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.

Effects of synchronisation during SiPAP-generated nasal intermittent positive pressure ventilation (NIPPV) in preterm infants.

OBJECTIVE: The SiPAP flow driver (Care Fusion, Dublin, Ohio, USA) offers synchronised nasal intermittent positive pressure ventilation (sNIPPV) using an abdominal capsule. This study aims to describe the accuracy and effects of synchronised NIPPV using SiPAP in preterm infants. DESIGN: Ten infants, born <28 weeks' gestation, receiving synchronised SiPAP-generated NIPPV, in 'biphasic trigger' mode, were observed. Abdominal capsule signals, delivered pressures, respiratory pattern and oxygen saturations were recorded. Tidal volume (VT), apnoeas, proportion of breaths supported by SiPAP and time between inspiration onset and SiPAP pressure rise were analysed. RESULTS: Infants were of median 26(+0) weeks' gestational age and birth weight 776 g. Mean (SD) respiratory rate (RR) was 53 (14)/min. 82% (17) of spontaneous breaths triggered a SiPAP pressure peak. Mean time between inspiration and SiPAP pressure rise was 28 (20) ms. There was no difference in VT when breaths triggered a SiPAP pressure peak compared with breaths without a pressure peak. No VT was generated by pressure peaks delivered during apnoea. Capsule signals were not recognised following >10% of breaths, resulting in asynchronous NIPPV delivery. Movements resulted in irregular SiPAP pressures and desaturation. When the RR was faster, >55/min, breaths irregularly triggered a SiPAP pressure peak (p=0.003). Compared with times when every breath resulted in a pressure peak, lower mean pressures were achieved, 7.9 vs 8.4 cm H2O (p=0.02). CONCLUSIONS: The SiPAP synchronisation system triggered rapidly with most spontaneous breaths, but did not result in larger tidal volumes. When the RR was >55/min, the SiPAP delivered fewer pressure peaks at lower pressures.

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.

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

AIM: 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. METHOD: Term infants born via elective caesarean section were studied. ECG leads were placed on the infant's chest and abdomen. Masimo and Nellcor PO sensors were randomly allocated to either foot. The monitors were placed on a trolley, and data from each monitor screen captured by a video camera. HR, SpO2 measurements and signal quality were extracted. Bland-Altman analysis was used to determine agreement between HR from the ECG and each oximeter, and between SpO2 from the oximeters. RESULTS: We studied 44 infants of whom 4 were resuscitated. More than 8000 pairs of observations were used for each comparison of HR and SpO2. The mean difference (±2SD) between HRECG and HRN ellcor was -0.8 (±11) beats per minute (bpm); between HRECG and HRM asimo was 0.2 (±9) bpm. The mean (±2SD) difference between SpO2Masimo and SpO2Nellcor was -3 (±15)%. The Nellcor PO measured 20% higher than the Masimo PO at SpO2 <70%. CONCLUSION: Both oximeters accurately measure HR. There was good agreement between SpO2 measurements when SpO2 ≥70%. At lower SpO2 , agreement was poorer.

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 H(2)O) 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.

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 H(2)O, received a median pressure of 15.9 (IQR 13.6-17.9) cm H(2)O. 37% of inflations were delivered at least 5 cm H(2)O below set PIP. 12.7% of inflations were delivered above set PIP. Five infants with set PIP of 25 cm H(2)O received a median PIP of 17.2 (IQR 15.0-18.3) cm H(2)O. 83% of inflations were delivered at least 5 cm H(2)O below set PIP, with 6.1% delivered higher than set PIP. The difference in delivered PIP between the groups was 1.3 cm H(2)O. 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.

Oral continuous positive airway pressure (CPAP) following nasal injury in a preterm infant.

Non-invasive respiratory support is increasingly popular but is associated with complications including nasal trauma. The present report describes a novel method of oral continuous positive airway pressure (CPAP) delivery in an extremely premature infant with severe nasal septum erosion. The distal end of a cut down endotracheal tube was passed through a small hole made in the teat of a dummy (infant pacifier) and sutured in place. The dummy was secured in the infant's mouth and CPAP was delivered to the pharynx. The device was well tolerated and the infant was successfully managed using this technique for 48 days, avoiding endotracheal intubation and ventilation.

Neonatal nasal intermittent positive pressure ventilation: a survey of practice in England.

BACKGROUND: Less invasive techniques of respiratory support are increasingly popular. OBJECTIVE: To determine how widespread the use of neonatal nasal intermittent positive airway pressure (NIPPV) has become and describe the range of practice used in NIPPV in England. METHODS: 95 English Neonatal intensive care units were asked to provide information about NIPPV devices, interfaces, indications, guidelines, use of synchronisation, complications, settings and weaning. RESULTS: 91 (96%) units replied. NIPPV was used by 44/91 (48%) units; few complications were seen. 34/44 (77%) used a synchronising device, 35/44 (80%) used NIPPV for "rescuing" babies for whom continuous positive airway pressure failed-59% routinely after extubation and 16% as a first-line treatment. A wide range of pressure and rate settings were used. CONCLUSIONS: In England, NIPPV is commonly used, with considerable variability in the techniques applied. The wide range of clinical approaches highlights the paucity of evidence available. More evidence is needed to establish best practice.

Intracellular transport of transferrin- and asialoorosomucoid-colloidal gold conjugates to lysosomes after receptor-mediated endocytosis.

Proteins coupled to colloidal gold particles have been widely used to visualize the uptake and intracellular transport of specific ligands by receptor-mediated endocytosis. The intracellular route of lysosome-directed ligands such as asialoglycoproteins (ASGP) are apparently unaltered by conjugation to gold, but the pathway of transferrin, a ligand that normally recycles to the cell surface, was reported to be altered by conjugation to 15-20 nm gold. In this study, we sought to determine whether a smaller transferrin-gold probe would recycle, and whether it might enter the same endosomal and lysosomal compartments as does a larger, lysosome-directed ASGP gold probe by visualizing their simultaneous uptake in human hepatoma (HepG2) cells. In the same cells, endocytosis of fluid-phase protein was followed using the soluble tracer native ferritin; lysosomal compartments were identified by acid phosphatase cytochemistry; and cell surfaces were labeled with ruthenium red or cationized ferritin. During the first 10 min of uptake at 37 degrees C, specific receptor-bound ferrotransferrin (FeTf)-8 nm gold and asialoorosomucoid (ASOR)-20 nm gold were clustered together in coated pits and entered the same coated vesicles, smooth vesicles, and tubules in the peripheral cytoplasm. At later times, however, transferrin-gold did not return to the cell surface; unlike native transferrin, this gold probe accompanied ASOR-gold into multivesicular bodies (MVB). The MVBs that contained probes were at first devoid of acid phosphatase activity, but at 30 min, enzyme activity was detected in a few MVBs. Native ferritin was present, along with gold probes, in all compartments of the endocytic pathway. We conclude that the normal intracellular pathway of transferrin is altered by its association with a colloidal gold particle.