Non-invasive ventilation with neurally adjusted ventilatory assist in newborns

Non-invasive neurally adjusted ventilatory assist (NIV-NAVA) reduces extubation failures in preterm neonates-A systematic review and meta-analysis

AIM

To analyse the evidence of non-invasive neurally adjusted ventilatory assist (NIV-NAVA) in preterm neonates compared to nasal continuous positive airway pressure (nCPAP) or nasal intermittent positive pressure ventilation (NIPPV).

METHODS

We performed a systematic review and meta-analysis of randomised controlled trials and included studies where NIV-NAVA was analysed in preterm (<37 gestational weeks) born neonates. Our main outcomes were the need for endotracheal intubation, the need for surfactant therapy, and reintubation rates. Risk ratios (RRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

A total of five studies were included. The endotracheal intubation rate was 25% in the NIV-NAVA group and 26% in the nCPAP group (RR 0.91, CI: 0.56-1.48). The respective rates for surfactant therapy were 30% and 35% (RR 0.85, CI: 0.56-1.29). The reintubation rate in neonates previously invasively ventilated was 8% in the NIV-NAVA group and 29% in the nCPAP/NIPPV group (RR 0.29, 95%CI: 0.10-0.81). Evidence certainty was rated as low for all outcomes.

CONCLUSIONS

NIV-NAVA as the primary respiratory support did not reduce the need for endotracheal intubation or surfactant therapy. NIV-NAVA seemed to reduce the reintubation rate after extubation in pre-term neonates.

NIV-NAVA versus non-invasive respiratory support in preterm neonates: a meta-analysis of randomized controlled trials

OBJECTIVE

To analyze the clinical and physiological outcomes of NIV-NAVA in preterm infants compared with other non-invasive respiratory support.

STUDY DESIGN

We conducted a meta-analysis of RCTs and randomized crossover studies comparing NIV-NAVA to other non-invasive strategies in preterm neonates.

RESULTS

NIV-NAVA was superior to other non-invasive support in maximum EAdi (MD - 0.66 µV; 95% CI - 1.17 to -0.15; p = 0.01), asynchrony index (MD - 49.8%; 95% CI - 63.1 to -36.5; p < 0.01), and peak inspiratory pressure (MD - 2.2 cmH2O; 95% CI - 2.7 to -1.7; p < 0.01). However, there were no significant differences in the incidences of intubation (RR 0.91; 95% CI 0.56-1.48; p = 0.71), reintubation (RR 0.72; 95% CI 0.45-1.16; p = 0.18), or bronchopulmonary dysplasia (RR 0.77; 95% CI 0.37-1.60; p = 0.48).

CONCLUSION

NIV-NAVA was associated with improvements in maximum Edi, asynchrony index, and peak inspiratory pressure relative to other non-invasive respiratory strategies, without significant differences in clinical outcomes between groups.

Continuous Positive Airway Pressure versus Nasal Intermittent Positive Pressure Ventilation in Preterm Neonates: What if Mean Airway Pressures Were Equivalent?

Respiratory support for preterm neonates in modern neonatal intensive care units is predominantly with the use of noninvasive interfaces. Continuous positive airway pressure (CPAP) and nasal intermittent positive pressure ventilation (NIPPV) are the prototypical and most commonly utilized forms of noninvasive respiratory support, and each has unique gas flow characteristics. In meta-analyses of clinical trials till date, NIPPV has been shown to likely reduce respiratory failure and need for intubation compared to CPAP. However, a significant limitation of the included studies has been the higher mean airway pressures used during NIPPV. Thus, it is unclear to what extent any benefits seen with NIPPV are due to the cyclic pressure application versus the higher mean airway pressures. In this review, we elaborate on these limitations and summarize the available evidence comparing NIPPV and CPAP at equivalent mean airway pressures. Finally, we call for further studies comparing noninvasive respiratory support modes at equal mean airway pressures. KEY POINTS: · Most current literature on CPAP vs. NIPPV in preterm neonates is confounded by use of higher mean airway pressures during NIPPV.. · In this review, we summarize existing evidence on CPAP vs. NIPPV at equivalent mean airway pressures.. · We call for future research on noninvasive support modes to account for mean airway pressures..

Non-invasive neurally adjusted ventilatory assist (NIV-NAVA) in the neonatal intensive care unit (NICU): an Australian NICU experience

BACKGROUND

Preterm infants often require non-invasive breathing support while their lungs and control of respiration are still developing. Non-invasive neurally adjusted ventilatory assist (NIV-NAVA) is an emerging technology that allows infants to breathe spontaneously while receiving support breaths proportional to their effort. This study describes the first Australian Neonatal Intensive Care Unit (NICU) experience of NIV-NAVA.

METHODS

Retrospective cohort study of infants admitted to a major tertiary NICU between October 2017 and April 2021 supported with NIV-NAVA. Infants were divided into three groups based on the indication to initiate NIV-NAVA (post-extubation; apnoea; escalation). Successful application of NIV-NAVA was based on the need for re-intubation within 48 h of application.

RESULTS

There were 169 NIV-NAVA episodes in 122 infants (82 post-extubation; 21 apnoea; 66 escalation). The median (range) gestational age at birth was 25 + 5 weeks (23 + 1 to 43 + 3 weeks) and median (range) birthweight was 963 g (365-4320 g). At NIV-NAVA application, mean (SD) age was 17 days (18.2), and median (range) weight was 850 g (501-4310 g). Infants did not require intubation within 48 h in 145/169 (85.2%) episodes [72/82 (87.8%) extubation; 21/21 (100%) apnoea; 52/66 (78.8%) escalation).

CONCLUSION

NIV-NAVA was successfully integrated for the three main indications (escalation; post-extubation; apnoea). Prospective clinical trials are still required to establish its effectiveness versus other modes of non-invasive support.

Feasibility of synchronized high flow nasal cannula

BACKGROUND

A high-flow nasal cannula (cHFNC) delivers flow continuously (during inspiration and expiration). Using the diaphragm electrical activity (Edi), synchronizing HFNC could be an alternative (cycling high/low flow on inspiration/expiration, respectively). The objective of this study was to demonstrate the feasibility of synchronized HFNC (sHFNC) and compare it to cHFNC.

METHODS

Different levels of cHFNC and sHFNC (4, 6, 8, and 10 liters per minute [LPM], with 2 LPM on expiration for sHFNC) were compared in eight rabbits (mean weight 3.16 kg), before and after acute lung injury (pre-ALI and post-ALI). Edi, tracheal pressure (Ptr), esophageal pressure (Pes), flow, and arterial CO2 were measured. In addition to the animal study, one 3.52 kg infant received sHFNC and cHFNC using a Servo-U ventilator.

RESULTS

In the animal study, there were more pronounced decreases in Edi, reduced Pes swings and reduced PaCO2 at comparable flows during sHFNC compared to cHFNC both pre and post-ALI (p < .05). Baseline (pre-inspiratory) Ptr was 2-7 cmH2O greater during cHFNC (p < .05) indicating more dynamic hyperinflation. In one infant, the ventilator performed as expected, delivering Edi-synchronized high/low flow.

CONCLUSION

Synchronizing high flow unloaded breathing, decreased Edi, and reduced PaCO2 in an animal model and is feasible in infants.

CPAP Versus NIPPV Postextubation in Preterm Neonates: A Comparative-Effectiveness Study

BACKGROUND AND OBJECTIVES

Nasal intermittent positive pressure ventilation (NIPPV) has been shown to be superior to nasal continuous positive airway pressure (CPAP) postextubation in preterm neonates. However, studies have not permitted high CPAP pressures or rescue with other modes. We hypothesized that if CPAP pressures >8 cmH2O and rescue with other modes were permitted, CPAP would be noninferior to NIPPV.

METHODS

We conducted a pragmatic, comparative-effectiveness, noninferiority study utilizing network-based real-world data from 22 Canadian NICUs. Centers self-selected CPAP or NIPPV as their standard postextubation mode for preterm neonates <29 weeks' gestation. The primary outcome was failure of the initial mode ≤72 hours. Secondary outcomes included failure ≤7 days, and reintubation ≤72 hours and ≤7 days. Groups were compared using a noninferiority adjusted risk-difference (aRD) margin of 0.05, and margin of no difference.

RESULTS

A total of 843 infants extubated to CPAP and 974 extubated to NIPPV were included. CPAP was not noninferior (and inferior) to NIPPV for failure of the initial mode ≤72 hours (33.0% vs 26.3%; aRD 0.07 [0.03 to 0.12], Pnoninferiority(NI) = .86), and ≤7 days (40.7% vs 35.8%; aRD 0.09 [0.05 to 0.13], PNI = 0.97). However, CPAP was noninferior (and equivalent) to NIPPV for reintubation ≤72 hours (13.2% vs 16.1%; aRD 0.01 [-0.05 to 0.02], PNI < .01), and noninferior (and superior) for reintubation ≤7 days (16.4% vs 22.8%; aRD -0.04 [-0.07 to -0.001], PNI < .01).

CONCLUSIONS

CPAP was not noninferior to NIPPV for failure ≤72 hours postextubation; however, it was noninferior to NIPPV for reintubation ≤72 hours and ≤7 days. This suggests CPAP may be a reasonable initial postextubation mode if alternate rescue strategies are available.

Noninvasive respiratory support preventing reintubation after pediatric cardiac surgery-A systematic review

OBJECTIVE

To analyze the optimal postextubation respiratory support in pediatric cardiac surgery patients.

DESIGN

Systematic review of randomized controlled trials.

SETTING

Pediatric or neonatal intensive care units.

PARTICIPANTS

All aged children (<16 years) having cardiac surgery and postoperative invasive ventilation.

INTERVENTION

Noninvasive respiratory support, including high flow nasal cannula (HFNC), conventional oxygen therapy (COT), noninvasive positive pressure ventilation (NIPPV), continuous positive pressure (CPAP), and noninvasive high-frequency oscillatory ventilation (NHFOV).

MEASUREMENT AND MAIN RESULTS

Studies were not pooled for statistical synthesis due to the limited number and quality of the included studies. Risk ratios with 95% confidence intervals were calculated for individual studies. A total of 167 studies were screened and six were included. The risk of bias was low in one, high in one, and had some concerns in four of the studies. Extubation failure (defined as reintubation) was the main outcome of interest. Risk ratio for reintubation was 0.10 (CI 0.02-0.40) and 1.07 (CI 0.16-7.26) in HFNC versus COT, 0.49 (CI 0.05-5.28) in HFNC versus NIPPV, 0.40 (CI 0.08-1.94) in HFNOV versus CPAP, 0.75 (CI 0.26-2.18) in HFNOV versus NIPPV, and 1.37 (CI 0.33-5.73) in CPAP versus NIPPV. Treatment durations did not differ between the groups.

CONCLUSION

We did not find clear evidence of a difference in reintubation rates and other clinical outcomes between different noninvasive ventilation strategies. Evidence certainty was assessed to be very low due to the risk of bias, the small number of included studies, and high imprecision. Future quality studies are needed to determine the optimal postextubation support in pediatric cardiac surgery patients.

Noninvasive Ventilation

Systematic Reviews and Randomized clinical trials have shown that the use of noninvasive ventilation (NIV) compared to invasive mechanical ventilation reduces the risk of bronchopulmonary dysplasia and or mortality. Most commonly used NIV modes include nasal continuous positive airway pressure, bi-phasic modes, such as, bi-level positive airway pressure, nasal intermittent positive pressure ventilation, high flow nasal cannula, noninvasive neurally adjusted ventilatory assist, and nasal high frequency ventilation are discussed in this review.

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.

Invasive and non-invasive ventilatory strategies for early and evolving bronchopulmonary dysplasia

In the age of surfactant and antenatal steroids, neonatal care has improved outcomes of preterm infants dramatically. Since the early 2000's neonatologists have strived to decrease bronchopulmonary dysplasia (BPD) by decreasing ventilator-associated lung injury and utilizing many novel modes of non-invasive respiratory support. After the initial success with nasal continuous positive airway pressure, it was established that discontinuing invasive ventilation early in favor of non-invasive respiratory support is the most effective way to reduce the incidence of BPD. In this review, we discuss the management of the preterm lung from the time of delivery, through the phases of respiratory distress syndrome (early BPD) and then evolving BPD. The goal remains to optimize respiratory support of the preterm lung while minimizing ventilator-associated lung injury and oxygen toxicity. A multidisciplinary approach involving the medical team and family is quintessential in reaching this goal and involves adequate respiratory support, optimizing nutrition and fluid balance as well as preventing infections.

State of the art on neonatal noninvasive respiratory support: How physiological and technological principles explain the clinical outcomes

Noninvasive respiratory support has gained significant popularity in neonatal units because of its potential to reduce lung injury associated with invasive mechanical ventilation. To minimize lung injury, clinicians aim to apply for noninvasive respiratory support as early as possible. However, the physiological background and the technology behind such support modes are not always clear, and many open questions remain regarding the indications of use and clinical outcomes. This narrative review discusses the currently available evidence for various noninvasive respiratory support modes applied in Neonatal Medicine in terms of physiological effects and indications. Reviewed modes include nasal continuous positive airway pressure, nasal high-flow therapy, noninvasive high-frequency oscillatory ventilation, nasal intermittent positive pressure ventilation (NIPPV), synchronized NIPPV and noninvasive neurally adjusted ventilatory assist. To enhance clinicians' awareness of each support mode's strengths and limitations, we summarize technical features related to the functioning mechanisms of devices and the physical properties of the interfaces commonly used for providing noninvasive respiratory support to neonates. We finally address areas of current controversy and suggest possible areas of research for implementing noninvasive respiratory support in neonatal intensive care units.

Improved respiratory parameters with skin-to-skin contact in premature infants with bronchopulmonary dysplasia on NIV-NAVA

AIM

To determine if skin-to-skin contact (SSC) improved respiratory parameters in premature infants with evolving or established bronchopulmonary dysplasia (BPD) on non-invasive neutrally adjusted ventilator assist (NIV-NAVA).

METHODS

Premature infants (<32 weeks gestational age) with BPD on NIV-NAVA were studied. Continuous readings from the Edi catheter (modified nasogastric feeding tube inserted for NAVA ventilation) were compared: pre-SSC (baby in incubator) and end-SSC (just before end of SSC).

RESULTS

Sixty-five episodes of SSC were recorded in 12 premature infants with median gestational age at birth of 24.4 (23.1-27.0) weeks and birth weight of 642 (530-960) grams. Peak Edi (uV) in end-SSC 11.5 (2.7-38.7) was significantly lower compared to pre-SSC 15.8 (4.0-36.6), p < 0.001. P mean (cmH₂ O) was significantly lower in end-SSC 9.7 (7.3-15.4) compared to pre-SSC 10.3 (7.5-15.5), p = 0.008. Respiratory rate (breaths/min) was significantly lower in end-SSC 52.9 (31.1-78.1) compared to pre-SSC 53.4 (35.1-74.1), p = 0.031. There was no significant difference in inspired oxygen requirement or time on back-up mode in end-SSC 40.0 (22.1-56.1) and 5.9 (0.0-56.0) compared to pre-SSC 39.0 (26.0-56.1) and 5.1 (0.0-29.3), p = 0.556 and p = 0.853 respectively.

CONCLUSION

SSC improved respiratory parameters in premature infants with evolving or established BPD on NIV-NAVA.

Respiratory management in the premature neonate

INTRODUCTION

Advances in neonatal care have made possible the increased survival of extremely preterm infants. Even though there is widespread recognition of the harmful effects of mechanical ventilation on the developing lung, its use has become imperative in the management of micro-/nano-preemies. There is an increased emphasis on the use of less-invasive approaches such as minimally invasive surfactant therapy and non-invasive ventilation that have been proven to result in improved outcomes.

AREAS COVERED

Here, we review the evidence-based practices surrounding the respiratory management of extremely preterm infants including delivery room interventions, invasive and non-invasive ventilation approaches, and specific ventilator strategies in respiratory distress syndrome and bronchopulmonary dysplasia. Adjuvant relevant respiratory pharmacotherapies used in preterm neonates are also discussed.

EXPERT OPINION

Early use of non-invasive ventilation and use of less invasive surfactant administration are key strategies in the management of respiratory distress syndrome in preterm infants. Ventilator management in bronchopulmonary dysplasia must be tailored according to the individual phenotype. There is strong evidence to start caffeine early to improve respiratory outcomes, but evidence is lacking on the use of other pharmacological agents in preterm neonates, and an individualized approach has to be considered for their use.

Respiratory support strategies in the prevention and treatment of bronchopulmonary dysplasia

Neonates who are born preterm frequently have inadequate lung development to support independent breathing and will need respiratory support. The underdeveloped lung is also particularly susceptible to lung injury, especially during the first weeks of life. Consequently, respiratory support strategies in the early stages of premature lung disease focus on minimizing alveolar damage. As infants grow and lung disease progresses, it becomes necessary to shift respiratory support to a strategy targeting the often severe pulmonary heterogeneity and obstructive respiratory physiology. With appropriate management, time, and growth, even those children with the most extreme prematurity and severe lung disease can be expected to wean from respiratory support.

Neurally adjusted ventilatory assist in infants: A review article

Neurally adjusted ventilatory assist (NAVA) and non-invasive (NIV)-NAVA are innovative modes of synchronized and proportional respiratory support. They can synchronize with the patients' breathing and promote patient comfort. Both techniques are increasingly being used these years, however experience with their use in newborns and premature infants in Taiwan is relatively few. Because increasing evidence supports the use of NAVA and NIV-NAVA in newborns and premature infants requiring respiratory assist to achieve better synchrony, the aim of this article is to discuss whether NAVA can provide better synchronization and comfort for ventilated newborns and premature babies. In a review of recent literature, we found that NAVA and NIV-NAVA appear to be superior to conventional invasive and non-invasive ventilation. Nevertheless, some of the benefits are controversial. For example, treatment failure in premature infants is common due to insufficient triggering of electrical activity of the diaphragm (EAdi) and frequent apnea, highlighting the differences between premature infants and adults in settings and titration. Further, we suggest how to adjust the settings of NAVA and NIV-NAVA in premature infants to reduce clinical adverse events and extubation failure. In addition to assist in the use of NAVA, EAdi can also serve as a continuous and real-time monitor of vital signs, assisting physicians in the administration of sedatives, evaluation of successful extubation, and as a reference for the patient's respiratory condition during special procedures.

Ultrasonographic assessment of diaphragmatic function in preterm infants on non-invasive neurally adjusted ventilatory assist (NIV-NAVA) compared to nasal intermittent positive-pressure ventilation (NIPPV): a prospective observational study

NIV-NAVA mode for respiratory support in preterm infants is not well-studied. This study aimed to describe the diaphragmatic function, diaphragmatic excursion (DE), and thickness fraction (DTF), in preterm infants < 30 weeks' gestation supported by NIV-NAVA compared to NIPPV using bedside ultrasonography. In this consecutive prospective study, DE, diaphragmatic thickness at end of expiration (DT_exp), end of inspiration (DT_ins), and DTF were assessed using bedside ultrasound. Lung aeration evaluation using lung ultrasound score (LUS) was performed for the two groups. Diaphragmatic measurements and LUS were compared for the 2 groups (NIV-NAVA group versus NIPPV group). Statistical analyses were conducted using the SPSS software version 22. Out of 70 infants evaluated, 40 were enrolled. Twenty infants were on NIV-NAVA and 20 infants on NIPPV with a mean [SD] study age of 25.7 [0.9] weeks and 25.1 [1.4] weeks respectively (p = 0.15). Baseline characteristics and respiratory parameters at the time of the scan showed no significant difference between groups. DE was significantly higher in NIV-NAVA with a mean SD of 4.7 (1.5) mm versus 3.5 (0.9) mm in NIPPV, p = 0.007. Additionally, the mean (SD) of DTF for the NIV-NAVA group was 81.6 (30) % vs 78.2 (27) % for the NIPPV group [p = 0.71]. Both groups showed relatively high LUS but no significant difference between groups [12.8 (2.6) vs 12.6 (2.6), p = 0.8].  Conclusion: Preterm infants managed with NIV-NAVA showed significantly higher DE compared to those managed on NIPPV. This study raises the hypothesis that NIV-NAVA could potentially improve diaphragmatic function due to its synchronization with patients' own breathing. Longitudinal studies to assess diaphragmatic function over time are needed.  Trial registry: Clinicaltrials.gov (NCT05079412). Date of registration September 30, 2021. What is Known: • NIV-NAVA utilizes diaphragmatic electrical activity to provide synchronized breathing support. • Evidence for the effect of NIV-NAVA on diaphragmatic thickness fraction (DTF) and excursion (DE) is limited. What is New: • Ultrasonographic assessment of diaphragmatic function (DTF and DE) is feasible. • In preterm infants, DE was significantly higher in infants supported with NIV-NAVA compared to those supported with NIPPV.

Non-invasive ventilatory support in neonates: An evidence-based update

Non-invasive ventilatory support (NIV) is considered the gold standard in the care of preterm infants with respiratory distress syndrome (RDS). NIV from birth is superior to mechanical ventilation (MV) for the prevention of death or bronchopulmonary dysplasia (BPD), with a number needed to treat between 25 and 35. Various methods of NIV are available, some of them extensively researched and with well proven efficacy, whilst others are needing further research. Nasal continuous positive airway pressure (nCPAP) has replaced routine invasive mechanical ventilation (MV) for the initial stabilization and the treatment of RDS. Choosing the most suitable form of NIV and the most appropriate patient interface depends on several factors, including gestational age, underlying lung pathophysiology and the local facilities. In this review, we present the currently available evidence on NIV as primary ventilatory support to preventing intubation and for secondary ventilatory support, following extubation. We review nCPAP, nasal high-flow cannula, nasal intermittent positive airway pressure ventilation, bi-level positive airway pressure, nasal high-frequency oscillatory ventilation and nasal neurally adjusted ventilatory assist modes. We also discuss most suitable NIV devices and patient interfaces during resuscitation of the newborn in the delivery room.

Reference values for diaphragm electrical activity (Edi) in newborn infants

Background

Neurally adjusted ventilatory assist is an emerging mode of respiratory support that uses the electrical activity of the diaphragm (Edi) to provide synchronised inspiratory pressure support, proportional to an infant’s changing inspiratory effort. Data on Edi reference values for neonates are limited. The objective of this study was to establish reference Edi values for preterm and term neonates who are not receiving respiratory support.

Methods

This was a prospective observational study of newborn infants breathing spontaneously in room air. The Edi waveform was monitored by a specialised naso/orogastric feeding tube with embedded electrodes positioned at the level of the diaphragm. Edi minimums and peaks were recorded continuously for 4 h without changes to routine clinical handling.

Results

Twenty-four newborn infants (16 preterm [< 37 weeks’ gestation]; 8 term) were studied. All infants were breathing comfortably in room air at the time of study. Edi data were successfully captured in all infants. The mean (±SD) Edi minimum was 3.02 (±0.94) μV and the mean Edi peak was 10.13 (±3.50) μV. In preterm infants the mean (±SD) Edi minimum was 3.05 (±0.91) μV and the mean Edi peak was 9.36 (±2.13) μV. In term infants the mean (±SD) Edi minimum was 2.97 (±1.05) μV and the mean Edi peak was 11.66 (±5.14) μV.

Conclusion

Reference Edi values were established for both preterm and term neonates. These values can be used as a guide when monitoring breathing support and when using diaphragm-triggered modes of respiratory support in newborn infants

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03619-1.

Patient-Ventilator Synchrony in Extremely Premature Neonates during Non-Invasive Neurally Adjusted Ventilatory Assist or Synchronized Intermittent Positive Airway Pressure: A Randomized Crossover Pilot Trial

INTRODUCTION

Synchronization of non-invasive ventilation is challenging in extremely premature infants. We compared patient-ventilator synchrony between non-invasive neurally adjusted ventilatory assist (NIV-NAVA) using transdiaphragmatic (Edi) catheter and synchronized intermittent positive airway pressure (SiPAP) using an abdominal trigger.

METHODS

This study was a monocentric, randomized, crossover trial in premature infants born before 28 weeks of gestation, aged 3 days or more, and below 32 weeks postmenstrual age. NIV-NAVA and SiPAP were applied in a random order for 2 h with analysis of data from the second hour. The primary outcome was the asynchrony index.

RESULTS

Fourteen patients were included (median [IQR] gestational age at birth 25.6 (25.3-26.4) weeks, median [IQR] birth weight 755 [680-824] g, median [IQR] postnatal age 26.5 [19.8-33.8] days). The median (IQR) asynchrony index was significantly lower in NIV-NAVA versus SiPAP (49.9% [44.1-52.6] vs. 85.8% [74.2-90.9], p < 0.001). Ineffective efforts and auto-triggering were significantly less frequent in NIV-NAVA versus SiPAP (3.0% vs. 32.0% p < 0.001 and 10.0% vs. 26.6%, p = 0.004, respectively). Double triggering was significantly less frequent in SiPAP versus NIV-NAVA (0.0% vs. 9.0%, p < 0.001). No significant difference was observed for premature cycling and late cycling. Peak Edi and swing Edi were significantly lower in NIV-NAVA as compared to SiPAP (7.7 [6.1-9.9] vs. 11.0 [6.7-14.5] μV, p = 0.006; 5.4 [4.2-7.6] vs. 7.6 [4.3-10.8] μV, p = 0.007, respectively). No significant difference was observed between NIV-NAVA and SiPAP for heart rate, respiratory rate, COMFORTneo scores, apnoea, desaturations, or bradycardias.

DISCUSSION/CONCLUSION

NIV-NAVA markedly improves patient-ventilator synchrony as compared to SiPAP in extremely premature infants.

Neurally Adjusted Ventilatory Assist in Very Prematurely Born Infants with Evolving/Established Bronchopulmonary Dysplasia

Background  During neurally adjusted ventilatory assist (NAVA)/noninvasive (NIV) NAVA, a modified nasogastric feeding tube with electrodes monitors the electrical activity of the diaphragm (Edi). The Edi waveform determines the delivered pressure from the ventilator. Objective  Our objective was to determine whether NAVA/NIV-NAVA has advantages in infants with evolving/established bronchopulmonary dysplasia (BPD). Methods  Each infant who received NAVA/NIV-NAVA and conventional invasive and NIV was matched with two historical controls. Eighteen NAVA/NIV-NAVA infants' median gestational age, 25.3 (23.6-28.1) weeks, was compared with 36 historical controls' median gestational age 25.2 (23.1-29.1) weeks. Results  Infants on NAVA/NIV-NAVA had lower extubation failure rates (median: 0 [0-2] vs. 1 [0-6] p  = 0.002), shorter durations of invasive ventilation (median: 30.5, [1-90] vs. 40.5 [11-199] days, p  = 0.046), and total duration of invasive and NIV to the point of discharge to the local hospital (median: 80 [57-140] vs. 103.5 [60-246] days, p  = 0.026). The overall length of stay (LOS) was lower in NAVA/NIVNAVA group (111.5 [78-183] vs. 140 [82-266] days, p  = 0.019). There were no significant differences in BPD (17/18 [94%] vs. 32/36 [89%] p  = 0.511) or home oxygen rates (14/18 [78%] vs. 23/36 [64%] p  = 0.305). Conclusion  The combination of NAVA/NIV-NAVA compared with conventional invasive and NIV modes may be advantageous for preterm infants with evolving/established BPD.

Cardiorespiratory effects of NIV-NAVA, NIPPV, and NCPAP shortly after extubation in extremely preterm infants: A randomized crossover trial

OBJECTIVE

Investigate the cardiorespiratory effects of noninvasive neurally adjusted ventilatory assist (NIV-NAVA), nonsynchronized nasal intermittent positive pressure ventilation (NIPPV), and nasal continuous positive airway pressure (NCPAP) shortly after extubation.

HYPOTHESIS

Types of noninvasive pressure support and the presence of synchronization may affect cardiorespiratory parameters.

STUDY DESIGN

Randomized crossover trial.

PATIENT-SUBJECT SELECTION

Infants with birth weight (BW) 1250 g or under, undergoing their first planned extubation were randomly assigned to all three modes using a computer-generated sequence.

METHODOLOGY

Electrocardiogram and electrical activity of the diaphragm (Edi) were recorded for 30 min on each mode. Analysis of heart rate variability (HRV), diaphragmatic activity (Edi area, breath area, amplitude, inspiratory and expiratory times), and respiratory variability were compared between modes.

RESULTS

Twenty-three infants had full data recordings and analysis: Median (IQR) gestational age = 25.9 weeks (25.2-26.4), BW = 760 g (595-900), and postnatal age 7 (4-19) days. There were no differences in HRV between modes. A significantly reduced Edi area and breath amplitude, and increased coefficient of variation (CV) of breath amplitude were observed during NIV-NAVA and NIPPV compared to NCPAP. A higher proportion of assisted breaths (99% vs. 51%; p < .001) provided a higher mean airway pressure (MAP; 9.4 vs. 8.2 cmH₂ O; p = .002) with lower peak inflation pressures (PIPs; 14 vs. 16 cmH₂ O; p < .001) during NIV-NAVA compared to NIPPV.

CONCLUSIONS

NIV-NAVA and NIPPV applied shortly after extubation were associated with lower respiratory efforts and higher respiratory variability. These effects were more evident for NIV-NAVA where optimal patient-ventilator synchronization provided a higher MAP with lower PIPs.

Non-Invasive Ventilatory Strategies to Decrease Bronchopulmonary Dysplasia-Where Are We in 2021?

Recent advances in neonatology have led to the increased survival of extremely low-birth weight infants. However, the incidence of bronchopulmonary dysplasia (BPD) has not improved proportionally, partly due to increased survival of extremely premature infants born at the late-canalicular stage of lung development. Due to minimal surfactant production at this stage, these infants are at risk for severe respiratory distress syndrome, needing prolonged ventilation. While the etiology of BPD is multifactorial with antenatal, postnatal, and genetic factors playing a role, ventilator-induced lung injury is a major, potentially modifiable, risk factor implicated in its causation. Infants with BPD are at a higher risk of developing complications including sepsis, pulmonary arterial hypertension, respiratory failure, and death. Long-term problems include increased risk of hospital readmissions, respiratory infections, and asthma-like symptoms during infancy and childhood. Survivors who have BPD are also at increased risk of poor neurodevelopmental outcomes. While the ultimate solution for avoiding BPD lies in the prevention of preterm births, strategies to decrease its incidence are the need of the hour. It is time to focus on gentler modes of ventilation and the use of less invasive surfactant administration techniques to mitigate lung injury, thereby potentially decreasing the burden of BPD. In this article, we discuss the use of non-invasive ventilation in premature infants, with an emphasis on studies showing an effect on BPD with different modes of non-invasive ventilation. Practical considerations in the use of nasal intermittent positive pressure ventilation are also discussed, considering the significant heterogeneity in clinical practices and management strategies in its use.

Diaphragmatic activity and neural breathing variability during a 5-min endotracheal continuous positive airway pressure trial in extremely preterm infants

BACKGROUND

Extremely preterm infants are often exposed to endotracheal tube continuous positive airway pressure (ETT-CPAP) trials to assess extubation readiness. The effects of ETT-CPAP trial on their diaphragmatic activity (Edi) and breathing variability is unknown.

METHODS

Prospective observational study enrolling infants with birth weight ≤1250 g undergoing their first extubation attempt. Diaphragmatic activity, expressed as the absolute minimum (Edi min) and maximum values (Edi max), area under the Edi signal, and breath-by-breath analyses for breath areas, amplitudes, widths, and neural inspiratory and expiratory times, were analyzed during mechanical ventilation (MV) and ETT-CPAP. Neural breathing variability of each of these parameters was also calculated and compared between MV and ETT-CPAP.

RESULTS

Thirteen infants with median (interquartile range) birth weight of 800 g [610-920] and gestational age of 25.4 weeks [24.4-26.3] were included. Diaphragmatic activity significantly increased during ETT-CPAP when compared to MV:Edi max (44.2 vs. 38.1 μV), breath area (449 vs. 312 μV·s), and amplitude (10.12 vs. 7.46 μV). Neural breathing variability during ETT-CPAP was characterized by increased variability for amplitude and area under the breath, and decreased for breath time and width.

CONCLUSIONS

A 5-min ETT-CPAP in extremely preterm infants undergoing extubation imposed significant respiratory load with changes in respiratory variability.

IMPACT

ETT-CPAP trials are often used to assess extubation readiness in extremely preterm infants, but its effects upon their respiratory system are not well known. Diaphragmatic activity analysis demonstrated that these infants are able to mount an important response to a short trial. A 5-min trial imposed a significant respiratory load evidenced by increased diaphragmatic activity and changes in breathing variability. Differences in breathing variability were observed between successful and failed extubations, which should be explored further in extubation readiness investigations. This type of trial cannot be recommended for preterm infants in clinical practice until clear standards and accuracy are established.

Best practices, challenges and innovations in pediatrics in 2019

This paper runs through key progresses in epidemiology, pathomechanisms and therapy of various diseases in children that were issued in the Italian Journal of Pediatrics at the end of last year. Novel research and documents that explore areas such as allergy, critical care, endocrinology, gastroenterology, infectious diseases, neonatology, neurology, nutrition, and respiratory tract illnesses in children have been reported. These observations will help to control childhood illnesses.

Nasal continuous positive airway pressure versus noninvasive NAVA in preterm neonates with apnea of prematurity: a pilot study with a novel approach

BACKGROUND

Neonates with apnea of prematurity often fail CPAP because it does not provide adequate support during apnea. NAVA provides proportional ventilator support based on electrical activity of the diaphragm. When the NAVA level is 0 cmH20/mcV, the patient receives minimal support above PEEP when breathing and backup ventilation when apneic. This study compares number of clinically significant events on CPAP versus noninvasive NAVA level 0.

METHODS

Retrospective study of preterm neonates having apnea of prematurity on nasal CPAP. Patients were then placed on NAVA level 0. The number of events on each mode was collected. Statistics were paired t-test.

RESULTS

Seventeen subjects with gestational age 26.1 ± 1.7 weeks, study age 19.5 ± 12.5 days. Events decreased from 17.9 ± 7.8 on CPAP to 10.2 ± 8.1 events on NAVA level 0 (p = 0.00047).

CONCLUSIONS

NAVA level 0 reduced the number of clinically significant events compared with CPAP in premature neonates with apnea of prematurity.

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.

Non-invasive respiratory support for preterm infants following extubation from mechanical ventilation. A narrative review and guideline suggestion

The recent introduction of different non-invasive ventilation modes for preterm has decreased the need for intubation, invasive ventilation and sedation. However, specific guidelines for each non-invasive mode are still lacking. This paper reviews available evidence for each of the commonly used noninvasive mode. Electronic search was carried out as a step forward towards a more comprehensive and detailed neonatal noninvasive ventilation guideline.

Diaphragm-triggered non-invasive respiratory support in preterm infants

BACKGROUND

Diaphragm-triggered non-invasive respiratory support, commonly referred to as NIV-NAVA (non-invasive neurally adjusted ventilatory assist), uses the electrical activity of the crural diaphragm to trigger the start and end of a breath. It provides variable inspiratory pressure that is proportional to an infant's changing inspiratory effort. NIV-NAVA has the potential to provide effective, non-invasive, synchronised, multilevel support and may reduce the need for invasive ventilation; however, its effects on short- and long-term outcomes, especially in the preterm infant, are unclear.

OBJECTIVES

To assess the effectiveness and safety of diaphragm-triggered non-invasive respiratory support in preterm infants (< 37 weeks' gestation) when compared to other non-invasive modes of respiratory support (nasal intermittent positive pressure ventilation (NIPPV); nasal continuous positive airway pressure (nCPAP); high-flow nasal cannulae (HFNC)), and to assess preterm infants with birth weight less than 1000 grams or less than 28 weeks' corrected gestation at the time of intervention as a sub-group.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2019, Issue 5), MEDLINE via PubMed (1946 to 10 May 2019), Embase (1947 to 10 May 2019), and CINAHL (1982 to 10 May 2019). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-randomised trials.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials that compared diaphragm-triggered non-invasive versus other non-invasive respiratory support in preterm infants.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted data from included studies. We performed fixed-effect analyses and expressed treatment effects as mean difference (MD), risk ratio (RR), and risk difference (RD) with 95% confidence intervals (CIs). We used the generic inverse variance method to analyse specific outcomes for cross-over trials. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

There were two small randomised controlled trials including a total of 23 infants eligible for inclusion in the review. Only one trial involving 16 infants included in the analysis reported on either of the primary outcomes of the review. This found no difference in failure of modality between NIV-NAVA and NIPPV (RR 0.33, 95% CI 0.02 to 7.14; RD -0.13, 95% CI -0.41 to 0.16; 1 study, 16 infants; heterogeneity not applicable). Both trials reported on secondary outcomes of the review, specific for cross-over trials (total 22 infants; 1 excluded due to failure of initial modality). One study involving seven infants reported a significant reduction in maximum FiO₂ with NIV-NAVA compared to NIPPV (MD -4.29, 95% CI -5.47 to -3.11; heterogeneity not applicable). There was no difference in maximum electric activity of the diaphragm (Edi) signal between modalities (MD -1.75, 95% CI -3.75 to 0.26; I² = 0%) and a significant increase in respiratory rate with NIV-NAVA compared to NIPPV (MD 7.22, 95% CI 0.21 to 14.22; I² = 72%) on a meta-analysis of two studies involving a total of 22 infants. The included studies did not report on other outcomes of interest.

AUTHORS' CONCLUSIONS

Due to limited data and very low certainty evidence, we were unable to determine if diaphragm-triggered non-invasive respiratory support is effective or safe in preventing respiratory failure in preterm infants. Large, adequately powered randomised controlled trials are needed to determine if diaphragm-triggered non-invasive respiratory support in preterm infants is effective or safe.

Noninvasive Neurally Adjusted Ventilatory Assist Versus High Flow Cannula Support After Congenital Heart Surgery

BACKGROUND

Extubation failure rates for critical patients in pediatric intensive care units (ICUs) range from 5% to 29%. Noninvasive (NIV) ventilation has been shown to decrease extubation failure. We compared reintubation rates and outcomes of patients supported with NIV neurally adjusted ventilation assist (NAVA) versus historical controls supported with high-flow nasal cannula (HFNC).

METHODS

Case-control study of infants less than three months of age who underwent cardiac surgery and received NIV support after extubation from January 2011 to May 2017. All patients supported with NIV NAVA after it became available in September 2013 were compared to matched patients extubated to HFNC from prior to September 2013.

RESULTS

Forty-two patients identified for the NIV NAVA group were matched with 42 historical controls supported with HFNC. Groups had similar baseline characteristics based on rate of acute kidney injury, number of single ventricle patients, Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) category, age, weight, bypass time, and duration of intubation. There was no significant difference in reintubation rates within 72 hours (14.3% in the HFNC group and 16.7% in the NIV NAVA group, P = 1.0). Median duration from extubation to coming off NIV support was longer in the NIV NAVA group (3.6 days vs 0.6 days, P < .001). Median time from extubation to ICU discharge was longer in the NIV NAVA group (10.5 vs 6.8 days, P = .02), as was total postoperative ICU length of stay (LOS; 17.6 vs 12.2, P = .01).

CONCLUSIONS

Introduction of NIV NAVA for postextubation support did not reduce reintubation rates compared to HFNC. Further study is needed as adoption of NIV NAVA may prolong LOS.

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.

Is noninvasive neurally adjusted ventilatory assistance (NIV-NAVA) an alternative to NCPAP in preventing extubation failure in preterm infants?

Background: Prolonged use of mechanical ventilation is associated with some complications as high mortality and high morbidities as bronchopulmonary dysplasia, ventilator-associated pneumonia, and pneumothorax. However, extubation failure in preterm infants is still high (40-60%) in very low birth weight infants (VLBW). Noninvasive neurally adjusted ventilatory assistance (NIV-NAVA) is triggered by the diaphragmatic electrical activity through a nasogastric tube that synchronizes patient/ventilator respiration, cycle by cycle effectively shortening the assisted cycle trigger and the degree of ventilatory assistance, optimizing the effects of intermittent inspiratory pressure on nasal continuous positive airway pressure (NCPAP). This study aims to compare reintubation rates until 72 h after extubation in preterm infants of high risk for reintubation using NIV-NAVA or NCPAP. Methods: A retrospective study of chart review data collection was performed in a private tertiary hospital. The study was approved by the local institutional Ethics Committee. We included infants considered at high risk of reintubation (BW < 1000 grams; use of invasive mechanical ventilation (IMV) for at least 7 days; or previous extubation failure episode) and compared the two groups according to the type of respiratory support after extubation: 1) NCPAP (n = 32); or 2) NIV-NAVA (n = 17). Demographics data were collected, the primary outcome was reintubation rate until 72 h after extubation. Secondary outcome was time to reintubation, BPD rate, IVH grade ≥ III, pneumothorax and death. Results: There was no difference between both groups in demographic data. The reintubation rate decreased significantly in the NIV-NAVA group compared to NCPAP (50.0-11.7, p < 0.02) despite the significantly higher length of invasive mechanical ventilation (IMV) before extubation attempt in NIV-NAVA group (12.4 versus 5.5 days, p < 0.04). There was no difference between both groups in secondary outcomes. Conclusions: In this small retrospective cohort study, the use of NIV-NAVA as postextubation strategy was effective in reducing extubation failure within 72 hours in preterm infants when compared to traditional NCPAP.

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.

Current insights in non-invasive ventilation for the treatment of neonatal respiratory disease

Deleterious consequences of the management of respiratory distress syndrome (RDS) with invasive ventilation have led to more in-depth investigation of non-invasive ventilation (NIV) modalities. NIV has significantly and positively altered the treatment outcomes and improved mortality rates of preterm infants with RDS. Among the different NIV modes, nasal intermittent positive pressure ventilation (NIPPV) has shown considerable benefits compared to nasal continuous positive airway pressure (NCPAP). Despite reports of heated humidified high-flow nasal cannula’s (HHHFNC) non-inferiority compared to NCPAP, some trials have been terminated due to high treatment failure rates with HHHFNC use. Moreover, RDS management with the combination of INSURE (INtubation SURfactant Extubation) technique and NIV ensures higher success rates. This review elaborates on the currently used various modes of NIV and novel techniques are also briefly discussed.

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.

Patient-ventilator asynchrony in preterm infants on nasal intermittent positive pressure ventilation

OBJECTIVE

To describe the incidence of patient-ventilator asynchrony and different types of asynchrony in preterm infants treated with non-synchronised nasal intermittent positive pressure ventilation (nIPPV).

DESIGN

An observational study was conducted including preterm infants born with a gestational age (GA) less than 32 weeks treated with non-synchronised nIPPV. During 1 hour, spontaneous breathing was measured with transcutaneous electromyography of the diaphragm simultaneous with ventilator inflations. An asynchrony index (AI), a percentage of asynchronous breaths, was calculated and the incidence of different types of inspiratory and expiratory asynchrony were reported.

RESULTS

Twenty-one preterm infants with a mean GA of 26.0±1.2 weeks were included in the study. The mean inspiratory AI was 68.3%±4.7% and the mean expiratory AI was 67.1%±7.3%. Out of 5044 comparisons of spontaneous inspirations and mechanical inflations, 45.3% of the mechanical inflations occurred late, 23.3% of the mechanical inflations were early and 31.4% of the mechanical inflation were synchronous. 40.3% of 5127 expiratory comparisons showed an early termination of ventilator inflations, 26.7% of the mechanical inflations terminated late and 33.0% mechanical inflations terminated in synchrony with a spontaneous expiration. In addition, 1380 spontaneous breaths were unsupported and 611 extra mechanical inflations were delivered.

CONCLUSION

Non-synchronised nIPPV results in high patient-ventilator asynchrony in preterm infants during both the inspiratory and expiratory phase of the breathing cycle. New synchronisation techniques are urgently needed and should address both inspiratory and expiratory asynchrony.

The evaluation of the efficacy and safety of non-invasive neurally adjusted ventilatory assist in combination with INtubation-SURfactant-Extubation technique for infants at 28 to 33 weeks of gestation with respiratory distress syndrome

Objectives:

The aim of this study is to evaluate the efficacy and safety of non-invasive neurally adjusted ventilatory assist used after INtubation-SURfactant-Extubation in preterm infants with respiratory distress syndrome.

Methods:

We conducted a prospective observational study that included 15 inborn preterm infants at 28 (0/7) to 33 (6/7) weeks of gestation with respiratory distress syndrome in the period from April 2017 to October 2018. After INtubation-SURfactant-Extubation, infants underwent non-invasive neurally adjusted ventilatory assist. INtubation-SURfactant-Extubation failure was defined as follows: fraction of inspired oxygen requirement >0.4, respiratory acidosis, and severe apnea within 5 days after surfactant administration.

Results:

Two of the 15 (13.3%) infants showed INtubation-SURfactant-Extubation failure and required mechanical ventilation. No infants experienced any major complications such as pneumothorax, patent ductus arteriosus ligation, severe intraventricular hemorrhage, periventricular leukomalacia, retinopathy of prematurity, or death.

Conclusion:

The rate of INtubation-SURfactant-Extubation failure when non-invasive neurally adjusted ventilatory assist was used after INtubation-SURfactant-Extubation for preterm infants with respiratory distress syndrome was 13.3%. Non-invasive neurally adjusted ventilatory assist can be safely performed without severe complications for preterm infants soon after birth.

Non-invasive neurally adjusted ventilatory assist versus nasal intermittent positive-pressure ventilation in preterm infants born before 30 weeks' gestation

BACKGROUND

Non-invasive neurally adjusted ventilatory assist (NIV-NAVA), a mode of non-invasive ventilation (NIV) controlled by diaphragmatic electrical activity, may be superior to other NIV as a respiratory support after extubation in preterm infants, but no report has compared NIV-NAVA with other NIV methods. We evaluated the effectiveness and adverse effects of NIV-NAVA after extubation in preterm infants <30 weeks of gestation.

METHODS

This retrospective study involved patients who were born before 30 weeks of gestation. We mainly used NIV-NAVA or nasal intermittent positive-pressure ventilation (NIPPV) for preterm infants as the NIV after extubation and compared these two groups. The primary outcome was treatment failure. The secondary outcomes were extubation failure and adverse events. Treatment failure was defined as a change of NIV (NIPPV was switched to NIV-NAVA, or NIV-NAVA was switched to NIPPV) or reintubation ≤7 days after extubation.

RESULTS

Fifteen patients were in the NIV-NAVA group, and 19 were in the NIPPV group. The gestational age of the NIV-NAVA group was younger than that of the NIPPV group (25.7 ± 2.4 weeks vs 27.3 ± 1.8 weeks). Treatment failure occurred in six cases (40%) in the NIV-NAVA group and in nine cases (47.4%) in the NIPPV group, and no significant difference was demonstrated. No significant difference in adverse events was noted.

CONCLUSIONS

NIV-NAVA has advantages compared with NIPPV as the NIV for premature infants after extubation. NIV-NAVA can also be used safely without a significant difference in the rate of complications compared with NIPPV.

A randomised cross-over study showed no difference in diaphragm activity during weaning from respiratory support

AIM

We measured electrical activity of the diaphragm (Edi) to compare the breathing effort in preterm infants during weaning from respiratory support with high-flow nasal cannulae (HFNC) or nasal continuous positive airway pressure (nCPAP).

METHODS

This randomised cross-over study was carried out at St Olav's University Hospital, Trondheim, Norway, from December 2013 to June 2015. We gave 21 preterm infants weighing at least 1000 g HFNC 6 L/minute for four hours and nCPAP 3 cmH₂ O for four hours with a one-hour wash-out period. Measurements included diaphragmatic load, Edi, vital signs and a modified Silverman-Andersen Retraction Score.

RESULTS

We found no differences in HFNC and nCPAP in the median Edi peak (8.0 μV versus 7.8 μV, p = 0.095), median Edi min (1.1 μV versus 1.2 μV in, p = 0.958) or mean heart rate (157 versus 159, p = 0.300) in the 21 infants who took part. The mean respiratory rate was significantly lower during HFNC than nCPAP (47 versus 52, p = 0.012). The modified Silverman-Andersen Retraction Score showed no significant differences.

CONCLUSION

This study of preterm infants found no difference in the breathing effort measured by Edi between HFNC 6 L/minute and nCPAP 3 cmH₂ O. HFNC could replace nCPAP when preterm infants are ready for weaning.

Classifying Apnea of Prematurity by Transcutaneous Electromyography of the Diaphragm

BACKGROUND

Treatment of apnea is highly dependent on the type of apnea. Chest impedance (CI) has inaccuracies in monitoring respiration, which compromises accurate apnea classification. Electrical activity of the diaphragm measured by transcutaneous electromyography (EMG) is feasible in preterm infants and might improve the accuracy of apnea classification.

OBJECTIVES

To compare the accuracy of apnea classification based on diaphragmatic EMG (dEMG) and CI tracings in preterm infants.

METHODS

Fifteen cases of central apnea, 5 of obstructive apnea, and 10 of mixed apnea were selected from recordings containing synchronized continuous tracings of respiratory inductive plethysmography (RIP), airway flow, heart rate (HR), oxygen saturation (SpO2), and breathing activity measured by dEMG and CI. Twenty-two assessors (neonatologists, pediatricians-in-training, and nurses) classified each apnea twice; once based on dEMG, HR, and SpO2 tracings, and once based on CI, HR, and SpO2. The assessors were blinded to the type of respiratory tracing (dEMG or CI) and to the RIP and flow tracings.

RESULTS

In total 1,320 assessments were performed, and in 71.1% the apnea was classified correctly. Subgroup analysis based on respiratory tracing showed that 74.8% of the dEMG tracings were classified correctly compared to 67.3% of the CI tracings (p < 0.001). This improved apnea classification based on dEMG was present for central (86.7 vs. 80.3%, p < 0.02) and obstructive (56.4 vs. 32.7%, p < 0.001) apnea. The improved apnea classification based on dEMG tracing was independent of the type of assessor.

CONCLUSION

Transcutaneous dEMG improves the accuracy of apnea classification when compared to CI in preterm infants, making this technique a promising candidate for future monitoring systems.

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.

Diaphragmatic activity during weaning from respiratory support in preterm infants

OBJECTIVE

To determine if weaning from nasal continuous positive airway pressure (nCPAP) to lesser supportive low flow nasal cannula (LFNC) results in a change in electrical activity of the diaphragm in preterm infants.

DESIGN

Prospective observational study.

SETTING

Neonatal intensive care unit.

PATIENTS

Stable preterm infants weaned from nCPAP to LFNC (1 L/min).

MAIN OUTCOME MEASURES

Change in diaphragmatic activity, expressed as amplitude, peak and tonic activity, measured by transcutaneous electromyography (dEMG) from 30 min before (baseline) until 180 min after weaning. Subgroup analysis was performed based on success or failure of the weaning attempt.

RESULTS

Fifty-nine preterm infants (gestational age: 29.0±2.4 weeks, birth weight: 1210±443 g) accounting for 74 weaning attempts were included. A significant increase in dEMG amplitude (median, IQR: 21.3%, 3.6-41.4), peak (22.1%, 8.7-40.5) and tonic activity (14.3%, -1.9-38.1) was seen directly after weaning. This effect slowly decreased over time. Infants failing the weaning attempt tended to have a higher diaphragmatic activity than those successfully weaned.

CONCLUSIONS

Weaning from nCPAP to LFNC leads to an increase in diaphragmatic activity measured by dEMG and is most prominent in preterm infants failing the weaning attempt. dEMG monitoring might be a useful parameter to guide weaning from respiratory support in preterm infants.

Bronchopulmonary Dysplasia: Chronic Lung Disease of Infancy and Long-Term Pulmonary Outcomes

Bronchopulmonary dysplasia (BPD) is a chronic lung disease most commonly seen in premature infants who required mechanical ventilation and oxygen therapy for acute respiratory distress. While advances in neonatal care have resulted in improved survival rates of premature infants, limited progress has been made in reducing rates of BPD. Lack of progress may in part be attributed to the limited therapeutic options available for prevention and treatment of BPD. Several lung-protective strategies have been shown to reduce risks, including use of non-invasive support, as well as early extubation and volume ventilation when intubation is required. These approaches, along with optimal nutrition and medical therapy, decrease risk of BPD; however, impacts on long-term outcomes are poorly defined. Characterization of late outcomes remain a challenge as rapid advances in medical management result in current adult BPD survivors representing outdated neonatal care. While pulmonary disease improves with growth, long-term follow-up studies raise concerns for persistent pulmonary dysfunction; asthma-like symptoms and exercise intolerance in young adults after BPD. Abnormal ventilatory responses and pulmonary hypertension can further complicate disease. These pulmonary morbidities, combined with environmental and infectious exposures, may result in significant long-term pulmonary sequalae and represent a growing burden on health systems. Additional longitudinal studies are needed to determine outcomes beyond the second decade, and define risk factors and optimal treatment for late sequalae of disease.

Neurally Adjusted Ventilatory Assist for Noninvasive Support in Neonates

Noninvasive ventilation (NIV) is frequently used in the NICU to avoid intubation or as postextubation support for spontaneously breathing infants experiencing respiratory distress. Neurally adjusted ventilatory assist (NAVA) is used as a mode of noninvasive support in which both the timing and degree of ventilatory assist are controlled by the patient. NIV-NAVA has been successfully used clinically in neonates as a mode of ventilation to prevent intubation, allow early extubation, and as a novel way to deliver nasal continuous positive airway pressure.

High-Frequency Ventilation as a Mode of Noninvasive Respiratory Support

High-frequency ventilation (HFV) as a mode of noninvasive respiratory support (NRS) in preterm neonates is gaining popularity. Benefits may accrue from combining the ventilatory efficiency of HFV delivered through a noninvasive interface, enhancing respiratory support while potentially limiting lung injury. Current evidence suggests that noninvasive HFV (NIHFV) may be superior to other NRS modes in eliminating carbon dioxide and preventing endotracheal ventilation after failure of other NRS modes. Animal data suggest NIHFV may promote improved alveolar development compared to endotracheal ventilation. However, adequately powered large-scale controlled trials are required to evaluate efficacy and safety prior to widespread use of NIHFV.