Faculty and Fellows

Our Faculty

Headshot Aaron Wallman-Stokes, MD

Aaron Wallman-Stokes, MD

Program Director, Assistant Professor of Pediatrics

Dr. Wallman-Stokes completed his pediatric residency at the Children’s Hospital of Philadelphia, after which he returned to his childhood home of New York City for fellowship training in Neonatal-Perinatal Medicine at the Columbia University Irving Medical Center. Following fellowship he remained at Columbia as a member of the faculty until joining the UVM Medical Center in 2020. His research has primarily focused on characterizing premature infants’ oxygen exposure and investigating how poor growth and hypoxemia are associated with the risk of developing retinal disease. He has also worked as part of multicenter research groups exploring the relationship between particular vital sign patterns early in life and the development of infection as well as diseases of the lungs, eyes and brain. He is passionate about teaching and working with trainees, dating to his time as an elementary school teacher prior to attending medical school.

Headshot Deirdre O'Reilly, MD, MPH

Deirdre O'Reilly, MD, MPH

Division Chief, Associate Program Director, Associate Professor of Pediatrics

Dr. O'Reilly, MD, MPH joined the division in 2016 from Boston Children's Hospital and Beth Israel Deaconess Medical Center, where she had been an attending neonatologist since 2007.  She completed her fellowship in Neonatal-Perinatal Medicine at the Harvard Neonatal-Perinatal Medicine Program, during which time she pursed an MPH in Maternal and Child Health from T.H. Chan School of Public Health.  She worked on a team of clinicians that established the first hypothermia program for hypoxic-ischemic encephalopathy in New England. Her research focuses on follow-up of high-risk infants after discharge from the NICU, educational strategies for assessment of learners, and coordination of perinatal outreach and quality improvement initiatives. Dr. O'Reilly is a member of the Organization of Neonatal Training Program Directors Executive Council and she co-chairs the Leadership Committe for the Mid-career Neonatologist (MiDCaN) group of the American Academy of Pediatrics, Section on Neonatal Perinatal Medicine (AAP SoNPM).

Headshot Whittney Barkhuff, MD, PhD

Whittney Barkhuff, MD, PhD

Medical Director, Assistant Professor of Pediatrics

Dr. Barkhuff completed her pediatric residency at Massachusetts General Hospital in Boston and the Neonatal-Perinatal Medicine fellowship at the University of New Mexico in 2017. She then returned to UVMMC, where she had previously completed her MD/PhD, to join the division of neonatology. During fellowship, she was involved in quality improvement aimed at reducing false positive blood cultures, as well as in evaluating the impact of the “baby-friendly” health initiative on NICU admissions for hypoglycemia.  At UVMMC, she serves as the Medical Director of the NICU and Co-Chairs the Neonatal Resuscitation Committee. She is currently focused on optimizing patient care through a collaborative multidisciplinary approach and continues to be passionate about medical student, resident, and fellow education.

Headshot of Charles E. Mercier, MD, Neonatologist, and Professor

Charles Mercier, MD, MPH

Professor of Pediatrics

Dr. Mercier is currently an active attending Neonatologist at the University of Vermont Children’s Hospital, and Professor of Pediatrics at the Larner College of Medicine. He is a lead physician in the Perinatal Quality Collaborative – Vermont, serves on the UVM Public Health Program Curriculum Committee and the board of the Northern New England Perinatal Quality Improvement Network, and co-leads the ELBW Infant Follow-up group of the Vermont Oxford Network. A graduate of the IHI Breakthrough Series College, he previously served as the Faculty Chair in the planning and design phase of the CMS Neonatal Outcomes Project and led several Expert Planning Groups in developing project specific change packages. A graduate of the Center for Medical Simulation, he leads a high-fidelity neonatal resuscitation program for University of Vermont Pediatric residents. His current research interests include NICU / Delivery Room simulation, ELBW infant follow-up outcomes, preventing chronic lung disease, and applying public health data to develop strategies supporting optimal perinatal health care delivery in hospitals anchored in rural settings. Dr. Mercier is the former UVMCH Chief of the Division of Neonatal-Perinatal Medicine, Medical Director of the NICU, and Director of the NICU Transport and Quality Improvement Teams.

Headshot Roger Soll, MD

Roger Soll, MD

Director of Research, Professor of Pediatrics

Dr. Soll is the H. Wallace Professor of Neonatology at the Larner College of Medicine and is President of the Vermont Oxford Network and Director of Network Clinical Trials and Follow-up.  Dr. Soll is an authority in evidence-based medicine and randomized clinical trials.  He is the coordinating editor of Cochrane Neonatal, part of the Cochrane Collaboration, and author or co-author of the Cochrane Reviews of surfactant therapy. He is the author of numerous peer reviewed articles and book chapters on the subject of surfactant replacement therapy and evidence-based medicine.  A native of New York City, Dr. Soll graduated from Cornell University with a degree in Genetics and History of Science in 1975. He received his M.D. degree from the University of Health Sciences/Chicago Medical School in 1978. He returned to New York City to complete his residency training in Pediatrics at Bellevue Hospital/New York University Medical Center in 1981. After 2 years with the Public Health Service, Dr. Soll returned to academic training. He completed the post graduate fellowship in Neonatal-Perinatal Medicine at the University of Vermont in 1983 and has remained in Vermont ever since.

Headshot Danielle Ehret, MD, MPH

Danielle Ehret, MD, MPH

Associate Professor of Pediatrics, Asfaw Yemiru Green and Gold Professor of Global Health

Dr. Ehret completed her pediatrics residency and the global heath track at Yale New Haven Children's Hospital. During neonatology fellowship at Boston Children's Hospital, she also completed her Masters in Public Health at the Harvard T. H. Chan School of Public Health. Dr. Ehret joined the faculty at UVMMC in 2015. Her academic interest in the implementation of quality improvement science in global newborn health, and se is the inaugural Director of Global health and Chief Medical Officer for Vermont Oxford Network. Her research focus is brining data-driven improvement to resource-limited neonatal settings globally, with the aim of reducing preventable newborn morbidities and mortality. She is the co-PI of the African Neonatal Network and has mentored neonatology fellows and MPH students in global health academic projects locally, nationally, and internationally.

Headshot Leslie Young, MD

Leslie Young, MD

Assistant Professor of Pediatrics

Dr. Young completed her pediatrics residency at the University of Vermont Children's Hospital before joining the NPM Fellowship, which she completed in 2014. Dr. Young' current research is focused on optimizing care provided to infants and families affected by the opioid epidemic. Additional academic interests are in transitional physiology, reducing iatrogenic contributors to morbidity and mortality and optimizing research output through trial design. She currently serves and IMPACT VT (IMproving Pediatric Access to Clinical Trials in Vermont) MPI and on the leadership committee for the IDeA States Pediatrics Clinical Trials Network (ISPCTN). The ISPCTN is funded through the NIH with the goal of improving the feasibility of translational research in rural and underserved areas. In addition to her clinical and research efforts, Dr. Young enjoys her work mentoring fellows and early-stage investigators locally and nationally in areas of research development and career building.

Headshot Delia Horn,MD

Delia Horn, MD

Assistant Professor of Pediatrics, Director of Neonatal Transport

Dr. Horn received her undergraduate degree in English from Vassar College, then went on to receive her medical degree from the Larner College of Medicine at the University of Vermont. She completed both her pediatrics residency and her neonatal-perinatal medicine fellowship at the University of Vermont Children's Hospital and joined the faculty at UVMMC in 2020. Her academic interests lie in quality improvement and implementation science to improve global neonatal health. She also has an interest in global health education, and is active in the design and implementation of the Global Health Track in the UVM neonatal-perinatal medicine fellowship program. Her research is focused on combining quality improvement, education, and advances in implementation to reduce neonatal morbidity and mortality worldwide. She enjoys mentoring neonatology fellows and modeling evidence-based practice. Additionally, Dr. Horn is interested in point of care ultrasound, and is active in bringing these services to the neonatology department at UVM.

Headshot Adrienne Pahl, MD

Adrienne Pahl, MD

Assistant Professor of Pediatrics

Dr. Pahl completed both her medical degree and Pediatrics Residency at the University of Vermont Children's Hospital (UVMCH). She worked as a primary care pediatrician in rural Vermont before returning to training to pursue a fellowship in Neonatal-Perinatal Medicine at the UVMCH. She has an academic interest in improving systems of care with a particular focus on work involving care of opioid exposed newborns and follow up of high-risk infants. During fellowship she planned, implemented, and now continues a quality improvement initiative to improve care of opioid exposed newborns. As an element of this project, she helped to introduce the Eat, Sleep, Console Care Tool at UVMCH. She continues to use quality improvement methodology with a goal to improve care and long term outcomes both in the NICU and in the neonatal follow up clinic.

Current Fellows

Headshot Luis Bolanos, DO

Luis Bolanos, DO

First Year Fellow


Sinai Hospital of Baltimore - Pediatrics

Medical School

Rowan University of Osteopathic Medicine - DO

Dr. Bolanos completed his undergraduate, graduate, and medical school education in his home state of New Jersey. He then ventured off to Baltimore, Maryland to complete his pediatric residency training at Sinai Hospital of Baltimore. He is now thrilled to be joining the UVMMC family to complete a fellowship in Neonatology. On his time off, you can likely find Dr. Bolanos Somewhere outdoors with his wife and dog enjoying everything Vermont has to offer.

Headshot Julia Litzky, MD, PhD

Julia Litzky, MD, PhD

First Year Fellow


Dartmouth-Hitchcock/Mary Hitchcock Memorial Hospital - Pediatrics

Medical School

Geisel School of Medicine - MD

Dr. Litzky grew up in Annapolis, MD, and completed her undergraduate degree in neuroscience at Hamilton College in NY. She then moved north to NH to pursue an MD/PhD at Dartmouth. Her work there focused on prenatal exposures and their effect on fetal growth and development. She stayed on at Dartmouth for her pediatrics residency where her interest shifted toward the effects of intra-uterine opiate use and other stressors on infant growth and how to improve outcomes for these families. She's thrilled to be moving north again to joining the UVM Neonatology Fellowship. Outside of the hospital, Dr. Litzky can be found hiking with her husband and three dogs, teaching yoga, and skiing in the winter.

Headshot William Chotas, MD

William Chotas, MD

Third Year Fellow


University of Florida College of Medicine - Pediatrics

Medical School

Ross University School of Medicine - MD

After Dr Chotas studied botany at the University of Florida and traveled through the Amazon, he then completed his medical training at Ross University School of Medicine on the wonderful island of Dominica. He then went on to do his pediatric residency in his home state at the University of Florida-Jacksonville. After residency, he spent one year working as a locums pediatrician in South Carolina prior to going to the beautiful island of Saipan. The time he spent working in the NICU on Saipan helped finalize his plans for completing a fellowship in Neonatology. He and his family are thrilled to be here in Vermont for his fellowship.