Ephrin-B and EphB are distributed in matching dorsoventral gradients in the embryonic Xenopus visual system with retinal axons bearing high levels of ligand (dorsal) projecting to tectal regions with high receptor expression (ventral). In vitro stripe assays show that dorsal retinal axons prefer to grow on EphB receptor stripes supporting an attractive guidance mechanism. In vivo disruption of EphB/ephrin-B function by application of exogenous EphB or expression of dominant-negative ephrin-B ligand in dorsal retinal axons causes these axons to shift dorsally in the tectum, while misexpression of wild-type ephrin-B in ventral axons causes them to shift ventrally. These dorsoventral targeting errors are consistent with the hypothesis that an attractive mechanism that requires ephrin-B cytoplasmic domain is critical for retinotectal mapping in this axis.

Objective To compare the predictive performance of 18 paediatric early warning systems (PEWS) in predicting critical deterioration. Design Retrospective case-controlled study. PEWS values were calculated from existing clinical data, and the area under the receiver operator characteristic curve (AUROC) compared. Setting UK tertiary referral children's hospital. Patients Patients without a 'do not attempt resuscitation' order admitted between 1 January 2011 and 31 December 2012. All patients on paediatric wards who suffered a critical deterioration event were designated 'cases' and matched with a control closest in age who was present on the same ward at the same time.Main outcome measures Respiratory and/or cardiac arrest, unplanned transfer to paediatric intensive care and/or unexpected death. Results 12 'scoring' and 6 'trigger' systems were suitable for comparative analysis. 297 case events in 224 patients were available for analysis. 244 control patients were identified for the 311 events. Three PEWS demonstrated better overall predictive performance with an AUROC of 0.87 or greater. Comparing each system with the highest performing PEWS with Bonferroni's correction for multiple comparisons resulted in statistically significant differences for 13 systems. Trigger systems performed worse than scoring systems, occupying the six lowest places in the AUROC rankings. Conclusions There is considerable variation in the performance of published PEWS, and as such the choice of PEWS has the potential to be clinically important. Trigger-based systems performed poorly overall, but it remains unclear what factors determine optimum performance. More complex systems did not necessarily demonstrate improved performance.

PurposeAlthough overall paediatric septic shock mortality is decreasing, refractory septic shock (RSS) is still associated with high mortality. A definition for RSS is urgently needed to facilitate earlier identification and treatment. We aim to establish a European society of paediatric and neonatal intensive care (ESPNIC) experts’ definition of paediatric RSS.MethodsWe conducted a two-round Delphi study followed by an observational multicentre retrospective study. One hundred and fourteen paediatric intensivists answered a clinical case-based, two-round Delphi survey, identifying clinical items consistent with RSS. Multivariate analysis of these items in a development single-centre cohort (70 patients, 30 % mortality) facilitated development of RSS definitions based on either a bedside or computed severity score. Both scores were subsequently tested in a validation cohort (six centres, 424 patients, 11.6 % mortality).ResultsFrom the Delphi process, the draft definition included evidence of myocardial dysfunction and high blood lactate levels despite high vasopressor treatment. When assessed in the development population, each item was independently associated with the need for extracorporeal life support (ECLS) or death. Resultant bedside and computed septic shock scores had high discriminative power against the need for ECLS or death, with areas under the receiver operating characteristics curve of 0.920 (95 % CI 0.89–0.94), and 0.956 (95 % CI 0.93–0.97), respectively. RSS defined by a bedside score equal to or higher than 2 and a computed score equal to or higher than 3.5 was associated with a significant increase in mortality.ConclusionsThis ESPNIC definition of RSS accurately identifies children with the most severe form of septic shock.Electronic supplementary materialThe online version of this article (doi:10.1007/s00134-016-4574-2) contains supplementary material, which is available to authorized users.

ObjectivesTo derive and validate a clinical score to risk stratify children presenting with acute infection.Study design and participantsObservational cohort study of children presenting with suspected infection to an emergency department in England. Detailed data were collected prospectively on presenting clinical features, laboratory investigations and outcome. Clinical predictors of serious bacterial infection (SBI) were explored in multivariate logistic regression models using part of the dataset, each model was then validated in an independent part of the dataset, and the best model was chosen for derivation of a clinical risk score for SBI. The ability of this score to risk stratify children with SBI was then assessed in the entire dataset.Main outcome measureFinal diagnosis of SBI according to criteria defined by the Royal College of Paediatrics and Child Health working group on Recognising Acute Illness in Children.ResultsData from 1951 children were analysed. 74 (3.8%) had SBI. The sensitivity of individual clinical signs was poor, although some were highly specific for SBI. A score was derived with reasonable ability to discriminate SBI (area under the receiver operator characteristics curve 0.77, 95% CI 0.71 to 0.83) and risk stratify children with suspected SBI.ConclusionsThis study demonstrates the potential utility of a clinical score in risk stratifying children with suspected SBI. Further work should aim to validate the score and its impact on clinical decision making in different settings, and ideally incorporate it into a broader management algorithm including additional investigations to further stratify a child's risk.

Hypoxia at admission is associated with increased mortality in critically ill children, whereas the association with hyperoxia is less clear. The cohort study demonstrated a U-shaped association between admission PaO2 and mortality. Further examination is needed to explore the effect of hyperoxia upon mortality prediction accuracy.

A definitive clinical trial of peripheral oxygen saturation targets is feasible in critically ill children.

The use of long-term ventilation (LTV) in children is growing in the UK and worldwide. This reflects the improvement in technology to provide LTV, the growing number of indications in which it can be successfully delivered and the acceptability of LTV to families and children. In this article, we discuss the various considerations to be made when deciding to initiate or continue LTV, describe the process that be followed, as decided by a consensus of experienced physicians, and outline the options available for resolution of conflict around LTV decision making. We recognise the uncertainty and hope provided by novel and evolving therapies for potential disease modification. This raises the question of whether LTV should be offered to allow time for a therapy to be trialled, or whether the therapy is unlikely to be effective, LTV would simply prolong suffering. We put this consensus view forward as an ethical framework for decision making in children requiring LTV.

This study provided no evidence to support early PICU admission for continuous positive airways pressure in children with acute respiratory failure and impaired immunity. There was a trend toward increased endotracheal intubation and a higher early mortality in the early continuous positive airways pressure group.