Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Amplitude-dependent internal friction in AZ31 alloy sheets submitted to accumulative roll bonding

Fine grained magnesium alloy AZ31 sheets were submitted to the accumulative roll bonding (ARB). After ARB, the microstructure of samples was refined, and the sheets exhibited pronounced texture. The amplitudedependent internal friction (ADIF) was measured at room temperature. Microstructure changes as the increased dislocation density, grain size refinement, twins, and texture influenced the ADIF. A significant anisotropy of the properties was observed. Experimental results are discussed on the base of physical mechanisms responsible for internal friction.Дрібнозернисті листи магнієвих сплавів AZ31 були піддані накопичувальному з’єднанню вальцюванням (ARB). Після застосування ARB мікроструктура зразків ставала більш фрагментованою, і в листах спостерігалась яскраво виражена текстура. Амплітудно-залежне внутрішнє тертя (АЗВТ) вимірювали при кімнатній температурі. Зміни мікроструктури, такі як збільшення щільності дислокацій, зменшення розміру зерна, поява двійників та текстури, приводили до змін АЗВТ. Спостерігалась суттєва анізотропія вивчених властивостей. Експериментальні результати обговорюються на базі відомих фізичних механізмів, що відповідають за внутрішнє тертя.Мелкозернистые листы магниевых сплавов AZ31 были подвергнуты накопительному соединению прокаткой (ARB). После применения ARB микроструктура образцов становилась более фрагментированной, и в листах наблюдалась ярко выраженная текстура. Амплитудно-зависимое внутреннее трение (АЗВТ) измеряли при комнатной температуре. Изменения микроструктуры, такие как увеличение плотности дислокаций, уменьшение размера зерна, появление двойников и текстуры, приводили к изменениям АЗВТ. Наблюдалась существенная анизотропия изученных свойств. Экспериментальные результаты обсуждаются на основе известных физических механизмов, отвечающих за внутреннее трение

Superplastic Behaviour of an Mg-Ag-RE Magnesium Alloy

Fine-grained magnesium alloy QE22 (Mg-2.5wt.%Ag-2.5wt.%RE-0.6wt.%Zr) was prepared from cast ingot which was submitted to a two stages heat treatment. Subsequently the billet was overaged and extruded at high temperature. Samples were deformed at elevated temperatures from 380°C up to 480°C at various strain rates. Microstructure of deformed samples was studied using light and electron microscopy. Conditions for superplasticity of the investigated alloys have been estimated. Possible deformation mechanisms are discussed

Thermo-physical properties investigation in relation to deposition orientation for SLM deposited H13 steel

Components produced by additive manufacturing (AM) exhibit a heterogeneous microstructure, hence results in anisotropic mechanical properties. There are very limited studies available on thermo-physical properties variation in relation to the deposition orientation. Variation in these properties may result in an uneven stress distribution. In this work, thermo-physical properties of H13 tool steel fabricated by selective laser melting (SLM) process were experimentally investigated. The effect of three deposition directions (vertical, horizontal and 45 degrees to base plane of build platform) on thermal expansion, thermal diffusivity, specific heat, thermal conductivity and simplified CCT diagram was studied. Additionally, mechanical properties and metallographic studies of the microstructure were carried out together with the porosity evaluation measurements across the specimens

Superplastic Behaviour of an Extruded AZ91 Alloy

Plastic deformation of extruded AZ91 magnesium alloy was investigated at various strain rates and in a temperature range of 360-420°C. Samples exhibiting superplastic behaviour were prepared with different thermo-mechanical treatments. Microstructure of samples was observed by light and scanning electron microscopy. The strain rate sensitivity parameter m has been estimated by the abrupt strain rate change method. Possible physical mechanisms of the superplastic flow are discussed