Cerebral Oxygenation during Neonatal Intubation with Nasal High Flow: A Sub-Study of the SHINE Randomized Trial

INTRODUCTION

Nasal high flow (nHF) improves the likelihood of successful neonatal intubation on the first attempt without physiological instability. The effect of nHF on cerebral oxygenation is unknown. The aim of this study was to compare cerebral oxygenation during endotracheal intubation in neonates receiving nHF and those receiving standard care.

METHODS

A sub-study of a multicentre randomized trial of nHF during neonatal endotracheal intubation. A subset of infants had near-infrared spectroscopy (NIRS) monitoring. Eligible infants were randomly assigned to nHF or standard care during the first intubation attempt. NIRS sensors provided continuous regional cerebral oxygen saturation (rScO2) monitoring. The procedure was video recorded, and peripheral oxygen saturation and rScO2 data were extracted at 2-second intervals. The primary outcome was the average difference in rScO2 from baseline during the first intubation attempt. Secondary outcomes included average rScO2 and rate of change of rScO2.

RESULTS

Nineteen intubations were analyzed (11 nHF; 8 standard care). Median (interquartile range [IQR]) postmenstrual age was 27 (26.5-29) weeks, and weight was 828 (716-1,135) g. Median change in rScO2 from baseline was -1.5% (-5.3 to 0.0) in the nHF group and -9.4% (-19.6 to -4.5) in the standard care group. rScO2 fell more slowly in infants managed with nHF compared with standard care: median (IQR) rScO2 change -0.08 (-0.13 to 0.00) % per second and -0.36 (-0.66 to -0.22) % per second, respectively.

CONCLUSIONS

In this small sub-study, regional cerebral oxygen saturation was more stable in neonates who received nHF during intubation compared with standard care.

Time to desaturation in preterm infants undergoing endotracheal intubation

BACKGROUND

Neonatal endotracheal intubation is often associated with physiological instability. The Neonatal Resuscitation Program recommends a time-based limit (30 s) for intubation attempts in the delivery room, but there are limited physiological data to support recommendations in the neonatal intensive care unit (NICU). We aimed to determine the time to desaturation after ceasing spontaneous or assisted breathing in preterm infants undergoing elective endotracheal intubation in the NICU.

METHODS

Observational study at The Royal Women's Hospital, Melbourne. A secondary analysis was performed of video recordings of neonates ≤32 weeks' postmenstrual age undergoing elective intubation. Infants received premedication including atropine, a sedative and muscle relaxant. Apnoeic oxygenation time (AOT) was defined as the time from the last positive pressure or spontaneous breath until desaturation (SpO₂ <90%).

RESULTS

Seventy-eight infants were included. The median (IQR) gestational age at birth was 27 (26-29) weeks and birth weight 946 (773-1216) g. All but five neonates desaturated to SpO₂ <90% (73/78, 94%). The median (IQR) AOT was 22 (14-32) s. The median (IQR) time from ceasing positive pressure ventilation to desaturation <80% was 35 (24-44) s and to desaturation <60% was 56 (42-68) s. No episodes of bradycardia were seen.

CONCLUSIONS

This is the first study to report AOT in preterm infants. During intubation of preterm infants in the NICU, desaturation occurs quickly after cessation of positive pressure ventilation. These data are important for the development of clinical guidelines for neonatal intubation.

TRIAL REGISTRATION NUMBER

ACTRN12614000709640.

Protocol for a randomised controlled trial comparing two CPAP levels to prevent extubation failure in extremely preterm infants

INTRODUCTION

Respiratory distress syndrome is a complication of prematurity and extremely preterm infants born before 28 weeks' gestation often require endotracheal intubation and mechanical ventilation. In this high-risk population, mechanical ventilation is associated with lung injury and contributes to bronchopulmonary dysplasia. Therefore, clinicians attempt to extubate infants as quickly and use non-invasive respiratory support such as nasal continuous positive airway pressure (CPAP) to facilitate the transition. However, approximately 60% of extremely preterm infants experience 'extubation failure' and require reintubation. While CPAP pressures of 5-8 cm H2O are commonly used, the optimal CPAP pressure is unknown, and higher pressures may be beneficial in avoiding extubation failure. Our trial is the Extubation CPAP Level Assessment Trial (ÉCLAT). The aim of this trial is to compare higher CPAP pressures 9-11 cm H2O with a current standard pressures of 6-8 cmH2O on extubation failure in extremely preterm infants.

METHODS AND ANALYSIS

200 extremely preterm infants will be recruited prior to their first extubation from mechanical ventilation to CPAP. This is a parallel group randomised controlled trial. Infants will be randomised to one of two set CPAP pressures: CPAP 10 cmH2O (intervention) or CPAP 7 cmH2O (control). The primary outcome will be extubation failure (reintubation) within 7 days. Statistical analysis will follow standard methods for randomised trials on an intention to treat basis. For the primary outcome, this will be by intention to treat, adjusted for the prerandomisation strata (GA and centre). We will use the appropriate parametric and non-parametric statistical tests.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the Monash Health Human Research Ethics Committees. Amendments to the trial protocol will be submitted for approval. The findings of this study will be written into a clinical trial report manuscript and disseminated via peer-reviewed journals (on-line or in press) and presented at national and international conferences.Trial registration numberACTRN12618001638224; pre-results.

Supraglottic airway devices for administration of surfactant to newborn infants with respiratory distress syndrome: a narrative review

Surfactant is an effective treatment for respiratory distress syndrome, being particularly important for infants in whom continuous positive airway pressure (CPAP) provides insufficient support. Supraglottic airway devices present an attractive option for surfactant delivery, particularly as an alternative to methods dependent on direct laryngoscopy, a procedural skill that is both difficult to learn and in which to maintain competence. Published studies provide encouraging data that surfactant administration by supraglottic airway device can be performed with a high rate of success and may reduce the need for subsequent intubation compared with either continued CPAP or surfactant administration via endotracheal tube. However, existing randomised controlled trials (RCTs) are heterogeneous in design and include just over 350 infants in total. To date, all RCT evidence has been generated in tertiary units, whereas the greatest potential for benefit from the use of these devices is likely to be in non-tertiary settings. Future research should investigate choice and utility of device in addition to safety and effectiveness of procedure. Importantly, studies conducted in non-tertiary settings should evaluate feasibility, meaningful clinical outcomes and the impact that this approach might have on infants and their families. Supraglottic airway devices may represent a simple and effective mode of surfactant administration that can be widely used by a variety of clinicians. However, further well-designed RCTs are required to determine their role, safety and effectiveness in both tertiary and non-tertiary settings before introduction into routine clinical practice.

Gas flow in preterm infants treated with bubble CPAP: an observational study

OBJECTIVE

To measure the nasal gas flow in infants treated with bubble continuous positive airway pressure (CPAP) and compare it with commonly used flows during nasal high flow (nHF) treatment.

DESIGN

This is a prospective, single-centre study. Bubble CPAP pressure was measured at the nasal prongs. Set gas flow was reduced until bubbling in the water chamber just ceased. Set gas flow without bubbling then approximated flow entering the infant's nose ('delivered flow').

SETTING

Neonatal intensive care at The Royal Women's Hospital, Melbourne, Australia.

PATIENTS

Clinically stable preterm infants receiving bubble CPAP therapy.

MAIN OUTCOME MEASURE

Delivered flow (L/min) when bubbling stopped at a range of clinically set CPAP pressures (cm H₂O).

RESULTS

Forty-four infants were studied, with a mean (SD) gestational age at birth of 28.4 (2.2) weeks and birth weight of 1154 (419) g. At the time of the study, infants had a median (IQR) age of 4.5 (2-12) days and a mean (SD) weight of 1205 (407) g. Delivered flow ranged from 0.5 to 9.0 L/min, and increased with higher set CPAP pressures (median 3.5 L/min at CPAP 5 cm H₂O vs 6.3 L/min at CPAP 8 cm H₂O) and heavier weights (median 3.5 L/min in infants <1000 g vs 6.5 L/min for infants >1500 g).

CONCLUSIONS

Nasal gas flows during bubble CPAP in preterm infants are similar to flows used during nHF and increase with higher set bubble CPAP pressures and in larger infants. Trial registration number ACTRN12619000197134.

A multicentre, randomised trial of stabilisation with nasal high flow during neonatal endotracheal intubation (the SHINE trial): a study protocol

INTRODUCTION

Neonatal endotracheal intubation is an essential but potentially destabilising procedure. With an increased focus on avoiding mechanical ventilation, particularly in preterm infants, there are fewer opportunities for clinicians to gain proficiency in this important emergency skill. Rates of successful intubation at the first attempt are relatively low, and adverse event rates are high, when compared with intubations in paediatric and adult populations. Interventions to improve operator success and patient stability during neonatal endotracheal intubations are needed. Using nasal high flow therapy extends the safe apnoea time of adults undergoing upper airway surgery and during endotracheal intubation. This technique is untested in neonates.

METHODS AND ANALYSIS

The Stabilisation with nasal High flow during Intubation of NEonates (SHINE) trial is a multicentre, randomised controlled trial comparing the use of nasal high flow during neonatal intubation with standard care (no nasal high flow). Intubations are randomised individually, and stratified by site, use of premedications, and postmenstrual age (<28 weeks' gestation; ≥28 weeks' gestation). The primary outcome is the incidence of successful intubation on the first attempt without physiological instability of the infant. Physiological instability is defined as an absolute decrease in peripheral oxygen saturation >20% from preintubation baseline and/or bradycardia (<100 beats per minute).

ETHICS AND DISSEMINATION

The SHINE trial received ethical approval from the Human Research Ethics Committees of The Royal Women's Hospital, Melbourne, Australia and Monash Health, Melbourne, Australia. The trial is currently recruiting in these two sites. The findings of this study will be disseminated via peer-reviewed journals and presented at national and international conferences.

TRIAL REGISTRATION NUMBER

ACTRN12618001498280.

Outcomes following antenatal identification of hydrops fetalis: a single-centre experience from 2001 to 2012

OBJECTIVE

To describe the aetiologies and outcomes of pregnancies complicated by hydrops fetalis (HF).

STUDY DESIGN

Case series of all pregnancies complicated by HF managed at The Royal Women's Hospital (RWH), Melbourne, Australia, between 2001 and 2012. Multiple pregnancies, and cases where antenatal care was not provided at RWH were excluded. Cases were identified from neonatal and obstetric databases. Data were extracted from maternal and neonatal case files, electronic pathology and radiology reports, and obstetric and neonatal databases.

RESULTS

Over 12 years, 131 fetuses with HF with a median (IQR) gestational age (GA) at diagnosis of 24 (20-30) weeks were included in the analysis. There were 65 liveborn infants with a median (IQR) GA at birth of 33 (31-37) weeks and a median (IQR) birthweight Z-score of 1.4 (0.4-2.2). Overall survival from diagnosis was 27% (36/131) increasing to 55% (36/65) if born alive.

CONCLUSIONS

The perinatal mortality risk for fetuses and newborn infants with HF is high with important differences dependent on underlying diagnosis and the time at which counselling is provided. Clinicians need to be aware of the outcomes of both fetuses and neonates with this condition.

High-flow support in very preterm infants in Australia and New Zealand

BACKGROUND

Randomised trials suggest that high-flow (HF) therapy is comparable with continuous positive airway pressure (CPAP) for postextubation respiratory support in neonates, and HF has been widely adopted in neonatal intensive care.

METHODS

We conducted a population-based study of very preterm infants born <32 weeks' gestation within the Australian and New Zealand Neonatal Network (ANZNN) data set from 2009 to 2012, who received respiratory support with HF.

RESULTS

3372 very preterm infants were treated with HF. HF use in this population increased significantly from 15% in 2009 to 35% in 2012. In 2012, 53% (542/1029) of extremely preterm infants born <28 weeks' gestation received HF. 98% (3308/3372) of infants had received endotracheal ventilation or CPAP prior to receiving HF. The maximum HF gas flow was ≤8 L/min in almost all infants.

CONCLUSIONS

HF use in extremely preterm and very preterm infants increased significantly within the ANZNN from 2009 to 2012.

Are high flow nasal cannulae noisier than bubble CPAP for preterm infants?

BACKGROUND

Noise exposure in the neonatal intensive care unit is believed to be a risk factor for hearing loss in preterm neonates. Continuous positive airway pressure (CPAP) devices exceed recommended noise levels. High flow nasal cannulae (HFNC) are an increasingly popular alternative to CPAP for treating preterm infants, but there are no in vivo studies assessing noise production by HFNC.

OBJECTIVE

To study whether HFNC are noisier than bubble CPAP (BCPAP) for preterm infants.

METHODS

An observational study of preterm infants receiving HFNC or BCPAP. Noise levels within the external auditory meatus (EAM) were measured using a microphone probe tube connected to a calibrated digital dosimeter. Noise was measured across a range of frequencies and reported as decibels A-weighted (dBA).

RESULTS

A total of 21 HFNC and 13 BCPAP noise measurements were performed in 21 infants. HFNC gas flows were 2-5 L/min, and BCPAP gas flows were 6-10 L/min with set pressures of 5-7 cm of water. There was no evidence of a difference in average noise levels measured at the EAM: mean difference (95% CI) of -1.6 (-4.0 to 0.9) dBA for HFNC compared to BCPAP. At low frequency (500 Hz), HFNC was mean (95% CI) 3.0 (0.3 to 5.7) dBA quieter than BCPAP. Noise increased with increasing BCPAP gas flow (p=0.007), but not with increasing set pressure. There was a trend to noise increasing with increasing HFNC gas flows.

CONCLUSIONS

At the gas flows studied, HFNC are not noisier than BCPAP for preterm infants.

Are high flow nasal cannulae noisier than bubble CPAP for preterm infants?

BACKGROUND

Noise exposure in the neonatal intensive care unit is believed to be a risk factor for hearing loss in preterm neonates. Continuous positive airway pressure (CPAP) devices exceed recommended noise levels. High flow nasal cannulae (HFNC) are an increasingly popular alternative to CPAP for treating preterm infants, but there are no in vivo studies assessing noise production by HFNC.

OBJECTIVE

To study whether HFNC are noisier than bubble CPAP (BCPAP) for preterm infants.

METHODS

An observational study of preterm infants receiving HFNC or BCPAP. Noise levels within the external auditory meatus (EAM) were measured using a microphone probe tube connected to a calibrated digital dosimeter. Noise was measured across a range of frequencies and reported as decibels A-weighted (dBA).

RESULTS

A total of 21 HFNC and 13 BCPAP noise measurements were performed in 21 infants. HFNC gas flows were 2-5 L/min, and BCPAP gas flows were 6-10 L/min with set pressures of 5-7 cm of water. There was no evidence of a difference in average noise levels measured at the EAM: mean difference (95% CI) of -1.6 (-4.0 to 0.9) dBA for HFNC compared to BCPAP. At low frequency (500 Hz), HFNC was mean (95% CI) 3.0 (0.3 to 5.7) dBA quieter than BCPAP. Noise increased with increasing BCPAP gas flow (p=0.007), but not with increasing set pressure. There was a trend to noise increasing with increasing HFNC gas flows.

CONCLUSIONS

At the gas flows studied, HFNC are not noisier than BCPAP for preterm infants.