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1.  Urinary tract infection concordance with positive blood and cerebrospinal fluid cultures in the neonatal intensive care unit 
Urinary tract infections (UTI) are common in the neonatal intensive care unit (NICU). Blood, urine, and cerebrospinal fluid (CSF) cultures are frequently obtained to evaluate for infection. We sought to determine the concordance between positive urine cultures and blood or CSF cultures.
Study design
Infants <121 days of age with a UTI admitted to 322 NICUs managed by the Pediatrix Medical Group from 1997–2010 were identified. UTIs were defined by isolation of a single pathogenic organism in a urine sample obtained by catheterization or suprapubic tap. The UTI was concordant if the same organism was identified in the blood or CSF within 3 days of the urine culture.
Of 5681 infants with a urine culture, 984 had 1162 UTIs. Nine hundred seventy-six UTIs (84%) had a blood culture collected within 3 days, and 127 (13%) were concordant. Of the 1162 UTIs, 77 (7%) had a CSF culture collected within 3 days, and 2 (3%) were concordant.
Collection of a urine culture in infants evaluated for late-onset sepsis is important. Concordance was observed in 13% of blood cultures and 3% of CSF cultures. These findings may be related to the initiation of empirical antimicrobial therapy before evaluation for disseminated infection or poor blood culture sensitivity.
PMCID: PMC3549035  PMID: 22935772
infant; sepsis
2.  Duration of empirical antibiotic therapy for infants suspected of early-onset sepsis 
Current opinion in pediatrics  2013;25(2):167-171.
Purpose of review
Clinicians’ adherence to AAP and CDC Guidelines to prevent Group B Streptococcal (GBS) early onset sepsis (EOS) have reduced GBS EOS. While evidence-based testing and empirical antibiotic initiation is likely saving lives, clinicians have less compelling data to guide duration of empirically initiated antibiotics when cultures remain sterile and clinical signs resolve quickly. Our purpose is to review current opinions and evidence influencing clinicians’ choices for duration of empirically initiated antibiotics in newborns with sterile cultures.
Recent findings
Retrospective cohort studies indicate potential for harm with longer duration of empirical antibiotics for EOS when cultures are sterile. Cohort studies indicate timing of widely used tests used to estimate EOS risk affects their predictive value, and tests acquired 24 – 48 hours postnatally may provide reassurance for safe discontinuation.
Every day clinicians caring for thousands of neonates in the US stop antibiotics which were started empirically to treat EOS on the first postnatal day. Evidence is lacking to support a universal approach to decisions on duration of empirical antibiotics when cultures remain sterile. Reviewing predictive value relative to timing of laboratory testing can help clinicians develop locally appropriate antimicrobial duration decision-making guidelines.
PMCID: PMC3596444  PMID: 23407181
empirical antibiotics; early onset sepsis
3.  Perinatal Factors Associated with Poor Neurocognitive Outcome in Early School Age Congenital Diaphragmatic Hernia Survivors 
Journal of pediatric surgery  2013;48(4):730-737.
Determine predictors of neurocognitive outcome in early school age congenital diaphragmatic hernia (CDH) survivors.
Study design
Prospective study of infants with CDH at Duke University Medical Center. Neurocognitive delay (NCD) at school age (4 to 7 years) was defined as a score < 80 in any of the following areas: Verbal Scale IQ, Performance Scale IQ, Expressive Language, or Receptive Language. Logistic regression, Fisher’s exact, and the Wilcoxon rank sum test were used to examine the relationship between NCD at early school age and 6 demographic and 18 medical variables.
Of 43 infants with CDH, twenty seven (63%) survived to hospital discharge, and 16 (59%) returned for school age testing at a median age of 4.9 years. Seven (44%) of the children evaluated had NCD. Patch repair (p=0.01), extracorporeal membrane oxygenation (ECMO; p=0.02), days on ECMO (p=0.01), days of mechanical ventilation (p=0.049), and post-operative use of inhaled nitric oxide (p=0.02) were found to be associated with NCD at early school age.
CDH survivors are at risk for neurocognitive delay persisting into school age. Perinatal factors such as patch repair and ECMO treatment may aid in identifying CDH survivors at high risk for continued learning difficulties throughout childhood.
PMCID: PMC3734202  PMID: 23583126
hernia, diaphragmatic; follow-up studies; neurobehavioral manifestations; growth & development; infant nutrition disorders
4.  Evaluation of a digital microfluidic real-time PCR platform to detect DNA of Candida albicans in blood 
Species of Candida frequently cause life-threatening infections in neonates, transplant and intensive care unit (ICU) patients, and others with compromised host defenses. The successful management of systemic candidiasis depends upon early, rapid diagnosis. Blood cultures are the standard diagnostic method, but identification requires days and less than half of the patients are positive. These limitations may be eliminated by using real-time polymerase chain reaction (PCR) to detect Candida DNA in the blood specimens of patients at risk. Here, we optimized a PCR protocol to detect 5–10 yeasts in low volumes of simulated and clinical specimens. We also used a mouse model of systemic candidiasis and determined that candidemia is optimally detectable during the first few days after infection. However, PCR tests are often costly, labor-intensive, and inconvenient for routine use. To address these obstacles, we evaluated the innovative microfluidic real-time PCR platform (Advanced Liquid Logic, Inc.), which has the potential for full automation and rapid turnaround. Eleven and nine of 16 specimens from individual patients with culture-proven candidemia tested positive for C. albicans DNA by conventional and microfluidic real-time PCR, respectively, for a combined sensitivity of 94%. The microfluidic platform offers a significant technical advance in the detection of microbial DNA in clinical specimens.
PMCID: PMC3939829  PMID: 22327343
5.  Group B Streptococcus and Escherichia coli Infections in the Intensive Care Nursery in the Era of Intrapartum Antibiotic Prophylaxis 
Group B Streptococcus (GBS) and Escherichia coli (E. coli) cause serious bacterial infections (SBIs) and are associated with morbidity and mortality in newborn infants. Intrapartum antibiotic prophylaxis (IAP) reduces early-onset SBIs caused by GBS. The effect of IAP on late-onset SBIs caused by these organisms is unknown.
We examined all blood, urine, and cerebrospinal fluid culture results from infants admitted from 1997–2010 to 322 neonatal intensive care units managed by the Pediatrix Medical Group. We identified infants with positive cultures for GBS or E. coli and compared the incidence of early- and late-onset SBI for each organism in the time period before (1997–2001) and after (2002–2010) universal IAP recommendations.
We identified 716,407 infants with cultures, 2520 (0.4%) with cultures positive for GBS and 2476 (0.3%) with cultures positive for E. coli. The incidence of GBS early-onset SBI decreased between 1997–2001 and 2002–2010 from 3.5 to 2.6 per 1000 admissions, and the incidence for E. coli early-onset SBI remained stable (1.4 per 1000 admissions in both time periods). Over the same time period, the incidence of GBS late-onset SBI increased from 0.8 to 1.1 per 1000 admissions, and incidence of E. coli late-onset SBI increased from 2.2 to 2.5 per 1000 admissions.
In our cohort, the incidence of early-onset GBS SBI decreased, while the incidence of late-onset SBI for E. coli and GBS increased.
PMCID: PMC3572304  PMID: 23011013
infection; infant; sepsis; group B Streptococcus; Escherichia coli
6.  Risk Factors for Invasive Candidiasis in Infants >1500 g Birth Weight 
We describe the incidence, risk factors, and outcomes of invasive candidiasis in infants >1500 g birth weight.
We conducted a retrospective cohort study of infants >1500 g birth weight discharged from 305 NICUs in the Pediatrix Medical Group from 2001–2010. Using multivariable logistic regression, we identified risk factors for invasive candidiasis.
Invasive candidiasis occurred in 330/530,162 (0.06%) infants. These were documented from positive cultures from ≥1 of these sources: blood (n=323), cerebrospinal fluid (n=6), or urine from catheterization (n=19). Risk factors included day of life >7 (OR 25.2; 95% CI 14.6–43.3), vaginal birth (OR 1.6 [1.2–2.3]), exposure to broad-spectrum antibiotics (OR 1.6 [1.1–2.4]), central venous line (OR 1.8 [1.3–2.6]), and platelet count <50,000/mm3 (OR 3.7 [2.1–6.7]). All risk factors had poor sensitivities, low positive likelihood ratios, and low positive predictive values. The combination of broad-spectrum antibiotics and low platelet count had the highest positive likelihood ratio (46.2), but the sensitivity of this combination was only 4%. Infants with invasive candidiasis had increased mortality (OR 2.2 [1.3–3.6]).
Invasive candidiasis is uncommon in infants >1500 g birth weight. Infants at greatest risk are those exposed to broad-spectrum antibiotics and with platelet counts of <50,000/mm3.
PMCID: PMC3578110  PMID: 23042050
candidiasis; candidemia; neonates; neonatal intensive care unit
7.  Tear Film Images and Breakup Analyzed Using Fluorescent Quenching 
Tear evaporation should increase fluorescein concentration, causing fluorescence dimming from self-quenching for high but not low fluorescein concentration. This prediction was tested and compared to the predicted effect of “tangential flow” that fluorescence dimming should be similar for high and low concentrations.
A custom optical system was used for video recording of tear film fluorescence in 30 subjects. The subjects were asked to blink at the start of the recording and try to keep their eyes open for the rest of the 60-second recording. An initial recording was made after instillation of 1 μL 0.1% fluorescein followed by further recordings at 5-minute intervals using 0.5% and 5% fluorescein.
Decay of fluorescence was considerably greater for the high (5%) concentration condition than for the low (0.1%) concentration. This is shown by “ratio images” (ratio of the intensity of a fluorescence image at a later time divided by that of an earlier image), fluorescence decay curves, fluorescence decay rates, and histograms of estimated tear thickness decrease. For example, for the high concentration condition, decay rates were higher than for the low concentration for all 30 subjects (P < 0.0001, binomial test). Additionally, breakup time was significantly reduced for the high compared to the low concentration condition.
The greater fluorescence decay and more rapid breakup for the high concentration condition are the results expected if thinning and breakup are mainly due to evaporation, hence causing self-quenching. Fluorescence decay rate for the low concentration condition was not significantly greater than zero.
Fluorescence self-screening can be used to study mechanisms of tear film breakup and thinning between blinks by comparing video fluorescence recordings using high and low fluorescein concentrations. Results show that the main contribution is from evaporation rather than “tangential flow."
PMCID: PMC3771556  PMID: 23920365
breakup; fluorescence; quenching; evaporation; tangential flow
8.  Pharmacokinetic-Pharmacodynamic Determinants of Oseltamivir Efficacy Using Data from Phase 2 Inoculation Studies 
Given the limited understanding about pharmacokinetic-pharmacodynamic (PK-PD) determinants of oseltamivir efficacy, data from two phase 2 influenza virus inoculation studies were evaluated. Healthy volunteers in studies 1 and 2 were experimentally infected with influenza A/Texas (the concentration of neuraminidase inhibitor which reduced neuraminidase activity by 50% [IC50] = 0.18 nM) or B/Yamagata (IC50 = 16.76 nM), respectively. In study 1, 80 subjects received 20, 100, or 200 mg of oral oseltamivir twice daily (BID), 200 mg oseltamivir once daily, or placebo for 5 days. In study 2, 60 subjects received 75 or 150 mg of oral oseltamivir BID or placebo for 5 days. Oseltamivir carboxylate (OC) (active metabolite) PK was evaluated using individual PK data and a population PK model to derive individual values for area under the concentration-time curve from 0 to 24 h (AUC0–24), minimum concentration of OC in plasma (Cmin), and maximum concentration of OC in plasma (Cmax). Exposure-response relationships were evaluated for continuous (area under composite symptom score curve [AUCSC], area under the viral titer curve, and peak viral titer) and time-to-event (alleviation of composite symptom scores and cessation of viral shedding) efficacy endpoints. Univariable analyses suggested the existence of intuitive and highly statistically significant relationships between OC AUC0–24 evaluated as a 3-group variable and AUCSC, time to alleviation of composite symptom scores, and time to cessation of viral shedding. The upper OC AUC0–24 threshold (∼14,000 ng · h/ml) was similar among these endpoints. Multivariable analyses failed to demonstrate the influence of study/strain on efficacy endpoints. These results provide the first demonstration of exposure-response relationships for efficacy for oseltamivir against influenza and suggest that OC exposures beyond those achieved with the approved oseltamivir dosing regimen will provide enhanced efficacy. The clinical applicability of these observations requires further investigation.
PMCID: PMC3719781  PMID: 23669386
9.  Proposed Model for the High Rate of Rearrangement and Rapid Migration Observed in Some IncA/C Plasmid Lineages 
Applied and Environmental Microbiology  2013;79(16):4806-4814.
IncA/C plasmids are a class of plasmids from the Enterobacteriaceae that are relatively large (49 to >180 kbp), that are readily transferred by conjugation, and that carry multiple antimicrobial resistance genes. Reconstruction of the phylogeny of these plasmids has been difficult because of the high rate of remodeling by recombination-mediated horizontal gene transfer (HGT). We hypothesized that evaluation of nucleotide polymorphisms relative to the rate of HGT would help to develop a clock to show whether anthropic practices have had significant influences on the lineages of the plasmid. A system was developed to rapidly sequence up to 191 known open reading frames from each of 39 recently isolated IncA/C plasmids from a diverse panel of Salmonella enterica and Escherichia coli strains. With these data plus sequences from GenBank, we were able to distinguish six distinct lineages that had extremely low numbers of polymorphisms within each lineage, especially among the largest group designated as group 1. Two regions, each about half the plasmid in size, could be distinguished with a separate lineal pattern. The distribution of group 1 showed that it has migrated extremely rapidly with fewer polymorphisms than can be expected in 2,000 years. Remodeling by frequent HGT was evident, with a pattern that appeared to have the highest rate just upstream of the putative conjugation origin of transfer (oriT). It seems likely that when an IncA/C plasmid is transferred by conjugation there is an opportunity for plasmid remodeling adjacent to the oriT, which was also adjacent to a multiple antimicrobial resistance gene cassette.
PMCID: PMC3754703  PMID: 23747695
10.  Sports Medicine and Ethics 
Physicians working in the world of competitive sports face unique ethical challenges, many of which center around conflicts of interest. Team-employed physicians have obligations to act in the club’s best interest while caring for the individual athlete. As such, they must balance issues like protecting versus sharing health information, as well as issues regarding autonomous informed consent versus paternalistic decision-making in determining whether an athlete may compete safely. Moreover, the physician has to deal with an athlete’s decisions about performance enhancement and return to play, pursuit of which may not be in the athlete’s long-term best interests but may benefit the athlete and team in the short term. These difficult tasks are complicated by the lack of evidence-based standards in a field influenced by the lure of financial gains for multiple parties involved. In this article, we review ethical issues in sports medicine with specific attention paid to American professional football.
PMCID: PMC3899648  PMID: 24024796
sports medicine; ethics; conflict of interest; sports; football; athletes
11.  Tear Film Breakup and Structure Studied by Simultaneous Video Recording of Fluorescence and Tear Film Lipid Layer Images 
The thinning of the precorneal tear film between blinks and tear film breakup can be logically analyzed into contributions from three components: evaporation, flow into the cornea, and tangential flow along the corneal surface. Whereas divergent tangential flow contributes to certain types of breakup, it has been argued that evaporation is the main cause of tear thinning and breakup. Because evaporation is controlled by the tear film lipid layer (TFLL) it should therefore be expected that patterns of breakup should match patterns in the TFLL, and this hypothesis is tested in this study.
An optical system is described for simultaneous video imaging of fluorescein tear film breakup and the TFLL. Recordings were made from 85 subjects, including both with healthy and dry eyes. After instillation of 5 μL2% fluorescein, subjects were asked to blink 1 second after the start of the recording and try to maintain their eyes open for the recording length of 30 or 60 seconds.
Areas of tear film thinning and breakup usually matched corresponding features in the TFLL. Whereas thinning and breakup were often matched to thin lipid, surprisingly, the corresponding lipid region was not always thinner than the surrounding lipid. Occasionally, a thin lipid region caused a corresponding region of greater fluorescence (thicker aqueous layer), due to convergent tangential flow.
Areas of tear thinning and breakup can generally be matched to corresponding regions of the TFLL as would be expected if breakup is largely due to evaporation. Surprisingly, in some examples, the corresponding lipid area was not thinner and possibly thicker than the surrounding lipid. This indicates that the lipid was a poor barrier to evaporation, perhaps because of deficiency in composition and/or structure. For example, bacterial lipases may have broken down esters into component acids and alcohols, causing a defective TFLL structure with increased evaporation.
Simultaneous video recordings were made of tear film fluorescein and lipid layer images. It was found that tear film breakup was commonly associated with regions in the lipid layer, indicating a defect in the thickness, structure, and/or composition of the lipid layer.
PMCID: PMC3720150  PMID: 23766476
tear film lipid layer; fluorescein breakup; evaporation; hyperosmolarity
12.  Regional Variation in Late Preterm Births in North Carolina 
Late preterm (LPT) neonates (34 0/7th to 36 6/7th weeks' gestation) account for 70% of all premature births in the United States. LPT neonates have a higher morbidity and mortality risk than term neonates. LPT birth rates vary across geographic regions. Unwarranted variation is variation in medical care that cannot be explained by sociodemographic or medical risk factors; it represents differences in health system performance, including provider practice variation. The purpose of this study is to identify regional variation in LPT births in North Carolina that cannot be explained by sociodemographic or medical/obstetric risk factors.
We searched the NC State Center for Health Statistics linked birth-death certificate database for all singleton term and LPT neonates born between 1999 and 2006. We used multivariable logistic regression analysis to control for socio-demographic and medical/obstetric risk factors. The main outcome was the percent of late preterm birth in each of the six perinatal regions in North Carolina.
We identified 884,304 neonates; 66,218 (7.5%) were LPT. After multivariable logistic regression, regions 2 (7.0%) and 6 (6.6%) had the highest adjusted percent of LPT birth.
Analysis of a statewide birth cohort demonstrates regional variation in the incidence of LPT births among NC's perinatal regions after adjustment for sociodemographic and medical risk factors. We speculate that provider practice variation might explain some of the remaining difference. This is an area where policy changes and quality improvement efforts can help reduce variation, and potentially decrease LPT births.
PMCID: PMC3725330  PMID: 22350629
late preterm; preterm birth; unwarranted variation; practice variation
13.  Safety and Effectiveness of Meropenem in Infants With Suspected or Complicated Intra-abdominal Infections 
The safety and effectiveness of meropenem in young infants with suspected or confirmed intra-abdominal infections were evaluated. was well tolerated in this cohort of critically-ill infants, and the majority of infants treated with meropenem (84%) met the definition of therapeutic success.
Background. Intra-abdominal infections are common in young infants and lead to significant morbidity and mortality. Meropenem is a broad-spectrum antimicrobial with excellent activity against pathogens associated with intra-abdominal infections. The purpose of this study was to determine the safety and effectiveness of meropenem in young infants with suspected or complicated intra-abdominal infections.
Methods. Preterm and term infants <91 days of age with suspected or confirmed intra-abdominal infections hospitalized in 24 neonatal intensive care units were studied in an open-label, multiple-dose study. Adverse events and serious adverse events were collected through 3 and 30 days following the last meropenem dose, respectively. Effectiveness was assessed by 3 criteria: death, bacterial cultures, and presumptive clinical cure score.
Results. Of 200 subjects enrolled in the study, 99 (50%) experienced an adverse event, and 34 (17%) had serious adverse events; no adverse events were probably or definitely related to meropenem. The most commonly reported adverse events were sepsis (6%), seizures (5%), elevated conjugated bilirubin (5%), and hypokalemia (5%). Only 2 of the serious adverse events were determined to be possibly related to meropenem (isolated ileal perforation and an episode of fungal sepsis). Effectiveness was evaluable in 192 (96%) subjects, and overall treatment success was 84%.
Conclusions. Meropenem was well tolerated in this cohort of critically ill infants, and the majority of infants treated with meropenem met the definition of therapeutic success.
Clinical Trials Registration. NCT00621192.
PMCID: PMC3491861  PMID: 22955430
14.  Isoflurane for Life-Threatening Bronchospasm – A 15 Year Single-Center Experience 
Respiratory care  2012;57(11):10.4187/respcare.01605.
Children with severe bronchospasm requiring mechanical ventilation may become refractory to conventional therapy. In these critically ill patients, isoflurane is an inhaled anesthetic agent available in some centers to treat bronchospasm. We hypothesized that isoflurane is safe and would lead to improved gas exchange in children with life-threatening bronchospasm refractory to conventional therapy.
A retrospective review was conducted and included mechanically ventilated children treated with isoflurane in a quaternary pediatric intensive care unit for life-threatening bronchospasm from 1993–2007. Demographic, blood gas, ventilator and outcome data were collected.
Thirty-one patients with a mean age of 9.5 years (range; 0.4 – 23 years) were treated with isoflurane from 1993–2007. Mean time to initiation of isoflurane after intubation was 13 hours (0–120 hours) and the mean maximum isoflurane dose was 1.1 % (0.3 – 2.5%). Mean duration of isoflurane administration was 54.5 hours (1 – 181), with a total mean duration of mechanical ventilation of 252 hours (33.3 – 1454.5). Isoflurane led to significant improvement in pH and pCO2 within four hours of initiation (p ≤ 0.001). Complications during isoflurane administration included hypotension requiring vasoactive infusions in 24 (77%), arrhythmia in 3 (10%), neurologic side effects in 3 (10%), and pneumothorax in 1 (3%) patient.
Isoflurane led to improvement in pH and pCO2 within four hours in this series of mechanically ventilated patients with life-threatening bronchospasm. The majority of patients in this series developed hypotension, but there was a low incidence of other side effects related to isoflurane administration. Isoflurane appears to be an effective therapy in patients with life-threatening bronchospasm refractory to conventional therapy. However, further investigation is warranted given the uncertain overall impact of isoflurane in this context.
PMCID: PMC3825849  PMID: 22417969
asthma; bronchospasm; mechanical ventilation; inhaled anesthetics; isoflurane; pediatric intensive care unit
15.  Very low birth weight neonates who survive early-onset sepsis do not have an increased risk of developing late-onset sepsis 
Early human development  2012;88(11):905-909.
Very low birth weight neonates (≤1500 g, VLBWs) have a high rate of infection and distinct baseline immune function compared with more mature populations. In critically ill children and adults, sepsis increases subsequent infection risk. It is unknown whether sepsis modifies the risk of subsequent infection in VLBWs.
We conducted a retrospective cohort study of VLBWs ≤32 weeks gestation at birth cared for in 312 neonatal intensive care units in the United States from 1997–2011 (n=103,376). Early-onset sepsis (EOS, culture-positive only) and late-onset sepsis (LOS, culture-positive or clinical) cases were identified. Cox proportional hazards models were used to control for clinical variables between neonates with and without EOS to determine if EOS modified risk of LOS, necrotizing enterocolitis (NEC), or death.
LOS occurred in 12,112/102,317 (11.8%) neonates without EOS and in 133/1059 (12.6%) of those with EOS. After adjustment for clinical variables, the risk of LOS was not different between neonates with or without a history of EOS (hazard ratio [HR]=0.92; 95% confidence interval [CI] 0.74, 1.16). EOS increased the risk of 120-day mortality (HR=1.78; 95% CI 1.49, 2.13).
In contrast to findings in children and adults, EOS was not associated with an increased risk of LOS in this cohort. Age-specific investigations are needed to determine if post-sepsis immunologic alterations are present.
PMCID: PMC3462255  PMID: 22840605
preterm; neonate; sepsis; immunoparalysis
16.  Pharmacokinetics and Safety of Fluconazole in Young Infants Supported with Extracorporeal Membrane Oxygenation 
Candida infections are a leading cause of infectious disease-related death in infants supported with extracorporeal membrane oxygenation (ECMO). The ECMO circuit can alter drug pharmacokinetics (PK), thus standard fluconazole dosing in children on ECMO may result in suboptimal drug exposure. This study determined the PK of fluconazole in infants on ECMO.
Infants <120 days old received either intravenous fluconazole prophylaxis (25 mg/kg once a week) or treatment (12 mg/kg daily) while on ECMO. Paired plasma samples were collected pre- and post-oxygenator around doses 1 and 2 to calculate PK indices and describe oxygenator extraction. A 1-compartment model was fit to the data using non-linear regression. Surrogate pharmacodynamic targets for efficacy were evaluated.
Ten infants were enrolled. After dose 1 (n=9), the median clearance was 17 mL/kg/h, the median volume of distribution was 1.5 L/kg, and the median exposure in the first 24 hours (AUC0–24) was 322 h*mg/L. After multiple doses (n=7), the median clearance was 22 mL/kg/h, the median volume of distribution was 1.9 L/kg, and the AUC0–24 was 352 h*mg/L. After dose 1, 78% of infants achieved the prophylaxis target, while only 11% achieved the therapeutic target. Oxygenator extraction of fluconazole was minimal (−2.0%, standard deviation 15.0), and extraction was not correlated with age of the ECMO circuit (rho= − 0.05). There were no adverse events related to fluconazole.
Infants on ECMO had higher volume of distribution but similar clearance when compared with historical controls not on ECMO. In infants on ECMO, a fluconazole dose of 25 mg/kg weekly provides adequate exposure for prophylaxis against Candida infections. However, higher doses may be needed for treatment.
PMCID: PMC3444624  PMID: 22627870
fluconazole; Candida; extracorporeal membrane oxygenation; pharmacokinetics; infants
18.  A framework for grouping nanoparticles based on their measurable characteristics 
International Journal of Nanomedicine  2013;8(Suppl 1):45-56.
There is a need to take a broader look at nanotoxicological studies. Eventually, the field will demand that some generalizations be made. To begin to address this issue, we posed a question: are metal colloids on the nanometer-size scale a homogeneous group? In general, most people can agree that the physicochemical properties of nanomaterials can be linked and related to their induced toxicological responses.
The focus of this study was to determine how a set of selected physicochemical properties of five specific metal-based colloidal materials on the nanometer-size scale – silver, copper, nickel, iron, and zinc – could be used as nanodescriptors that facilitate the grouping of these metal-based colloids.
The example of the framework pipeline processing provided in this paper shows the utility of specific statistical and pattern recognition techniques in grouping nanoparticles based on experimental data about their physicochemical properties. Interestingly, the results of the analyses suggest that a seemingly homogeneous group of nanoparticles could be separated into sub-groups depending on interdependencies observed in their nanodescriptors.
These particles represent an important category of nanomaterials that are currently mass produced. Each has been reputed to induce toxicological and/or cytotoxicological effects. Here, we propose an experimental methodology coupled with mathematical and statistical modeling that can serve as a prototype for a rigorous framework that aids in the ability to group nanomaterials together and to facilitate the subsequent analysis of trends in data based on quantitative modeling of nanoparticle-specific structure–activity relationships. The computational part of the proposed framework is rather general and can be applied to other groups of nanomaterials as well.
PMCID: PMC3790278  PMID: 24098078
structure-activity relationships; principal component analysis; linear discriminant analysis; nanoparticle; modeling framework
19.  Bilateral spontaneous, simultaneous lower extremity hematomas in a patient on dalteparin☆ 
Bleeding related to low-molecular-weight heparins (LMWHs) is typically described as an excess of minor bleeding; however, several reports of spontaneous major bleeding have been noted.
A 58-year-old female presented to the hospital with bilateral spontaneous lower extremity hematomas which rapidly enlarged. CT studies demonstrated active arterial extravasation from small vessels at multiple sites within each leg with no dominant feeding artery identified on either side. She required multiple transfusions, administration of protamine, fresh frozen plasma (FFP), recombinant activated Factor VII and eventual surgery.
Dalteparin provides an effective and economical method of anticoagulation, however there is a risk of significant, spontaneous arterial hemorrhage even in the absence of risk factors.
Dalteparin can cause major spontaneous bleeding from multiple arterial sources.
PMCID: PMC3860035  PMID: 24240072
Low molecular weight heparin; Hemorrhage; Hematoma; Spontaneous; Lower extremity
20.  Changes in Neurocognitive Functioning Following Lung Transplantation 
Although neurocognitive impairment is relatively common among patients with advanced lung disease, little is known regarding changes in neurocognition following lung transplantation. We therefore administered ten tests of neurocognitive functioning before and 6-months following lung transplantation and sought to identify predictors of change. Among the 49 study participants, native diseases included COPD (n = 22), cystic fibrosis (n = 12), non-fibrotic diseases (n = 11) and other (n = 4). Although composite measures of executive function and verbal memory scores were generally within normal limits both before and after lung transplantation, verbal memory performance was slightly better posttransplant compared to baseline (p < .0001). Executive function scores improved in younger patients but worsened in older patients (p = .03). A minority subset of patients (29%) exhibited significant cognitive decline (i.e., > 1 standard deviations on at least 20% of tests) from baseline to post-transplant. Patients who declined were older (p < .004) and tended to be less educated (p = .07). Lung transplantation, like cardiac revascularization procedures, appears to be associated with cognitive decline in a subset of older patients, which could impact daily functioning post-transplant.
PMCID: PMC3411880  PMID: 22548872
Neurocognition; Neuropsychological Testing; Lung Transplantation; Outcomes
21.  Pharmacokinetics and Tolerability of Single-Dose Daptomycin in Young Infants 
Daptomycin is approved for the treatment of complicated skin and skin structure infections and Staphylococcus aureus bacteremia. We sought to characterize daptomycin single-dose pharmacokinetics and tolerability in young infants.
Subjects <120 days of age with suspected systemic infections were eligible for inclusion. Each subject was given a single 6 mg/kg intravenous dose of daptomycin. An average of 4 post-dose concentrations per infant was obtained.
Data from 20 infants are presented. Median gestational age at birth and postnatal age were 32 weeks (range 23, 40) and 3 days (1, 85), respectively. The median area under the concentration curve at 24 hours, volume of distribution, total body clearance, and half-life of daptomycin were 262.4 mg*h/L (166.7, 340.2), 0.21 L/kg (0.11, 0.34), 0.021 L/hr/kg (0.016, 0.034), and 6.2 hours (3.7, 9.0), respectively. No adverse events related to daptomycin were observed, including changes in creatine phosphokinase concentrations.
Daptomycin clearance in young infants was similar to that in 2–6-year-olds and higher than that observed in adolescents and adults.
PMCID: PMC3421038  PMID: 22627869
daptomycin; complicated skin and skin structure infections; Staphylococcus aureus; pharmacokinetics
23.  Emperic Antifungal Therapy and Outcomes in Extremely-Low-Birth-Weight Infants with Invasive Candidiasis 
The Journal of Pediatrics  2012;161(2):264-269.e2.
To assess the impact of emperic antifungal therapy of invasive candidiasis on subsequent outcomes in premature infants.
Study design
This was a cohort study of infants ≤1000 g birth weight cared for at Neonatal Research Network sites. All infants had at least 1 positive culture for Candida. Emperic antifungal therapy was defined as receipt of a systemic antifungal on the day of or the day before the first positive culture for Candida was drawn. We created Cox proportional hazards and logistic regression models stratified on propensity score quartiles to determine the effect of emperic antifungal therapy on survival, time to clearance of infection, retinopathy of prematurity, bronchopulmonary dysplasia, end-organ damage, and neurodevelopmental impairment (NDI).
136 infants developed invasive candidiasis. The incidence of death or NDI was lower for infants who received emperic antifungal therapy (19/38, 50%) compared with those who had not (55/86, 64%; odds ratio=0.27 [95% confidence interval 0.08–0.86]). There was no significant difference between the groups for any single outcome or other combined outcomes.
Emperic antifungal therapy was associated with increased survival without NDI. A prospective randomized trial of this strategy is warranted.
PMCID: PMC3380169  PMID: 22424952
Candida; neonate; mortality; neurodevelopmental impairment
24.  Use of the Complete Blood Cell Count in Early-Onset Neonatal Sepsis 
Early-onset sepsis is an important cause of morbidity and mortality in neonates, and its diagnosis remains challenging. The complete blood cell count and differential have been previously evaluated as diagnostic tools for early-onset sepsis in small, single-center reports. We evaluated the diagnostic accuracy of the complete blood count and differential in early-onset sepsis in a large, multicenter population of neonates admitted to the neonatal intensive care unit.
Using a cohort of 166,092 neonates with suspected early-onset sepsis with cultures admitted to 293 neonatal intensive care units, we calculated odds ratios and receiver operating characteristic curves for complete blood cell count indices and prediction of a positive culture. We determined sensitivity, specificity, and likelihood ratios for various commonly used cut-off values from the complete blood cell count.
Low white blood cell counts, low absolute neutrophil counts, and high immature-to-total neutrophil ratios were associated with increasing odds of infection (highest odds ratios: 5.38, 6.84, and 7.97, respectively). Specificity and negative predictive values were high (73.7–99.9% and >99.8%). However, sensitivities were low (0.3–54.5%) for all complete blood cell count indices analyzed.
Low white blood cell count, absolute neutrophil count, and high immature-to-total neutrophil ratio were associated with increasing odds of infection, but no complete blood cell count-derived index possesses the sensitivity to rule out reliably early-onset sepsis in neonates.
PMCID: PMC3399972  PMID: 22531231
neonatal; early-onset sepsis; blood cell count
25.  Use of the Complete Blood Cell Count in Late-Onset Neonatal Sepsis 
Late-onset sepsis is an important cause of morbidity and mortality in infants. Diagnosis of late-onset sepsis can be challenging. The complete blood cell count and differential have been previously evaluated as diagnostic tools for late-onset sepsis in small, single-center reports.
We evaluated the diagnostic accuracy of the complete blood count and differential in late-onset sepsis in a large multicenter population.
Study design
Using a cohort of all infants with cultures and complete blood cell count data from a large administrative database, we calculated odds ratios for infection, as well as sensitivity, specificity, positive and negative predictive values, and likelihood ratios for various commonly used cut-off values.
High and low white blood cell counts, high absolute neutrophil counts, high immature-to-total neutrophil ratios, and low platelet counts were associated with late-onset sepsis. Associations were weaker with increasing postnatal age at the time of the culture. Specificity was highest for white blood cell counts <1000/mm3 and >50,000/mm3 (>99%). Positive likelihood ratios were highest for white blood cell counts <1000/mm3 (4.1) and platelet counts <50,000/mm3 (3.5).
No complete blood count index possessed adequate sensitivity to reliably rule out late-onset sepsis in this population.
PMCID: PMC3399981  PMID: 22531232
neonatal; late-onset sepsis; blood cell count

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