Anisotropy in the dielectric spectrum of hydration water and its relation to water dynamics

Proteins, molecules, and macromolecular assemblies in water are surrounded by a nanometer-sized hydration layer with properties very different from bulk water. Here, we use classical molecular dynamics simulations to study the dielectric response of hydration water next to hydrophobic and hydrophilic planar surfaces. We find the interfacial dielectricabsorption of water to be strongly anisotropic: compared to bulk water, which shows a broad dielectricabsorption maximum around 15 GHz in the imaginary part of the dielectric function, the absorption for electric fields parallel to the surface is of similar strength and shows a slight redshift, while for perpendicular electric fields it is strongly attenuated and blueshifted. This anisotropy is generic for hydrophobic and hydrophilic surfaces. From our spatially resolved dielectric functions and a modified Maxwell-Garnett theory that accounts for anisotropic hydration layers around spherical particles, the dielectricabsorption of solutions of organic molecules and micelles is derived to exhibit the experimentally known attenuation in combination with a redshift. These two features are traced back to the subtle interplay of interfacial depolarization effects and the dielectricanisotropy in the hydration layer. By a detailed analysis of the individual water molecule dynamics the perpendicular blueshift is shown not to be linked to accelerated water reorientation, but rather to dielectric boundary effects. Carefully conducted angularly resolved experiments at planar aqueous interfaces will be able to resolve this dielectricanisotropy and thus to confirm the subtle connection between spectralabsorption features and the molecular water dynamics in hydration layers

A Novel Approach to Neonatal Resuscitation Education for Senior Emergency Medicine Residents

The majority of pediatric visits occur in general emergency departments. Caring for critically ill neonates is a low-frequency but high-stakes event for emergency physicians, which requires specialized knowledge and hands-on training. We describe a novel clinical rotation for emergency medicine (EM) residents that specifically augments skills in neonatal resuscitation through direct participation as a member of the neonatal resuscitation team. The neonatal resuscitation rotation evaluation median score of 4 (interquartile range [IQR] 3,4) was higher compared to all other off-service senior resident rotations combined (median 3, IQR 3,4) for the academic year 2018-2019. Ninety-two percent of residents evaluated the curriculum change as beneficial (median 4, IQR 4,4). The neonatal resuscitation rotation was rated more favorably than the pediatric intensive care rotation (median 4 IQR 3,4 vs median 3, IQR 2, 3) at a tertiary care children’s hospital during the third year. Residency programs may want to consider implementing a directed neonatal resuscitation experience as part of a comprehensive pediatric curriculum for EM residents

A Novel Approach to Neonatal Resuscitation Education for Senior Emergency Medicine Residents

The majority of pediatric visits occur in general emergency departments. Caring for critically ill neonates is a low-frequency but high-stakes event for emergency physicians, which requires specialized knowledge and hands-on training. We describe a novel clinical rotation for emergency medicine (EM) residents that specifically augments skills in neonatal resuscitation through direct participation as a member of the neonatal resuscitation team. The neonatal resuscitation rotation evaluation median score of 4 (interquartile range [IQR] 3,4) was higher compared to all other off-service senior resident rotations combined (median 3, IQR 3,4) for the academic year 2018-2019. Ninety-two percent of residents evaluated the curriculum change as beneficial (median 4, IQR 4,4). The neonatal resuscitation rotation was rated more favorably than the pediatric intensive care rotation (median 4 IQR 3,4 vs median 3, IQR 2, 3) at a tertiary care children’s hospital during the third year. Residency programs may want to consider implementing a directed neonatal resuscitation experience as part of a comprehensive pediatric curriculum for EM residents

Time to Positive Blood and Cerebrospinal Fluid Cultures in Febrile Infants ≤60 Days of Age

ObjectivesTo determine the time to positivity for bacterial pathogens and contaminants in blood and cerebrospinal fluid (CSF) cultures in a cohort of febrile infants ≤60 days of age.MethodsThis was a secondary analysis of prospective observational multicenter study of noncritically ill infants ≤60 days of age with temperatures ≥38°C and blood cultures (December 2008 to May 2013). The main outcome was time to positivity for bacterial pathogens and contaminants.ResultsA total of 256 of 303 (84.49%) patients with positive blood cultures, and 73 of 88 (82.95%) with positive CSF cultures met inclusion criteria. Median time (interquartile range [IQR]) to positivity for blood cultures was 16.6 hours (IQR 12.6-21.9) for bacterial pathogens (n = 74) and 25.1 hours (IQR 19.8-33.0) for contaminants (n = 182); P < .001. Time to bacterial pathogen positivity was similar in infants 0 to 28 days of age (15.8 hours [IQR 12.6-21.0]) and 29 to 60 days of age (17.2 [IQR 12.9-24.3]; P = .328). Median time to positivity for CSF was 14.0 hours (IQR 1.5-21.0) for bacterial pathogens (n = 22) and 40.5 hours (IQR 21.2-62.6) for contaminants (n = 51); P < .001. A total of 82.4% (95% confidence interval, 71.8-90.3) and 81.8% (95% confidence interval, 59.7%-94.8%) of blood and CSF cultures showed bacterial pathogen positivity within 24 hours.ConclusionsAmong febrile infants ≤60 days of age, time to blood and CSF positivity was significantly shorter for bacterial pathogens than contaminants. Most blood and CSF cultures for bacterial pathogens were positive within 24 hours. With our findings, there is potential to reduce duration of hospitalization and avoid unnecessary antibiotics

Practice Variation in the Evaluation and Disposition of Febrile Infants ≤60 Days of Age

BackgroundFebrile infants commonly present to emergency departments for evaluation.ObjectiveWe describe the variation in diagnostic testing and hospitalization of febrile infants ≤60 days of age presenting to the emergency departments in the Pediatric Emergency Care Applied Research Network.MethodsWe enrolled a convenience sample of non-critically ill-appearing febrile infants (temperatures ≥38.0°C/100.4°F) ≤60 days of age who were being evaluated with blood cultures in 26 Pediatric Emergency Care Applied Research Network emergency departments between 2008 and 2013. Patients were divided into younger (0-28 days of age) and older (29-60 days of age) cohorts for analysis. We evaluated diagnostic testing and hospitalization rates by infant age group using chi-square tests and by site using analysis of variance.ResultsFour thousand seven hundred seventy-eight patients were eligible for analysis, of whom 1517 (32%) were 0-28 days of age. Rates of lumbar puncture and hospitalization were high (>90%) among infants ≤28 days of age, with chest radiography (35.5%) and viral testing (66.2%) less commonly obtained. Among infants 29-60 days of age, lumbar puncture (69.5%) and hospitalization (64.4%) rates were lower and declined with increasing age, with chest radiography (36.5%) use unchanged and viral testing (52.7%) slightly decreased. There was substantial variation between sites in the older cohort of infants, with lumbar puncture and hospitalization rates ranging from 40% to 90%.ConclusionsThe evaluation and disposition of febrile infants ≤60 days of age is highly variable, particularly among infants who are 29-60 days of age. This variation demonstrates an opportunity to modify diagnostic and management strategies based on current epidemiology to safely decrease invasive testing and hospitalization