Repeated intravenous doses of human umbilical cord-derived mesenchymal stromal cells for bronchopulmonary dysplasia: results of a phase 1 clinical trial with 2-year follow-up

BACKGROUND

Currently, there is a lack of effective treatments or preventive strategies for bronchopulmonary dysplasia (BPD). Pre-clinical studies with mesenchymal stromal cells (MSCs) have yielded encouraging results. The safety of administering repeated intravenous doses of umbilical cord tissue-derived mesenchymal stromal cells (UC-MSCs) has not yet been tested in extremely-low-gestational-age newborns (ELGANs).

AIMS

to test the safety and feasibility of administering three sequential intravenous doses of UC-MSCs every 7 days to ELGANs at risk of developing BPD.

METHODS

In this phase 1 clinical trial, we recruited ELGANs (birth weight ≤1250 g and ≤28 weeks in gestational age [GA]) who were on invasive mechanical ventilation (IMV) with FiO2 ≥ 0.3 at postnatal days 7-14. Three doses of 5 × 106/kg of UC-MSCs were intravenously administered at weekly intervals. Adverse effects and prematurity-related morbidities were recorded.

RESULTS

From April 2019 to July 2020, 10 patients were recruited with a mean GA of 25.2 ± 0.8 weeks and a mean birth weight of 659.8 ± 153.8 g. All patients received three intravenous UC-MSC doses. The first dose was administered at a mean of 16.6 ± 2.9 postnatal days. All patients were diagnosed with BPD. All patients were discharged from the hospital. No deaths or any serious adverse events related to the infusion of UC-MSCs were observed during administration, hospital stays or at 2-year follow-up.

CONCLUSIONS

The administration of repeated intravenous infusion of UC-MSCs in ELGANs at a high risk of developing BPD was feasible and safe in the short- and mid-term follow-up.

Prediction of bronchopulmonary dysplasia in very preterm infants: competitive risk model nomogram

Objective

To develop predictive clinical models of bronchopulmonary dysplasia (BPD) through competing risk analysis.

Methods

Retrospective observational cohort study, including preterm newborns ≤32 weeks gestational age, conducted between January 1, 2013 and September 30, 2022 in a third-level Neonatal Intensive Care Unit in Spain. A prediction study was carried out using competing risk models, where the event of interest was BPD and the competing event was death. A multivariate competing risk model was developed separately for each postnatal day (days 1, 3, 7 and 14). Nomograms to predict BPD risk were developed from the coefficients of the final models and internally validated.

Results

A total of 306 patients were included in the study, of which 73 (23.9%) developed BPD and 29 (9.5%) died. On day 1, the model with the greatest predictive capacity was that including birth weight, days since rupture of membranes, and surfactant requirement (area under the receiver operating characteristic (ROC) curve (AUC), 0.896; 95% CI, 0.792-0.999). On day 3, the final predictive model was based on the variables birth weight, surfactant requirement, and Fraction of Inspired Oxygen (FiO2) (AUC, 0.891; 95% CI, 0.792-0.989).

Conclusions

Competing risk analysis allowed accurate prediction of BPD, avoiding the potential bias resulting from the exclusion of deceased newborns or the use of combined outcomes. The resulting models are based on clinical variables measured at bedside during the first 3 days of life, can be easily implemented in clinical practice, and can enable earlier identification of patients at high risk of BPD.

Morbidity and Mortality of Very-Low-Birthweight Twin Infants according to Their Sex and the Sex of the Co-Twin: A Retrospective Cohort Study

INTRODUCTION

The concept of male disadvantage regarding the prognosis of premature newborns was introduced more than half a century ago, and it has been corroborated over time. However, the influence of the sex of one twin on the outcomes of the other has yielded contradictory results.

OBJECTIVE

The aim of the study was to determine if, in twin pregnancies of VLBW infants, the outcomes of one twin are modified by the sex of the co-twin.

METHODS

A multicentre retrospective study of a cohort of infants admitted to the collaborating units of the Spanish SEN1500 neonatal network was conducted. Liveborn VLBW twin infants, from 23+0 to 31+6 weeks of gestational age (GA), admitted from 2011 to 2020 were included. Outborn patients, infants with major congenital anomalies, and cases with only one twin admitted were excluded. The main outcomes were survival until first hospital discharge, survival without moderate or severe bronchopulmonary dysplasia (BPD), survival without major brain damage (MBD), and survival without major morbidity. Incidence rate ratios (IRR) and 95% confidence intervals (CI) were calculated.

RESULTS

2,111 twin pairs were included. Male infants exhibited worse outcomes than females (IRR; 95% CI) regarding survival (0.96; 0.94, 0.98), survival without moderate or severe BPD (0.89; 0.86, 0.93), survival without MBD (0.94; 0.91, 0.97), and survival without major morbidity (0.87; 0.81, 0.93). Differences disappeared when the co-twin was a female infant: survival (1.00; 0.97, 1.03), survival without moderate or severe BPD (0.96; 0.91, 1.01), survival without MBD (0.99; 0.95, 1.04), and survival without major morbidity (0.94; 0.85, 1.03). Results for female infants did not change significantly with co-twin sex.

CONCLUSIONS

Among VLBW twins from 23+0 to 31+6 weeks of GA, male infants have higher risk of morbidity and mortality overall. In cases of pregnancies with different-sex foetuses, males seem to improve their results, while these do not change for females. The underlying mechanism of this influence deserves further investigation.

Human Milk Feeding Is Associated with Decreased Incidence of Moderate-Severe Bronchopulmonary Dysplasia in Extremely Preterm Infants

BACKGROUND

An increased rate of bronchopulmonary dysplasia (BPD) is reported in extremely preterm infants. A potential role of human milk feeding in protecting against this condition has been suggested.

METHODS

A retrospective descriptive study was conducted based on data about morbidity in the population of infants born between 22+0 and 26+6 weeks of gestation, included in the Spanish network SEN1500 during the period 2004-2019 and discharged alive. The primary outcome was moderate-severe BPD. Associated conditions were studied, including human milk feeding at discharge. The temporal trends of BPD and human milk feeding rates at discharge were also studied.

RESULTS

In the study population of 4341 infants, the rate of moderate-severe BPD was 43.7% and it increased to >50% in the last three years. The factors significantly associated with a higher risk of moderate-severe BPD were birth weight, male sex, high-frequency oscillatory ventilation, duration of invasive mechanical ventilation, inhaled nitric oxide, patent ductus arteriosus, and late-onset sepsis. Exclusive human milk feeding and any amount of human milk at discharge were associated with a lower incidence of moderate-severe BPD (OR 0.752, 95% CI 0.629-0.901 and OR 0.714, 95% CI 0.602-0.847, respectively). During the study period, the proportion of infants with moderate-severe BPD fed any amount of human milk at discharge increased more than twofold. And the proportion of infants with moderate-severe BPD who were exclusively fed human milk at discharge increased at the same rate.

CONCLUSIONS

Our work shows an inverse relationship between human milk feeding at discharge from the neonatal unit and the occurrence of BPD.

Active approach in delivery room and survival of infants born between 22 and 26 gestational weeks are increasing in Spain

AIM

To describe the trends in the delivery room approach and survival of extremely premature infants over the past two decades.

METHODS

Time-series analysis of infants included in the Spanish SEN1500 network from 2004 to 2019. Patients born from 22 + 0 to 26 + 6 weeks were included. The primary outcome was an active approach in the delivery room. Survival and temporal trends were also studied.

RESULTS

The study population included 8284 patients. At 22 and 23 weeks, an active approach was followed in 41.4% and 80.8%. A temporal trend toward a more active approach was observed at 23 weeks. Antenatal steroids were administered in 19.6% and 58.1% at 22 and 23 weeks. From 24 weeks, an active approach was applied in nearly all cases throughout the period, and more than 80% of patients received antenatal steroids. The rates of survival after an active approach were 8.7%, 21.6%, 40.6%, 59.9%, and 74.7% at 22, 23, 24, 25, and 26 weeks and significantly increased over the period, except for infants born at 22 weeks.

CONCLUSION

Active management and survival of infants born from 23 weeks increased over the period, but the frequency of antenatal steroid administration was lower than the intention to resuscitate.

The Respiratory Management of the Extreme Preterm in the Delivery Room

The fetal-to-neonatal transition poses an extraordinary challenge for extremely low birth weight (ELBW) infants, and postnatal stabilization in the delivery room (DR) remains challenging. The initiation of air respiration and the establishment of a functional residual capacity are essential and often require ventilatory support and oxygen supplementation. In recent years, there has been a tendency towards the soft-landing strategy and, subsequently, non-invasive positive pressure ventilation has been generally recommended by international guidelines as the first option for stabilizing ELBW in the delivery room. On the other hand, supplementation with oxygen is another cornerstone of the postnatal stabilization of ELBW infants. To date, the conundrum concerning the optimal initial inspired fraction of oxygen, target saturations in the first golden minutes, and oxygen titration to achieve desired stability saturation and heart rate values has not yet been solved. Moreover, the retardation of cord clamping together with the initiation of ventilation with the patent cord (physiologic-based cord clamping) have added additional complexity to this puzzle. In the present review, we critically address these relevant topics related to fetal-to-neonatal transitional respiratory physiology, ventilatory stabilization, and oxygenation of ELBW infants in the delivery room based on current evidence and the most recent guidelines for newborn stabilization.

Birth order and morbidity and mortality to hospital discharge among inborn very low-birthweight, very preterm twin infants admitted to neonatal intensive care: a retrospective cohort study

OBJECTIVE

To know the association of birth order with the risk of morbidity and mortality in very low-birthweight (VLBW) twin infants less than 32 weeks' gestational age (GA).

DESIGN

Retrospective cohort study.

SETTING

Infants admitted to the collaborating centres of the Spanish SEN1500 neonatal network.

PATIENTS

Liveborn VLBW twin infants, with GA from 23⁺⁰ weeks to 31⁺⁶ weeks, without congenital anomalies, admitted from 2011 to 2020. Outborn patients were excluded.

MAIN OUTCOME MEASURES

Respiratory distress syndrome (RDS), patent ductus arteriosus, bronchopulmonary dysplasia (BPD), necrotising enterocolitis, major brain damage (MBD), late-onset neonatal sepsis, severe retinopathy of prematurity, survival and survival without morbidity. Crude and adjusted incidence rate ratios were calculated.

RESULTS

Among 2111 twin pairs included, the second twin had higher risk (adjusted risk ratio (aRR) of RDS (aRR 1.08, 95% CI 1.03 to 1.12) and need for surfactant (aRR1.10, 95% CI 1.05 to 1.16). No other significant differences were found, neither in survival (aRR 1.01, 95% CI 0.99 to 1.03) nor in survival without BPD (aRR 1.02, 95% CI 0.99 to 1.05), survival without MBD (aRR 1.02, 95% CI 0.99 to 1.06) nor in survival without major morbidity (aRR 0.97, 95% CI 0.92 to 1.03). However, second twins born by caesarean section (C-section) after a vaginally delivered first twin had less overall survival and survival without MBD.

CONCLUSION

In modern perinatology, second twins are still more unstable immediately after birth and require more resuscitation. After admission to the neonatal intensive care unit, they are at increased risk of RDS, but not other conditions, except for second twins delivered by C-section after a first twin delivered vaginally, who have decreased overall survival and survival without major brain injury.

Time to improve documentation of neonatal resuscitation: a narrative review

A complete, objective and systematic documentation of delivery room resuscitation is important for research, for quality improvement, for teaching and as a reference for postresuscitation care. However, documentation during neonatal resuscitation is usually paper-based, retrospective, inaccurate and unreliable. In this narrative review, we discuss the strengths and pitfalls of current documentation methods in neonatal resuscitation, as well as the challenges of introducing new or emerging technologies in this field. In particular, we discuss innovations in electronic and automated medical records, video recording and Smartphones and Tablet Apps. Given the lack of a consensus standard, we finally propose a list of items that should be part of any neonatal resuscitation documentation method.

Incidence, Risk Factors and Prediction of Secondary Hyperparathyroidism in Preterm Neonates under 32 Weeks’ Gestational Age

In preterm newborns, secondary hyperparathyroidism (HPTH) is an underdiagnosed and undertreated entity. Its detection in the context of metabolic bone mineral disease (MBD) screening programs may be important to guide nutritional treatment. We designed a retrospective cohort study to determine the incidence of HPTH in very premature infants. As secondary objectives, we studied the risk factors, morbidities, and biochemical alterations associated with HPTH. A total of 154 preterm newborns ≤32 weeks gestational age (GA) were included. Of these, 40.3% (n = 62) presented with HPTH. In the multivariate analysis, independent risk factors for HPTH were cesarean section (OR: 4.00; 95% CI: 1.59–10.06), oxygen during resuscitation (OR: 3.43; 95% CI: 1.09–10.81), invasive mechanical ventilation (OR: 3.56; 95% CI: 1.63–7.77) and anemia requiring transfusion (OR: 2.37; 95% CI: 1.01–5.57). Among the analytical variables, serum calcium (OR: 0.53; 95% CI: 0.29–0.97), serum phosphate (OR: 2.01; 95% CI: 1.39–2.92), vitamin D (OR: 0.96; 95% CI: 0.93–1), and the calcium/creatinine ratio in urine (OR: 0.05; 95% CI: 0.01–0.28) were independently associated with HPTH. The simplified predictive model included GA and calcium/creatinine ratio in urine and demonstrated an AUC of 0.828. We concluded that HPTH is a frequent entity among very premature infants and that further studies are required to determine the role of HPTH in MBD and the clinical applicability of prediction models.

Time at birth and short-term outcomes among extremely preterm infants in Spain: a multicenter cohort study

The first hours after birth entail a window of opportunity to decrease morbidity and mortality among extremely preterm infants. The availability of staff and its tiredness vary depending on the timing and day of the week. We hypothesized that these circumstances may impact neonatal outcomes. We have conducted a multicenter cohort study with data obtained from the Spanish neonatal network database SEN1500, where staff doctors are in the house 24/7. The main study exposure was the time of birth; secondary exposures were cumulative work hours from the medical and nurses' shifts and day of the week. The primary outcome was survival to hospital discharge. Secondary outcomes included common preterm infants' in-hospital complications. Univariate and multivariate analysis adjusting for potential confounders was performed. All extremely preterm infants (N = 8798) born between 2011 and 2019 were eligible; 35.7% of them were admitted during the night shift. No differences were found between day and night births regarding survival or morbidity. No differences were found between weekdays and weekends or when considering cumulative worked hours in the shifts. Infants born during the night shift were more likely to be intubated at birth (OR 1.20, CI95% 1.06-1.37), receive surfactant (OR 1.24, CI95% 1.08-1.44), and having anemia requiring transfusion (OR 1.23, CI 95% 1.08-1.42).

CONCLUSION

the time of birth did not seem to affect mortality and morbidity of extremely preterm infants.

WHAT IS KNOWN

• The first hours after birth in extremely preterm infants are a very valuable opportunity to decrease mortality and morbidity. • Time and day of birth have long been linked to outcomes in preterm infants, with night shifts and weekends classically having higher rates of mortality and morbidity.

WHAT IS NEW

• In this study, no differences were found between day and night births regarding survival or major morbidity. • Infants born during the night shift were more likely to be intubated at birth, receive surfactant and having anemia requiring transfusion.

Incidence, Predictors and Outcomes of Noninvasive Ventilation Failure in Very Preterm Infants

Non-invasive ventilation (NIV) is now considered the first-line treatment for respiratory distress syndrome in preterm infants. We aimed to evaluate the rates of non-invasive ventilation failure rate in very preterm infants, as well as to identify its predictors and associated outcomes. We designed a single-center retrospective cohort study including infants ≤32 weeks gestational age and ≤1500 g. The NIV failure was defined as the need for intubation at <72 h of life. After applying inclusion and exclusion criteria, 154 patients were included in the study, with a mean GA of 29.7 ± two weeks. The NIV failure rate was 16.2% (n = 25) and it was associated with lower bronchopulmonary dysplasia (BPD)-free survival (OR 0.08; 95% CI 0.02−0.32) and higher incidence of intraventricular hemorrhage > II (OR 6.22; 95% CI 1.36−28.3). These infants were significantly smaller in GA and weight. Higher FiO2 during resuscitation (OR 1.14; 95% CI 1.06−1.22) and after surfactant administration (OR 1.17; 95% CI 1.05−1.31) represented independent risk factors for NIV failure. In conclusion, NIV failure is frequent and it could be predicted by a higher oxygen requirement during resuscitation and a modest response to surfactant therapy. Importantly, this NIV failure is associated with worse clinical outcomes.

Temporal trends in respiratory care and bronchopulmonary dysplasia in very preterm infants over a 10-year period in Spain

OBJECTIVE

To evaluate trends in respiratory care practices and bronchopulmonary dysplasia (BPD) among very preterm infants born in Spain between 2010 and 2019.

STUDY DESIGN

This was a retrospective cohort study of data obtained from a national population-based database (SEN1500 network). Changes in respiratory care and BPD-free survival of infants with gestational age (GA) of 23⁰-31⁶ weeks and <1500 g were assessed over two 5-year periods. Temporal trends were examined by joinpoint and Poisson regression models and expressed as the annual per cent change and adjusted relative risk (RR) for the change per year.

RESULTS

A total of 17 952 infants were included. In the second period, infants were less frequently intubated in the delivery room and during neonatal intensive care unit stay. This corresponded with an increase in use of non-invasive ventilation techniques. There were no significant differences between the periods in BPD-free survival or survival without moderate-to-severe BPD. After adjusting for covariates, the RR for the change per year was significant for the following variables: never intubated (RR 1.03, 95% CI 1.02 to 1.04); intubation in the delivery room (RR 0.98, 95% CI 0.97 to 0.99); use of nasal intermittent positive pressure ventilation (RR 1.08, 95% CI 1.05 to 1.11); and BPD-free survival (only in the group with the lowest GA; RR 0.98, 95% CI 0.97 to 0.99).

CONCLUSION

Our findings reveal significant changes in respiratory care practices between 2009 and 2019. Despite an increase in use of non-invasive respiratory strategies, BPD-free survival did not improve and even worsened in the group with the lowest GA (23⁰-25⁶).

Nasal Intermittent Positive Pressure Ventilation and Bronchopulmonary Dysplasia Among Very Preterm Infants Never Intubated During the First Neonatal Admission: A Multicenter Cohort Study

INTRODUCTION

While non-invasive positive-pressure ventilation (NIPPV) is increasingly used as a mode of respiratory support for preterm infants, it remains unclear whether this technique translates into improved respiratory outcomes. We assessed the association between NIPPV use and bronchopulmonary dysplasia (BPD)-free survival in never intubated very preterm infants.

METHODS

This multicenter cohort study analyzed data from the Spanish Neonatal Network SEN1500 corresponding to preterm infants born at <32 weeks gestational age and <1,500 g and not intubated during first admission. The exposure of interest was use of NIPPV at any time and the main study outcome was survival without moderate-to-severe BPD. Analyses were performed both by patients and by units. Primary and secondary outcomes were compared using multilevel logistic-regression models. The standardized observed-to-expected (O/E) ratio was calculated to classify units by NIPPV utilization and outcome rates were compared among groups.

RESULTS

Of the 6,735 infants included, 1,776 (26.4%) received NIPPV during admission and 6,441 (95.6%) survived without moderate-to-severe BPD. After adjusting for confounding variables, NIPPV was not associated with survival without moderate-to-severe BPD (OR 0.84; 95%CI 0.62-1.14). A higher incidence of moderate-to-severe BPD-free survival was observed in high- vs. very low-utilization units, but no consistent association was observed between O/E ratio and either primary or secondary outcomes.

CONCLUSION

NIPPV use did not appear to decisively influence the incidence of survival without moderate-to-severe BPD in patients managed exclusively with non-invasive ventilation.

Utility of Gene Panels for the Diagnosis of Inborn Errors of Metabolism in a Metabolic Reference Center

Next-generation sequencing (NGS) technologies have been proposed as a first-line test for the diagnosis of inborn errors of metabolism (IEM), a group of genetically heterogeneous disorders with overlapping or nonspecific phenotypes. Over a 3-year period, we prospectively analyzed 311 pediatric patients with a suspected IEM using four targeted gene panels. The rate of positive diagnosis was 61.86% for intermediary metabolism defects, 32.84% for complex molecular defects, 19% for hypoglycemic/hyperglycemic events, and 17% for mitochondrial diseases, and a conclusive molecular diagnosis was established in 2-4 weeks. Forty-one patients for whom negative results were obtained with the mitochondrial diseases panel underwent subsequent analyses using the NeuroSeq panel, which groups all genes from the individual panels together with genes associated with neurological disorders (1870 genes in total). This achieved a diagnostic rate of 32%. We next evaluated the utility of a tool, Phenomizer, for differential diagnosis, and established a correlation between phenotype and molecular findings in 39.3% of patients. Finally, we evaluated the mutational architecture of the genes analyzed by determining z-scores, loss-of-function observed/expected upper bound fraction (LOEUF), and haploinsufficiency (HI) scores. In summary, targeted gene panels for specific groups of IEMs enabled rapid and effective diagnosis, which is critical for the therapeutic management of IEM patients.

[Spanish guide for neonatal stabilization and resuscitation 2021: Analysis, adaptation and consensus on international recommendations]

After the publication of the recommendations, agreed by all the scientific societies through the ILCOR, at the end of 2020, the GRN-SENeo began a process of analysis and review of the main changes since the last guidelines, to which a specific consensus positioning on controversial issues, trying to avoid ambiguities and trying to adapt the evidence to our environment. This text summarizes the main conclusions of this work and reflects the positioning of that group.

Documentation during neonatal resuscitation: a systematic review

OBJECTIVE

Accurate documentation in healthcare is necessary for ethical, legal, research and quality improvement purposes. In this review, we aimed to evaluate the accuracy of methods of documentation of delivery room resuscitations.

METHODS

A systematic literature search in MEDLINE was conducted to identify original studies that reported the quality of documentation records during newborn resuscitation in the delivery room. Data extracted from the studies included population characteristics, methodology, documentation protocols, use of gold standard and main results (initial assessment of heart rate and peripheral oxygen saturation, respiratory support and supplementary oxygen).

RESULTS

In total, 197 records were screened after initial database search, of which seven studies met the inclusion criteria and were finally included in this review. Four studies were chart reviews and three studies compared conventional documentation methods with video recording. Only one study tested an intervention to improve documentation. Documentation was often inaccurate and important resuscitation events and interventions were poorly recorded. Lack of uniformity among studies preclude pooled analysis, but it seems that complex or advanced procedures were more accurately reported than basic interventions.

CONCLUSIONS

There is little literature regarding accuracy of documentation during neonatal resuscitation, but current quality of documentation seems to be unsatisfactory. There is a need for consensus guidelines and innovative solutions in newborn resuscitation documentation.

Metabolic Bone Disease of Prematurity: Risk Factors and Associated Short-Term Outcomes

Despite the importance of early recognition of metabolic bone disease (MBD) of prematurity, there is still significant variability in screening practices across institutions. We conducted an observational study of infants born at ≤32 weeks of gestation with a birth weight of ≤1500 g (n = 218) to identify clinical factors associated with biochemical indicators of MBD. Bone mineral status was assessed by measuring alkaline phosphatase and phosphate levels between weeks 3 and 5 of life. Two comparisons were performed after classifying infants as either MBD (cases) or non-MBD (controls), and as either high or low risk for MBD, as determined based on the results of MBD screening. In total, 27 infants (12.3%) were classified as cases and 96 (44%) as high-risk. Compared with controls, MBD infants had a significantly lower gestational age and birth weight, and a longer duration of parenteral nutrition and hospital stay. Respiratory outcomes were significantly poorer in high- versus low-risk infants. Multivariate logistic regression showed that birth weight was the only independent risk factor for MBD (odds ratio [OR]/100 g, 0.811; confidence interval [CI95%], 0.656-0.992; p = 0.045) and that birth weight (OR/100 g, 0.853; CI95%, 0.731-0.991; p = 0.039) and red blood cell transfusion (OR, 2.661; CI95%, 1.308-5.467; p = 0.007) were independent risk factors for high risk of MBD. Our findings provide evidence of risk factors for MBD that could help clinicians to individualize perinatal management. The association of red blood cell transfusion with MBD is a novel finding that may be related to iron overload and that merits further study.

[Prevention, diagnosis and treatment of necrotising enterocolitis in newborns less than 32 weeks at birth in Spain]

OBJECTIVES

To describe preventive, diagnostic and therapeutic strategies regarding necrotising enterocolitis in Spain and to identify the strengths, areas of further improvement, and future research lines.

METHODS

Two questionnaires on the management of preterm infants less than 32 weeks, at risk of, or with diagnosed necrotising enterocolitis, were distributed among selected representatives of the surgeons and neonatologists of the Spanish Neonatal Network (SEN1500) participant hospitals with a Paediatric Surgery Department.

RESULTS

Percentage of response was 77.1% of contacted surgeons and 88.6% of neonatologists. There is a written protocol on the diagnosis and medical management of necrotising enterocolitis in 52% of the hospitals, and as regards surgical treatment in 33%. There is wide access to donor bank milk and to staff dedicated to breastfeeding promotion (87%). On the contrary, only 52% of the centres perform delayed cord clamping, and probiotics are used in just 23%. The use of abdominal ultrasound is increasing. There are no large differences as regards duration of antibiotic use and bowel rest, whereas there was as regards antibiotic selection, surgical indication, and type of intervention.

CONCLUSIONS

As regards prevention, delayed cord clamping and extended access to donor milk are two possible aspects of further improvement. The observed discrepancies noted in diagnostic and therapeutic aspects are common in precisely the areas where evidence in the literature is weakest.

Incidence, Treatment, and Outcome Trends of Necrotizing Enterocolitis in Preterm Infants: A Multicenter Cohort Study

Background: Data regarding the incidence and mortality of necrotizing enterocolitis trends are scarce in the literature. Recently, some preventive strategies have been confirmed (probiotics) or increased (breastfeeding rate). This study aims to describe the trends of necrotizing enterocolitis incidence, treatment, and mortality over the last decade in Spain. Methods: Multicenter cohort study with data from the Spanish Neonatal Network-SEN1500 database. The study period comprised from January 2005 to December 2017. Preterm infants <32 weeks of gestational age at birth without major congenital malformations were included for analysis. The main study outcomes were necrotizing enterocolitis incidence, co-morbidity (bronchopulmonary dysplasia, late-onset sepsis, cystic periventricular leukomalacia, retinopathy of prematurity, acute kidney injury), mortality, and surgical/non-surgical treatment. Results: Among the 25,821 included infants, NEC incidence was 8.8% during the whole study period and remained stable when comparing 4-year subperiods. However, more cases were surgically treated (from 48.8% in 2005-2008 to 70.2% in 2015-2017, p < 0.001). Mortality improved from 36.7% in the 2005-2008 to 26.6% in 2015-2017 (p < 0.001). Breastfeeding rates improved over the studied years (24.3% to 40.5%, p < 0.001), while gestational age remained invariable (28.5 weeks, p = 0.20). Prophylactic probiotics were implemented during the study period in some units, reaching 18.6% of the patients in 2015-2017. Conclusions: The incidence of necrotizing enterocolitis remained stable despite the improvement regarding protective factors frequency. Surgical treatment became more frequent over the study period, whereas mortality decreased.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star-black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square degrees for all types of binary systems during O3 with the Advanced LIGO and Virgo (HLV) network. The median sky localization area will improve to a few tens of square degrees during O4 with the Advanced LIGO, Virgo, and KAGRA (HLVK) network. During O3, the median localization volume (90% credible region) is expected to be on the order of 10 5 , 10 6 , 10 7 Mpc 3 for binary neutron star, neutron star-black hole, and binary black hole systems, respectively. The localization volume in O4 is expected to be about a factor two smaller than in O3. We predict a detection count of 1 - 1 + 12 ( 10 - 10 + 52 ) for binary neutron star mergers, of 0 - 0 + 19 ( 1 - 1 + 91 ) for neutron star-black hole mergers, and 17 - 11 + 22 ( 79 - 44 + 89 ) for binary black hole mergers in a one-calendar-year observing run of the HLV network during O3 (HLVK network during O4). We evaluate sensitivity and localization expectations for unmodeled signal searches, including the search for intermediate mass black hole binary mergers.

[Current surgical options and outcomes for newborns with hypoplastic left heart syndrome]

Since the first successful palliation was performed by Norwood et al. in 1983, there have been substantial changes in diagnosis, management, and outcomes of hypoplastic left heart syndrome, Survival for stage 1 palliation has increased to 90% in many centres, with patients potentially surviving into adulthood. However, the associated morbidity and mortality remain substantial. Although the principles of staged surgical palliation of hypoplastic left heart syndrome are well established, there is significant variability in surgical procedure and management between centres, and several controversial aspects remain unresolved. In this review, we summarize the current surgical and management options for newborns with hypoplastic left heart syndrome and their outcomes.

Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2  M_{⊙}-1.0  M_{⊙}. We use the null result to constrain the binary merger rate of (0.2  M_{⊙}, 0.2  M_{⊙}) binaries to be less than 3.7×10^{5}  Gpc^{-3} yr^{-1} and the binary merger rate of (1.0  M_{⊙}, 1.0  M_{⊙}) binaries to be less than 5.2×10^{3}  Gpc^{-3} yr^{-1}. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2  M_{⊙} black holes to account for less than 16% of the dark matter density and a population of merging 1.0  M_{⊙} black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries.

[Splanchnic oximetry in small for gestational age neonates in relation to prenatal doppler study]

INTRODUCTION

Among small for gestational age neonates, foetal Doppler enables the identification of placental insufficency aetiology and the classification of severity in small for gestational age neonates. There are studies that associate the Doppler data with alterations in the intestinal flow of the newborn, but its relationship with intestinal oximetry has been little studied.

OBJECTIVE

To assess whether there is a relationship between prenatal Doppler data and abdominal oximetry in small for gestational age neonates MATERIAL AND METHODS: A prospective observational study carried out on neonates>32 weeks with a birth weight<P10. The severity of placental insufficiency was classified according to prenatal Doppler criteria. Splanchnic oximetry was monitored during the first three days of life and a comparative analysis of the oximetry data was performed according to the prenatal Doppler alteration severity.

RESULTS

A total of 53 patients were evaluated. Significant differences were observed in the mean regional oximetry (rSO₂) between patients with moderate or severe placental failure and those with normal or slightly altered prenatal Doppler: 42±10 vs. 71.3±10 (P<.001). These differences were maintained during the first 3 days of life. Standard patterns of splanchnic oximetry were identified depending on the degree of placental insufficiency.

CONCLUSIONS

There is a correlation between the foetal Doppler and the splanchnic oximetry pattern during the first days of life. Neonates with moderate or severe placental insufficiency have more altered abdominal oximetry patterns, making it a useful technique to evaluate the degree of placental insufficiency and the risk of oral intolerance in small for gestational age neonates.

Tests of General Relativity with GW170817

The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR.

Exploring clinical, echocardiographic and molecular biomarkers to predict bronchopulmonary dysplasia

Introduction

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease in childhood, related to prematurity, and the most common cause of pulmonary hypertension (PH) secondary to pulmonary disease in children. Moderate and severe BPD have a worse outcome and relate more frequently with PH. The prediction of moderate or severe BPD development in extremely premature newborns is vital to implement preventive strategies. Starting with the hypothesis that molecular biomarkers were better than clinical and echocardiographic factors, this study aims to explore the ability of clinical, echocardiographic and analytical variables to predict moderate or severe BPD in a cohort of extremely preterm infants.

Patients and methods

We designed a prospective longitudinal study, in which we followed a cohort of preterm newborns (gestational age <28 weeks and weight ≤ 1250 grams). In these newborns we recorded weekly clinical and echocardiographic variables as well as blood and tracheal aspirate samples, to analyze molecular biomarkers (IL-6, IL-1, IP10, uric acid, HGF, endothelin-1, VEGF, CCL5). Variables and samples were collected since birth up to week 36 (postmenstrual age), time-point at which the diagnosis of BPD is established.

Results

We included 50 patients with a median gestational age of 26 weeks (IQR 25–27) and weight of 871 g (SD 161,0) (range 590-1200g). Three patients were excluded due to an early death. Thirty-five patients (74.5%) developed BPD (mild n = 14, moderate n = 15, severe n = 6). We performed a logistic regression in order to identify risk factors for moderate or severe BPD. We compared two predictive models, one with two variables (mechanical ventilation and inter-ventricular septum flattening), and another-one with an additional molecular biomarker (ET-1).

Conclusions

The combination of clinical and echocardiographic variables is a valuable tool for determining the risk of BPD. We find the two variable model (mechanical ventilation and echocardiographic signs of PH) more practical for clinical and research purposes. Future research on BPD prediction should be oriented to explore the potential role of ET-1.

Constraining the p-Mode-g-Mode Tidal Instability with GW170817

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnB_{!pg}^{pg}) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with lnB_{!pg}^{pg}=0.03_{-0.58}^{+0.70} (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ≃50% probability of obtaining similar lnB_{!pg}^{pg} even when p-g effects are absent. We find that the p-g amplitude for 1.4  M_{⊙} neutron stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-tenth this maximum and p-g saturation frequency ∼70  Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest ≲10^{3} modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ≲10^{51}  erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

[Use of off-label drugs in neonatal intensive care]

OBJECTIVE

To evaluate the prevalence of non-approved prescriptions (off-label and unlicensed) in a Neonatal Intensive Care Unit (NICU), and to describe factors of the neonate associated with its use.

MATERIALS AND METHODS

Observational prospective study in a level III NICU during a 6-month period. Every prescription was analysed using the summary of product characteristics as a reference. A sequential algorithm was used to create a classification of prescriptions based on current status: approved, unlicensed, off-label (by age, route of administration, dosage, or indication).

RESULTS

The study included 84 patients and 564 prescriptions. A total of 127 (22.5%) prescriptions were considered off-label, and 45 (8%) were considered unlicensed. More than half (59.5%) of the patients received at least one of these drugs, and this increases to 100% among very preterm neonates and surgical patients (P<.001). A positive linear correlation was found between duration of NICU stay and the number of off-label prescriptions (correlation coefficient 0.6; P<.001).

CONCLUSIONS

Non-licensed drugs are frequently prescribed in NICU, especially in the most vulnerable patients. Our results show the need to move forward on clinical research in order to homogenise the existing data about neonatology drugs, with the aim of making an efficient and safe prescription.

The Effect of Morbidity and Sex on Postnatal Growth of Very Preterm Infants: A Multicenter Cohort Study

BACKGROUND

Extrauterine growth restriction is common in the preterm infant, and it is associated with poor neurodevelopment. Nutrition plays an important role in postnatal growth, but growth is also influenced by other factors like co-morbidity, and, also, there might be sex differences.

METHODS

This is a cohort study including preterm infants < 32 weeks at birth (n = 21,825) from the Spanish Neonatal Network database. The effect of sex and morbidity (patent ductus arteriosus, bronchopulmonary dysplasia, necrotizing enterocolitis and late-onset sepsis) on weight gain as well as linear and head growth from birth to discharge/death was assessed with linear regression models adjusted by gestational age and Z-scores at birth.

RESULTS

The 4 selected morbidities had an independent effect on all 6 growth parameters studied, which was greater in the case of necrotizing enterocolitis: changes in weight, length and head Z-scores were -0.60 (95% CI: -0.66 to -0.55), -0.62 (95% CI: -0.70 to -0.54) and -0.63 (95% CI: -0.71 to -0.56), respectively. Weight gain and linear growth were overall more affected than head growth. Girls lost slightly more weight Z-scores (-0.03; 95% CI: -0.06 to -0.002) than boys after adjustment by morbidity. There were no significant gender differences regarding linear and head growth velocity (cm/week), although girls lost more head Z-scores (-0.14; 95% CI: -0.18 to -0.10).

CONCLUSIONS

Main co-morbidities associated with prematurity have an impact on postnatal growth. Head growth is less affected than length and weight. Girls are at slightly higher risk of postnatal weight and head restriction after adjustment by morbidity.

Search for Subsolar-Mass Ultracompact Binaries in Advanced LIGO's First Observing Run

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2  M_{⊙}-1.0  M_{⊙} using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2  M_{⊙}, 0.2  M_{⊙}) ultracompact binaries to be less than 1.0×10^{6}  Gpc^{-3}  yr^{-1} and the coalescence rate of a similar distribution of (1.0  M_{⊙}, 1.0  M_{⊙}) ultracompact binaries to be less than 1.9×10^{4}  Gpc^{-3}  yr^{-1} (at 90% confidence). Neither black holes nor neutron stars are expected to form below ∼1  M_{⊙} through conventional stellar evolution, though it has been proposed that similarly low mass black holes could be formed primordially through density fluctuations in the early Universe and contribute to the dark matter density. The interpretation of our constraints in the primordial black hole dark matter paradigm is highly model dependent; however, under a particular primordial black hole binary formation scenario we constrain monochromatic primordial black hole populations of 0.2  M_{⊙} to be less than 33% of the total dark matter density and monochromatic populations of 1.0  M_{⊙} to be less than 5% of the dark matter density. The latter strengthens the presently placed bounds from microlensing surveys of massive compact halo objects (MACHOs) provided by the MACHO and EROS Collaborations.

GW170817: Measurements of Neutron Star Radii and Equation of State

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0}  km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1}  km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97  M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4}  km and R_{2}=11.9_{-1.4}^{+1.4}  km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34}  dyn cm^{-2} at the 90% level.

Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω_{0}^{T}<5.58×10^{-8}, Ω_{0}^{V}<6.35×10^{-8}, and Ω_{0}^{S}<1.08×10^{-7} at a reference frequency f_{0}=25  Hz.

GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences

The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude Ω_{GW}(f=25  Hz)=1.8_{-1.3}^{+2.7}×10^{-9} with 90% confidence, compared with Ω_{GW}(f=25  Hz)=1.1_{-0.7}^{+1.2}×10^{-9} from binary black holes alone. Assuming the most probable rate for compact binary mergers, we find that the total background may be detectable with a signal-to-noise-ratio of 3 after 40 months of total observation time, based on the expected timeline for Advanced LIGO and Virgo to reach their design sensitivity.

First Search for Nontensorial Gravitational Waves from Known Pulsars

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper limits for scalar and vector strains, finding values comparable in magnitude to previously published limits for tensor strain. Our results may be translated into constraints on specific alternative theories of gravity.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and [Formula: see text] credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5-[Formula: see text] requires at least three detectors of sensitivity within a factor of [Formula: see text] of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0×10^{4}  years. We infer the component masses of the binary to be between 0.86 and 2.26  M_{⊙}, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17-1.60  M_{⊙}, with the total mass of the system 2.74_{-0.01}^{+0.04}M_{⊙}. The source was localized within a sky region of 28  deg^{2} (90% probability) and had a luminosity distance of 40_{-14}^{+8}  Mpc, the closest and most precisely localized gravitational-wave signal yet. The association with the γ-ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ-ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology.

GW170814: A Three-Detector Observation of Gravitational Waves from a Binary Black Hole Coalescence

On August 14, 2017 at 10∶30:43 UTC, the Advanced Virgo detector and the two Advanced LIGO detectors coherently observed a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes, with a false-alarm rate of ≲1 in 27 000 years. The signal was observed with a three-detector network matched-filter signal-to-noise ratio of 18. The inferred masses of the initial black holes are 30.5_{-3.0}^{+5.7}M_{⊙} and 25.3_{-4.2}^{+2.8}M_{⊙} (at the 90% credible level). The luminosity distance of the source is 540_{-210}^{+130}  Mpc, corresponding to a redshift of z=0.11_{-0.04}^{+0.03}. A network of three detectors improves the sky localization of the source, reducing the area of the 90% credible region from 1160   deg^{2} using only the two LIGO detectors to 60  deg^{2} using all three detectors. For the first time, we can test the nature of gravitational-wave polarizations from the antenna response of the LIGO-Virgo network, thus enabling a new class of phenomenological tests of gravity.

Assessment of continuous pain in newborns admitted to NICUs in 18 European countries

AIM

Continuous pain occurs routinely, even after invasive procedures, or inflammation and surgery, but clinical practices associated with assessments of continuous pain remain unknown.

METHODS

A prospective cohort study in 243 neonatal intensive care units (NICUs) from 18 European countries recorded the frequency of pain assessments, use of mechanical ventilation, sedation, analgesia or neuromuscular blockade for each neonate for up to 28 days after NICU admission.

RESULTS

Only 2113 of 6648 (31.8%) of neonates received assessments of continuous pain, occurring variably among tracheal ventilation (TrV, 46.0%), noninvasive ventilation (NiV, 35.0%) and no ventilation (NoV, 20.1%) groups (p < 0.001). Daily assessments for continuous pain occurred in only 10.4% of all neonates (TrV: 14.0%, NiV: 10.7%, NoV: 7.6%; p < 0.001). More frequent assessments of continuous pain occurred in NICUs with pain guidelines, nursing champions and surgical admissions (all p < 0.01), and for newborns <32 weeks gestational age, those requiring ventilation, or opioids, sedatives-hypnotics, general anaesthetics (O-SH-GA) (all p < 0.001), or surgery (p = 0.028). Use of O-SH-GA drugs increased the odds for pain assessment in the TrV (OR:1.60, p < 0.001) and NiV groups (OR:1.40, p < 0.001).

CONCLUSION

Assessments of continuous pain occurred in less than one-third of NICU admissions and daily in only 10% of neonates. NICU clinical practices should consider including routine assessments of continuous pain in newborns.

GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2

We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31.2_{-6.0}^{+8.4}M_{⊙} and 19.4_{-5.9}^{+5.3}M_{⊙} (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χ_{eff}=-0.12_{-0.30}^{+0.21}. This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 880_{-390}^{+450}  Mpc corresponding to a redshift of z=0.18_{-0.07}^{+0.08}. We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to m_{g}≤7.7×10^{-23}  eV/c^{2}. In all cases, we find that GW170104 is consistent with general relativity.