Single Amino Acid Change Underlies Distinct Roles of H2A.Z Subtypes in Human Syndrome.

The developmental disorder Floating-Harbor syndrome (FHS) is caused by heterozygous truncating mutations in SRCAP, a gene encoding a chromatin remodeler mediating incorporation of histone variant H2A.Z. Here, we demonstrate that FHS-associated mutations result in loss of SRCAP nuclear localization, alter neural crest gene programs in human in vitro models and Xenopus embryos, and cause craniofacial defects. These defects are mediated by one of two H2A.Z subtypes, H2A.Z.2, whose knockdown mimics and whose overexpression rescues the FHS phenotype. Selective rescue by H2A.Z.2 is conferred by one of the three amino acid differences between the H2A.Z subtypes, S38/T38. We further show that H2A.Z.1 and H2A.Z.2 genomic occupancy patterns are qualitatively similar, but quantitatively distinct, and H2A.Z.2 incorporation at AT-rich enhancers and expression of their associated genes are both sensitized to SRCAP truncations. Altogether, our results illuminate the mechanism underlying a human syndrome and uncover selective functions of H2A.Z subtypes during development.

Krause corpuscles are genital vibrotactile sensors for sexual behaviours.

Krause corpuscles, which were discovered in the 1850s, are specialized sensory structures found within the genitalia and other mucocutaneous tissues1-4. The physiological properties and functions of Krause corpuscles have remained unclear since their discovery. Here we report the anatomical and physiological properties of Krause corpuscles of the mouse clitoris and penis and their roles in sexual behaviour. We observed a high density of Krause corpuscles in the clitoris compared with the penis. Using mouse genetic tools, we identified two distinct somatosensory neuron subtypes that innervate Krause corpuscles of both the clitoris and penis and project to a unique sensory terminal region of the spinal cord. In vivo electrophysiology and calcium imaging experiments showed that both Krause corpuscle afferent types are A-fibre rapid-adapting low-threshold mechanoreceptors, optimally tuned to dynamic, light-touch and mechanical vibrations (40-80 Hz) applied to the clitoris or penis. Functionally, selective optogenetic activation of Krause corpuscle afferent terminals evoked penile erection in male mice and vaginal contraction in female mice, while genetic ablation of Krause corpuscles impaired intromission and ejaculation of males and reduced sexual receptivity of females. Thus, Krause corpuscles of the clitoris and penis are highly sensitive mechanical vibration detectors that mediate sexually dimorphic mating behaviours.

A vagal reflex evoked by airway closure.

Airway integrity must be continuously maintained throughout life. Sensory neurons guard against airway obstruction and, on a moment-by-moment basis, enact vital reflexes to maintain respiratory function1,2. Decreased lung capacity is common and life-threatening across many respiratory diseases, and lung collapse can be acutely evoked by chest wall trauma, pneumothorax or airway compression. Here we characterize a neuronal reflex of the vagus nerve evoked by airway closure that leads to gasping. In vivo vagal ganglion imaging revealed dedicated sensory neurons that detect airway compression but not airway stretch. Vagal neurons expressing PVALB mediate airway closure responses and innervate clusters of lung epithelial cells called neuroepithelial bodies (NEBs). Stimulating NEBs or vagal PVALB neurons evoked gasping in the absence of airway threats, whereas ablating NEBs or vagal PVALB neurons eliminated gasping in response to airway closure. Single-cell RNA sequencing revealed that NEBs uniformly express the mechanoreceptor PIEZO2, and targeted knockout of Piezo2 in NEBs eliminated responses to airway closure. NEBs were dispensable for the Hering-Breuer inspiratory reflex, which indicated that discrete terminal structures detect airway closure and inflation. Similar to the involvement of Merkel cells in touch sensation3,4, NEBs are PIEZO2-expressing epithelial cells and, moreover, are crucial for an aspect of lung mechanosensation. These findings expand our understanding of neuronal diversity in the airways and reveal a dedicated vagal pathway that detects airway closure to help preserve respiratory function.

Eat, Sleep, Console Approach or Usual Care for Neonatal Opioid Withdrawal.

BACKGROUND: Although clinicians have traditionally used the Finnegan Neonatal Abstinence Scoring Tool to assess the severity of neonatal opioid withdrawal, a newer function-based approach - the Eat, Sleep, Console care approach - is increasing in use. Whether the new approach can safely reduce the time until infants are medically ready for discharge when it is applied broadly across diverse sites is unknown. METHODS: In this cluster-randomized, controlled trial at 26 U.S. hospitals, we enrolled infants with neonatal opioid withdrawal syndrome who had been born at 36 weeks' gestation or more. At a randomly assigned time, hospitals transitioned from usual care that used the Finnegan tool to the Eat, Sleep, Console approach. During a 3-month transition period, staff members at each hospital were trained to use the new approach. The primary outcome was the time from birth until medical readiness for discharge as defined by the trial. Composite safety outcomes that were assessed during the first 3 months of postnatal age included in-hospital safety, unscheduled health care visits, and nonaccidental trauma or death. RESULTS: A total of 1305 infants were enrolled. In an intention-to-treat analysis that included 837 infants who met the trial definition for medical readiness for discharge, the number of days from birth until readiness for hospital discharge was 8.2 in the Eat, Sleep, Console group and 14.9 in the usual-care group (adjusted mean difference, 6.7 days; 95% confidence interval [CI], 4.7 to 8.8), for a rate ratio of 0.55 (95% CI, 0.46 to 0.65; P<0.001). The incidence of adverse outcomes was similar in the two groups. CONCLUSIONS: As compared with usual care, use of the Eat, Sleep, Console care approach significantly decreased the number of days until infants with neonatal opioid withdrawal syndrome were medically ready for discharge, without increasing specified adverse outcomes. (Funded by the Helping End Addiction Long-term (HEAL) Initiative of the National Institutes of Health; ESC-NOW ClinicalTrials.gov number, NCT04057820.).

Opportunistic dried blood spot sampling validates and optimizes a pediatric population pharmacokinetic model of metronidazole.

Pharmacokinetic models rarely undergo external validation in vulnerable populations such as critically ill infants, thereby limiting the accuracy, efficacy, and safety of model-informed dosing in real-world settings. Here, we describe an opportunistic approach using dried blood spots (DBS) to evaluate a population pharmacokinetic model of metronidazole in critically ill preterm infants of gestational age (GA) ≤31 weeks from the Metronidazole Pharmacokinetics in Premature Infants (PTN_METRO, NCT01222585) study. First, we used linear correlation to compare 42 paired DBS and plasma metronidazole concentrations from 21 preterm infants [mean (SD): post natal age 28.0 (21.7) days, GA 26.3 (2.4) weeks]. Using the resulting predictive equation, we estimated plasma metronidazole concentrations (ePlasma) from 399 DBS collected from 122 preterm and term infants [mean (SD): post natal age 16.7 (15.8) days, GA 31.4 (5.1) weeks] from the Antibiotic Safety in Infants with Complicated Intra-Abdominal Infections (SCAMP, NCT01994993) trial. When evaluating the PTN_METRO model using ePlasma from the SCAMP trial, we found that the model generally predicted ePlasma well in preterm infants with GA ≤31 weeks. When including ePlasma from term and preterm infants with GA >31 weeks, the model was optimized using a sigmoidal Emax maturation function of postmenstrual age on clearance and estimated the exponent of weight on volume of distribution. The optimized model supports existing dosing guidelines and adds new data to support a 6-hour dosing interval for infants with postmenstrual age >40 weeks. Using an opportunistic DBS to externally validate and optimize a metronidazole population pharmacokinetic model was feasible and useful in this vulnerable population.

Neonatal Morbidities, Neurodevelopmental Impairments, and Positive Health among Children Surviving Birth Before 32 Weeks of Gestation.

OBJECTIVES: To evaluate positive health outcomes among children born at < 32 weeks of gestation, and to determine whether children with three common neonatal morbidities and two neurodevelopmental impairments would have similar positive health outcomes to children and adolescents without these exposures and impairments. STUDY DESIGN: In this secondary analysis of prospectively acquired data derived from three multi-center cohorts of children born very preterm (the ELGAN cohort [birth years 2001 to 2004], the NOVI cohort [birth years 2014 to 2016], and the DINE cohort [birth years 2010 to 2020]), we examined associations between the three common neonatal morbidities (bronchopulmonary dysplasia, necrotizing enterocolitis, and intraventricular hemorrhage, diagnosed before hospital discharge), two neurodevelopmental impairments (developmental delays and cerebral palsy, diagnosed at preschool age follow-up), and perceptions of physical, mental, and social well-being (in either early childhood or adolescence), using the Patient-Reported Outcomes Measurement Information System (PROMIS®) scales for positive health. RESULTS: After adjusting for confounders, bronchopulmonary dysplasia, intraventricular hemorrhage, and cerebral palsy were associated with lower positive health scores, reported by parent-proxy during early childhood. None of the exposures or impairments were associated with lower positive health scores at adolescence, reported by the children themselves. CONCLUSION: Parents of children born very preterm with bronchopulmonary dysplasia, intraventricular hemorrhage, or cerebral palsy rated their children's positive health lower than did parents of children without these morbidities. However, adolescents' own reports of positive health outcomes were not associated with either neonatal pre-discharge morbidities or preschool neurodevelopmental impairments.

Pharmacoepidemiology of combination pulmonary vasodilator therapy in critically ill infants.

BACKGROUND: New drugs to target different pathways in pulmonary hypertension has resulted in increased combination therapy, but details of this use in infants are not well described. In this large multicenter database study, we describe the pharmacoepidemiology of combination pulmonary vasodilator therapy in critically ill infants. METHODS: We identified inborn infants discharged home from a Pediatrix neonatal ICU from 1997 to 2020 exposed to inhaled nitric oxide, sildenafil, epoprostenol, or bosentan for greater than two consecutive days. We compared clinical variables and drug utilisation between infants receiving simultaneous combination and monotherapy. We reported each combination's frequency, timing, and duration and graphically represented drug use over time. RESULTS: Of the 7681 infants that met inclusion criteria, 664 (9%) received combination therapy. These infants had a lower median gestational age and birth weight, were more likely to have cardiac and pulmonary anomalies, receive cardiorespiratory support, and had higher in-hospital mortality than those receiving monotherapy. Inhaled nitric oxide and sildenafil were most frequently used, and utilisation of combination and monotherapy for all drugs increased over time. Inhaled nitric oxide and epoprostenol were used in infants with a higher gestational age, earlier postnatal age, and shorter duration than sildenafil and bosentan. Dual therapy with inhaled nitric oxide and sildenafil was the most common combination therapy. CONCLUSION: Our study revealed an increased use of combination pulmonary vasodilator therapy, favouring inhaled nitric oxide and sildenafil, yet with considerable practice variation. Further research is needed to determine the optimal combination, sequence, dosing, and disease-specific indications for combination therapy.

Generalizability of the Necrotizing Enterocolitis Surgery Trial to the Target Population of Eligible Infants.

OBJECTIVE: The objective of this study was to evaluate whether infants randomized in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network Necrotizing Enterocolitis Surgery Trial differed from eligible infants and whether differences affected the generalizability of trial results. STUDY DESIGN: Secondary analysis of infants enrolled in Necrotizing Enterocolitis Surgery Trial (born 2010-2017, with follow-up through 2019) at 20 US academic medical centers and an observational data set of eligible infants through 2013. Infants born ≤1000 g and diagnosed with necrotizing enterocolitis or spontaneous intestinal perforation requiring surgical intervention at ≤8 weeks were eligible. The target population included trial-eligible infants (randomized and nonrandomized) born during the first half of the study with available detailed preoperative data. Using model-based weighting methods, we estimated the effect of initial laparotomy vs peritoneal drain had the target population been randomized. RESULTS: The trial included 308 randomized infants. The target population included 382 (156 randomized and 226 eligible, non-randomized) infants. Compared with the target population, fewer randomized infants had necrotizing enterocolitis (31% vs 47%) or died before discharge (27% vs 41%). However, incidence of the primary composite outcome, death or neurodevelopmental impairment, was similar (69% vs 72%). Effect estimates for initial laparotomy vs drain weighted to the target population were largely unchanged from the original trial after accounting for preoperative diagnosis of necrotizing enterocolitis (adjusted relative risk [95% CI]: 0.85 [0.71-1.03] in target population vs 0.81 [0.64-1.04] in trial) or spontaneous intestinal perforation (1.02 [0.79-1.30] vs 1.11 [0.95-1.31]). CONCLUSION: Despite differences between randomized and eligible infants, estimated treatment effects in the trial and target population were similar, supporting the generalizability of trial results. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT01029353.

Incidence of group B streptococcus early-onset sepsis in term neonates with second-line prophylaxis maternal intrapartum antibiotics: a multicenter retrospective study.

BACKGROUND: The difference in the incidence of early-onset sepsis caused by group B streptococcus among term neonates whose mothers received first-line vs second-line intrapartum prophylaxis is poorly described. OBJECTIVE: This study aimed to compare the incidence of group B streptococcus early-onset sepsis among term neonates born to mothers who receive first-line, second-line, or no intrapartum antibiotics and to describe the short-term and survival outcomes of neonates who developed group B streptococcus early-onset sepsis stratified by maternal antepartum prophylaxis. STUDY DESIGN: This was a retrospective review of electronic medical records. We queried the Pediatrix Medical Group Clinical Data Warehouse to evaluate the outcomes of term neonates born to group B streptococcus positive mothers between 2003 and 2020 and compared the incidence and outcomes of neonates with group B streptococcus early-onset sepsis whose mothers received first-line vs second-line or no intrapartum prophylaxis. RESULTS: Among the 496,180 neonates, 104,196 (21%) were born to mothers who were group B streptococcus positive. Of 97,983 mothers who were group B streptococcus positive with adequate prenatal antibiotic documentation, 49,234 (50%), 12,679 (13%), and 36,070 (37%) received first-line, second-line, and no intrapartum prophylaxis, respectively. The incidence of group B streptococcus early-onset sepsis among all neonates with maternal group B streptococcus carriage was 0.22% (231/104,196). Neonates whose mothers received second-line intrapartum antibiotics and no antibiotics had a higher risk for group B streptococcus early-onset sepsis infection than those whose mothers received first-line intrapartum antibiotics (adjusted odds ratio, 4.12; 95% confidence interval, 2.66-6.38 and adjusted odds ratio, 3.80; 95% confidence interval, 2.66-5.44, respectively). There was no statistically significant difference in the risk for group B streptococcus early-onset sepsis among neonates born to mothers who received second-line vs no antibiotics (adjusted odds ratio, 0.92; 95% confidence interval, 0.64-1.33). CONCLUSION: Neonates exposed to second-line maternal group B streptococcus prophylaxis had an increased risk for group B streptococcus early-onset sepsis when compared with those exposed to first-line maternal group B streptococcus prophylaxis. There was no statistically significant difference in group B streptococcus early-onset sepsis incidence between second-line antibiotic prophylaxis and no antibiotics in mothers with group B streptococcus carriage.

Structural Investigation of Technetium Dibutylphosphate Species Using X-ray Absorption Fine Structure Spectroscopy.

The speciation of Tc after the extraction of Tc(IV) from H2O and 1 M HNO3 by dibutylphosphoric acid (HDBP) in dodecane has been studied by X-ray absorption fine structure (XAFS) spectroscopy. Results show the formation of dimeric species with Tc2O2 and Tc2O units, and the formulas [Tc2O2(DBP·HDBP)4] (1) and [Tc2O(NO3)2(DBP)2(DBP·HDBP)2] (2) were, respectively, proposed for the species extracted from H2O and 1 M HNO3. The interatomic Tc-Tc distances found in the Tc2O2 and Tc2O units [2.55(3) and 3.57(4) Å, respectively] are similar to the ones found in Tc(IV) dinuclear species. It is likely that the speciation of Tc(IV) in dodecane is due to the extraction of a species with a Tc2O unit for (2) and to the redissolution of a Tc(IV)-DBP solid for (1). The XAFS results for (1) and (2) were compared to that obtained for the extraction of Tc(IV) with TBP/HDBP/dodecane from 0.5 M HNO3, (3) which highlight the formation of Tc mononuclear nitrate species {i.e., [Tc(NO3)3(DBP)] or [Tc(NO3)2(DBP·HDBP)]}. These results confirm the importance of the preparation and speciation of the Tc(IV) aqueous solutions prior to extraction and how much this influences and drives the final Tc speciation in organic extraction. These studies outline the complexity of Tc separation chemistry and provide insights into the behavior of Tc during the reprocessing of used nuclear fuel.

Endotoxin content in neonatal formulas, fortification, and lactoferrin products: association with outcomes and guidance on acceptable limits.

While endotoxin (lipopolysaccharide) can be harmful and contribute to morbidity and mortality with Gram-negative sepsis or necrotizing enterocolitis in preterm infants, non-toxic amounts are produced as part of the neonatal microbiome and may be present in enteral nutrition and medications administered. The United States Food and Drug Administration has given guidance for endotoxin concentration limits for intravenous medications and fluids of 5 endotoxin units/kg/hour (120 endotoxin units/kg/day), but no guidance for amounts of endotoxin in enteral products. To determine baseline exposure to infants in the neonatal intensive care unit, we examined endotoxin content of enteral formulas and fortification used for preterm infants, as well as bovine lactoferrin products. We also examined endotoxin exposure and outcomes in very low birth weight infants. Endotoxin content was measured using kinetic chromogenic limulus amebocyte lysate analysis. Daily endotoxin exposure from enteral formulas ranged between < 75 to 7110 endotoxin units/kg and from lactoferrin products from 7 to 3720 endotoxin units/kg. In examining neonatal outcomes from a bovine lactoferrin product studied at three different escalating doses (100, 200, and 300 mg/kg/day), we measured endotoxin in the lactoferrin product and daily exposure was 1089 (N = 10), 2178 (N = 10) and 3287 (N = 11) endotoxin units/kg, respectively. There were no cases of necrotizing enterocolitis or mortality and no lactoferrin-related adverse effects in these patients. Enteral endotoxin daily exposures from lactoferrin products are similar to amounts in preterm enteral nutrition and appear safe and not associated with patient harm. Testing enteral products and establishing safety limits may improve care of high risk patients.

Congenital anomalies of the kidney and urinary tract (CAKUT) in critically ill infants: a multicenter cohort study.

BACKGROUND: The aim of the study was to determine the prevalence of congenital anomalies of the kidney and urinary tract (CAKUT) in the neonatal intensive care unit (NICU) and to evaluate risk factors associated with worse outcomes. We hypothesized that infants with CAKUT with extra-renal manifestations have higher mortality. METHODS: This is a cohort study of all inborn infants who were diagnosed with any form of CAKUT discharged from NICUs managed by the Pediatrix Medical Group from 1997 to 2018. Logistic and linear regression models were used to analyze risk factors associated with in-hospital mortality. RESULTS: The prevalence of CAKUT was 1.5% among infants hospitalized in 419 NICUs. Among the 13,383 infants with CAKUT analyzed, median gestational age was 35 (interquartile range [IQR] 31-38) weeks and median birth weight was 2.34 (IQR 1.54-3.08) kg. Overall in-hospital mortality for infants with CAKUT was 6.8%. Oligohydramnios (adjusted odds ratio [aOR] 4.5, 95% confidence interval [CI] 2.2-9.1, p < 0.001), extra-renal anomalies (aOR 2.5, 95% CI 2.0-3.1, p < 0.001), peak SCr (aOR 1.02, 95% CI 1.01-1.03, p < 0.001) and exposure to nephrotoxic medications (aOR 1.4, 95% CI 1.1-1.7, p = 0.01) were associated with increased mortality, while a history of urological surgery or intervention was associated with lower mortality (aOR 0.6, 95% CI 0.4-0.7, p < 0.001). CONCLUSIONS: Infants hospitalized in the NICU who have CAKUT and the independent risk factors for mortality (e.g., oligohydramnios and presence of extra-renal anomalies) require close monitoring, minimizing of exposure to nephrotoxic drugs, and timely urological surgery or intervention. A higher resolution version of the Graphical abstract is available as Supplementary information.

Urinary Tract Infection Epidemiology in NICUs in the United States.

OBJECTIVE: Our objective was to characterize the incidence, associated clinical factors, timing of infection, microbiology, and incidence of concordant blood culture of urinary tract infections (UTIs) in very low birth weight (VLBW <1,500g) infants. STUDY DESIGN: Multicenter observational cohort study of VLBW infants with gestational age (GA) ≤32 weeks, still hospitalized on postnatal day 7, and discharged 2010 to 2018 from Pediatrix Medical Group neonatal intensive care units. Demographic and clinical characteristics of infants with and without UTI were compared. Multivariable logistic regression evaluated adjusted odds of UTI diagnosis. RESULTS: Of 86,492 included infants, 5,988 (7%) had a UTI. The most common pathogen was Enterococcus spp. (20%), followed by Escherichia coli (19%) and Klebsiella spp. (18%). Candida spp. (6%) was the most common nonbacterial pathogen. Concordant-positive blood culture was present in 8% of infants with UTI diagnoses. UTI was associated with lower GA, male sex, vaginal delivery, prenatal steroid exposure, and longer duration of hospitalization. CONCLUSION: UTI is a common cause of infection in VLBW infants, especially among the smallest, most premature, male infants, and those with a longer duration of hospitalization. Neonatal clinicians should consider obtaining urine culture in the setting of late-onset sepsis evaluations in VLBW infants. KEY POINTS: · UTI is a common cause of LOS in VLBW infants.. · The most common pathogens are Enterococcus spp. and E. coli.. · UTI risk varies among different VLBW infant populations.. · Next steps should include evaluation of preventative measures..

Safety and Pharmacokinetics of Exebacase in an Infant With Disseminated Staphylococcus aureus Infection.

Exebacase, an antistaphylococcal lysin produced from a bacteriophage-encoded gene, is a promising adjunctive therapy for severe methicillin-resistant Staphylococcus aureus infections. We describe the first infant to receive exebacase, dosing, and pharmacokinetics. Exebacase may be safe and efficacious in children; however, further clinical trials are needed to optimize dosing.

Group B Streptococcus Infection in Extremely Preterm Neonates and Neurodevelopmental Outcomes at 2 Years.

BACKGROUND: This study was performed to determine the incidence of group B Streptococcus (GBS) disease among extremely preterm infants and assess to risk of death or neurodevelopmental impairment (NDI) at a corrected age of 18-26 months. METHODS: In this observational cohort study of infants enrolled in a multicenter registry, the incidence of GBS disease was assessed in infants born in 1998-2016 at 22-28 weeks' gestation and surviving for >12 hours. The composite outcome, death or NDI, was assessed in infants born in 1998-2014 at 22-26 weeks' gestation. Infection was defined as GBS isolation in blood or cerebrospinal fluid culture at ≤72 hours (early-onset disease [EOD]) or >72 hours (late-onset disease [LOD]) after birth. Using Poisson regression models, the outcome was compared in infants with GBS disease, infants infected with other pathogens, and uninfected infants. RESULTS: The incidence of GBS EOD (2.70/1000 births [95% confidence interval (CI), 2.15-3.36]) and LOD (8.47/1000 infants [7.45-9.59]) did not change significantly over time. The adjusted relative risk of death/NDI was higher among infants with GBS EOD than in those with other infections (adjusted relative risk, 1.22 [95% CI, 1.02-1.45]) and uninfected infants (1.44 [1.23-1.69]). Risk of death/NDI did not differ between infants with GBS LOD and comparator groups. GBS LOD occurred at a significantly later age than non-GBS late-onset infection. Among infants surviving >30 days, the risk of death was higher with GBS LOD (adjusted relative risk, 1.90 [95% CI, 1.36-2.67]), compared with uninfected infants. CONCLUSIONS: In a cohort of extremely preterm infants, the incidence of GBS disease did not change during the study period. The increased risk of death or NDI with GBS EOD, and of death among some infants with GBS LOD, supports the need for novel preventive strategies for disease reduction. CLINICAL TRIALS REGISTRATION: NCT00063063.

Pharmacodynamics of Meropenem and Tobramycin for Neonatal Meningoencephalitis: Novel Approaches to Facilitate the Development of New Agents to Address the Challenge of Antimicrobial Resistance.

Neonatal sepsis is an underrecognized burden on health care systems throughout the world. Antimicrobial drug resistance (AMR) is increasingly prevalent and compromises the use of currently recommended first-line agents. The development of new antimicrobial agents for neonates and children is mandated by regulatory agencies. However, there remains uncertainty about suitable development pathways, especially because of the propensity of premature babies to develop meningoencephalitis as a complication of neonatal sepsis and difficulties studying this disease in clinical settings. We developed a new platform and approach to accelerate the development of antimicrobial agents for neonatal bacterial meningoencephalitis using Pseudomonas aeruginosa as the challenge organism. We defined the pharmacodynamics of meropenem and tobramycin in these models. The percentage of partitioning of meropenem and tobramycin into the cerebrospinal fluid was comparable at 14.3 and 13.7%, respectively. Despite this similarity, there were striking differences in their pharmacodynamics. Meropenem resulted in bactericidal activity in both the cerebrospinal fluid and cerebrum, whereas tobramycin had minimal antibacterial activity. A hollow fiber infection model (HFIM) using neonatal CSF concentration time profiles yielded pharmacodynamics comparable to those observed in the rabbit model. These new experimental models can be used to estimate the pharmacodynamics of currently licensed agents and those in development and their potential efficacy for neonatal bacterial meningoencephalitis.

Mortality Risk Factors among Infants Receiving Dialysis in the Neonatal Intensive Care Unit.

OBJECTIVES: To identify risk factors associated with mortality for infants receiving dialysis in the neonatal intensive care unit (NICU). STUDY DESIGN: In this retrospective cohort study, we extracted data from the Pediatrix Clinical Data Warehouse on all infants who received dialysis in the NICU from 1999 to 2018. Using a Cox proportional hazards model with robust SEs we estimated the mortality hazard ratios associated with demographics, birth details, medical complications, and treatment exposures. RESULTS: We identified 273 infants who received dialysis. Median gestational age at birth was 35 weeks (interquartile values 33-37), median birth weight was 2570 g (2000-3084), 8% were small for gestational age, 41% white, and 72% male. Over one-half of the infants (59%) had a kidney anomaly; 71 (26%) infants died before NICU hospital discharge. Factors associated with increased risk of dying after dialysis initiation included lack of kidney anomalies, Black race, gestational age of <32 weeks, necrotizing enterocolitis, dialysis within 7 days of life, and receipt of paralytics or vasopressors (all P < .05). CONCLUSION: In this cohort of infants who received dialysis in the NICU over 2 decades, more than 70% of infants survived. The probability of death was greater among infants without a history of a kidney anomaly and those with risk factors consistent with greater severity of illness at dialysis initiation.

Medication Use in the Neonatal Intensive Care Unit and Changes from 2010 to 2018.

OBJECTIVE: To provide up-to-date medication prescribing patterns in US neonatal intensive care units (NICUs) and to examine trends in prescribing patterns over time. STUDY DESIGN: We performed a cohort study of 799 016 infants treated in NICUs managed by the Pediatrix Medical Group from 2010 to 2018. We used 3 different methods to report counts of medication: exposure, courses, and days of use. We defined the change in frequency of medication administration by absolute change and relative change. We examined the Food and Drug Administration (FDA) package insert for each medication to determine whether a medication was labeled for use in infants and used PubMed to search for pharmacokinetics (PK) studies. RESULTS: The most frequently prescribed medications included ampicillin, gentamicin, caffeine citrate, poractant alfa, morphine, vancomycin, furosemide, fentanyl, midazolam, and acetaminophen. Of the top 50 medications used in infants with extremely low birth weight, only 20 (40%) are FDA-labeled for use in infants; of the 30 that are not labeled for use in infants, 13 (43%) had at least 2 published PK studies. The medications with the greatest relative increase in use from 2010 to 2018 included dexmedetomidine, clonidine, rocuronium, levetiracetam, atropine, and diazoxide. The medications with the greatest relative decrease in use included tromethamine acetate, pancuronium, chloral hydrate, imipenem + cilastatin, and amikacin. CONCLUSION: Trends of medication use in the NICU change substantially over time. It is imperative to identify changes in medication use in the NICU to better inform further prospective studies.

Insulin for Treatment of Neonatal Hyperglycemia in Premature Infants: Prevalence over Time and Association with Outcomes.

OBJECTIVE: Our objective was to determine the prevalence of insulin treatment in premature infants with hyperglycemia and evaluate the association of length of treatment with outcomes. STUDY DESIGN: The study included cohort of 29,974 infants 22 to 32 weeks gestational age (GA) admitted to over 300 neonatal intensive care unit (NICU) from 1997 to 2018 and diagnosed with hyperglycemia. RESULTS: Use of insulin significantly decreased during the study period (p = 0.002) among studied NICUs. The percentage of hyperglycemic infants exposed to insulin ranged from 0 to 81%. Infants who received insulin were more likely to have lower GA, birth weight, 5-minute Apgar score, longer duration of stay, and require mechanical ventilation. After adjustment for GA, infants requiring insulin for >14 days were more likely to have treated retinopathy of prematurity (ROP) and develop chronic lung disease (CLD). Insulin treatment of 1 to 7 days had increased odds of death, death/ROP, and death/CLD compared with no exposure. CONCLUSION: Insulin use decreased over time, and differing durations of use were associated with adverse outcomes. KEY POINTS: · Insulin use decreased over time.. · There is a temporal relation between the duration of treatment and adverse outcomes.. · Further studies are needed to determine the efficacy and safety of insulin use..