Calum T. Roberts

Nasal high-flow therapy for primary respiratory support in preterm infants

BACKGROUND Treatment with nasal high-flow therapy has efficacy similar to that of nasal continuous positive airway pressure (CPAP) when used as postextubation support in neonates. The efficacy of high-flow therapy as the primary means of respiratory support for preterm infants with respiratory distress has not been proved. METHODS In this international, multicenter, randomized, noninferiority trial, we assigned 564 preterm infants (gestational age, ≥28 weeks 0 days) with early respiratory distress who had not received surfactant replacement to treatment with either nasal high-flow therapy or nasal CPAP. The primary outcome was treatment failure within 72 hours after randomization. Noninferiority was determined by calculating the absolute difference in the risk of the primary outcome; the chosen margin of noninferiority was 10 percentage points. Infants in whom high-flow therapy failed could receive rescue CPAP; infants in whom CPAP failed were intubated and mechanically ventilated. RESULTS Trial recruitment stopped early at the recommendation of the independent data and safety monitoring committee because of a significant difference in the primary outcome between treatment groups. Treatment failure occurred in 71 of 278 infants (25.5%) in the high-flow group and in 38 of 286 infants (13.3%) in the CPAP group (risk difference, 12.3 percentage points; 95% confidence interval [CI], 5.8 to 18.7; P<0.001). The rate of intubation within 72 hours did not differ significantly between the high-flow and CPAP groups (15.5% and 11.5%, respectively; risk difference, 3.9 percentage points; 95% CI, -1.7 to 9.6; P=0.17), nor did the rate of adverse events. CONCLUSIONS When used as primary support for preterm infants with respiratory distress, high-flow therapy resulted in a significantly higher rate of treatment failure than did CPAP. (Funded by the National Health and Medical Research Council and others; Australian New Zealand Clinical Trials Registry number, ACTRN12613000303741 .).

Nursing perceptions of high‐flow nasal cannulae treatment for very preterm infants

This study aims to assess nursing perceptions of high‐flow nasal cannulae (HFNC) in comparison with nasal continuous positive airway pressure (NCPAP) as post‐extubation respiratory support for very preterm infants.

Videolaryngoscopy to Teach Neonatal Intubation: A Randomized Trial

BACKGROUND: Neonatal endotracheal intubation is a necessary skill. However, success rates among junior doctors have fallen to <50%, largely owing to declining opportunities to intubate. Videolaryngoscopy allows instructor and trainee to share the view of the pharynx. We compared intubations guided by an instructor watching a videolaryngoscope screen with the traditional method where the instructor does not have this view. METHODS: A randomized, controlled trial at a tertiary neonatal center recruited newborns from February 2013 to May 2014. Eligible intubations were performed orally on infants without facial or airway anomalies, in the delivery room or neonatal intensive care, by doctors with <6 months’ tertiary neonatal experience. Intubations were randomized to having the videolaryngoscope screen visible to the instructor or covered (control). The primary outcome was first-attempt intubation success rate confirmed by colorimetric detection of expired carbon dioxide. RESULTS: Two hundred six first-attempt intubations were analyzed. Median (interquartile range) infant gestation was 29 (27 to 32) weeks, and weight was 1142 (816 to 1750) g. The success rate when the instructor was able to view the videolaryngoscope screen was 66% (69/104) compared with 41% (42/102) when the screen was covered (P < .001, OR 2.81, 95% CI 1.54 to 5.17). When premedication was used, the success rate in the intervention group was 72% (56/78) compared with 44% (35/79) in the control group (P < .001, OR 3.2, 95% CI 1.6 to 6.6). CONCLUSIONS: Intubation success rates of inexperienced neonatal trainees significantly improved when the instructor was able to share their view on a videolaryngoscope screen.

Neonatal Non-Invasive Respiratory Support: Synchronised NIPPV, Non-Synchronised NIPPV or Bi-Level CPAP: What Is the Evidence in 2013?

Nasal continuous positive airway pressure (NCPAP) has proven to be an effective mode of non-invasive respiratory support in preterm infants; however, many infants still require endotracheal ventilation, placing them at an increased risk of morbidities such as bronchopulmonary dysplasia. Several other modes of non-invasive respiratory support beyond NCPAP, including synchronised and non-synchronised nasal intermittent positive pressure ventilation (SNIPPV and nsNIPPV) and bi-level positive airway pressure (BiPAP) are now also available. These techniques require different approaches, and the exact mechanisms by which they act remain unclear. SNIPPV has been shown to reduce the rate of reintubation in comparison to NCPAP when used as post-extubation support, but the evidence for nsNIPPV and BiPAP in this context is less convincing. There is some evidence that NIPPV (whether synchronised or non-synchronised) used as primary respiratory support is beneficial, but the variation in study methodology makes this hard to translate confidently into clinical practice. There is currently no evidence to suggest a reduction in mortality or important morbidities such as bronchopulmonary dysplasia, with NIPPV or BiPAP in comparison to NCPAP, and there is a lack of appropriately designed studies in this area. This review discusses the different approaches and proposed mechanisms of action of SNIPPV, nsNIPPV and BiPAP, the challenges of applying the available evidence for these distinct modalities of non-invasive respiratory support to clinical practice, and possible areas of future research.

A multicentre, randomised controlled, non-inferiority trial, comparing high flow therapy with nasal continuous positive airway pressure as primary support for preterm infants with respiratory distress (the HIPSTER trial): study protocol

Introduction High flow (HF) therapy is an increasingly popular mode of non-invasive respiratory support for preterm infants. While there is now evidence to support the use of HF to reduce extubation failure, there have been no appropriately designed and powered studies to assess the use of HF as primary respiratory support soon after birth. Our hypothesis is that HF is non-inferior to the standard treatment—nasal continuous positive airway pressure (NCPAP)— as primary respiratory support for preterm infants. Methods and analysis The HIPSTER trial is an unblinded, international, multicentre, randomised, non-inferiority trial. Eligible infants are preterm infants of 28–36+6 weeks’ gestational age (GA) who require primary non-invasive respiratory support for respiratory distress in the first 24 h of life. Infants are randomised to treatment with either HF or NCPAP. The primary outcome is treatment failure within 72 h after randomisation, as determined by objective oxygenation, blood gas, and apnoea criteria, or the need for urgent intubation and mechanical ventilation. Secondary outcomes include the incidence of intubation, pneumothorax, bronchopulmonary dysplasia, nasal trauma, costs associated with hospital care and parental stress. With a specified non-inferiority margin of 10%, using a two-sided 95% CI and 90% power, the study requires 375 infants per group (total 750 infants). Ethics and dissemination Ethical approval has been granted by the relevant human research ethics committees at The Royal Womens Hospital (13/12), The Royal Childrens Hospital (33144A), The Mercy Hospital for Women (R13/34), and the South-Eastern Norway Regional Health Authority (2013/1657). The trial is currently recruiting at 9 centres in Australia and Norway. The trial results will be published in peer-reviewed international journals, and presented at national and international conferences. Trial registration number Australian New Zealand Clinical Trials Registry ID: ACTRN12613000303741.

The effects of non-invasive respiratory support on oropharyngeal temperature and humidity: a neonatal manikin study

Objective Heating and humidification of inspired gases is routine during neonatal non-invasive respiratory support. However, little is known about the temperature and humidity delivered to the upper airway. The International Standards Organization (ISO) specifies that for all patients with an artificial airway humidifiers should deliver ≥33 g/m3 absolute humidity (AH). We assessed the oropharyngeal temperature and humidity during different non-invasive support modes in a neonatal manikin study. Methods Six different modes of non-invasive respiratory support were applied at clinically relevant settings to a neonatal manikin, placed in a warmed and humidified neonatal incubator. Oropharyngeal temperature and relative humidity (RH) were assessed using a thermohygrometer. AH was subsequently calculated. Results Measured temperature and RH varied between devices. Bubble and ventilator continuous positive airway pressure (CPAP) produced temperatures >34°C and AH >38 g/m3. Variable flow CPAP resulted in lower levels of AH than bubble or ventilator CPAP, and AH decreased with higher gas flow. High-flow (HF) therapy delivered by Optiflow Junior produced higher AH with higher gas flow, whereas with Vapotherm HF the converse was true. Conclusions Different non-invasive devices deliver inspiratory gases of variable temperature and humidity. Most AH levels were above the ISO recommendation; however, with some HF and variable flow CPAP devices at higher gas flow this was not achieved. Clinicians should be aware of differences in the efficacy of heating and humidification when choosing modes of non-invasive respiratory support.

Interventions to improve rates of successful extubation in preterm infants a systematic review and meta-analysis

Importance Clinicians aim to extubate preterm infants as early as possible, to minimize the risks of mechanical ventilation. Extubation is often unsuccessful owing to lung disease or inadequate respiratory drive. Objective To conduct a systematic review and meta-analysis of interventions to improve rates of successful extubation in preterm infants. Data Sources Searches were undertaken in PubMed and The Cochrane Library. Study Selection The review was conducted using the methods of the Cochrane Collaboration and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were included if they were randomized clinical trials published in English, enrolled intubated preterm infants (born <37 weeks’ gestation), and reported 1 or both of the primary outcomes. Data Extraction and Synthesis One thousand three hundred seventy-nine titles were screened independently by 2 investigators to assess need for full-text review. Disagreements were resolved via consensus of all authors. Where no Cochrane Review existed for an intervention, or not all identified studies were included, a new pooled analysis was performed. Main Outcomes and Measures Primary outcomes were treatment failure or reintubation within 7 days of extubation. Results Fifty studies were eligible for inclusion. Continuous positive airway pressure reduced extubation failure in comparison with head-box oxygen (risk ratio [RR], 0.59; 95% CI, 0.48-0.72; number needed to treat [NNT], 6; 95% CI, 3-9). Nasal intermittent positive pressure ventilation was superior to continuous positive airway pressure in preventing extubation failure (RR, 0.70; 95% CI, 0.60-0.81; NNT, 8; 95% CI, 5-13). High-flow nasal cannula therapy and continuous positive airway pressure had similar efficacy (RR, 1.11; 95% CI, 0.84-1.47). Methylxanthines reduced extubation failure (RR, 0.48; 95% CI, 0.32-0.71; NNT, 4; 95% CI, 2-7) compared with placebo or no treatment. Corticosteroids (RR, 0.18; 95% CI, 0.04-0.97; NNT, 12; 95% CI, 6-100) and chest physiotherapy (RR, 0.32; 95% CI, 0.13-0.82; NNT, 15; 95% CI, 7-50) both reduced extubation failure rates but were associated with significant adverse effects. Doxapram did not aid successful extubation (RR, 0.80; 95% CI, 0.22-2.97). Conclusions and Relevance Preterm infants should be extubated to noninvasive respiratory support. Caffeine should be used routinely, while corticosteroids should be used judiciously, weighing up the competing risks of bronchopulmonary dysplasia and neurodevelopmental harm.

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.

Retrospective Consent in a Neonatal Randomized Controlled Trial

The authors of this study found that using retrospective consent in an RCT improved recruitment and altered study population demographics, potentially affecting outcomes and applicability to practice. BACKGROUND AND OBJECTIVES: The requirement for prospective consent in clinical trials in acute settings may result in samples unrepresentative of the study population, potentially altering study findings. However, using retrospective consent may raise ethical issues. We assessed whether using retrospective consent affected recruitment, participant characteristics, and outcomes within a randomized controlled trial. METHODS: We conducted a secondary analysis of a randomized trial, which compared nasal high flow (nHF) with nasal continuous positive airway pressure (CPAP) for primary respiratory support in preterm infants. In Era 1, all infants were consented prospectively; in Era 2, retrospective consent was available. We assessed inclusion rates of eligible infants, demographic data, and primary trial outcome (treatment failure within 72 hours). RESULTS: In Era 1, recruitment of eligible infants was lower than in Era 2: 111 of 220 (50%) versus 171 of 209 (82%), P < .001; intrapartum antibiotic administration was lower: 23 of 111 (21%) versus 84 of 165 (51%), P < .001; full courses of antenatal steroids were higher: 86 of 111 (78%) versus 103 of 170 (61%), P = .004; and more infants received pre-randomization CPAP: 77 of 111 (69%) versus 48 of 171 (28%), P < .001. In Era 1, nHF failure (15 of 56, 27%) and CPAP failure (14 of 55, 26%) rates were similar, P = .9. In Era 2, failure rates differed: 24 of 85 (28%) nHF infants versus 13 of 86 (15%) CPAP infants, P = .04. The χ2 interaction test was nonsignificant (P = .20). CONCLUSIONS: The use of retrospective consent resulted in greater recruitment and differences in risk factors between eras. Using retrospective consent altered the study sample, which may be more representative of the whole population. This may improve scientific validity but requires further ethical evaluation.