Nasal high-frequency oscillation ventilation in neonates: a survey in five European countries

The effect of NHFOV on hemodynamics in mild and moderately preterm neonates: a randomized clinical trial

The aim of this study is to study cardio-respiratory effects of nasal high-frequency oscillatory ventilation (NHFOV) vs. NCPAP as an initial mode of ventilation in moderate-late-preterm infants. A randomized controlled trial was conducted in NICU of Alexandria University Maternity Hospital (AUMH). One-hundred late-moderate-preterm infants were randomly assigned to either NHFOV-group (n = 50) or NCPAP-group (n = 50). For both groups, functional echocardiography was performed in the first 24 h to detect hemodynamic changes and respiratory outcome was monitored throughout the hospital stay. The main outcomes were hemodynamic measurements and myocardial function using functional echocardiography of those infants along with the respiratory outcome and complications. Kaplan-Meier survival plot was used representing time course of NCPAP and NHFOV failure. Left ventricular output values were not significantly different in both groups with median 202 ml/kg /min and IQR (176-275) in NCPAP-group and 226 ml/kg/min with IQR (181-286) in NHFOV group. Nevertheless, ejection fraction and fractional shortening were significantly higher in NHFOV-group with P 0.001. The time to weaning, the time to reach 30%-FIO2, the need for invasive ventilation, oxygen support duration, and maximal-FIO2 were significantly more in NCAPAP group.     Conclusion: NHFOV is an effective and promising tool of non-invasive-ventilation which can be used as a primary modality of respiratory support in preterm infants with variable forms of respiratory distress syndrome without causing detrimental effect on hemodynamics or significant respiratory complications.     Trial registration: NCT05706428 (registered on January 21, 2023). What is Known: • NHFOV might be beneficial as a secondary mode of ventilation and might have an impact on hemodynamics. What is New: • NHFOV can be used as an initial mode of ventilation with CDP beyond the reported pressure limits of CPAP without causing neither CO2 retention nor adverse hemodynamic consequences.

Noninvasive high-frequency oscillation ventilation as post- extubation respiratory support in neonates: Systematic review and meta-analysis

INTRODUCTION

Noninvasive High-Frequency Oscillatory Ventilation (NHFOV) is increasingly being adopted to reduce the need for invasive ventilation after extubation.

OBJECTIVES

To evaluate the benefits and harms of NHFOV as post-extubation respiratory support in newborns compared to other non-invasive respiratory support modes.

MATERIAL & METHODS

We included randomized controlled trials comparing NHFOV with other non-invasive modes post-extubation in newborns. Data sources were MEDLINE (via Pubmed), Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, WHO international clinical trials registry platform and Clinical Trial Registry, forward and backward citation search. Methodological quality of studies was assessed by Cochrane's Risk of Bias tool 1.0.

RESULTS

This systematic review included 21 studies and 3294 participants, the majority of whom were preterm. NHFOV compared to nasal continuous positive airway pressure (NCPAP) reduced reintubation within seven days (RR 0.34, 95% CI 0.22 to 0.53) after extubation. It also reduced extubation failure (RR 0.39, 95% CI 0.30 to 0.51) and reintubation within 72 hrs (RR 0.40, 95% CI 0.31 to 0.53), bronchopulmonary dysplasia (RR 0.59, 95% CI 0.37 to 0.94) and pulmonary air leak (RR 0.46, 95% CI 0.27 to 0.79) compared to NCPAP. The rate of reintubation within seven days (RR 0.62, 95% CI 0.18 to 2.14) was similar whereas extubation failure (RR 0.65, 95% CI 0.50 to 0.83) and reintubation (RR 0.68, 95% CI 0.52 to 0.89) within 72 hrs were lower in NHFOV group compared to nasal intermittent positive pressure ventilation. There was no effect on other outcomes. Overall quality of the evidence was low to very low in both comparisons.

CONCLUSIONS

NHFOV may reduce the rate of reintubation and extubation failure post-extubation without increasing complications. Majority of the trials were exclusively done in preterm neonates. Further research with high methodological quality is warranted.

Nasal High-Frequency Oscillatory Ventilation Use in Romanian Neonatal Intensive Care Units-The Results of a Recent Survey

BACKGROUND

Nasal high-frequency oscillatory ventilation (nHFOV) has emerged as an effective initial and rescue noninvasive respiratory support mode for preterm infants with respiratory distress syndrome (RDS); however, little is known about nHFOV use in Romanian neonatal intensive care units (NICUs).

OBJECTIVES

We aimed to identify the usage extent and clinical application of nHFOV in Romania.

METHODS

A structured web-based questionnaire was designed to find the rate of nHFOV use and knowledge of this new method of noninvasive respiratory support in Romanian level III NICUs. Using multiple-choice, open-ended, and yes/no questions, we collected information on the NICU's size, noninvasive respiratory support modes used, nHFOV use, indications, settings, nasal interfaces, secondary effects, and equipment used. Descriptive statistics and comparisons were performed using IBM SPSS Statistics 26.0.

RESULTS

A total of 21/23 (91.3%) leaders from level III NICUs (median [IQR] number of beds of 10 [10-17.5]) responded to the survey. The most frequently used noninvasive ventilation modes were CPAP mode on mechanical ventilators (76.2%), followed by NIPPV (76.2%); heated, humidified high-flow nasal cannula (HHHFNC) (61.9%); and nHFOV (11/21 units; 52.4%). A total of 5/11 units reported frequent nHFOV use (in two or more newborns/month) in both term and preterm infants. The main indications reported for nHFOV use were CPAP failure (90.9%), hypercapnia (81.8%), and bronchopulmonary dysplasia (72.7%). Face/nasal masks and short binasal prongs are the most commonly used nasal interfaces (90.9% and 72.7%, respectively). Air leaks at the interface level (90.9%), thick secretions (81.8%), and airway obstruction (63.6%) were the most frequently mentioned adverse effects of nHFOV. Only three of the NICUs had a written protocol for nHFOV use. Most units not yet using nHFOV cited lack of equipment, experience, training, or insufficient information and evidence for the clinical use and outcome of nHFOV use in neonates as the main reasons for not implementing this noninvasive respiratory mode.

CONCLUSIONS

Our survey showed that nHFOV is already used in more than half of the Romanian level III NICUs to support term and preterm infants with respiratory distress despite a lack of consensus regarding indications and settings during nHFOV.

Non-invasive high-frequency oscillatory ventilation (NHFOV) versus nasal continuous positive airway pressure (NCPAP) for preterm infants: a systematic review and meta-analysis

OBJECTIVE

To compare the efficacy and safety of non-invasive high-frequency oscillatory ventilation (NHFOV) and nasal continuous positive airway pressure (NCPAP) in preterm infants.

DESIGN

The study conducted a comprehensive analysis across three databases, namely EMBASE, MEDLINE and Cochrane Central, to identify randomised controlled trials comparing NHFOV and NCPAP. Statistical analysis was performed using Review Manager V.5.3 software.

MAIN OUTCOMES MEASURES

The primary outcomes of the study were the intubation or reintubation rate in the NHFOV and NCPAP groups. Additionally, secondary outcomes included the partial pressure of carbon dioxide levels and major complications associated with non-invasive respiratory support ventilation.

RESULTS

Ten randomised controlled studies, involving 2031 preterm infants, were included in this meta-analysis. When compared with NCPAP, NHFOV demonstrated a significant reduction in the intubation or reintubation rate (p<0.01, relative risk=0.45, 95% CI 0.37 to 0.55), and there was no statistical difference in related complications.

CONCLUSION

In preterm infants, NHFOV appears to be an effective intervention for decreasing the intubation or reintubation rate compared with NCPAP, with no increase in associated complications.

TRIAL REGISTRATION NUMBER

CRD42023403968.

Non-invasive high-frequency ventilation in newborn infants with respiratory distress

BACKGROUND

Respiratory distress occurs in up to 7% of newborns, with respiratory support (RS) provided invasively via an endotracheal (ET) tube or non-invasively via a nasal interface. Invasive ventilation increases the risk of lung injury and chronic lung disease (CLD). Using non-invasive strategies, with or without minimally invasive surfactant, may reduce the need for mechanical ventilation and the risk of lung damage in newborn infants with respiratory distress.

OBJECTIVES

To evaluate the benefits and harms of nasal high-frequency ventilation (nHFV) compared to invasive ventilation via an ET tube or other non-invasive ventilation methods on morbidity and mortality in preterm and term infants with or at risk of respiratory distress.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL and three trial registries in April 2023.

SELECTION CRITERIA

Randomised controlled trials (RCTs), cluster- or quasi-RCTs of nHFV in newborn infants with respiratory distress compared to invasive or non-invasive ventilation.

DATA COLLECTION AND ANALYSIS

Two authors independently selected the trials for inclusion, extracted data, assessed the risk of bias, and undertook GRADE assessment.

MAIN RESULTS

We identified 33 studies, mostly in low- to middle-income settings, that investigated this therapy in 5068 preterm and 46 term infants. nHFV compared to invasive respiratory therapy for initial RS We are very uncertain whether nHFV reduces mortality before hospital discharge (RR 0.67, 95% CI 0.20 to 2.18; 1 study, 80 infants) or the incidence of CLD (RR 0.38, 95% CI 0.09 to 1.59; 2 studies, 180 infants), both very low-certainty. ET intubation, death or CLD, severe intraventricular haemorrhage (IVH) and neurodevelopmental disability (ND) were not reported. nHFV vs nasal continuous positive airway pressure (nCPAP) used for initial RS We are very uncertain whether nHFV reduces mortality before hospital discharge (RR 1.00, 95% CI 0.41 to 2.41; 4 studies, 531 infants; very low-certainty). nHFV may reduce ET intubation (RR 0.52, 95% CI 0.33 to 0.82; 5 studies, 571 infants), but there may be little or no difference in CLD (RR 1.35, 95% CI 0.80 to 2.27; 4 studies, 481 infants); death or CLD (RR 2.50, 95% CI 0.52 to 12.01; 1 study, 68 participants); or severe IVH (RR 1.17, 95% CI 0.36 to 3.78; 4 studies, 531 infants), all low-certainty evidence. ND was not reported. nHFV vs nasal intermittent positive-pressure ventilation (nIPPV) used for initial RS nHFV may result in little to no difference in mortality before hospital discharge (RR 1.86, 95% CI 0.90 to 3.83; 2 studies, 84 infants; low-certainty). nHFV may have little or no effect in reducing ET intubation (RR 1.33, 95% CI 0.76 to 2.34; 5 studies, 228 infants; low-certainty). There may be a reduction in CLD (RR 0.63, 95% CI 0.42 to 0.95; 5 studies, 307 infants; low-certainty). A single study (36 infants) reported no events for severe IVH. Death or CLD and ND were not reported. nHFV vs high-flow nasal cannula (HFNC) used for initial RS We are very uncertain whether nHFV reduces ET intubation (RR 2.94, 95% CI 0.65 to 13.27; 1 study, 37 infants) or reduces CLD (RR 1.18, 95% CI 0.46 to 2.98; 1 study, 37 participants), both very low-certainty. There were no mortality events before hospital discharge or severe IVH. Other deaths, CLD and ND, were not reported. nHFV vs nCPAP used for RS following planned extubation nHFV probably results in little or no difference in mortality before hospital discharge (RR 0.92, 95% CI 0.52 to 1.64; 6 studies, 1472 infants; moderate-certainty). nHFV may result in a reduction in ET reintubation (RR 0.42, 95% CI 0.35 to 0.51; 11 studies, 1897 infants) and CLD (RR 0.78, 95% CI 0.67 to 0.91; 10 studies, 1829 infants), both low-certainty. nHFV probably has little or no effect on death or CLD (RR 0.90, 95% CI 0.77 to 1.06; 2 studies, 966 infants) and severe IVH (RR 0.80, 95% CI 0.57 to 1.13; 3 studies, 1117 infants), both moderate-certainty. We are very uncertain whether nHFV reduces ND (RR 0.92, 95% CI 0.37 to 2.29; 1 study, 74 infants; very low-certainty). nHFV versus nIPPV used for RS following planned extubation nHFV may have little or no effect on mortality before hospital discharge (RR 1.83, 95% CI 0.70 to 4.79; 2 studies, 984 infants; low-certainty). There is probably a reduction in ET reintubation (RR 0.69, 95% CI 0.54 to 0.89; 6 studies, 1364 infants), but little or no effect on CLD (RR 0.88, 95% CI 0.75 to 1.04; 4 studies, 1236 infants); death or CLD (RR 0.92, 95% CI 0.79 to 1.08; 3 studies, 1070 infants); or severe IVH (RR 0.78, 95% CI 0.55 to 1.10; 4 studies, 1162 infants), all moderate-certainty. One study reported there might be no difference in ND (RR 0.88, 95% CI 0.35 to 2.16; 1 study, 72 infants; low-certainty). nHFV versus nIPPV following initial non-invasive RS failure nHFV may have little or no effect on mortality before hospital discharge (RR 1.44, 95% CI 0.10 to 21.33); or ET intubation (RR 1.23, 95% CI 0.51 to 2.98); or CLD (RR 1.01, 95% CI 0.70 to 1.47); or severe IVH (RR 0.47, 95% CI 0.02 to 10.87); 1 study, 39 participants, all low- or very low-certainty. Other deaths or CLD and ND were not reported.

AUTHORS' CONCLUSIONS

For initial RS, we are very uncertain if using nHFV compared to invasive respiratory therapy affects clinical outcomes. However, nHFV may reduce intubation when compared to nCPAP. For planned extubation, nHFV may reduce the risk of reintubation compared to nCPAP and nIPPV. nHFV may reduce the risk of CLD when compared to nCPAP. Following initial non-invasive respiratory support failure, nHFV when compared to nIPPV may result in little to no difference in intubation. Large trials, particularly in high-income settings, are needed to determine the role of nHFV in initial RS and following the failure of other non-invasive respiratory support. Also, the optimal settings of nHVF require further investigation.

Peri-extubation settings in preterm neonates: a systematic review and meta-analysis

OBJECTIVE

To systematically review: 1) peri-extubation settings; and 2) association between peri-extubation settings and outcomes in preterm neonates.

STUDY DESIGN

In this systematic review, studies were eligible if they reported patient-data on peri-extubation settings (objective 1) and/or evaluated peri-extubation levels in relation to clinical outcomes (objective 2). Data were meta-analyzed when appropriate using random-effects model.

RESULTS

Of 9681 titles, 376 full-texts were reviewed and 101 included. The pooled means of peri-extubation settings were summarized. For objective 2, three experimental studies were identified comparing post-extubation CPAP levels. Meta-analyses revealed lower odds for treatment failure [pooled OR 0.46 (95% CI 0.27-0.76); 3 studies, 255 participants] but not for re-intubation [pooled OR 0.66 (0.22-1.97); 3 studies, 255 participants] with higher vs. lower CPAP.

CONCLUSIONS

Summary of peri-extubation settings may guide clinicians in their own practices. Higher CPAP levels may reduce extubation failure, but more data on peri-extubation settings that optimize outcomes are needed.

Nasal high frequency oscillatory highflow therapy in preterm infants: A randomized crossover trial

OBJECTIVES

To assess the clinical efficacy, safety, and potential physiological mechanisms of highflow therapy with superimposed high frequency oscillations ("osciflow").

STUDY DESIGN

In this prospective, randomized, single center crossover trial, 30 preterm infants were randomized to receive osciflow or highflow therapy first, each for 180 min. During osciflow, an oscillatory amplitude of 20 mbar and a frequency of 6 Hz were set. The flow rate was 4 L/min during both interventions. Primary outcome was the paired difference in the combined number of desaturations (SpO2  < 80%) and bradycardia (heart rate <80 beats per min) between interventions. Safety outcomes included nasal trauma, pneumothorax and treatment failure, and a pain score was assessed. In 20 infants, electrical impedance tomography (EIT) recordings were performed to evaluate oscillatory (VOsc ) and tidal volumes (VT ) at the lung level.

RESULTS

Infants with a mean (SD) postnatal age of 33.1 ± 1.2 weeks were included. The median (IQR) number of episodes of desaturation and bradycardia was 19.5 (6-49) during osciflow and 26 (6-44) during highflow therapy (paired difference -2; IQR -10 to 9; p = .37). There were no differences in safety outcomes and pain scores. During osciflow, EIT recordings showed a signal at 6 Hz, which was not detectable during highflow. Corresponding mean (SD) VOsc /VT ratio was 9% (±5%).

CONCLUSIONS

In preterm infants, osciflow did not reduce the number of desaturations and bradycardia compared with highflow therapy. Although VOsc were transmitted to the lung during osciflow, their magnitude was small. Osciflow was safe and well tolerated.

The effect of non-invasive high-frequency oscillatory ventilation on the duration of non-invasive respiratory support in late preterm and term infants with transient tachypnea of the newborn: a randomized controlled trial

Nasal continuous positive airway pressure (nCPAP) is one of the most commonly used non-invasive respiratory support modes in neonates with transient tachypnea of the newborn (TTN). Non-invasive high-frequency oscillatory ventilation (nHFOV) is a non-invasive respiratory support mode that has been increasingly used in neonatal respiratory disorders. This prospective randomized controlled study compared the efficacy of nHFOV and nCPAP in reducing the duration of non-invasive respiratory support. Late preterm and term infants > 34 weeks' gestation were included in the study. The infants were randomly assigned to receive either nHFOV or nCPAP. Treatment was started with standard settings in both groups. Infants who met treatment failure criteria were switched to nasal intermittent mandatory ventilation for further positive-pressure support. A total of 60 infants were included in the study. Thirty of these infants were included in the nHFOV group and 30 were included in the nCPAP group. The median duration of non-invasive respiratory support was not significantly different between the two groups (21 h [IQR: 16-68] for nHFOV vs 15 h [IQR: 11-33] for nCPAP; p = 0.09). However, after adjusting for potential confounders, nHFOV was associated with a shorter duration of non-invasive respiratory support than nCPAP (adjusted mean difference: 16.3 h; 95% CI: 0.7 to 31.9; p = 0.04). nHFOV was well tolerated and did not increase the risk of complications.    Conclusion: Our findings suggest that nHFOV is an effective and safe ventilation mode for late preterm and term neonates with TTN.   Trial registry: Clinicaltrials.gov (NCT03006354). Date of registration: December 30, 2016. What is Known: • nHFOV is a ventilation model that has been increasingly used for the management of RDS. • TTN is one of the most common causes of neonatal respiratory distress. What is New: • nHFOV is associated with shorter duration of non-invasive respiratory support and duration of oxygen support. • nHFOV may be a safe and effective alternative to nCPAP for neonates with TTN.

Optimising success of neonatal extubation: Respiratory support

In this review, we examine lung physiology before, during and after neonatal extubation and propose a three-phase model for the extubation procedure. We perform meta-analyses to compare different modes of non-invasive respiratory support after neonatal extubation and based on the findings, the following clinical recommendations are made.

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.

[Efficacy of noninvasive high-frequency oscillatory ventilation versus nasal intermittent positive pressure ventilation as post-extubation respiratory support in preterm infants: a Meta analysis]

OBJECTIVES

To systematically evaluate the efficacy and safety of noninvasive high-frequency oscillatory ventilation (NHFOV) versus nasal intermittent positive pressure ventilation (NIPPV) as post-extubation respiratory support in preterm infants.

METHODS

China National Knowledge Infrastructure, Wanfang Data, Chinese Journal Full-text Database, China Biology Medicine disc, PubMed, Web of Science, and the Cochrane Library were searched for articles on NHFOV and NIPPV as post-extubation respiratory support in preterm infants published up to August 31, 2022. RevMan 5.4 software and Stata 17.0 software were used for a Meta analysis to compare related indices between the NHFOV and NIPPV groups, including reintubation rate within 72 hours after extubation, partial pressure of carbon dioxide (PCO2) at 6-24 hours after switch to noninvasive assisted ventilation, and the incidence rates of bronchopulmonary dysplasia (BPD), air leak, nasal damage, periventricular leukomalacia (PVL), intraventricular hemorrhage (IVH), and retinopathy of prematurity (ROP).

RESULTS

A total of 9 randomized controlled trials were included. The Meta analysis showed that compared with the NIPPV group, the NHFOV group had significantly lower reintubation rate within 72 hours after extubation (RR=0.67, 95%CI: 0.52-0.88, P=0.003) and PCO2 at 6-24 hours after switch to noninvasive assisted ventilation (MD=-4.12, 95%CI: -6.12 to -2.13, P<0.001). There was no significant difference between the two groups in the incidence rates of complications such as BPD, air leak, nasal damage, PVL, IVH, and ROP (P>0.05).

CONCLUSIONS

Compared with NIPPV, NHFOV can effectively remove CO2 and reduce the risk of reintubation, without increasing the incidence of complications such as BPD, air leak, nasal damage, PVL, and IVH, and therefore, it can be used as a sequential respiratory support mode for preterm infants after extubation.

Noninvasive high-frequency oscillatory ventilation versus nasal intermittent positive pressure ventilation for preterm infants as an extubation support: A systematic review and meta-analysis

OBJECTIVE

We aimed to explore whether noninvasive high-frequency oscillatory ventilation (NHFOV) could reduce the incidence of reintubation compared with nasal intermittent positive pressure ventilation (NIPPV) in the postextubation phase of preterm infants.

METHODS

Randomized controlled trials of NHFOV versus NIPPV were searched in PubMed, EMBASE, Cochrane Central, and MEDLINE. Meta-analysis was performed using Review Manager 5.3.

RESULTS

Four randomized controlled trials including 1138 preterm infants were included in this study. Compared with NIPPV, NHFOV reduced the incidence of reintubation in the post-extubation phase of preterm infants (p = 0.01, RR = 0.72, 95% confidence interval (CI): 0.56∼0.94), and no heterogeneity was found in the four studies (p = 0.55, I²  = 0%). In the sensitivity analysis, the result showed that there was no significant difference in the incidence of reintubation between NHFOV and NIPPV after excluding one study (p = 0. 05, RR = 0.76 95% CI: 0.58∼1.00), and no heterogeneity was found in the other three studies (p = 0.95, I²  = 0%). There was no statistical difference between NHFOV and NIPPV in BPD, air leak, IVH (≥Grade III) and mortality.

CONCLUSION

Among mechanically ventilated preterm infants, compared with NIPPV, NHFOV was potentially beneficial to reduce the incidence of reintubation after extubation and did not increase the risk of complications.

Lung volume changes during apnoeas in preterm infants

OBJECTIVE

Mechanisms of non-invasive high-frequency oscillatory ventilation (nHFOV) in preterm infants are unclear. We aimed to compare lung volume changes during apnoeas in preterm infants on nHFOV and nasal continuous positive airway pressure (nCPAP).

METHODS

Analysis of electrical impedance tomography (EIT) data from a randomised crossover trial comparing nHFOV with nCPAP in preterm infants at 26-34 weeks postmenstrual age. EIT data were screened by two reviewers to identify apnoeas ≥10 s. End-expiratory lung impedance (EELI) and tidal volumes (V_T) were calculated before and after apnoeas. Oxygen saturation (SpO₂) and heart rate (HR) were extracted for 60 s after apnoeas.

RESULTS

In 30 preterm infants, 213 apnoeas were identified. During apnoeas, oscillatory volumes were detectable during nHFOV. EELI decreased significantly during apnoeas (∆EELI nCPAP: -8.0 (-11.9 to -4.1) AU/kg, p<0.001; ∆EELI nHFOV: -3.4 (-6.5 to -0.3), p=0.03) but recovered over the first five breaths after apnoeas. Compared with before apnoeas, V_T was increased for the first breath after apnoeas during nCPAP (∆V_T: 7.5 (3.1 to 11.2) AU/kg, p=0.001). Falls in SpO₂ and HR after apnoeas were greater during nCPAP than nHFOV (mean difference (95% CI): SpO₂: 3.6% (2.7 to 4.6), p<0.001; HR: 15.9 bpm (13.4 to 18.5), p<0.001).

CONCLUSION

Apnoeas were characterised by a significant decrease in EELI which was regained over the first breaths after apnoeas, partly mediated by a larger V_T. Apnoeas were followed by a considerable drop in SpO₂ and HR, particularly during nCPAP, leading to longer episodes of hypoxemia during nCPAP. Transmitted oscillations during nHFOV may explain these benefits.

TRIAL REGISTRATION NUMBER

ACTRN12616001516471.

European Consensus Guidelines on the Management of Respiratory Distress Syndrome: 2022 Update

Respiratory distress syndrome (RDS) care pathways evolve slowly as new evidence emerges. We report the sixth version of "European Guidelines for the Management of RDS" by a panel of experienced European neonatologists and an expert perinatal obstetrician based on available literature up to end of 2022. Optimising outcome for babies with RDS includes prediction of risk of preterm delivery, appropriate maternal transfer to a perinatal centre, and appropriate and timely use of antenatal steroids. Evidence-based lung-protective management includes initiation of non-invasive respiratory support from birth, judicious use of oxygen, early surfactant administration, caffeine therapy, and avoidance of intubation and mechanical ventilation where possible. Methods of ongoing non-invasive respiratory support have been further refined and may help reduce chronic lung disease. As technology for delivering mechanical ventilation improves, the risk of causing lung injury should decrease, although minimising time spent on mechanical ventilation by targeted use of postnatal corticosteroids remains essential. The general care of infants with RDS is also reviewed, including emphasis on appropriate cardiovascular support and judicious use of antibiotics as being important determinants of best outcome. We would like to dedicate this guideline to the memory of Professor Henry Halliday who died on November 12, 2022.These updated guidelines contain evidence from recent Cochrane reviews and medical literature since 2019. Strength of evidence supporting recommendations has been evaluated using the GRADE system. There are changes to some of the previous recommendations as well as some changes to the strength of evidence supporting recommendations that have not changed. This guideline has been endorsed by the European Society for Paediatric Research (ESPR) and the Union of European Neonatal and Perinatal Societies (UENPS).

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.

Lung volume distribution in preterm infants on non-invasive high-frequency ventilation

INTRODUCTION

Non-invasive high-frequency oscillatory ventilation (nHFOV) is an extension of nasal continuous positive airway pressure (nCPAP) support in neonates. We aimed to compare global and regional distribution of lung volumes during nHFOV versus nCPAP.

METHODS

In 30 preterm infants enrolled in a randomised crossover trial comparing nHFOV with nCPAP, electrical impedance tomography data were recorded in prone position. For each mode of respiratory support, four episodes of artefact-free tidal ventilation, each comprising 30 consecutive breaths, were extracted. Tidal volumes (V_T) in 36 horizontal slices, indicators of ventilation homogeneity and end-expiratory lung impedance (EELI) for the whole lung and for four horizontal regions of interest (non-gravity-dependent to gravity-dependent; EELI_NGD, EELI_midNGD, EELI_midGD, EELI_GD) were compared between nHFOV and nCPAP. Aeration homogeneity ratio (AHR) was determined by dividing aeration in non-gravity-dependent parts of the lung through gravity-dependent regions.

MAIN RESULTS

Overall, 228 recordings were analysed. Relative V_T was greater in all but the six most gravity-dependent lung slices during nCPAP (all p<0.05). Indicators of ventilation homogeneity were similar between nHFOV and nCPAP (all p>0.05). Aeration was increased during nHFOV (mean difference (95% CI)=0.4 (0.2 to 0.6) arbitrary units per kilogram (AU/kg), p=0.013), mainly due to an increase in non-gravity-dependent regions of the lung (∆EELI_NGD=6.9 (0.0 to 13.8) AU/kg, p=0.028; ∆EELI_midNGD=6.8 (1.2 to 12.4) AU/kg, p=0.009). Aeration was more homogeneous during nHFOV compared with nCPAP (mean difference (95% CI) in AHR=0.01 (0.00 to 0.02), p=0.0014).

CONCLUSION

Although regional ventilation was similar between nHFOV and nCPAP, end-expiratory lung volume was higher and aeration homogeneity was slightly improved during nHFOV. The aeration difference was greatest in non-gravity dependent regions, possibly due to the oscillatory pressure waveform. The clinical importance of these findings is still unclear.

Non-invasive respiratory support in preterm infants

Survival of preterm infants has increased steadily over recent decades, primarily due to improved outcomes for those born before 28 weeks of gestation. However, this has not been matched by similar improvements in longer-term morbidity. One of the key long-term sequelae of preterm birth remains bronchopulmonary dysplasia (also called chronic lung disease of prematurity), contributed primarily by the effect of early pulmonary inflammation superimposed on immature lungs. Non-invasive modes of respiratory support have been rapidly introduced providing modest success in reducing the incidence of bronchopulmonary dysplasia when compared with invasive mechanical ventilation, and improved clinical practice has been reported from population-based studies. We present a comprehensive review of the key modes of non-invasive respiratory support currently used in preterm infants, including their mechanisms of action and evidence of benefit from clinical trials.

Evaluation of three non-invasive ventilation modes after extubation in the treatment of preterm infants with severe respiratory distress syndrome

OBJECTIVE

To evaluate the efficacy and safety of three different modes of non-invasive post-extubation ventilation support in preterm infants with severe respiratory distress syndrome (RDS).

METHODS

Infants diagnosed with severe RDS after extubation were randomized to receive nasal continuous positive airway pressure ventilation (NCPAP), nasal intermittent positive pressure ventilation (NIPPV), and non-invasive high-frequency oscillatory ventilation (NHFO). The clinical outcomes and complications of infants in different groups were recorded.

RESULTS

In infants less than 32 weeks, NCPAP had a significant increase in extubation failure when compared with NIPPV and NHFO, and the gastrointestinal feeding time, the numbers of apnea, and hospitalization costs in the NCPAP group were significantly higher. The incidence of complications was also higher in the NCPAP group. There was no difference in clinical outcomes and complications in infants greater than 32 weeks.

CONCLUSION

For infants with severe RDS less than 32 weeks after extubation, NIPPV and NHFO are more cost-effective in comparison to NCPAP.

Noninvasive High-Frequency Oscillatory Ventilation vs Nasal Continuous Positive Airway Pressure vs Nasal Intermittent Positive Pressure Ventilation as Postextubation Support for Preterm Neonates in China: A Randomized Clinical Trial

IMPORTANCE

Several respiratory support techniques are available to minimize the use of invasive mechanical ventilation (IMV) in preterm neonates. It is unknown whether noninvasive high-frequency oscillatory ventilation (NHFOV) is more efficacious than nasal continuous positive airway pressure (NCPAP) or nasal intermittent positive pressure ventilation (NIPPV) in preterm neonates after their first extubation.

OBJECTIVE

To test the hypothesis that NHFOV is more efficacious than NCPAP or NIPPV in reducing IMV after extubation and until neonatal intensive care unit discharge among preterm neonates.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, pathophysiology-based, assessor-blinded, 3-group, randomized clinical trial was conducted in 69 tertiary referral neonatal intensive care units in China, recruiting participants from December 1, 2017, to May 31, 2021. Preterm neonates who were between the gestational age of 25 weeks plus 0 days and 32 weeks plus 6 days and were ready to be extubated were randomized to receive NCPAP, NIPPV or NHFOV. Data were analyzed on an intention-to-treat basis.

INTERVENTIONS

The NCPAP, NIPPV, or NHFOV treatment was initiated after the first extubation and lasted until discharge.

MAIN OUTCOMES AND MEASURES

Primary outcomes were total duration of IMV, need for reintubation, and ventilator-free days. These outcomes were chosen to describe the effect of noninvasive ventilation strategy on the general need for IMV.

RESULTS

A total of 1440 neonates (mean [SD] age at birth, 29.4 [1.8] weeks; 860 boys [59.7%]) were included in the trial. Duration of IMV was longer in NIPPV (mean difference, 1.2; 95% CI, 0.01-2.3 days; P = .04) and NCPAP (mean difference, 1.5 days; 95% CI, 0.3-2.7 days; P = .01) compared with NHFOV. Neonates who were treated with NCPAP needed reintubations more often than those who were treated with NIPPV (risk difference: 8.1%; 95% CI, 2.9%-13.3%; P = .003) and NHFOV (risk difference, 12.5%; 95% CI, 7.5%-17.4%; P < .001). There were fewer ventilator-free days in neonates treated with NCPAP than in those treated with NIPPV (median [25th-75th percentile] difference, -3 [-6 to -1] days; P = .01). There were no differences between secondary efficacy or safety outcomes, except for the use of postnatal corticosteroids (lower in NHFOV than in NCPAP group; risk difference, 7.3%; 95% CI, 2.6%-12%; P = .002), weekly weight gain (higher in NHFOV than in NCPAP group; mean difference, -0.9 g/d; 95% CI, -1.8 to 0 g/d; P = .04), and duration of study intervention (shorter in NHFOV than in NIPPV group; median [25th-75th percentile] difference, -1 [-3 to 0] days; P = .01).

CONCLUSIONS AND RELEVANCE

Results of this trial indicated that NHFOV, if used after extubation and until discharge, slightly reduced the duration of IMV in preterm neonates, and both NHFOV and NIPPV resulted in a lower risk of reintubation than NCPAP. All 3 respiratory support techniques were equally safe for this patient population.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03181958.

Moving Bronchopulmonary Dysplasia Research from the Bedside to the Bench

Although advances in the respiratory management of extremely preterm infants have led to improvements in survival, this progress has not yet extended to a reduction in the incidence of bronchopulmonary dysplasia (BPD). BPD is a complex multifactorial condition that primarily occurs due to disturbances in the regulation of normal pulmonary airspace and vascular development. Preterm birth and exposure to invasive mechanical ventilation also compromises large airway development, leading to significant morbidity and mortality. Although both predisposing and protective genetic and environmental factors have been frequently described in the clinical literature, these findings have had limited impact on the development of effective therapeutic strategies. This gap is likely because the molecular pathways that underlie these observations are yet not fully understood, limiting the ability of researchers to identify novel treatments that can preserve normal lung development and/or enhance cellular repair mechanisms. In this review article, we will outline various well-established clinical observations whilst identifying key knowledge gaps that need to be filled with carefully designed pre-clinical experiments. We will address these issues by discussing controversial topics in the pathophysiology, the pathology and the treatment of BPD, including an evaluation of existing animal models that have been used to answer important questions.

Noninvasive High-Frequency Oscillatory Ventilation: A Retrospective Chart Review

OBJECTIVE

This study aimed to review the feasibility of nasal high-frequency oscillatory ventilation (NHFOV) in preventing reintubation in preterm infants.

STUDY DESIGN

This is a retrospective cohort study of all premature newborn infants placed on NHFOV in a single-center neonatal intensive care unit.

RESULTS

Twenty-seven patients (birth weight: 765 ± 186 g, gestational age: 28 ± 2 weeks) were commenced on NHFOV on 32 occasions. NHFOV was used immediately postextubation as the primary mode of noninvasive ventilation (NIV; prophylaxis) in 10 of 32 occasions and as "rescue" (failure of NCPAP or biphasic CPAP) in 22 of 32 occasions. Treatment with NHFOV was successful in 22 occasions (69%) while on 10 occasions (31%) reintubation was required within 72 hours. In the rescue group, there was significant reduction in the mean (standard deviation [SD]) number of apneas (0.9 ± 1.07 vs. 0.3 ± 0.29, p < 0.005), but there were no significant changes in the PCO₂ level (52 [ ±  9.8] vs. 52 [ ±  8.6] mm Hg, p = 0.8), or the FiO₂ requirement (0.39 ± 0.19 vs. 0.33 ± 0.10, p = 0.055) before and after commencing NHFOV, respectively.

CONCLUSION

The use of NHFOV is feasible as a prophylactic or rescue mode of NIV following extubation and was associated with decrease in the number of apneas without significant changes in PCO₂ or oxygen requirements. A well-designed randomized control trial is needed to determine the indications, clinical outcomes, and safety of this treatment modality.

KEY POINTS

· NHFOV is a new and evolving mode of noninvasive ventilation.. · The use of NHFOV is feasible as a prophylactic or rescue mode of noninvasive ventilation.. · A well-designed randomized control is needed to evaluate the efficacy and safety of NHFOV safe..

Interventions for the management of transient tachypnoea of the newborn - an overview of systematic reviews

BACKGROUND

Transient tachypnoea of the newborn (TTN) is characterised by tachypnoea and signs of respiratory distress. It is caused by delayed clearance of lung fluid at birth. TTN typically appears within the first two hours of life in term and late preterm newborns. Although it is usually a self-limited condition, admission to a neonatal unit is frequently required for monitoring, the provision of respiratory support, and drugs administration. These interventions might reduce respiratory distress during TTN and enhance the clearance of lung liquid. The goals are reducing the effort required to breathe, improving respiratory distress, and potentially shortening the duration of tachypnoea. However, these interventions might be associated with harm in the infant.

OBJECTIVES

The aim of this overview was to evaluate the benefits and harms of different interventions used in the management of TTN.

METHODS

We searched the Cochrane Database of Systematic Reviews on 14 July 2021 for ongoing and published Cochrane Reviews on the management of TTN in term (> 37 weeks' gestation) or late preterm (34 to 36 weeks' gestation) infants. We included all published Cochrane Reviews assessing the following categories of interventions administered within the first 48 hours of life: beta-agonists (e.g. salbutamol and epinephrine), corticosteroids, diuretics, fluid restriction, and non-invasive respiratory support. The reviews compared the above-mentioned interventions to placebo, no treatment, or other interventions for the management of TTN. The primary outcomes of this overview were duration of tachypnoea and the need for mechanical ventilation. Two overview authors independently checked the eligibility of the reviews retrieved by the search and extracted data from the included reviews using a predefined data extraction form. Any disagreements were resolved by discussion with a third overview author. Two overview authors independently assessed the methodological quality of the included reviews using the AMSTAR 2 (A MeaSurement Tool to Assess systematic Reviews) tool. We used the GRADE approach to assess the certainty of evidence for effects of interventions for TTN management. As all of the included reviews reported summary of findings tables, we extracted the information already available and re-graded the certainty of evidence of the two primary outcomes to ensure a homogeneous assessment. We provided a narrative summary of the methods and results of each of the included reviews and summarised this information using tables and figures.

MAIN RESULTS

We included six Cochrane Reviews, corresponding to 1134 infants enrolled in 18 trials, on the management of TTN in term and late preterm infants, assessing salbutamol (seven trials), epinephrine (one trial), budesonide (one trial), diuretics (two trials), fluid restriction (four trials), and non-invasive respiratory support (three trials). The quality of the included reviews was high, with all of them fulfilling the critical domains of the AMSTAR 2. The certainty of the evidence was very low for the primary outcomes, due to the imprecision of the estimates (few, small included studies) and unclear or high risk of bias. Salbutamol may reduce the duration of tachypnoea compared to placebo (mean difference (MD) -16.83 hours, 95% confidence interval (CI) -22.42 to -11.23, 2 studies, 120 infants, low certainty evidence). We did not identify any review that compared epinephrine or corticosteroids to placebo and reported on the duration of tachypnoea. However, one review reported on "trend of normalisation of respiratory rate", a similar outcome, and found no differences between epinephrine and placebo (effect size not reported). The evidence is very uncertain regarding the effect of diuretics compared to placebo (MD -1.28 hours, 95% CI -13.0 to 10.45, 2 studies, 100 infants, very low certainty evidence). We did not identify any review that compared fluid restriction to standard fluid rates and reported on the duration of tachypnoea. The evidence is very uncertain regarding the effect of continuous positive airway pressure (CPAP) compared to free-flow oxygen therapy (MD -21.1 hours, 95% CI -22.9 to -19.3, 1 study, 64 infants, very low certainty evidence); the effect of nasal high-frequency (oscillation) ventilation (NHFV) compared to CPAP (MD -4.53 hours, 95% CI -5.64 to -3.42, 1 study, 40 infants, very low certainty evidence); and the effect of nasal intermittent positive pressure ventilation (NIPPV) compared to CPAP on duration of tachypnoea (MD 4.30 hours, 95% CI -19.14 to 27.74, 1 study, 40 infants, very low certainty evidence). Regarding the need for mechanical ventilation, the evidence is very uncertain for the effect of salbutamol compared to placebo (risk ratio (RR) 0.60, 95% CI 0.13 to 2.86, risk difference (RD) 10 fewer, 95% CI 50 fewer to 30 more per 1000, 3 studies, 254 infants, very low certainty evidence); the effect of epinephrine compared to placebo (RR 0.67, 95% CI 0.08 to 5.88, RD 70 fewer, 95% CI 460 fewer to 320 more per 1000, 1 study, 20 infants, very low certainty evidence); and the effect of corticosteroids compared to placebo (RR 0.52, 95% CI 0.05 to 5.38, RD 40 fewer, 95% CI 170 fewer to 90 more per 1000, 1 study, 49 infants, very low certainty evidence). We did not identify a review that compared diuretics to placebo and reported on the need for mechanical ventilation. The evidence is very uncertain regarding the effect of fluid restriction compared to standard fluid administration (RR 0.73, 95% CI 0.24 to 2.23, RD 20 fewer, 95% CI 70 fewer to 40 more per 1000, 3 studies, 242 infants, very low certainty evidence); the effect of CPAP compared to free-flow oxygen (RR 0.30, 95% CI 0.01 to 6.99, RD 30 fewer, 95% CI 120 fewer to 50 more per 1000, 1 study, 64 infants, very low certainty evidence); the effect of NIPPV compared to CPAP (RR 4.00, 95% CI 0.49 to 32.72, RD 150 more, 95% CI 50 fewer to 350 more per 1000, 1 study, 40 infants, very low certainty evidence); and the effect of NHFV versus CPAP (effect not estimable, 1 study, 40 infants, very low certainty evidence). Regarding our secondary outcomes, duration of hospital stay was the only outcome reported in all of the included reviews. One trial on fluid restriction reported a lower duration of hospitalisation in the restricted-fluids group, but with very low certainty of evidence. The evidence was very uncertain for the effects on secondary outcomes for the other five reviews. Data on potential harms were scarce, as all of the trials were underpowered to detect possible increases in adverse events such as pneumothorax, arrhythmias, and electrolyte imbalances. No adverse effects were reported for salbutamol; however, this medication is known to carry a risk of tachycardia, tremor, and hypokalaemia in other settings.

AUTHORS' CONCLUSIONS

This overview summarises the evidence from six Cochrane Reviews of randomised trials regarding the effects of postnatal interventions in the management of TTN. Salbutamol may reduce the duration of tachypnoea slightly. We are uncertain as to whether salbutamol reduces the need for mechanical ventilation. We are uncertain whether epinephrine, corticosteroids, diuretics, fluid restriction, or non-invasive respiratory support reduces the duration of tachypnoea and the need for mechanical ventilation, due to the extremely limited evidence available. Data on harms were lacking.

Nasal high-frequency oscillatory ventilation versus nasal continuous positive airway pressure as primary respiratory support strategies for respiratory distress syndrome in preterm infants: a systematic review and meta-analysis

Nasal high-frequency oscillatory ventilation (NHFOV) is a new respiratory support strategy despite lacking of enough evidence in preterm infants with respiratory distress syndrome (RDS). The aim of the present systematic review was to explore whether NHFOV reduced the intubation rate as compared with nasal continuous positive airway pressure (NCPAP) as the primary respiratory support strategies in preterm infants with RDS. Medline, the Cochrane library, the Cochrane Controlled Trials Register, EMBASE, Chinese National Knowledge Infrastructure (CNKI), and Wanfang data Information Site were searched from inception to Jan 1, 2021(Prospero2019 CRD42019129316, date and name of registration: Apr 23,2019, The clinical effectiveness of NHFOV vs NCPAP for preterm babies with respiratory distress syndrome). Pooled data from clinically randomized controlled trials (RCTs) comparing NHFOV with NCPAP as the primary respiratory supporting strategies in preterm infants with RDS were performed using the fixed-effects models whenever no heterogeneity was shown. The primary outcome was intubation rate. Four randomized controlled trials involving 570 participants were included. Comparing with NCPAP, NHFOV resulted in less intubation (relative risk (RR) 0.44; 95% confidence interval (CI) 0.29-0.67, P = 0.0002), and heterogeneity was not found among the trials in the fixed-effects model (P = 0.78, I² = 0%). Similar result also appeared in sensitivity analysis after excluding one study with significant difference (RR 0.44; 95% CI 0.25-0.78, P = 0.005) (P = 0.58, I² = 0%).Conclusion: NHFOV decreased the intubation rate as compared with NCPAP as primary respiratory supporting strategies in preterm infants suffering from RDS. Future research should assess whether NHFOV can reduce the incidence of bronchopulmonary dysplasia (BPD) and intubation rate in preterm infants with BPD. Fund by Natural Science Foundation of Chongqing (cstc2020jcyj-msxmX0197), and "guan'ai" preterm Study Program of Renze Foundation of Beijing(K022). What is Known: • Nasal high-frequency oscillatory ventilation (NHFOV) has been described to be another advanced version of nasal continuous positive airway pressure (NCPAP). However, its beneficial effects among different studies as the primary modes in the early life of preterm infants with respiratory distress syndrome (RDS) were inconsistent. What is New: • Comparing with NCPAP, NHFOV decreases the risk of intubation as a primary respiratory supporting strategy in early life for preterm infants suffering from RDS.

Use of NHFOV vs. NIPPV for the respiratory support of preterm newborns after extubation: A meta-analysis

OBJECTIVES

This meta-analysis evaluated and compared the efficacy and safety of noninvasive high-frequency oscillatory ventilation (NHFOV) and nasal intermittent positive-pressure ventilation (NIPPV) for preterm newborns after extubation.

METHODS

We searched the PubMed, Cochrane Library, EMBASE, Web of Science, CNKI, Wanfang and VIP databases from inception to August 28, 2022. Randomized controlled trials (RCTs) that evaluated and compared the efficacy and safety of NHFOV and NIPPV in newborns were included in the review and meta-analysis, which followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines.

RESULTS

Eight studies involving 1,603 patients were included. Compared with NIPPV, NHFOV could reduce the reintubation rates (RR = 0.68, 95% CI 0.53, 0.86, P = 0.002). Subgroup analysis showed that the significant difference was found in reintubation rates within 72 h (RR = 0.48, 95% CI 0.32, 0.73, P = 0.0005). NHFOV also could decrease the duration of non-invasive ventilation (standard mean difference (SMD) = -1.52, 95% CI -2.58, -0.45, P = 0.005). However, all included studies had a high risk of bias, and the overall quality of the evidence of the outcomes was low or very low.

CONCLUSION

In our study, compared with NIPPV, NHFOV seems to reduce the reintubation rates without increasing adverse outcomes. Nevertheless, definite recommendations cannot be made based on the quality of the published evidence.

Nasal High-Frequency Ventilation

Noninvasive high-frequency oscillatory (NHFOV) and percussive (NHFPV) ventilation represent 2 nonconventional techniques that may be useful in selected neonatal patients. We offer here a comprehensive review of physiology, mechanics, and biology for both techniques. As NHFOV is the technique with the wider experience, we also provided a meta-analysis of available clinical trials, suggested ventilatory parameters boundaries, and proposed a physiology-based clinical protocol to use NHFOV.

Transmission of Oscillatory Volumes into the Preterm Lung during Noninvasive High-Frequency Ventilation

Rationale: There is increasing evidence for a clinical benefit of noninvasive high-frequency oscillatory ventilation (nHFOV) in preterm infants. However, it is still unknown whether the generated oscillations are effectively transmitted to the alveoli.Objectives: To assess magnitude and regional distribution of oscillatory volumes (V_Osc) at the lung level.Methods: In 30 prone preterm infants enrolled in a randomized crossover trial comparing nHFOV with nasal continuous positive airway pressure, electrical impedance tomography recordings were performed. During nHFOV, the smallest amplitude to achieve visible chest wall vibration was used, and the frequency was set at 8 hertz.Measurements and Main Results: Thirty consecutive breaths during artifact-free tidal ventilation were extracted for each of the 228 electrical impedance tomography recordings. After application of corresponding frequency filters, Vt and V_Osc were calculated. There was a signal at 8 and 16 Hz during nHFOV, which was not detectable during nasal continuous positive airway pressure, corresponding to the set oscillatory frequency and its second harmonic. During nHFOV, the mean (SD) V_Osc/Vt ratio was 0.20 (0.13). Oscillations were more likely to be transmitted to the non-gravity-dependent (mean difference [95% confidence interval], 0.041 [0.025-0.058]; P < 0.001) and right-sided lung (mean difference [95% confidence interval], 0.040 [0.019-0.061]; P < 0.001) when compared with spontaneous Vt.Conclusions: In preterm infants, V_Osc during nHFOV are transmitted to the lung. Compared with the regional distribution of tidal breaths, oscillations preferentially reach the right and non-gravity-dependent lung. These data increase our understanding of the physiological processes underpinning nHFOV and may lead to further refinement of this novel technique.

Nasal HFOV versus nasal IPPV as a post-extubation respiratory support in preterm infants-a randomised controlled trial

Early and successful extubation prevents several morbidities in preterm newborns. Several secondary non-invasive respiratory modalities exist but with their merits and demerits. Given the benefits of nasal high-frequency oscillatory ventilation (nHFOV), we tried to examine whether nHFOV could reduce reintubation rates compared to nasal intermittent positive pressure ventilation (NIPPV) during the post-extubation phase in preterm infants. Stratified randomisation based on gestational age was done for 86 mechanically ventilated preterm infants between 26 and 36⁺⁶ weeks of gestation within 2 weeks of age to receive either nHFOV or NIPPV post-extubation. The main objective was to compare extubation failure within 72 h following extubation and secondarily feed intolerance, intraventricular haemorrhage (IVH) (> grade 3), composite bronchopulmonary dysplasia (BPD)/mortality, composite duration of oxygen supplementation/ventilation support and SpO2/FiO2 ratio. No statistical difference was noted for primary outcome (RR 0.8, 95% CI: 0.23 to 2.78; p = 1.00) and secondary outcomes. However, nHFOV appeared possibly better in respect to feed tolerance rates and pCO2 washout.Conclusion: Extubation failure within 72 h in infants less than 37 weeks of gestation did not differ between the two groups. However, nHFOV seems promising in reducing enteral feeding issues and pCO2 elimination. Larger multicentre studies are required for exploring benefits of nHFOV.Trial registration: www.ctri.nic.in id CTRI/2019/07/020055, registration date July 5, 2019 What is Known: • NIPPV is superior to nCPAP as a secondary mode of respiratory support. • Synchronisation is preferred for optimum ventilation. What is New: • nHFOV, a novel non-invasive respiratory modality without need for synchronisation, appears promising as a secondary mode subject to further trials. • It seems promising in reducing enteral feeding issues and pCO2 elimination.

Nasal High-Frequency Oscillatory Ventilation in Preterm Infants with Moderate Respiratory Distress Syndrome: A Multicenter Randomized Clinical Trial

OBJECTIVE

To determine whether nasal high-frequency oscillatory ventilation (NHFOV) as a primary mode of respiratory support as compared with nasal continuous airway pressure (NCPAP) will reduce the need for invasive mechanical ventilation in preterm infants (260/7-336/7 weeks of gestational age [GA]) with respiratory distress syndrome (RDS).

METHODS

This multicenter randomized controlled trial was conducted in 18 tertiary neonatal intensive care units in China. A total of 302 preterm infants born at a GA of 260/7-336/7 weeks with a diagnosis of RDS were randomly assigned to either the NCPAP (n = 150) or the NHFOV (n = 152) group. The primary outcome was the need for invasive mechanical ventilation during the first 7 days after birth.

RESULTS

Treatment failure occurred in 15 of 152 infants (9.9%) in the -NHFOV group and in 26 of 150 infants (17.3%) in the NCPAP group (95% CI of risk difference: -15.2 to 0.4, p = 0.06). In the subgroup analysis, NHFOV resulted in a significantly lower rate of treatment failure than did NCPAP in the strata of 26+0/7-29+6/7weeks of GA (11.9 vs. 32.4%, 95% CI of risk difference: -39.3 to -1.7, p = 0.03) and birth weight <1,500 g (10.4 vs. 29.6%, 95% CI of risk difference: -33.8 to -4.6, p = 0.01). The rate of thick secretions causing an airway obstruction was higher in the NHFOV group than in the NCPAP group (13.8 vs. 5.3%, 95% CI of risk difference: 1.9-15.1, p = 0.01). No significant differences in other secondary outcomes were found between the NHFOV and NCPAP groups.

CONCLUSIONS

NHFOV was not superior to NCPAP with regard to the primary outcome when applied as the primary respiratory support for RDS in infants between 26+0/7 and 33+6/7 weeks of GA. In the subgroup analysis, NHFOV seemed to improve effectiveness than NCPAP in preterm infants <30 weeks of GA.

Non-invasive respiratory support for the management of transient tachypnea of the newborn

BACKGROUND

Transient tachypnea of the newborn (TTN) is characterized by tachypnea and signs of respiratory distress. Transient tachypnea typically appears within the first two hours of life in term and late preterm newborns. Supportive management might be sufficient. Non-invasive (i.e. without endotracheal intubation) respiratory support may, however, be administered to reduce respiratory distress during TTN. In addition, non-invasive respiratory support might improve clearance of lung liquid thus reducing the effort required to breathe, improving respiratory distress and potentially reducing the duration of tachypnea.

OBJECTIVES

To assess benefits and harms of non-invasive respiratory support for the management of transient tachypnea of the newborn.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 2), MEDLINE (1996 to 19 February 2019), Embase (1980 to 19 February 2019) and CINAHL (1982 to 19 February 2019). We applied no language restrictions. We searched clinical trial registries for ongoing studies.

SELECTION CRITERIA

Randomized controlled trials, quasi-randomized controlled trials and cluster trials on non-invasive respiratory support provided to infants born at 34 weeks' gestational age or more and less than three days of age with transient tachypnea of the newborn.

DATA COLLECTION AND ANALYSIS

For each of the included trials, two review authors independently extracted data (e.g. number of participants, birth weight, gestational age, duration of oxygen therapy, need for continuous positive airway pressure [CPAP] and need for mechanical ventilation, duration of mechanical ventilation, etc.) and assessed the risk of bias (e.g. adequacy of randomization, blinding, completeness of follow-up). The primary outcomes considered in this review were need for mechanical ventilation and pneumothorax. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included three trials (150 infants) comparing either CPAP to free-flow oxygen, nasal intermittent mandatory ventilation to nasal CPAP, or nasal high-frequency percussive ventilation versus nasal CPAP. Due to these different comparisons and to high clinical heterogeneity in the baseline clinical characteristics, we did not pool the three studies. The use of CPAP versus free oxygen did not improve the primary outcomes of this review: need for mechanical ventilation (risk ratio [RR] 0.30, 95% confidence interval [CI] 0.01 to 6.99; 1 study, 64 participants); and pneumothorax (not estimable, no cases occurred). Among secondary outcomes, CPAP reduced the duration of tachypnea as compared to free oxygen (mean difference [MD] -21.10 hours, 95% CI -22.92 to -19.28; 1 study, 64 participants). Nasal intermittent ventilation did not reduce the need for mechanical ventilation as compared with CPAP (RR 4.00, 95% CI 0.49 to 32.72; 1 study, 40 participants) or the incidence of pneumothorax (RR 1.00, 95% CI 0.07 to 14.90; 1 study, 40 participants); duration of tachypnea did not differ (MD 4.30, 95% CI -19.14 to 27.74; 1 study, 40 participants). In the study comparing nasal high-frequency ventilation to CPAP, no cases of mechanical ventilation of pneumothorax occurred (not estimable; 1 study, 46 participants); duration of tachypnea was reduced in the nasal high-frequency ventilation group (MD -4.53, 95% CI -5.64 to -3.42; 1 study, 46 participants). The quality of the evidence was very low due to the imprecision of the estimates and unclear risk of bias for detection bias and high risk of bias for reporting bias. Tests for heterogeneity were not applicable for any of the analyses as no studies were pooled. Two trials are ongoing.

AUTHORS' CONCLUSIONS

There is insufficient evidence to establish the benefit and harms of non-invasive respiratory support in the management of transient tachypnea of the newborn. Though two of the included trials showed a shorter duration of tachypnea, clinically relevant outcomes did not differ amongst the groups. Given the limited and low quality of the evidence available, it was impossible to determine whether non-invasive respiratory support was safe or effective for the treatment of transient tachypnea of the newborn.

Nasal High-Frequency Oscillatory Ventilation in Preterm Infants With Respiratory Distress Syndrome and ARDS After Extubation: A Randomized Controlled Trial

BACKGROUND

Nasal high-frequency oscillatory ventilation (NHFOV) has been described as supplying the combined advantages of nasal CPAP (NCPAP) and HFOV. However, its effect on preterm infants needs to be further elucidated. Our objective was to assess whether NHFOV could reduce intubation and Pco₂ levels as compared with NCPAP during the postextubation phase in preterm infants.

METHODS

This was a single-center, randomized, controlled trial, and it was registered at clinicaltrials.gov (NCT03140891) and conducted between May 2017 and May 2018. Ventilated infants born at less than 37 weeks' gestational age and ready to be extubated were included and randomized to either the NHFOV or NCPAP group. Primary outcomes were the incidence of reintubation within 1 week and the Pco₂ level within 6 h.

RESULTS

A total of 206 preterm infants were included. Of them, 127 (61.7%) were diagnosed with respiratory distress syndrome, 53 (25.7%) with ARDS, and 26 (12.6%) with both respiratory distress syndrome and ARDS. Comparing with NCPAP, NHFOV significantly reduced the reintubation rate (16:87 vs 35:68; 95% CI, 0.18-0.70; P = .002), especially in the subgroup with a gestational age of ≤ 32 weeks (12:34 vs 25:20; 95% CI, 0.12-0.68; P = .004). The Pco₂ level was also significant lower in the NHFOV group (49.6 ± 8.7 vs 56.9 ± 9.9; 95% CI, -9.95 to -4.80; P = < .001). Moreover, NHFOV significantly reduced the reintubation rate in preterm infants with ARDS (10:33 vs 21:15; 95% CI, 0.08-0.57; P = .002).

CONCLUSIONS

NHFOV was shown to be superior to NCPAP in avoiding reintubation, especially in very preterm infants and those infants diagnosed with ARDS.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03140891; URL: www.clinicaltrials.gov.

Is Nasal High Flow Inferior to Continuous Positive Airway Pressure for Neonates?

Nasal high-flow therapy (nHF) is increasingly used for neonates, with perceived benefits including reduced rates of nasal trauma and parent and nursing staff preference. Current evidence suggests that although nHF is a reasonable alternative for postextubation support of preterm infants, continuous positive airway pressure is a superior modality for primary support of respiratory distress syndrome. Minimal evidence exists for use of nHF in extremely preterm infants less than 28 weeks' gestation. Depending on clinician preference, units may still choose nHF in some settings, although careful choice of appropriate patients, and availability of rescue continuous positive airway pressure, is essential.

Nasal Intermittent Mandatory Ventilation Versus Nasal Continuous Positive Airway Pressure Before and After Invasive Ventilatory Support

Continuous positive airway pressure (CPAP), noninvasive intermittent positive pressure ventilation (NIPPV), and heated humidified high-flow nasal cannula (HHFNC) are modes of noninvasive respiratory support used in neonatal practice. These modes of noninvasive respiratory support may obviate mechanical ventilation, prevent extubation failure, and reduce the risk of developing bronchopulmonary dysplasia. Although the physiologic bases of CPAP and HHFNC are well delineated, and their modes and practical application consistent, those of NIPPV are unproven and varied. Available evidence suggests that NIPPV is superior to CPAP as a primary and postextubation respiratory support in preterm infants.

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.

Continuous positive airway pressure (CPAP) vs noninvasive positive pressure ventilation (NIPPV) vs noninvasive high frequency oscillation ventilation (NHFOV) as post-extubation support in preterm neonates: protocol for an assessor-blinded, multicenter, randomized controlled trial

BACKGROUND

Various noninvasive respiratory support modalities are available in neonatal critical care in order to minimize invasive ventilation. Continuous positive airway pressure (CPAP) is the more commonly used but noninvasive positive pressure ventilation (NIPPV) seems more efficacious in the early post-extubation phase, although it is not clear if NIPPV may influence longterm outcomes. A recently introduced alternative is noninvasive high frequency oscillatory ventilation (NHFOV) which might be especially useful in babies needing high constant distending pressure. Preterm neonates may receive these respiratory supports for several weeks. Nonetheless, no data are available for the longterm use of NIPPV and NHFOV; few data exist on NHFOV and clinical outcomes, although its safety and suitability are reported in a number of preliminary short-term studies.

METHODS

We designed an assessor-blinded, multicenter, three-arms, parallel, pragmatic, randomized, controlled trial with a superiority design, investigating the use of CPAP vs NIPPV vs NHFOV during the whole stay in neonatal intensive care units in China. Since safety data will also be analyzed it may be considered a phase II/III trial. Moreover, subgroup analyses will be performed on patients according to prespecified criteria based on physiopathology traits: these subgroup analyses should be considered preliminary. At least 1440 neonates are supposed to be enrolled. The trial has been designed with the collaboration of international colleagues expert in NHFOV, who will also perform an interim analysis at the about 50% of the enrolment.

DISCUSSION

The study is applying the best trial methodology to neonatal ventilation, a field where it is often difficult to do so for practical reasons. Nonetheless, ours is also a physiology-driven trial, since interventions are applied based on physiological perspective, in order to use ventilatory techniques at their best. The pragmatic design will increase generalizability of our results but subgroup analyses according to predefined physiopathological criteria are also previewed trying to have some advantages of an explanatory design. Since not all clinicians are well versed in all respiratory techniques, the training is pivotal. We intend to apply particular care to train the participating units: a specific 3-month period and several means have been dedicated to this end.

TRIAL REGISTRATION

NCT03181958 (registered on June 9, 2017).

Carbon dioxide diffusion coefficient in noninvasive high-frequency oscillatory ventilation

OBJECTIVES

The carbon dioxide (CO₂ ) diffusion coefficient (DCO ₂ ) reflects CO ₂ removal during high-frequency oscillatory ventilation (HFOV). We hypothesized that despite leak flow during noninvasive HFOV (nHFOV) DCO ₂ continues to indicate ventilation efficacy.

METHODS

A neonatal airway model including CO₂ production and an adjustable oropharyngeal leak was connected to a ventilator via bi-nasal prongs. Pressures and gas flows were measured at prongs, trachea, and leak. Oscillatory tidal volumes below (V _{T trachea} ) and above the leak (V _{T prong} ) were calculated from tracheal and leak flows. DCO ₂ was calculated using V _{T trachea} (DCO _{2 trachea} ) and V _{T prong} (DCO _{2 prong} ) and compared with CO ₂ partial pressure (pCO ₂ ). Effects of leak flow (0, 5, or 10 L/min) on DCO ₂ were assessed at fixed pressure amplitudes or predefined oscillatory volumes under steady-state pCO ₂ conditions in the modeled lung.

RESULTS

DCO_{2 trachea} correlated strongly with pCO ₂ , independent of the leak flow level (P < 0.0001). DCO _{2 prong} correlated with pCO ₂ without and with moderate leak (P < 0.0001) but not with maximum leak (P = 0.1432). V _{T trachea} correlated with the quotient of tracheal pressure amplitude and frequency irrespective of the leak (P < 0.0001). Based on the pressure amplitude at prong level (A _prong ) V _{T trachea} continued to follow a linear model of which the slopes decreased with increasing leak flow. V _{T prong} correlated with the quotient of A _prong and frequency, irrespective of the leak (P < 0.0001).

CONCLUSIONS

DCO₂ obtained at the airway opening at prong level reflects ventilation efficacy during nHFOV even in the presence of moderate oropharyngeal leak.

Hazards to avoid in future neonatal studies of nasal high-frequency oscillatory ventilation: lessons from an early terminated trial

Objective

To investigate whether nasal high-frequency oscillatory ventilation (nHFOV) started immediately after extubation of mechanically ventilated very low birth weight infants reduces the partial pressure of carbon dioxide at 72 h after extubation in comparison with nasal continuous positive airway pressure. This randomised controlled single-centre trial aimed to include 68 preterm infants at high risk of extubation failure.

Results

Implementation of the study protocol was feasible. However, from 2015 to 2017, only six patients could be recruited, leading to early termination of the trial. The slow recruitment was due to the introduction of new strategies to avoid endotracheal mechanical ventilation, which reduced the number of eligible infants. Moreover, the included infants failed their extubation more often than anticipated, thereby increasing the required sample size. Based on our single-centre experience, we provide information for study planning and discuss the specific requirements for future trial protocols on nHFOV. The extubation of high-risk infants into nHFOV could well be beneficial, but a multicentric approach is necessary to investigate this hypothesis.

Trial Registration Clinicaltrials.gov NCT02340299, on 16 January 2015

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4268-2) contains supplementary material, which is available to authorized users.

Noninvasive high-frequency oscillatory ventilation as respiratory support in preterm infants: a meta-analysis of randomized controlled trials

BACKGROUND

Noninvasive high-frequency oscillatory ventilation (nHFOV), a relatively new modality, is gaining popularity despite scarce evidence. This meta-analysis was designed to evaluate the efficacy and safety of nHFOV as respiratory support in premature infants.

METHODS

We searched MEDLINE, EMBASE, CINAHL, and Cochrane CENTRAL from inception of the database to January 2019. All published randomized controlled trials (RCTs) evaluating the effect of nHFOV therapy with nasal continuous positive airway pressure (nCPAP) or biphasic nCPAP (BP-CPAP) in newborns for respiratory support were included. All meta-analyses were performed using Review Manager 5.3.

RESULTS

A total of 8 RCTs involving 463 patients were included. The meta-analysis estimated a lower risk of intubation (relative risk = 0.50, 95% confidence interval of 0.36 to 0.70) and more effective clearance of carbon dioxide (weighted mean difference = - 4.61, 95% confidence interval of - 7.94 to - 1.28) in the nHFOV group than in the nCPAP/BP-CPAP group.

CONCLUSIONS

Our meta-analysis of RCTs suggests that nHFOV, as respiratory support in preterm infants, significantly remove carbon dioxide and reduce the risk of intubation compared with nCPAP/BP-CPAP. The appropriate parameter settings for different types of noninvasive high-frequency ventilators, the effect of nHFOV in extremely preterm infants, and the long-term safety of nHFOV need to be assessed in large trials.

Nasal high-frequency oscillatory ventilation (nHFOV) versus nasal continuous positive airway pressure (NCPAP) as an initial therapy for respiratory distress syndrome (RDS) in preterm and near-term infants

BACKGROUND

Currently, various forms of non-invasive respiratory support have been used in the management of respiratory distress syndrome (RDS) in preterm neonates. However, nasal high-frequency oscillatory ventilation (nHFOV) has not yet been applied commonly as an initial treatment.

OBJECTIVES

This study was designed to investigate the efficacy and safety of nHFOV compared with nasal continuous positive airway pressure (NCPAP) in preterm and near-term infants with RDS.

METHODS

In a randomised clinical trial, a total of 68 neonates (gestational age (GA) between 30 and 36 weeks and 6 days) with a clinical diagnosis of RDS were randomly assigned to either the NCPAP (n=34) or the nHFOV (n=34) group. The primary outcome was the duration of non-invasive respiratory support (duration of using NCPAP or nHFOV).

RESULT

The median (IQR) duration of non-invasive respiratory support, was significantly shorter in the nHFOV group than that in the NCPAP group (20 (15-25.3) versus 26.5 (15-37.4) hours, respectively; p=0.02). The need for a ventilator occurred in 4 out of 34 (11.8%) neonates in the NCPAP group and in none of the neonates in the nHFOV group (p=0.03). In addition, intraventricular haemorrhage (IVH) occurred in nine cases (6.9%) in the NCPAP group and two cases (3.3%) in the nHFOV group, which showed a significant difference (p=0.04). The incidence of pneumothorax, chronic lung disease, pulmonary haemorrhage and necrotising enterocolitis was similar between the two groups.

CONCLUSION

This study showed that nHFOV significantly reduced the duration of non-invasive respiratory support and decreased the need for intubation compared with NCPAP in infants with RDS. Furthermore, nHFOV seems to reduce the incidence of IVH without increasing other complications.

TRIAL REGISTRATION NUMBER

IRCT2017062734782N1.

Sustained inflations and avoiding mechanical ventilation to prevent death or bronchopulmonary dysplasia: a meta-analysis

Sustained inflations and avoidance of endotracheal mechanical ventilation (eMV) are delivery room interventions aimed at preventing bronchopulmonary dysplasia (BPD). Their effectiveness is the subject of the present meta-analysis.The databases MEDLINE, EMBASE and CENTRAL were searched for randomised controlled trials (RCTs) of preterm infants that compared: 1) sustained inflations with intermittent positive-pressure ventilation; and 2) a non-intubated strategy of respiratory support with one that prescribed eMV at an earlier stage. Data extraction and analysis followed the standard methods of the Cochrane Collaboration. The primary outcome was death or BPD, defined as need for oxygen or positive pressure treatment at 36 weeks' postmenstrual age.Avoiding eMV (nine RCTs, 3486 infants) reduced the risk of death or BPD, with a risk ratio of 0.90 (95% CI 0.84-0.97) and a number needed to treat of 35. After sustained inflations (six RCTs, 854 infants), the risk ratio was 0.85 (95% CI 0.65-1.12). A current multicentre RCT of sustained inflations in very preterm infants was halted for increased early mortality in the sustained inflations arm.While strategies aimed at avoiding eMV had a small but significant impact on preventing BPD, sustained inflations had no effect and may even increase mortality in very preterm infants.

The Effect of Noninvasive High-Frequency Oscillatory Ventilation on Desaturations and Bradycardia in Very Preterm Infants: A Randomized Crossover Trial

Noninvasive high-frequency oscillatory ventilation compared with nasal continuous positive airway pressure significantly reduced the number of desaturations and bradycardia in preterm infants. However, noninvasive high-frequency oscillatory ventilation was associated with increased oxygen requirements and higher heart rates.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trial Registry: ACTRN12616001516471.

Non-invasive high-frequency oscillatory ventilation in preterm infants: a randomised controlled cross-over trial

OBJECTIVE

Non-invasive high-frequency oscillatory ventilation (nHFOV) has recently been described as a novel mode of respiratory support for premature infants. This study was designed to determine whether nHFOV decreases CO₂ partial pressure (pCO₂) in premature infants more effectively than non-invasive continuous positive airway pressure (nCPAP).

DESIGN

Non-blinded prospective randomised controlled cross-over study.

SETTING

University Medical Center tertiary neonatal intensive care unit.

PATIENTS

26 premature infants of 27±2 weeks of gestational age after extubation or non-invasive surfactant treatment.

INTERVENTIONS

Infants were treated with 4 hours of nHFOV and 4 hours of nCPAP in a cross-over design. The sequence of the ventilation mode was randomly allocated.

MAIN OUTCOME MEASURES

The primary outcome measure was pCO₂ of arterial or arterialised blood 4 hours after commencing the respective mode of respiratory support. Secondary outcome criteria included events of apnoea and bradycardia, respiratory rate, heart rate, pain and/or discomfort, mean airway pressure, fraction of inspired oxygen and failure of non-invasive respiratory support.

RESULTS

pCO₂ after 4 hours of nHFOV was similar compared with 4 hours of nCPAP (p=0.33). pCO₂ was 54.8 (14.6) vs 52.7 (9.3) mm Hg mean (SD) for the nHFOV-nCPAP period (n=13) and 49.0 (8.1) vs 47.7 (9.5) mm Hg for the nCPAP-nHFOV period (n=13). There was no difference in any of the secondary outcome measures. nHFOV was terminated prematurely in five cases for predefined failure criteria (p=0.051).

CONCLUSIONS

We could not demonstrate an increased carbon dioxide clearance applying nHFOV compared with nCPAP in this cohort of preterm infants.

TRIAL REGISTRATION NUMBER

DRKS00007171, results.

Non-invasive high-frequency oscillatory ventilation versus nasal continuous positive airway pressure in preterm infants with respiratory distress syndrome: Study protocol for a multi-center prospective randomized controlled trial

BACKGROUND

Invasive mechanical ventilation (IMV) is associated with the development of adverse pulmonary and non-pulmonary outcomes in very premature infants. Various modes of non-invasive respiratory support are increasingly being used to decrease the incidence of bronchopulmonary dysplasia. The aim of this trial is to compare the effect of non-invasive high-frequency oscillatory ventilation (NHFOV) and nasal continuous positive airway pressure (NCPAP) in preterm infants with respiratory distress syndrome (RDS) as a primary non-invasive ventilation support mode.

METHODS/DESIGN

In this multi-center randomized controlled trial, 300 preterm infants born at a gestational age of 266/7 to 336/7 weeks with a diagnosis of RDS will be randomized to NHFOV or NCPAP as a primary mode of non-invasive respiratory support. The study will be conducted in 18 tertiary neonatal intensive care units in China. The primary outcome is the need for IMV during the first 7 days after enrollment in preterm infants randomized to the two groups. The prespecified secondary outcomes include days of hospitalization, days on non-invasive respiratory support, days on IMV, days on supplemental oxygen, mortality, need for a surfactant, severe retinopathy of prematurity requiring laser treatment or surgery, patent ductus arteriosus needing ligation, bronchopulmonary dysplasia, abdominal distention, air leak syndromes, intraventricular hemorrhage (≥ grade 3), spontaneous intestinal perforation, necrotizing enterocolitis (≥II stage), and nasal trauma. Other secondary outcomes include Bayley Scales of Infant Development at 18-24 months of corrected age.

DISCUSSION

In recent decades, several observational studies have compared the effects of NHFOV and NCPAP in neonates as a rescue mode or during weaning from IMV. To our knowledge, this will be the first multi-center prospective, randomized controlled trial to evaluate NHFOV as a primary mode in preterm infants with RDS in China or any other part of the world. Our trial may help to establish guidelines for NHFOV in preterm infants with RDS to minimize the need for IMV, and to decrease the significant pulmonary and non-pulmonary morbidities associated with IMV.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03099694 . Registered on 4 April 2017.

Nasal high-frequency oscillatory ventilation inhibits gastroesophageal reflux in the neonatal period

Nasal high-frequency oscillatory ventilation (nHFOV) in neonates is increasingly considered due to enhanced alveolar ventilation, absence of patient-ventilator asynchrony and lessened ventilator-induced lung injury. Although any type of non-invasive respiratory support can lead to gastric distension via esophageal air passage and thus promote gastroesophageal refluxes (GERs), we have shown that nasal continuous positive airway pressure (CPAP; 6 cmH₂O) and intermittent positive pressure ventilation (15/4 cmH₂O) conversely inhibit GERs in lambs. The current objective was to test the hypothesis that nHFOV also inhibits GERs compared to spontaneous ventilation without respiratory support. Eight lambs underwent five hours of polysomnographic and esophageal multichannel intraluminal impedance pHmetry recordings to assess GERs and air passage into the esophagus, with and without nHFOV (mean airway pressure = 8 cmH₂O, oscillation frequency = 8 Hz, amplitude ≈ 20 cmH₂O and I:E = 1:2). Results revealed that GERs were decreased with nHFOV (p = .03), despite an increase in gas-containing swallows (p = .01). In conclusion, similarly to nasal CPAP and intermittent positive pressure ventilation, nHFOV inhibits GERs in newborn lambs.

Nasal high-frequency oscillatory ventilation impairs heated humidification: A neonatal bench study

OBJECTIVE

Nasal high-frequency oscillatory ventilation (nHFOV) is a novel mode of non-invasive ventilation used in neonates. However, upper airway obstructions due to viscous secretions have been described as specific adverse effects. We hypothesized that high-frequency oscillations reduce air humidity in the oropharynx, resulting in upper airway desiccation. Therefore, we aimed to investigate the effects of nHFOV ventilatory settings on oropharyngeal gas conditions.

METHODS

NHFOV or nasal continuous positive airway pressure (nCPAP) was applied, along with heated humidification, to a previously established neonatal bench model that simulates oropharyngeal gas conditions during spontaneous breathing through an open mouth. A digital thermo-hygro sensor measured oropharyngeal temperature (T) and humidity at various nHFOV frequencies (7, 10, 13 Hz), amplitudes (10, 20, 30 cmH₂ O), and inspiratory-to-expiratory (I:E) ratios (25:75, 33:66, 50:50), and also during nCPAP.

RESULTS

Relative humidity was always >99%, but nHFOV resulted in lower mean T and absolute humidity (AH) in comparison to nCPAP (P < 0.001). Specifically, decreasing the nHFOV frequency and increasing nHFOV amplitude caused a decline in T and AH (P < 0.001). Mean T and AH were highest during nCPAP (T 34.8 ± 0.6°C, AH 39.3 ± 1.3 g · m^-3 ) and lowest during nHFOV at a frequency of 7 Hz and an amplitude of 30 cmH₂ O (T 32.4 ± 0.3°C, AH 34.7 ± 0.5 g · m^-3 ). Increasing the I:E ratio also reduced T and AH (P = 0.03).

CONCLUSION

Intensified nHFOV settings with low frequencies, high amplitudes, and high I:E ratios may place infants at an increased risk of upper airway desiccation. Future studies should investigate strategies to optimize heated humidification during nHFOV.

Noninvasive high-frequency oscillatory ventilation versus nasal continuous positive airway pressure in preterm infants with moderate-severe respiratory distress syndrome: A preliminary report

OBJECTIVE

The aim of this study was to compare the effect of noninvasive high-frequency oscillatory ventilation (nHFOV) with nasal continuous positive airway pressure (nCPAP) in preterm infants with moderate-severe respiratory distress syndrome (RDS) after surfactant administration via INSURE (intubation, surfactant, extubation) method on the need for invasive mechanical ventilation (IMV).

METHODS

A total of 81 infants with a gestational age (GA) of 28-34 weeks were eligible and were randomized to nCPAP (n = 42) or to nHFOV (n = 39). The need for IMV was the primary outcome. The incidence of bronchopulmonary dysplasia (BPD), occurrence of intraventricular hemorrhage (IVH), and air leaks, and mortality were considered as secondary outcomes.

RESULT

A total 76 infants finally completed the study. The need for IMV was significantlylower in the nHFOV group compared with the nCPAP group(24.3% vs 56.4%, P < 0.01). The incidence of IVH, air leaks or BPD was similar between the two groups. In addition, the mortality rate was not statistically different.

CONCLUSION

In this prospective, randomized controlled study, nHFOV significantly reduced the need for IMV as compared with nCPAP in preterm infants with moderate-severe RDS without increase in adverse effects.