uncomfortable to the patient, and contributes to the failure of the non-invasive approaches resulting in the need to intubate and initiate invasive mechanical ventilation.12 NAVA appears to be superior to the conventional strategies to reduce asynchrony in triggering a breath, adjusting the characteristics of the breath, and cycling into expiration.13

A study published in 2022 found that use of unsynchronized NIPPV or nHFOV in extremely pre-term infants resulted in 15% to 28% fewer reintubations when compared with nCPAP and patients had fewer days receiving mechanical ventilation (the NASONE trial).14 Finally, another study published in 2023 performed a meta-analysis of the data on use of noninvasive positive pressure ventilation (NPPV) in children with acute asthma (excluding nHFNC). The research found that within four hours of initiating the therapy there was a significant improvement in SaO2, PaO2 and (eventually) length of hospitalization, and a significant decreased in PaCO2 compared to conventional therapy alone. In addition, the asthma symptom scores and respiratory rate showed acute improvement over conventional therapy.15

Conclusions

Respiratory care for neonatal and pediatric patients has evolved significantly over the past 50 years and has offered much hope and success in saving lives. The range of options has expanded a great deal, moving from providing only supplemental oxygen to high-tech (and expensive) ventilation strategies along with greatly improved monitoring systems to gauge the effectiveness of the various approaches. New modes and methods are to be expected as research continues in this arena. It is imperative for therapists to keep up with the continuing evolution to provide the best of care.

RT

Bill Pruitt, MBA, RRT, CPFT, FAARC, is a writer, lecturer, and consultant. Bill has over 40 years of experience in respiratory care in a wide variety of settings and has over 20 years teaching at the University of South Alabama in Cardiorespiratory Care. Now retired from teaching, Bill continues to provide guest lectures, participates in podcasts, and writes professionally. For more info, contact [email protected].


References

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  2. Adapted from UpToDate website: Classification of prematurity categorized by birth weight or gestational age. 2023. https://www.uptodate.com/contents/image?imageKey=PEDS%2F119362.
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