Publications by authors named "Karen Martz"

Bronchopulmonary dysplasia (BPD) is a disease of chronic respiratory insufficiency stemming from premature birth and iatrogenic lung injury leading to alveolar simplification, impaired alveolar-capillary development, interstitial fibrosis, and often pulmonary hypertension. BPD is the most common pulmonary sequela of prematurity and is often fatal; however, there remains no FDA-approved therapies to treat or prevent BPD. Sildenafil is increasingly used off-label in premature infants despite scant safety and efficacy data.

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Objective: To characterize the safety of sildenafil in premature infants.

Study Design: A phase I, open-label trial of sildenafil in premature infants receiving sildenafil per usual clinical care (cohort 1) or receiving a single IV dose of sildenafil (cohort 2). Safety was evaluated based on adverse events (AEs), transaminase levels, and mean arterial pressure monitoring.

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Background: There is no consensus on rabbit antithymocyte globulin (rATG) dose used for induction immunosuppression in pediatric kidney transplants. We aimed to identify whether a lower rATG dose provides safe and effective immunosuppression compared with a higher dose.

Methods: We retrospectively analyzed all first-time kidney transplant recipients (aged <21 y) in the North American Pediatric Renal Trials and Collaborative Studies registry since 1998 on mycophenolate mofetil- and tacrolimus-based immunosuppression with rATG induction.

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Physiologically-based pharmacokinetic (PBPK) modeling can potentially predict pediatric drug-drug interactions (DDIs) when clinical DDI data are limited. In infants for whom treatment of pulmonary hypertension and prevention or treatment of invasive candidiasis are indicated, sildenafil with fluconazole may be given concurrently. To account for developmental changes in cytochrome P450 (CYP) 3A, we determined and incorporated fluconazole inhibition constants (K ) for CYP3A4, CYP3A5, and CYP3A7 into a PBPK model developed for sildenafil and its active metabolite, N-desmethylsildenafil.

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Background: While adult hemodialysis (HD) patients have increased morbidity with higher target hemoglobin levels, similar findings have not been demonstrated in pediatric patients. We evaluated changes in transfusions, anemia frequency, and erythropoietin (epo) dosing among pediatric HD patients before, during, and after implementation of federal dialysis payment policies regarding epo dosing for adult HD patients.

Methods: This is a retrospective cohort study of pediatric HD patients enrolled in NAPRTCS.

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The NAPRTCS has collected clinical information on children undergoing renal transplantation since 1987 and now includes information on 12 920 renal transplants in 11 870 patients. Since the first data analysis in 1989, NAPRTCS reports have documented marked improvements in patient and allograft outcomes after pediatric renal transplantation in addition to identifying factors associated with both favorable and poor outcomes. The registry has served to document and influence practice patterns, clinical outcomes, and changing trends in renal transplantation and also provides historical perspective.

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Aims: To characterize the population pharmacokinetics (PK) of sildenafil and its active metabolite, N-desmethyl sildenafil (DMS), in premature infants.

Methods: We performed a multicentre, open-label trial to characterize the PK of sildenafil in infants ≤28 weeks gestation and < 365 postnatal days (cohort 1) or < 32 weeks gestation and 3-42 postnatal days (cohort 2). In cohort 1, we obtained PK samples from infants receiving sildenafil as ordered per the local standard of care (intravenous [IV] or enteral).

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Background: With improved outcomes for children transplanted with FSGS since previous NAPRTCS registry reports, this study re-evaluates the association of living donation, immunosuppression, and DGF on graft survival.

Setting: Patients transplanted between 2002 and 2016, comparing FSGS diagnosis vs other glomerular diseases.

Methods: Primary outcomes were allograft survival and FSGS recurrent-free graft survival.

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Objective: This study examined the role of lithium in the maintenance treatment of pediatric patients with bipolar I disorder (BP-I).

Method: Participants aged 7 to 17 years who presented with a manic or mixed episode received 24 weeks of lithium treatment in one of two multiphase studies, the Collaborative Lithium Trials (CoLT 1 and CoLT 2). Responders were randomized to continue lithium or to be cross-titrated to placebo for up to 28 weeks.

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Diazepam is labeled for status epilepticus (SE) in children, but there are limited data characterizing its disposition in pediatric patients. We developed a population pharmacokinetic (PK) model of i.v.

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Background: The 2011 annual report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) registry comprises data on 6482 dialysis patients over the past 20 years of the registry.

Methods: The study compared clinical parameters and patient survival in the first 10 years of the registry (1992-2001) with the last decade of the registry (2002-2011).

Results: There was a significant increase in hemodialysis as the initiating dialysis modality in the most recent cohort (42% vs.

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Although obesity is prevalent among children in the United States, pharmacokinetic (PK) data for obese children are limited. Clindamycin is a commonly used antibiotic that may require dose adjustment in obese children due to its lipophilic properties. We performed a clindamycin population PK analysis using data from three separate trials.

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Background: Lithium is a benchmark treatment for bipolar disorder in adults. Definitive studies of lithium in pediatric bipolar I disorder (BP-I) are lacking.

Methods: This multicenter, randomized, double-blind, placebo-controlled study of pediatric participants (ages 7-17 years) with BP-I/manic or mixed episodes compared lithium (n = 53) versus placebo (n = 28) for up to 8 weeks.

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Background And Objective: Among children with end-stage renal disease (ESRD), those who abstract initiated chronic dialysis during the first year of life historically were less likely to survive or receive a kidney transplant compared with those who initiated dialysis later in childhood.We hypothesized that recently treated infants have experienced improved outcomes.

Methods: We queried the North American Pediatric Renal Trials and Collaborative Studies database, obtaining information on 628 children who initiated maintenance peritoneal dialysis for treatment of ESRD at ,1 year of age.

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The Standardizing Care to Improve Outcomes in Pediatric End Stage Renal Disease (SCOPE) Collaborative is a North American multi-center quality transformation effort whose primary aim is to minimize exit-site infection and peritonitis rates among pediatric chronic peritoneal dialysis patients. The project, developed by the quality improvement faculty and staff at the Children's Hospital Association's Quality Transformation Network (QTN) and content experts in pediatric nephrology and pediatric infectious diseases, is modeled after the QTN's highly successful Pediatric Intensive Care Unit and Hematology-Oncology central line-associated blood-stream infection (CLABSI) Collaboratives. Like the Association's other QTN efforts, the SCOPE Collaborative is part of a broader effort to assist pediatric nephrology teams in learning about and using quality improvement methods to develop and implement evidence-based practices.

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Objective: To determine the evolution of cognitive and academic deficits and risk factors in children after liver transplantation.

Study Design: Patients ≥2 years after liver transplantation were recruited through Studies of Pediatric Liver Transplantation. Participants age 5-6 years at Time 1 completed the Wechsler Preschool and Primary Scale of Intelligence, 3rd edition, Wide Range Achievement Test, 4th edition, and Behavior Rating Inventory of Executive Function (BRIEF).

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Kidney transplant recipients have an increased risk of cancer. Data on non-LPD malignancies (solid tumors) in pediatric renal transplant recipients are limited. We performed a cohort study using the NAPRTCS transplant registry to describe the incidence of non-LPD malignancy compared with the general pediatric population.

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Data from 997 pediatric LT recipients were used to model demographic and medical variables as predictors of lower levels of HRQOL. Data were collected through SPLIT FOG project. Patients were between 2 and 18 yr of age and survived LT by at least 12 months.

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Background: Limited pharmacokinetic (PK) data of metronidazole in premature infants have led to various dosing recommendations. Surrogate efficacy targets for metronidazole are ill-defined and therefore aimed to exceed minimum inhibitory concentration of organisms responsible for intra-abdominal infections.

Methods: We evaluated the PK of metronidazole using plasma and dried blood spot samples from infants ≤32 weeks gestational age in an open-label, PK, multicenter (N = 3) study using population PK modeling (NONMEM).

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The NAPRTCS transplant registry has collected clinical information on children undergoing kidney transplantation since 1987 and now includes information on 11 603 kidney transplants in 10 632 patients. Since the first data analysis in 1989, NAPRTCS reports have documented marked improvements in outcome after kidney transplantation in addition to identifying factors associated with both favorable and poor outcomes. Patient demographics have changed over the course of the registry with a decrease in the percentage of white recipients from a high of 72% in 1987 to less than 43% in 2007.

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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.

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