Louise S. Owen

High-Flow Nasal Cannulae in Very Preterm Infants after Extubation

BACKGROUND The use of high-flow nasal cannulae is an increasingly popular alternative to nasal continuous positive airway pressure (CPAP) for noninvasive respiratory support of very preterm infants (gestational age, <32 weeks) after extubation. However, data on the efficacy or safety of such cannulae in this population are lacking. METHODS In this multicenter, randomized, noninferiority trial, we assigned 303 very preterm infants to receive treatment with either high-flow nasal cannulae (5 to 6 liters per minute) or nasal CPAP (7 cm of water) after extubation. The primary outcome was treatment failure within 7 days. Noninferiority was determined by calculating the absolute difference in the risk of the primary outcome; the margin of noninferiority was 20 percentage points. Infants in whom treatment with high-flow nasal cannulae failed could be treated with nasal CPAP; infants in whom nasal CPAP failed were reintubated. RESULTS The use of high-flow nasal cannulae was noninferior to the use of nasal CPAP, with treatment failure occurring in 52 of 152 infants (34.2%) in the nasal-cannulae group and in 39 of 151 infants (25.8%) in the CPAP group (risk difference, 8.4 percentage points; 95% confidence interval, -1.9 to 18.7). Almost half the infants in whom treatment with high-flow nasal cannulae failed were successfully treated with CPAP without reintubation. The incidence of nasal trauma was significantly lower in the nasal-cannulae group than in the CPAP group (P=0.01), but there were no significant differences in rates of serious adverse events or other complications. CONCLUSIONS Although the result for the primary outcome was close to the margin of noninferiority, the efficacy of high-flow nasal cannulae was similar to that of CPAP as respiratory support for very preterm infants after extubation. (Funded by the National Health and Medical Research Council; Australian New Zealand Clinical Trials Network number, ACTRN12610000166077.).

Improved techniques reduce face mask leak during simulated neonatal resuscitation: Study 2

Background: Techniques of positioning and holding neonatal face masks vary. Studies have shown that leak at the face mask is common and often substantial irrespective of operator experience. Aims: (1) To identify a technique for face mask placement and hold which will minimise mask leak. (2) To investigate the effect of written instruction and demonstration of the identified technique on mask leak for two round face masks. Method: Three experienced neonatologists compared methods of placing and holding face masks to minimise the leak for Fisher & Paykel 60 mm and Laerdal size 0/1 masks. 50 clinical staff gave positive pressure ventilation to a modified manikin designed to measure leak at the face mask. They were provided with written instructions on how to position and hold each mask and then received a demonstration. Face mask leak was measured after each teaching intervention. Results: A technique of positioning and holding the face masks was identified which minimised leak. The mean (SD) mask leaks before instruction, after instruction and after demonstration were 55% (31), 49% (30), 33% (26) for the Laerdal mask and 57% (25), 47% (28), 32% (30) for the Fisher & Paykel mask. There was no significant difference in mask leak between the two masks. Written instruction alone reduced leak by 8.8% (CI 1.4% to 16.2%) for either mask; when combined with a demonstration mask leak was reduced by 24.1% (CI 16.4% to 31.8%). Conclusion: Written instruction and demonstration of the identified optimal technique resulted in significantly reduced face mask leak.

Effects of non-synchronised nasal intermittent positive pressure ventilation on spontaneous breathing in preterm infants

Background Nasal intermittent positive pressure ventilation (NIPPV) may be beneficial but the mechanisms of action are undetermined. Aim To investigate the effects of non-synchronised NIPPV on spontaneous breathing in premature infants. Methods 10 infants receiving ventilator generated non-synchronised NIPPV were studied for 30 min. Delivered pressure was measured at the nose; respiration was recorded using respiratory inductance plethysmography. Oxygen saturation, carbon dioxide, heart rate, inspired oxygen and video images were recorded. Results Median gestational age, birth weight, age and study weight were 25+3 weeks, 797 g, 24 days and 1076 g. When the NIPPV pressure peak commenced during spontaneous inspiration the inspiratory time increased by 21% (p=0.002), relative tidal volume increased by 15% (p=0.01) and expiratory time was unchanged. When the NIPPV pressure peak commenced during spontaneous expiration the expiratory time increased by 13% (p=0.04). NIPPV pressures delivered during apnoea (range 8–28 cm H2O) produced chest inflation 5% of the time, resulting in small tidal volumes (26.7% of spontaneous breath size) but reduced oxygen desaturation. NIPPV pressure peaks occurred throughout spontaneous respiration proportional to the inspiratory: expiratory ratio. Conclusion NIPPV pressure peaks only resulted in a small increase in relative tidal volumes when delivered during spontaneous inspiration. During apnoea pressure peaks occasionally resulted in chest inflation, which ameliorated oxygen desaturations. Infants did not become entrained with the NIPPV pressure changes. Synchronising every rise in applied pressure with spontaneous inspiration may increase the effectiveness of NIPPV and warrants investigation.

High-flow nasal cannulae and nasal continuous positive airway pressure use in non-tertiary special care nurseries in Australia and New Zealand

Aim:  Non‐tertiary centres (NTCs) in Australia and New Zealand are increasingly providing non‐invasive respiratory support, including high‐flow nasal cannulae (HFNC) and nasal continuous positive airway pressure (nCPAP), to newborn infants. We aimed to determine the proportion of NTCs in these countries treating newborn infants with HFNC and nCPAP, and how these therapies are used.

Neonatal nasal intermittent positive pressure ventilation: what do we know in 2007?

Although neonatal nasal intermittent positive pressure ventilation (NIPPV) is widely used today, its place in neonatal respiratory support is yet to be fully defined. Current evidence indicates that NIPPV after extubation of very premature infants reduces the rate of reintubation. However, much is still not known about NIPPV including its mechanisms of action. It may improve pulmonary mechanisms, tidal volume and minute ventilation but more studies are required to confirm these findings. There is some evidence that NIPPV marginally improves gas exchange. More research is needed to establish which device is best, what settings to use or whether to use synchronised rather than non-synchronised NIPPV, and about the way to wean NIPPV. Future studies should enrol sufficient infants to detect uncommon serious complications and include long-term follow up to determine important neurodevelopment and pulmonary outcomes.

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 .).

Comparison of heart rate and oxygen saturation measurements from Masimo and Nellcor pulse oximeters in newly born term infants.

To compare heart rate (HR) measurements from Masimo and Nellcor pulse oximeters (POs) against HR measured via a three lead electrocardiograph (ECG) (HRECG). We also compared peripheral oxygen saturation (SpO2) measurements between Nellcor and Masimo oximeters.

Pressure variation during ventilator generated nasal intermittent positive pressure ventilation in preterm infants

Background Nasal intermittent positive pressure ventilation (NIPPV) is a mode of non-invasive respiratory support. Its mechanisms of action and optimal delivery techniques are unknown. Aim This observational study aimed to investigate and quantify delivered peak pressures during non-synchronised ventilator-generated NIPPV. Methods Infants born below 30 weeks gestation receiving ventilator-generated NIPPV delivered via Hudson prongs were recruited. Intraprong pressure, change in tidal volume, respiratory rate, oxygen saturations, inspired oxygen and video images were recorded. Results Eleven infants (four infants were female) of median (interquartile range; IQR) gestational age 25±3 (25±2 26+/-0) weeks and birth weight 732 (699–895) g, were studied at 24 (19–41) days of age. Six infants, with set peak pressure (peak inflation pressure; PIP) of 20 cm H2O, received a median pressure of 15.9 (IQR 13.6–17.9) cm H2O. 37% of inflations were delivered at least 5 cm H2O below set PIP. 12.7% of inflations were delivered above set PIP. Five infants with set PIP of 25 cm H2O received a median PIP of 17.2 (IQR 15.0–18.3) cm H2O. 83% of inflations were delivered at least 5 cm H2O below set PIP, with 6.1% delivered higher than set PIP. The difference in delivered PIP between the groups was 1.3 cm H2O. PIP was highest and most variable when the infant was moving. Delivered PIP did not vary whether it coincided with spontaneous inspiration or expiration. Conclusion During ventilator-generated non-synchronised NIPPV delivered PIP was variable and frequently lower than set PIP. Delivered PIP was occasionally greater than set PIP.

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.

An international survey of volume-targeted neonatal ventilation

Objective To evaluate clinical practice of volume-targeted ventilation (VTV). Design Internet-based survey of all 50 tertiary neonatal units in Australia, New Zealand, Sweden, Denmark, Finland and Norway. Results Response rate was 100%. VTV was routinely used in 25 (50%) units; 15/25 (60%) in Australasia and 10/25 (40%) in the Nordic countries. The most common reason given for using VTV was that it reduces bronchopulmonary dysplasia (13/25; 52%). The median (IQR) of upper limits of target tidal volume were (1) for initial ventilation of preterm infants with respiratory distress syndrome 5.0 (4.6–6.0) ml/kg and (2) for infants with ventilator-dependent bronchopulmonary dysplasia 6.0 (5.0–8.0) ml/kg. The median (IQR) maximum peak inspiratory pressure limit units were prepared to use in VTV-mode was 35 (30–42.5) cm H2O. Conclusion Half of the units used VTV routinely, but with a considerable variation in VTV practice. More studies are required to establish best VTV practice.