Peripheral intravenous cannula (PIVC) insertion is one of the most common invasive procedures performed in neonates and is frequently associated with adverse events. There are no studies in the neonatal population looking at the possibility of reducing the risk of PIVC-related complications by elective replacement of PIVC. A randomised, non-blinded, control trial was conducted in a tertiary level neonatal unit in Melbourne, Australia, to examine rates of extravasation in neonates with elective replacement of PIVC as compared to standard practice. Neonates born at 32 weeks of gestation or more were randomly assigned to have their PIVC replaced electively (every 72-96 h) or when clinically indicated in a 1:1 allocation ratio after parental consent. Primary outcome studied was rate of extravasation. Secondary outcomes included rates of phlebitis, leakage or spontaneous dislodgement of PIVC. One hundred thirteen infants were enrolled. Extravasation was noted in 33 (60%) of standard practice group vs. 28 (48.3%) of elective replacement (RR 0.80, CI 0.57-1.13, p = 0.21) infants. Time to first extravasation was similar between the groups (hazard ratio 0.69, CI 0.42-1.15). Extravasation events per 1000 IV hours were also similar between groups. Similar results were seen by both intention to treat and per protocol analyses. There was an increase in leaking rates (HR1.98, CI 1.03-3.81, p = 0.04) in the elective group, while phlebitis and spontaneous dislodgement rates were similar to standard group.Conclusion: Elective replacement of PIVC in neonates is not associated with reduction in extravasation rates.Trial registration: This trial has been registered with the Australian and New Zealand Clinical Trials Register. Identifier: ACTRN12615000827538. What is Known: • The reported incidence of extravasation injury is as high as 70% in the neonatal and paediatric population and has an association with cannula dwell time. • Adult studies have done to look at the possibility of reducing intravenous cannula-related complications with routine replacement of the cannulas but no similar studies have been done in the neonatal population. What is New: • Routine replacement of intravenous cannula in neonates between 72 and 96 h of use does not reduce the rate of extravasation injuries. • There might be some added complications associated with such a practice.
Introduction Congenital lobar emphysema (CLE) and Williams-Beuren Syndrome are two rare conditions that have only been reported together in a single case study. Case Presentation We report another case of a male Caucasian newborn with nonspecific initial respiratory distress, with detection of CLE on repeat chest X-ray on Day 25 of life and concurrent ventricular septal defect, supravalvular aortic stenosis, and branch pulmonary stenosis, in whom a 7q11.23 deletion consistent with Williams-Beuren Syndrome was made. Conclusion A diagnosis of congenital lobar emphysema should prompt further screening for congenital heart disease and genetic deletion, and further research is needed to investigate the role of elastin gene mutation in the development of the neonatal lung.
Four types of AlGaN/GaN high electron mobility transistor (HEMT) structures have been epitaxially grown on Si substrates by metalorganic chemical vapor deposition (MOCVD) and fabricated into devices. To achieve crack-free device structures, various stress-engineering methods have been employed including the use of AlGaN/AlGaN-graded layers, insertion of low-temperature AlN layers and ion implantation of the AlN/Si substrate. To improve material quality, pulsed MOCVD is used to enhance adatom diffusion length during (Al) GaN epitaxy of various layers in the HEMT structure. A comparison between structural and morphological characteristics of the HEMTs shows improvement in the (0 0 0 2) symmetric rocking curve value to 837.9 s −1 and the surface roughness of 0.21 nm for HEMT structures grown using pulsed epitaxy. An OFF-state breakdown voltage of 217 V at a drain current of 1 mA mm −1 at Vg = −8 V was measured for the structure with enhanced material quality.
III-nitride structures on Si are of great technological importance due to the availability of large area, epi ready Si substrates and the ability to heterointegrate with mature silicon micro and nanoelectronics. High voltage, high power density, and high frequency attributes of GaN make the III-N on Si platform the most promising technology for next-generation power devices. However, the large lattice and thermal mismatch between GaN and Si (111) introduces a large density of dislocations and cracks in the epilayer. Cracking occurs along three equivalent {1−100} planes which limits the useable device area. Hence, efforts to obtain crack-free GaN on Si have been put forth with the most commonly reported technique being the insertion of low temperature (LT) AlN interlayers. However, these layers tend to further degrade the quality of the devices due to the poor quality of films grown at a lower temperature using metal organic chemical vapor deposition (MOCVD). Our substrate engineering technique shows a considerable improvement in the quality of 2 μm thick GaN on Si (111), with a simultaneous decrease in dislocations and cracks. Dislocation reduction by an order of magnitude and crack separation of > 1 mm has been achieved. Here we combine our method with step-graded AlGaN layers and LT AlN interlayers to obtain crack-free structures greater than 3.5 μm on 2” Si (111) substrates. A comparison of these film stacks before and after substrate engineering is done using atomic force microscopy (AFM) and optical microscopy. High electron mobility transistor (HEMT) devices developed on a systematic set of samples are tested to understand the effects of our technique in combination with crack reduction techniques. Although there is degradation in the quality upon the insertion of LT AlN interlayers, this degradation is less prominent in the stack grown on the engineered substrates. Also, this methodology enables a crack-free surface with the capability of growing thicker layers.
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