Neurally adjusted ventilatory assist (NAVA) in preterm newborn infants with respiratory distress syndrome-a randomized controlled trial

Neurally adjusted ventilatory assist in preterm infants: A systematic review and meta-analysis

To compare the effects of neurally adjusted ventilatory assist (NAVA) with other forms of synchronized artificial ventilation in preterm infants. A systematic review of randomized and quasi-randomized controlled trials with individual group allocation, both parallel-group trials as well as crossover trials, that included preterm infants born at less than 37 weeks gestational age and compared NAVA with any other form of synchronized mechanical ventilation with or without volume guarantee. Primary outcomes were death or bronchopulmonary dysplasia (BPD) at 36 weeks, total duration of respiratory support and neurodevelopmental outcome at 2 years. Secondary outcomes consisted of important procedural and clinical outcomes. Seven studies with a total of 191 infants were included, five randomized crossover trials and two parallel group randomized trials. No significant difference in the primary outcome of death or BPD (RR: 1.08, 95% CI: 0.33-3.55) was found. Peak inspiratory pressures were significantly lower with NAVA than with other forms of ventilation (MD -1.83 cmH2O [95% CI: -2.95 to -0.71]). No difference in any other clinical or ventilatory outcome was detected. Although associated with lower peak inspiratory pressures, the use of NAVA does not result in a reduced risk of death or BPD as compared to other forms of synchronized ventilation in preterm infants. However, the certainty of evidence is low due to imprecision of the effect estimate. Larger studies are needed to detect possible short- and long-term differences between ventilation modes.

The Diaphragmatic Initiated Ventilatory Assist (DIVA) trial: study protocol for a randomized controlled trial comparing rates of extubation failure in extremely premature infants undergoing extubation to non-invasive neurally adjusted ventilatory assist versus non-synchronized nasal intermittent positive pressure ventilation

BACKGROUND

Invasive mechanical ventilation contributes to bronchopulmonary dysplasia (BPD), the most common complication of prematurity and the leading respiratory cause of childhood morbidity. Non-invasive ventilation (NIV) may limit invasive ventilation exposure and can be either synchronized or non-synchronized (NS). Pooled data suggest synchronized forms may be superior. Non-invasive neurally adjusted ventilatory assist (NIV-NAVA) delivers NIV synchronized to the neural signal for breathing, which is detected with a specialized catheter. The DIVA (Diaphragmatic Initiated Ventilatory Assist) trial aims to determine in infants born 240/7-276/7 weeks' gestation undergoing extubation whether NIV-NAVA compared to non-synchronized nasal intermittent positive pressure ventilation (NS-NIPPV) reduces the incidence of extubation failure within 5 days of extubation.

METHODS

This is a prospective, unblinded, pragmatic, multicenter phase III randomized clinical trial. Inclusion criteria are preterm infants 24-276/7 weeks gestational age who were intubated within the first 7 days of life for at least 12 h and are undergoing extubation in the first 28 postnatal days. All sites will enter an initial run-in phase, where all infants are allocated to NIV-NAVA, and an independent technical committee assesses site performance. Subsequently, all enrolled infants are randomized to NIV-NAVA or NS-NIPPV at extubation. The primary outcome is extubation failure within 5 days of extubation, defined as any of the following: (1) rise in FiO2 at least 20% from pre-extubation for > 2 h, (2) pH ≤ 7.20 or pCO2 ≥ 70 mmHg; (3) > 1 apnea requiring positive pressure ventilation (PPV) or ≥ 6 apneas requiring stimulation within 6 h; (4) emergent intubation for cardiovascular instability or surgery. Our sample size of 478 provides 90% power to detect a 15% absolute reduction in the primary outcome. Enrolled infants will be followed for safety and secondary outcomes through 36 weeks' postmenstrual age, discharge, death, or transfer.

DISCUSSION

The DIVA trial is the first large multicenter trial designed to assess the impact of NIV-NAVA on relevant clinical outcomes for preterm infants. The DIVA trial design incorporates input from clinical NAVA experts and includes innovative features, such as a run-in phase, to ensure consistent technical performance across sites.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov , trial identifier NCT05446272 , registered July 6, 2022.

Novel forms of ventilation in neonates: Neurally adjusted ventilatory assist and proportional assist ventilation

Patient-triggered modes of ventilation are currently the standard of practice in the care of term and preterm infants. Maintaining spontaneous breathing during mechanical ventilation promotes earlier weaning and possibly reduces ventilator-induced diaphragmatic dysfunction. A further development of assisted ventilation provides support in proportion to the respiratory effort and enables the patient to have full control of their ventilatory cycle. In this paper we will review the literature on two of these modes of ventilation: neurally adjusted ventilatory assist (NAVA) and proportional assist ventilation (PAV), propose future studies and suggest clinical applications of these modes.

Study protocol for a randomised cross-over trial of Neurally adjusted ventilatory Assist for Neonates with Congenital diaphragmatic hernias: the NAN-C study

BACKGROUND

Neurally adjusted ventilatory assist (NAVA) is a mode of mechanical ventilation that delivers oxygen pressures in proportion to electrical signals of the diaphragm. The proportional assistance can be adjusted by the clinician to reduce the patient's work of breathing. Several case series of infants with congenital diaphragmatic hernias (CDH) have shown that NAVA may reduce oxygenation index and mean airway pressures. To date, no clinical trial has compared NAVA to standard methods of mechanical ventilation for babies with CDH.

METHODS

The aim of this dual-centre randomised cross-over trial is to compare post-operative NAVA with assist control ventilation (ACV) for infants with CDH. If eligible, infants will be enrolled for a ventilatory support tolerance trial (VSTT) to assess their suitability for randomisation. If clinically stable during the VSTT, infants will be randomised to receive either NAVA or ACV first in a 1:1 ratio for a 4-h period. The oxygenation index, respiratory severity score and cumulative sedative medication use will be measured.

DISCUSSION

Retrospective studies comparing NAVA to ACV in neonates with congenital diaphragmatic hernia have shown the ventilatory mode may improve respiratory parameters and benefit neonates. To our knowledge, this is the first prospective cross-over trial comparing NAVA to ACV.

TRIAL REGISTRATION

NAN-C was prospectively registered on ClinicalTrials.gov NCT05839340  Registered on May 2023.

Trends in the Incidence of Bronchopulmonary Dysplasia after the Introduction of Neurally Adjusted Ventilatory Assist (NAVA)

OBJECTIVE

This study investigates the difference in the rates of bronchopulmonary dysplasia in very low birth weight infants before and after the introduction of neurally adjusted ventilatory assist (NAVA).

STUDY DESIGN

A retrospective cohort study comparing rates of Bronchopulmonary dysplasia (BPD) before and after implementation of NAVA. Eligibility criteria included all very low birth weight VLBW neonates needing ventilation. For analysis, each cohort was divided into three subgroups based on gestational age. Changes in the rate of BPD, length of stay, tracheostomy rates, invasive ventilator days, and home oxygen therapy were compared.

RESULTS

There were no differences in the incidence of BPD in neonates at 23-25 6/7 weeks' and 29-32 weeks' gestation between the two cohorts. A higher incidence of BPD was seen in the 26-28 5/7 weeks' gestation NAVA subgroup compared to controls (86% vs. 68%, p = 0.05). No significant difference was found for ventilator days, but infants in the 26-28 6/7 subgroup in the NAVA cohort had a longer length of stay (98 ± 34 days vs. 82 ± 24 days, p = 0.02), a higher percentage discharged on home oxygen therapy (45% vs. 18%, respectively, p = 0.006), and higher tracheostomy rates (3/36 vs. 0/60, p = 0.02), compared to the control group.

CONCLUSIONS

The NAVA mode was not associated with a reduction in BPD when compared to other modes of ventilation. Unexpected increases were seen in BPD rates, home oxygen therapy rates, tracheostomy rates, and the length of stay in the NAVA subgroup born at 26-28 6/7 weeks' gestation.

Diaphragmatic electromyography in infants: an overview of possible clinical applications

Preterm infants often experience breathing instability and a hampered lung function. Therefore, these infants receive cardiorespiratory monitoring and respiratory support. However, the current respiratory monitoring technique may be unreliable for especially obstructive apnea detection and classification and it does not provide insight in breathing effort. The latter makes the selection of the adequate mode and level of respiratory support difficult. Electromyography of the diaphragm (dEMG) has the potential of monitoring heart rate (HR) and respiratory rate (RR), and it provides additional information on breathing effort. This review summarizes the available evidence on the clinical potential of dEMG to provide cardiorespiratory monitoring, to synchronize patient-ventilator interaction, and to optimize the mode and level of respiratory support in the individual newborn infant. We also try to identify gaps in knowledge and future developments needed to ensure widespread implementation in clinical practice. IMPACT: Preterm infants require cardiorespiratory monitoring and respiratory support due to breathing instability and a hampered lung function. The current respiratory monitoring technique may provide unreliable measurements and does not provide insight in breathing effort, which makes the selection of the optimal respiratory support settings difficult. Measuring diaphragm activity could improve cardiorespiratory monitoring by providing insight in breathing effort and could potentially have an important role in individualizing respiratory support in newborn infants.

Spinal cord perfusion pressure correlates with breathing function in patients with acute, cervical traumatic spinal cord injuries: an observational study

OBJECTIVE

This study aims to determine the relationship between spinal cord perfusion pressure (SCPP) and breathing function in patients with acute cervical traumatic spinal cord injuries.

METHODS

We included 8 participants without cervical TSCI plus 13 patients with cervical traumatic spinal cord injuries, American Spinal Injury Association Impairment Scale grades A-C. In the TSCI patients, we monitored intraspinal pressure from the injury site for up to a week and computed the SCPP as mean arterial pressure minus intraspinal pressure. Breathing function was quantified by diaphragmatic electromyography using an EDI (electrical activity of the diaphragm) nasogastric tube as well as by ultrasound of the diaphragm and the intercostal muscles performed when sitting at 20°-30°.

RESULTS

We analysed 106 ultrasound examinations (total 1370 images/videos) and 198 EDI recordings in the patients with cervical traumatic spinal cord injuries. During quiet breathing, low SCPP (< 60 mmHg) was associated with reduced EDI-peak (measure of inspiratory effort) and EDI-min (measure of the tonic activity of the diaphragm), which increased and then plateaued at SCPP 60-100 mmHg. During quiet and deep breathing, the diaphragmatic thickening fraction (force of diaphragmatic contraction) plotted versus SCPP had an inverted-U relationship, with a peak at SCPP 80-90 mmHg. Diaphragmatic excursion (up and down movement of the diaphragm) during quiet breathing did not correlate with SCPP, but diaphragmatic excursion during deep breathing plotted versus SCPP had an inverse-U relationship with a peak at SCPP 80-90 mmHg. The thickening fraction of the intercostal muscles plotted versus SCPP also had inverted-U relationship, with normal intercostal function at SCPP 80-100 mmHg, but failure of the upper and middle intercostals to contract during inspiration (i.e. abdominal breathing) at SCPP < 80 or > 100 mmHg.

CONCLUSIONS

After acute, cervical traumatic spinal cord injuries, breathing function depends on the SCPP. SCPP 80-90 mmHg correlates with optimum diaphragmatic and intercostal muscle function. Our findings raise the possibility that intervention to maintain SCPP in this range may accelerate ventilator liberation which may reduce stay in the neuro-intensive care unit.

Respiratory physiology during NAVA ventilation in neonates born with a congenital diaphragmatic hernia: The "NAVA-diaph" pilot study

BACKGROUND

Neurally adjusted ventilatory assist (NAVA) is a ventilatory mode that delivers synchronized ventilation, proportional to the electrical activity of the diaphragm (EAdi). Although it has been proposed in infants with a congenital diaphragmatic hernia (CDH), the diaphragmatic defect and the surgical repair could alter the physiology of the diaphragm.

AIM

To evaluate, in a pilot study, the relationship between the respiratory drive (EAdi) and the respiratory effort in neonates with CDH during the postsurgical period under either NAVA ventilation or conventional ventilation (CV).

METHODS

This prospective physiological study included eight neonates admitted to a neonatal intensive care unit with a diagnosis of CDH. EAdi, esophageal, gastric, and transdiaphragmatic pressure, as well as clinical parameters, were recorded during NAVA and CV (synchronized intermittent mandatory pressure ventilation) in the postsurgical period.

RESULTS

EAdi was detectable and there was a correlation between the ΔEAdi (maximal - minimal values) and the transdiaphragmatic pressure (r = 0.26, 95% confidence interval [CI] [0.222; 0.299]). There was no significant difference in terms of clinical or physiological parameters during NAVA compared to CV, including work of breathing.

CONCLUSION

Respiratory drive and effort were correlated in infants with CDH and therefore NAVA is a suitable proportional mode in this population. EAdi can also be used to monitor the diaphragm for individualized support.

The prevention and management strategies for neonatal chronic lung disease

INTRODUCTION

Survival from even very premature birth is improving, but long-term respiratory morbidity following neonatal chronic lung disease (bronchopulmonary dysplasia (BPD)) has not reduced. Affected infants may require supplementary oxygen at home, because they have more hospital admissions particularly due to viral infections and frequent, troublesome respiratory symptoms requiring treatment. Furthermore, adolescents and adults who had BPD have poorer lung function and exercise capacity.

AREAS COVERED

Antenatal and postnatal preventative strategies and management of infants with BPD. A literature review was undertaken using PubMed and Web of Science.

EXPERT OPINION

There are effective preventative strategies which include caffeine, postnatal corticosteroids, vitamin A, and volume guarantee ventilation. Side-effects, however, have appropriately caused clinicians to reduce use of systemically administered corticosteroids to infants only at risk of severe BPD. Promising preventative strategies which need further research are surfactant with budesonide, less invasive surfactant administration (LISA), neurally adjusted ventilatory assist (NAVA) and stem cells. The management of infants with established BPD is under-researched and should include identifying the optimum form of respiratory support on the neonatal unit and at home and which infants will most benefit in the long term from pulmonary vasodilators, diuretics, and bronchodilators.

New developments in neonatal respiratory management

Respiratory distress syndrome (RDS) is the major cause of respiratory failure in preterm infants due to immature lung development and surfactant deficiency. Although the concepts and methods of managing respiratory problems in neonates have changed continuously, determining appropriate respiratory treatment with minimal ventilation-induced lung injury and complications is crucially important. This review summarizes neonatal respiratory therapy's advances and available strategies (i.e., exogenous surfactant therapy, noninvasive ventilation, and different ventilation modes), focusing on RDS management.

Effect of doxapram on the electrical activity of the diaphragm waveform pattern of preterm infants

OBJECTIVE

This study aimed to evaluate the change in the waveform pattern of the electrical activity of the diaphragm (Edi) following the administration of doxapram in extremely preterm infants ventilated with neurally adjusted ventilatory assist (NAVA).

STUDY DESIGN

We conducted this retrospective cohort study in our neonatal intensive care unit between November 2019 and September 2021. The study participants were extremely preterm infants under the gestational age of 28 weeks who were ventilated with NAVA and administered doxapram. We collected the data of the Edi waveform pattern and calculated the proportion. To analyze the change in the proportion of the Edi waveform pattern, we compared the proportion of the data for 1 h before and after doxapram administration.

RESULTS

Ten extremely preterm infants were included. Almost all the patients' respiratory condition improved after doxapram administration. The ventilatory parameters-Edi peak, Edi minimum, peak inspiratory pressure, time in backup ventilation, and number of switches to backup ventilation-did not change significantly. However, the proportion of phasic pattern significantly increased (before: 46% vs. after: 72%; p < 0.05), whereas the central apnea pattern significantly decreased after doxapram administration (before: 31% vs. after: 8.3%; p < 0.05). The proportion of irregular low-voltage patterns tended to decrease, albeit with no significant changes.

CONCLUSION

Our results indicated that the proportion of Edi waveform patterns changed following doxapram administration. Edi waveform pattern analysis could be a sensitive indicator of effect with other intervention for respiratory conditions.

Implementation of neurally adjusted ventilatory assist and high flow nasal cannula in very preterm infants in a tertiary level NICU

Preterm infants treated with invasive ventilation are often affected by bronchopulmonary dysplasia, brain structure alterations, and later neurodevelopmental impairment. We studied the implementation of neurally adjusted ventilatory assist (NAVA) and high flow nasal cannula (HFNC) in a level III neonatal unit, and its effects on pulmonary and central nervous system outcomes. This retrospective cohort study included 193 surviving infants born below 32 weeks of gestation in preimplementation (2007-2008) and postimplementation (2016-2017) periods in a single study center in Finland. The proportion of infants requiring invasive ventilation decreased from 67% in the pre- to 48% in the postimplementation period (p = 0.009). Among infants treated with invasive ventilation, 68% were treated with NAVA after its implementation. At the same time, the duration of invasive ventilation of infants born at or below 28 weeks increased threefold compared with the preimplementation period (p = 0.042). The postimplementation period was characterized by a gradual replacement of nasal continuous positive airway pressure (nCPAP) with HFNC, earlier discontinuation of nCPAP, but a longer duration of positive pressure support. The proportion of normal magnetic resonance imaging (MRI) findings at term corrected age increased from 62% to 84% (p = 0.018). Cognitive outcome improved by one standard score between the study periods (p = 0.019). NAVA was used as the primary mode of ventilation in the postimplementation period. During this period, invasive ventilation time was significantly prolonged. HFNC led to a decrease in the use of nCPAP. The change in the respiratory support might have contributed to the improvement in brain MRI findings and cognitive outcomes.

Novel Ventilation Strategies to Reduce Adverse Pulmonary Outcomes

Extremely preterm infants who must suddenly support their own gas exchange with lungs that are incompletely developed and lacking adequate amount of surfactant and antioxidant defenses are susceptible to lung injury. The decades-long quest to prevent bronchopulmonary dysplasia has had limited success, in part because of increasing survival of more immature infants. The process must begin in the delivery room with gentle assistance in establishing and maintaining adequate lung aeration, followed by noninvasive support and less invasive surfactant administration. Various modalities of invasive and noninvasive support have been used with varying degree of effect and are reviewed in this article.

Neurally Adjusted Ventilatory Assist in Newborns

Patient-ventilator asynchrony is very common in newborns. Achieving synchrony is quite challenging because of small tidal volumes, high respiratory rates, and the presence of leaks. Leaks also cause unreliable monitoring of respiratory metrics. In addition, ventilator adjustment must take into account that infants have strong vagal reflexes and demonstrate central apnea and periodic breathing, with a high variability in breathing pattern. Neurally adjusted ventilatory assist (NAVA) is a mode of ventilation whereby the timing and amount of ventilatory assist is controlled by the patient's own neural respiratory drive. As NAVA uses the diaphragm electrical activity (Edi) as the controller signal, it is possible to deliver synchronized assist, both invasively and noninvasively (NIV-NAVA), to follow the variability in breathing pattern, and to monitor patient respiratory drive, independent of leaks. This article provides an updated review of the physiology and the scientific literature pertaining to the use of NAVA in children (neonatal and pediatric age groups). Both the invasive NAVA and NIV-NAVA publications since 2016 are summarized, as well as the use of Edi monitoring. Overall, the use of NAVA and Edi monitoring is feasible and safe. Compared with conventional ventilation, NAVA improves patient-ventilator interaction, provides lower peak inspiratory pressure, and lowers oxygen requirements. Evidence from several studies suggests improved comfort, less sedation requirements, less apnea, and some trends toward reduced length of stay and more successful extubation.

Neurally adjusted ventilatory assist in ventilated very preterm infants: A crossover study

OBJECTIVE

To assess the effects of neurally adjusted ventilatory assist (NAVA) ventilation on oxygenation and respiratory parameters in preterm infants.

STUDY DESIGN

An observational crossover study with a convenience sample of 19 infants born before 30 gestational weeks. Study parameters were recorded during 3-h periods of both NAVA and conventional ventilation. The proportion of time peripheral oxygen saturation (SpO₂ ) and cerebral regional oxygen saturation (cRSO₂ ) were within their target ranges, plus the number and severity of desaturation episodes were analyzed. In addition, electrical activity of the diaphragm (Edi), neural respiratory rates, and peak inspiratory pressures (PIPs) were recorded.

RESULTS

Infants were born at a median age of 26^4/7 gestational weeks (range: 23^0/7 -29^3/7 ); the study was performed at a median age of 20 days (range: 1-82). The proportion of time SpO₂ was within the target range, the number of peripheral desaturations or cRSO₂ did not differ between the modes. However, the desaturation severity index was lower (131 vs. 152; p = .03) and fewer manual supplemental oxygen adjustments (1.3 vs. 2.2/h; p = .006) were needed during the period of NAVA ventilation following conventional ventilation. The mean Edi (8.1 vs. 11.4 µV; p < .006) and PIP values (14.9 vs. 19.1; p < .001) were lower during the NAVA mode.

CONCLUSIONS

Although NAVA ventilation did not increase the proportion of time with optimal saturation, it was associated with decreased diaphragmatic activity, lower PIPs, less severe hypoxemic events, and fewer manual oxygen adjustments in very preterm infants.

Modes and strategies for providing conventional mechanical ventilation in neonates

Neonatal respiratory failure is a common and serious clinical problem which in a considerable proportion of infants requires invasive mechanical ventilation. The basic goal of mechanical ventilation is to restore lung function while limiting ventilator-induced lung injury, which is considered an important risk factor in the development of bronchopulmonary dysplasia (BPD). Over the last decades, new conventional mechanical ventilation (CMV) modalities have been introduced in clinical practice, aiming to assist clinicians in providing lung protective ventilation strategies. These modalities use more sophisticated techniques to improve patient-ventilator interaction and transfer control of ventilation from the operator to the patient. Knowledge on how these new modalities work and how they interact with lung physiology is essential for optimal and safe use. In this review, we will discuss some important basic lung physiological aspects for applying CMV, the basic principles of the old and new CMV modalities, and the evidence to support their use in daily clinical practice.

The Intertemporal Role of Respiratory Support in Improving Neonatal Outcomes: A Narrative Review

Defining improvements in healthcare can be challenging due to the need to assess multiple outcomes and measures. In neonates, although progress in respiratory support has been a key factor in improving survival, the same degree of improvement has not been documented in certain outcomes, such as bronchopulmonary dysplasia. By exploring the evolution of neonatal respiratory care over the last 60 years, this review highlights not only the scientific advances that occurred with the application of invasive mechanical ventilation but also the weakness of the existing knowledge. The contributing role of non-invasive ventilation and less-invasive surfactant administration methods as well as of certain pharmacological therapies is also discussed. Moreover, we analyze the cost-benefit of neonatal care-respiratory support and present future challenges and perspectives.

Multicenter Experience with Neurally Adjusted Ventilatory Assist in Infants with Severe Bronchopulmonary Dysplasia

OBJECTIVE

The aim of this study is to determine patterns of neurally adjusted ventilatory assist (NAVA) use in ventilator-dependent preterm infants with evolving or established severe bronchopulmonary dysplasia (sBPD) among centers of the BPD Collaborative, including indications for its initiation, discontinuation, and outcomes.

STUDY DESIGN

Retrospective review of infants with developing or established sBPD who were placed on NAVA after ≥4 weeks of mechanical ventilation and were ≥ 30 weeks of postmenstrual age (PMA).

RESULTS

Among the 13 sites of the BPD collaborative, only four centers (31%) used NAVA in the management of infants with evolving or established BPD. A total of 112 patients met inclusion criteria from these four centers. PMA, weight at the start of NAVA and median number of days on NAVA, were different among the four centers. The impact of NAVA therapy was assessed as being successful in 67% of infants, as defined by the ability to achieve respiratory stability at a lower level of ventilator support, including extubation to noninvasive positive pressure ventilation or support with a home ventilator. In total 87% (range: 78-100%) of patients survived until discharge.

CONCLUSION

We conclude that NAVA can be used safely and effectively in selective infants with sBPD. Indications and current strategies for the application of NAVA in infants with evolving or established BPD, however, are highly variable between centers. Although this pilot study suggests that NAVA may be successfully used for the management of infants with BPD, sufficient experience and well-designed clinical studies are needed to establish standards of care for defining the role of NAVA in the care of infants with sBPD.

Proportional assist and neurally adjusted ventilation: Clinical knowledge and future trials in newborn infants

Different types of patient triggered ventilator modes have become the mainstay of ventilation in term and preterm newborn infants. Maintaining spontaneous breathing has allowed for earlier weaning and the additive effects of respiratory efforts combined with pre-set mechanical inflations have reduced mean airway pressures, both of which are important components in trying to avoid lung injury and promote normal lung development. New sophisticated modes of assisted ventilation have been developed during the last decades where the control of ventilator support is turned over to the patient. The ventilator detects the respiratory effort and adjusts ventilatory assistance proportionally to each phase of the respiratory cycle, thus enabling the patient to have full control of the start, the duration and the amount of ventilatory assistance. In this paper we will review the literature on the ventilatory modes of proportional assist ventilation and neurally adjusted ventilatory assistance, examine the different ways the signals are analyzed, propose future studies, and suggest ways to apply these modes in the clinical environment.

Effect of electrical activity of the diaphragm waveform patterns on SpO2 for extremely preterm infants ventilated with neurally adjusted ventilatory assist

OBJECTIVE

This study aimed to evaluate the association between electrical activity of the diaphragm (Edi) waveform patterns and peripheral oxygen saturation (SpO₂ ) in extremely preterm infants who are ventilated with neurally adjusted ventilatory assist (NAVA).

STUDY DESIGN

We conducted a retrospective cohort study at a level III neonatal intensive care unit. Extremely preterm infants born at our hospital between November 2019 and November 2020 and ventilated with NAVA were included. We collected Edi waveform data and classified them into four Edi waveform patterns, including the phasic pattern, central apnea pattern, irregular low-voltage pattern, and tonic burst pattern. We analyzed the Edi waveform pattern for the first 15 h of collectable data in each patient. To investigate the association between Edi waveform patterns and SpO₂ , we analyzed the dataset every 5 min as one data unit. We compared the proportion of each waveform pattern between the desaturation (Desat [+]) and non-desaturation (Desat [-]) groups.

RESULTS

We analyzed collected data for 105 h (1260 data units). The proportion of the phasic pattern in the Desat (+) group was significantly lower than that in the Desat (-) group (p < .001). However, the proportions of the central apnea, irregular low-voltage, and tonic burst patterns in the Desat (+) group were significantly higher than those in the Desat (-) group (all p < .05).

CONCLUSION

Our results indicate that proportions of Edi waveform patterns have an effect on desaturation of SpO₂ in extremely preterm infants who are ventilated with NAVA.

Evidence for the Management of Bronchopulmonary Dysplasia in Very Preterm Infants

Background: Very preterm birth often results in the development of bronchopulmonary dysplasia (BPD) with an inverse correlation of gestational age and birthweight. This very preterm population is especially exposed to interventions, which affect the development of BPD. Objective: The goal of our review is to summarize the evidence on these daily procedures and provide evidence-based recommendations for the management of BPD. Methods: We conducted a systematic literature research using MEDLINE/PubMed on antenatal corticosteroids, surfactant-replacement therapy, caffeine, ventilation strategies, postnatal corticosteroids, inhaled nitric oxide, inhaled bronchodilators, macrolides, patent ductus arteriosus, fluid management, vitamin A, treatment of pulmonary hypertension and stem cell therapy. Results: Evidence provided by meta-analyses, systematic reviews, randomized controlled trials (RCTs) and large observational studies are summarized as a narrative review. Discussion: There is strong evidence for the use of antenatal corticosteroids, surfactant-replacement therapy, especially in combination with noninvasive ventilation strategies, caffeine and lung-protective ventilation strategies. A more differentiated approach has to be applied to corticosteroid treatment, the management of patent ductus arteriosus (PDA), fluid-intake and vitamin A supplementation, as well as the treatment of BPD-associated pulmonary hypertension. There is no evidence for the routine use of inhaled bronchodilators and prophylactic inhaled nitric oxide. Stem cell therapy is promising, but should be used in RCTs only.

Successful conservative managements of extensive pneumatoceles in a preterm girl: A case report

We describe a preterm girl with severe respiratory distress syndrome, which was managed with mechanical ventilation. She developed severe ventilator induced lung injury, causing extensive unilateral emphysema. CT-scan of the lungs corresponded with extensive pneumatoceles. She was managed conservatively, using neurally adjusted ventilatory assist, with success and was extubated on day of life 38. She was discharged home without any respiratory support at 39 weeks of postmenstrual age. Our case illustrates the ongoing risk of severe ventilator induced lung injury and highlights a unique injury pattern in a preterm newborn that was managed conservatively using neurally adjusted ventilatory assist with an excellent outcome.

Non-invasive Respiratory Support of the Premature Neonate: From Physics to Bench to Practice

Premature births continue to rise globally with a corresponding increase in various morbidities among this population. Rates of respiratory distress syndrome and the consequent development of Bronchopulmonary Dysplasia (BPD) are highest among the extremely preterm infants. The majority of extremely low birth weight premature neonates need some form of respiratory support during their early days of life. Invasive modes of respiratory assistance have been popular amongst care providers for many years. However, the practice of prolonged invasive mechanical ventilation is associated with an increased likelihood of developing BPD along with other comorbidities. Due to the improved understanding of the pathophysiology of BPD, and technological advances, non-invasive respiratory support is gaining popularity; whether as an initial mode of support, or for post-extubation of extremely preterm infants with respiratory insufficiency. Due to availability of a wide range of modalities, wide variations in practice exist among care providers. This review article aims to address the physical and biological basis for providing non-invasive respiratory support, the current clinical evidence, and the most recent developments in this field of Neonatology.

Application of Neurally Adjusted Ventilatory Assist in Premature Neonates Less Than 1,500 Grams With Established or Evolving Bronchopulmonary Dysplasia

Background: Very low birth weight premature (VLBW) infants with bronchopulmonary dysplasia (BPD) often need prolonged respiratory support, which is associated with worse outcomes. The application of neurally adjusted ventilatory assist ventilation (NAVA) in infants with BPD has rarely been reported. This study investigated whether NAVA is safe and can reduce the duration respiratory support in VLBW premature infants with established or evolving BPD. Methods: This retrospective matched-cohort study included patients admitted to our NICU between April 2017 to April 2019 who were born at <32 weeks' gestation with birthweight of <1,500 g. The study groups (NAVA group) were infants who received NAVA ventilation as a sequel mode of ventilation after at least 2 weeks of traditional respiratory support after birth. The control group were preterm infants who required traditional respiratory support beyond first 2 weeks of life and were closely matched to the NAVA patients by gestational age and birthweight. The primary outcome was to compare the total duration of respiratory support between the NAVA group and the control group. The secondary outcomes were comparisons of duration of invasive and non-invasive support, oxygen therapy, length of stay, severity of BPD, weight gain and sedation need between the groups. Results: There were no significant differences between NAVA group and control group in the primary and most of the secondary outcomes (all P > 0.05). However, NAVA was well tolerated and there was a decrease in the need of sedation (p = 0.012) after switching to NAVA. Conclusion: NAVA, when used as a sequel mode of ventilation, in premature neonates <1,500 g with evolving or established BPD showed a similar effect compared to conventional ventilation in respiratory outcomes. NAVA can be safely used in this patient population and potentially can decrease the need of sedation.

Proportional assist ventilation (PAV) versus neurally adjusted ventilator assist (NAVA): effect on oxygenation in infants with evolving or established bronchopulmonary dysplasia

Both proportional assist ventilation (PAV) and neurally adjusted ventilatory assist (NAVA) provide pressure support synchronised throughout the respiratory cycle proportional to the patient's respiratory demand. Our aim was to compare the effect of these two modes on oxygenation in infants with evolving or established bronchopulmonary dysplasia. Two-hour periods of PAV and NAVA were delivered in random order to 18 infants born less than 32 weeks of gestation. Quasi oxygenation indices ("OI") and alveolar-arterial ("A-a") oxygen gradients at the end of each period on PAV, NAVA and baseline ventilation were calculated using capillary blood samples. The mean "OI" was not significantly different on PAV compared to NAVA (7.8 (standard deviation (SD) 3.2) versus 8.1 (SD 3.4), respectively, p = 0.70, but lower on both than on baseline ventilation (mean baseline "OI" 11.0 (SD 5.0)), p = 0.002, 0.004, respectively). The "A-a" oxygen gradient was higher on PAV and baseline ventilation than on NAVA (20.8 (SD 12.3) and 22.9 (SD 11.8) versus 18.5 (SD 10.8) kPa, p = 0.015, < 0.001, respectively).Conclusion: Both NAVA and PAV improved oxygenation compared to conventional ventilation. There was no significant difference in the mean "OI" between the two modes, but the mean "A-a" gradient was better on NAVA.What is Known:• Proportional assist ventilation (PAV) and neurally adjusted ventilatory assist (NAVA) can improve the oxygenation index (OI) in prematurely born infants.• Both PAV and NAVA can provide support proportional to respiratory drive or demand throughout the respiratory cycle.What is New:• In infants with evolving or established BPD, using capillary blood samples, both PAV and NAVA compared to baseline ventilation resulted in improvement in the "OI", but there was no significant difference in the "OI" on PAV compared to NAVA.• The "alveolar-arterial" oxygen gradient was better on NAVA compared to PAV.

Comparison of extubation success using noninvasive positive pressure ventilation (NIPPV) versus noninvasive neurally adjusted ventilatory assist (NI-NAVA)

OBJECTIVE

Compare rates of initial extubation success in preterm infants extubated to NIPPV or NI-NAVA.

STUDY DESIGN

In this pilot study, we randomized 30 mechanically ventilated preterm infants at the time of initial elective extubation to NI-NAVA or NIPPV in a 1:1 assignment. Primary study outcome was initial extubation success.

RESULTS

Rates of continuous extubation for 120 h were 92% in the NI-NAVA group and 69% in the NIPPV group (12/13 vs. 9/13, respectively, p = 0.14). Infants extubated to NI-NAVA remained extubated longer (median 18 vs. 4 days, p = 0.02) and experienced lower peak inspiratory pressures (PIP) than infants managed with NIPPV throughout the first 3 days after extubation. Survival analysis through 14 days post extubation showed a sustained difference in the primary study outcome until 12 days post extubation.

CONCLUSIONS

Our study is the first to suggest that a strategy of extubating preterm infants to NI-NAVA may be more successful.

A Review on Non-invasive Respiratory Support for Management of Respiratory Distress in Extremely Preterm Infants

Majority of extremely preterm infants require positive pressure ventilatory support at the time of delivery or during the transitional period. Most of these infants present with respiratory distress (RD) and continue to require significant respiratory support in the neonatal intensive care unit (NICU). Bronchopulmonary dysplasia (BPD) remains as one of the major morbidities among survivors of the extremely preterm infants. BPD is associated with long-term adverse pulmonary and neurological outcomes. Invasive mechanical ventilation (IMV) and supplemental oxygen are two major risk factors for the development of BPD. Non-invasive ventilation (NIV) has been shown to decrease the need for IMV and reduce the risk of BPD when compared to IMV. This article reviews respiratory management with current NIV support strategies in extremely preterm infants both in delivery room as well as in the NICU and discusses the evidence to support commonly used NIV modes including nasal continuous positive airway pressure (NCPAP), nasal intermittent positive pressure ventilation (NIPPV), bi-level positive pressure (BI-PAP), high flow nasal cannula (HFNC), and newer NIV strategies currently being studied including, nasal high frequency ventilation (NHFV) and non-invasive neutrally adjusted ventilatory assist (NIV-NAVA). Randomized, clinical trials have shown that early NIPPV is superior to NCPAP to decrease the need for intubation and IMV in preterm infants with RD. It is also important to understand that selection of the device used to deliver NIPPV has a significant impact on its success. Ventilator generated NIPPV results in significantly lower rates of extubation failures when compared to Bi-PAP. Future studies should address synchronized NIPPV including NIV-NAVA and early rescue use of NHFV in the respiratory management of extremely preterm infants.

Nasal continuous positive airway pressure (NCPAP) or noninvasive neurally adjusted ventilatory assist (NIV-NAVA) for preterm infants with respiratory distress after birth: A randomized controlled trial

OBJECTIVES

To compare rates of treatment failure between the use of nasal continuous positive airway pressure (NCPAP) and noninvasive neurally adjusted ventilatory assist (NIV-NAVA) in infants with respiratory distress after birth.

METHODS

A randomized, unblinded, double-center trial was conducted in infants with birth weights (BWs) less than or equal to 1500 g and respiratory distress receiving noninvasive respiratory support for less than or equal to 48 hours of life; some infants were initially treated with minimally invasive surfactant therapy as the standard of care.

PRIMARY OUTCOME

need for endotracheal intubation with use of mechanical ventilation (MV) at less than or equal to 72 hours of life using prespecified failure criteria.

SECONDARY OUTCOMES

use of surfactant, duration of noninvasive support, duration of MV, bronchopulmonary dysplasia (BPD) and death.

RESULTS

A total of 123 infants were included (NCPAP group = 64 and NIV-NAVA group = 59). Population characteristics were similar between groups. No difference in the primary outcome was observed: NCPAP = 10 (15.6%) and NIV-NAVA = 12 (20.3%), P = .65. Groups were also similar in the use of surfactant (19 vs 17), duration of noninvasive support (147 ± 181 hours vs 127 ± 137 hours), BPD incidence and death. However, duration of MV was significantly longer in NCPAP group (95.6 ± 45.8 hours vs 28.25 ± 34.1 hour), P = .01.

CONCLUSION

In infants with respiratory distress after birth, no differences in treatment failures were observed between NIV-NAVA and NCPAP. These results require further evaluation in a larger study.

Alterations in Respiratory Mechanics and Neural Respiratory Drive After Restoration of Spontaneous Circulation in a Porcine Model Subjected to Different Downtimes of Cardiac Arrest

Background

The potential alterations of respiratory pathophysiology after cardiopulmonary resuscitation (CPR) are relatively undefined. While untreated arrest is known to affect post–cardiopulmonary resuscitation circulation, whether it affects respiratory pathophysiology remains unclear. We aimed to investigate the post–cardiopulmonary resuscitation changes in respiratory mechanics and neural respiratory drive with varying delays (5 or 10 minutes) in the treatment of ventricular fibrillation (VF).

Methods and Results

Twenty‐six male Yorkshire pigs were used. Anesthetized pigs weighing 38±5 kg were randomized into 3 groups (n=10 each in the VF5 and VF10 groups, with VF kept untreated for 5 and 10 minutes, respectively, and n=6 in the sham group without VF). Defibrillation was attempted after 6 minutes of cardiopulmonary resuscitation. Pulse‐induced contour cardiac output, respiratory mechanics, diaphragmatic electromyogram, blood gas, lung imaging, and histopathology were evaluated for 12 hours. Significantly elevated mean root mean square of diaphragmatic electromyogram, transdiaphragmatic pressure, and minute ventilation were observed, but reduced minute ventilation/mean root mean square, dynamic pulmonary compliance, and Pao₂ were noted in both VF groups. Despite recovery of spontaneous breathing, the abnormalities in respiratory mechanics and neural respiratory drive, Pao₂, and extravascular lung water continued to last for >12 hours. The changes in imaging (P=0.027) and histopathology (P=0.012) were more severe in the VF10 group compared with the VF5 group.

Conclusions

There is an uncoupling between the respiratory center and ventilation after restoration of spontaneous circulation. Prolonged untreated arrest from cardiac arrest contributes to more serious alterations in lung pathophysiology.

Managing neonatal pain in the era of non-invasive respiratory support

Non-invasive ventilation is currently the preferred respiratory support for premature infants with respiratory distress. The lung-protective effects of non-invasive ventilation should however not prompt disregard for the possible pain and discomfort it can generate. Non-pharmacological interventions should be used in all premature infants, regardless of their respiratory support, and are not detailed in this review. This review includes currently available evidence and gaps in knowledge regarding three aspects of pain management in premature infants receiving non-invasive ventilation: optimisation of non-invasive ventilation especially through the choice of positive pressure source, appropriate interface and synchronisation; sedative or analgesic drug use for strategies aiming at administering surfactant with reduction or avoidance of tracheal ventilation; risks and benefits of some analgesic and/or sedative drugs used to treat or prevent prolonged pain and discomfort during non-invasive ventilation. In spite of limited robust evidence, this overview should trigger caregivers' reflections on their daily practice.

Approaches to Noninvasive Respiratory Support in Preterm Infants: From CPAP to NAVA

Endotracheal intubation and invasive mechanical ventilation have been mainstays in respiratory care of neonates with respiratory distress syndrome. Together with antenatal steroids and surfactant, this approach has accounted for significant reductions in neonatal mortality. However, with the increased survival of very low birthweight infants, the incidence of bronchopulmonary dysplasia (BPD), the primary respiratory morbidity of prematurity, has also increased. Arrest of alveolar growth and development and the abnormal development of the pulmonary vasculature after birth are the primary causes of BPD. However, invasive ventilation-associated lung inflammation and airway injury have long been believed to be important contributors. In fact, discontinuing invasive ventilation in favor of noninvasive respiratory support has been considered the single best approach that neonatologists can implement to reduce BPD. In this review, we present and discuss the mechanisms, efficacy, and long-term outcomes of the four main approaches to noninvasive respiratory support of the preterm infant currently in use: nasal continuous positive airway pressure, high-flow nasal cannula, nasal intermittent mandatory ventilation, and neurally adjusted ventilatory assist. We show that noninvasive ventilation can decrease rates of intubation and the need for invasive ventilation in preterm infants with respiratory distress syndrome. However, none of these noninvasive approaches decrease rates of BPD. Accordingly, noninvasive respiratory support should be considered for clinical goals other than the reduction of BPD.

NIV NAVA versus Nasal CPAP in Premature Infants: A Randomized Clinical Trial

BACKGROUND

Noninvasive ventilation is recommended for neonatal respiratory distress to avoid adverse effects of invasive ventilation.

OBJECTIVE

The aim of this study was to compare the feasibility of noninvasive neurally adjusted ventilatory assist (NIV NAVA) and continuous positive airway pressure (CPAP) in preterm newborn infants.

METHODS

Forty preterm infants (gestational age 28+0 to 36+6 weeks) requiring CPAP and supplemental oxygen (FiO2 >0.23) for respiratory distress at <48 h of postnatal age were randomized to NIV NAVA or CPAP. The primary endpoint was the inspired oxygen concentration 12 h after study inclusion. Secondary endpoints were the duration of oxygen treatment, total duration of respiratory support, parenteral nutrition, blood gas values, patient comfort, need for invasive ventilation, and treatment complications.

RESULTS

The mean FiO2 at the time of study inclusion was 0.29 in both groups. After 12 h of treatment, FiO2 was 0.26 ± 0.07 and 0.26 ± 0.04 in the NIV NAVA and CPAP groups, respectively (difference 0.006, 95% CI -0.4 to 0.5), with no difference between the groups during the course of noninvasive ventilation (p = 0.80). Seven patients (35%) in the NIV NAVA group and 10 (50%) in the control group required intubation (difference 15%, 95% CI -15.5 to 4.3, p = 0.36). Time to intubation, gas exchange, vital parameters, pain scale, treatment complications, and neonatal outcome did not differ between the groups.

CONCLUSIONS

In the present trial, NIV NAVA had no statistically significant effect on oxygen requirements or the need for invasive ventilation in preterm newborn infants.

Neurally adjusted ventilatory assist in extremely low-birthweight infants

BACKGROUND

Neurally adjusted ventilatory assist (NAVA) is expected to improve respiratory outcomes in preterm infants, but it has not yet been evaluated. We investigated whether NAVA could improve respiratory outcomes and reduce sedation use in extremely low-birthweight infants (ELBWI).

METHODS

A retrospective cohort study was conducted based on patient charts at the Nagano Children's Hospital neonatal intensive care unit, Japan. Infants who were born at <27 weeks' gestation were included. We assessed the prevalence of bronchopulmonary dysplasia (BPD), home oxygen therapy (HOT), duration of intubation, and sedation use.

RESULTS

The NAVA group consisted of 14 ELBWI who were born at <27 weeks' gestation between September 2013 and September 2015. A total of 21 ELBWI born between September 2011 and September 2013, before NAVA implementation, served as the control group. There were no significant differences in the perinatal background characteristics between the two groups. For respiratory outcomes, no significant between-group differences were found in the prevalence of BPD and HOT or the duration of intubation. The total duration of sedation use was not significantly different between the two groups, but in the NAVA group, midazolam was discontinued in all cases after the infants were switched to NAVA.

CONCLUSIONS

NAVA was safe in preterm infants and had a similar effect to conventional mechanical ventilation with regard to respiratory outcomes and sedation use in the chronic phase; thus, NAVA could be used in the early phase, at least before BPD worsens to improve respiratory outcomes in ELBWI.

The impact of neurally adjusted ventilatory assist mode on respiratory severity score and energy expenditure in infants: a randomized crossover trial

OBJECTIVE

Examine respiratory severity scores (RSS) (mean airway pressure × fraction of inspired oxygen) and resting energy expenditure (REE) on neurally adjusted ventilatory assist (NAVA) compared with synchronized intermittent mandatory ventilation with pressure controlled and supported breath (SIMV (PC)PS).

STUDY DESIGN

A randomized, crossover trial in a level IV neonatal intensive care unit. Twenty-four patients were ventilated with NAVA or SIMV (PC) PS for 12 h and then crossed over to the alternative mode for 12 h. The primary outcome (RSS) and additional secondary respiratory outcomes were analyzed.

RESULTS

RSS and measured REE were not different between modes. On NAVA, peak inspiratory pressures were lower (17.8 vs 19.9 cmH₂O (P<0.05)) without higher oxygen requirements. Respiratory rates were higher on NAVA (52 vs 39 (P<0.05)), estimated work of breathing (WOB) (0.01 vs 0.04 J l^-1 (P<0.05)) was improved.

CONCLUSION

NAVA mode can be safe without increase in RSS or REE. Although respiratory rates were higher, this was offset by lower peak inspiratory pressures and WOB during NAVA.

Neurally adjusted ventilatory assist compared to other forms of triggered ventilation for neonatal respiratory support

BACKGROUND

Effective synchronisation of infant respiratory effort with mechanical ventilation may allow adequate gas exchange to occur at lower peak airway pressures, potentially reducing barotrauma and volutrauma and development of air leaks and bronchopulmonary dysplasia. During neurally adjusted ventilatory assist ventilation (NAVA), respiratory support is initiated upon detection of an electrical signal from the diaphragm muscle, and pressure is provided in proportion to and synchronous with electrical activity of the diaphragm (EADi). Compared to other modes of triggered ventilation, this may provide advantages in improving synchrony.

OBJECTIVES

Primary• To determine whether NAVA, when used as a primary or rescue mode of ventilation, results in reduced rates of bronchopulmonary dysplasia (BPD) or death among term and preterm newborn infants compared to other forms of triggered ventilation• To assess the safety of NAVA by determining whether it leads to greater risk of intraventricular haemorrhage (IVH), periventricular leukomalacia, or air leaks when compared to other forms of triggered ventilation Secondary• To determine whether benefits of NAVA differ by gestational age (term or preterm)• To determine whether outcomes of cross-over trials performed during the first two weeks of life include peak pressure requirements, episodes of hypocarbia or hypercarbia, oxygenation index, and the work of breathing SEARCH METHODS: We performed searches of the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cohrane Library; MEDLINE via Ovid SP (January 1966 to March 2017); Embase via Ovid SP (January 1980 to March 2017); the Cumulative Index to Nursing and Allied Health Literature (CINAHL) via EBSCO host (1982 to March 2017); and the Web of Science (1985 to 2017). We searched abstracts from annual meetings of the Pediatric Academic Societies (PAS) (2000 to 2016); meetings of the European Society of Pediatric Research (published in Pediatric Research); and meetings of the Perinatal Society of Australia and New Zealand (PSANZ) (2005 to 2016). We also searched clinical trials databases to March 2017.

SELECTION CRITERIA

We included randomised and quasi-randomised clinical trials including cross-over trials comparing NAVA with other modes of triggered ventilation (assist control ventilation (ACV),synchronous intermittent mandatory ventilation plus pressure support (SIMV ± PS), pressure support ventilation (PSV), or proportional assist ventilation (PAV)) used in neonates.

DATA COLLECTION AND ANALYSIS

Primary outcomes of interest from randomised controlled trials were all-cause mortality, bronchopulmonary dysplasia (BPD; defined as oxygen requirement at 28 days), and a combined outcome of all-cause mortality or BPD. Secondary outcomes were duration of mechanical ventilation, incidence of air leak, incidence of IVH or periventricular leukomalacia, and survival with an oxygen requirement at 36 weeks' postmenstrual age.Outcomes of interest from cross-over trials were maximum fraction of inspired oxygen, mean peak inspiratory pressure, episodes of hypocarbia, and episodes of hypercarbia measured across the time period of each arm of the cross-over. We planned to assess work of breathing; oxygenation index, and thoraco-abdominal asynchrony at the end of the time period of each arm of the cross-over study.

MAIN RESULTS

We included one randomised controlled study comparing NAVA versus patient-triggered time-cycled pressure-limited ventilation. This study found no significant difference in duration of mechanical ventilation, nor in rates of BPD, pneumothorax, or IVH.

AUTHORS' CONCLUSIONS

Risks and benefits of NAVA compared to other forms of ventilation for neonates are uncertain. Well-designed trials are required to evaluate this new form of triggered ventilation.

Feasibility and physiological effects of noninvasive neurally adjusted ventilatory assist in preterm infants

BackgroundNoninvasive neurally adjusted ventilator assist (NIV-NAVA) was introduced to our clinical practice via a pilot and a randomized observational study to assess its safety, feasibility, and short-term physiological effects.MethodsThe pilot protocol applied NIV-NAVA to 11 infants on nasal CPAP, high-flow nasal cannula, or nasal intermittent mandatory ventilation (NIMV), in multiple 2- to 4-h periods of NIV-NAVA for comparison. This provided the necessary data to design a randomized, controlled observational crossover study in eight additional infants to compare the physiological effects of NIV-NAVA with NIMV during 2-h steady-state conditions. We recorded the peak inspiratory pressure (PIP), FiO2, Edi, oxygen saturations (histogram analysis), transcutaneous PCO2, and movement with an Acoustic Respiratory Movement Sensor.ResultsThe NAVA catheter was used for 81 patient days without complications. NIV-NAVA produced significant reductions (as a percentage of measurements on NIMV) in the following: PIP, 13%; FiO2, 13%; frequency of desaturations, 42%; length of desaturations, 32%; and phasic Edi, 19%. Infant movement and caretaker movement were reduced by 42% and 27%, respectively. Neural inspiratory time was increased by 39 ms on NIV-NAVA, possibly due to Head's paradoxical reflex.ConclusionNIV-NAVA was a safe, alternative mode of noninvasive support that produced beneficial short-term physiological effects, especially compared with NIMV.