Our Trauma Team

Fredric Pieracci, MD, MPH, FACS is from Chicago, Illinois. He received both his Bachelor of Arts degree in biology and his medical degree from The University of Pennsylvania. Dr. Pieracci completed residencies in both general surgery and general preventive medicine at the New York Presbyterian Hospital/Weill Cornell Medical College in New York City. During this time, he also obtained a Master’s Degree in Public Health from Columbia University.

Additional fellowship training in Trauma, Acute Care Surgery, and Surgical Critical Care was completed at the University of Colorado and Denver Health Medical Center. He is the Medical Director of the Denver Health Surgical Weight Loss Program and the Medical Director of the Thoracic and Pulmonary Nodule Clinics at Denver Health.

Research interests include trauma, surgical critical care, and bariatric surgery, with a focus on rib fracture stabilization, ventilator-associated pneumonia, and emergency department thoracotomy.

Dr. Bailee Williams Olliff is a Florida native and trained in surgery and surgical critical care at the University of South Florida and Brown University, respectively. Since then, she has made Colorado home, where she’s known for her energy in the trauma bay, her dedication to teaching, and her work empowering the next generation of surgeons and emergency providers.

Dr. Olliff brings extensive experience in trauma systems leadership, robotic and minimally invasive surgery, and emergency medical services (EMS) education. She has held faculty appointments with the Swedish Medical Center General Surgery Residency Program and Rocky Vista University, where she is recognized for her commitment to surgical education and mentorship.

An active member of the State Trauma Advisory Committee and CDPHE Trauma Section, Dr. Olliff is passionate about advancing trauma care through system improvement, multidisciplinary education, and innovation in operative technology. She is especially committed to providing equitable, high-quality surgical care for underinsured and disadvantaged populations, reflecting her long-standing dedication to community health and access to care.

Outside of medicine, Dr. Olliff enjoys skiing, Pilates, and exploring the Colorado outdoors with her husband of 12 years, embracing the balance of wellness and adventure that fuels her work both inside and outside the hospital.

Dr. Bensard is a Colorado native who earned his medical degree from the University of Colorado School of Medicine. He completed residency training in General Surgery and additional training in critical care and vascular surgery, followed by a pediatric surgery fellowship at Columbus Children’s Hospital.

He has served as Chief of Pediatric Surgery at Denver Health, Director of Trauma at Children’s Hospital, and Professor of Surgery at the University of Cincinnati. He is board certified in General Surgery, Surgical Critical Care, and Pediatric Surgery.

Dr. Bensard is widely published, active in national surgical societies, and has received multiple national teaching and professional awards.

Dr. Coleoglou Centeno was born and raised in Venezuela where he attended medical school at Universidad de Oriente and graduated at the top of his class. He began his general surgery residency in Caracas at one of the country's largest trauma centers, where his passion for trauma surgery developed.

Due to political turmoil in Venezuela, Dr. Coleoglou Centeno moved to the United States to continue his training. He completed a postdoctoral research fellowship at Washington University in St. Louis in the Division of Trauma and Acute Care Surgery, participating in numerous presentations and peer-reviewed publications. He completed his General Surgery residency at the University of Texas Medical Branch in Galveston, followed by a Surgical Critical Care fellowship and an AAST-accredited Trauma and Acute Care Surgery fellowship at the University of Colorado and Denver Health. He is board certified in General Surgery and Surgical Critical Care.

Dr. Coleoglou Centeno joined Denver Health Medical Center as a Trauma and Acute Care Surgeon after training. He is a member of several professional societies, where he also participates in multiple committees, including the Eastern Association for the Surgery of Trauma, the American Association for the Surgery of Trauma, SAGES, and the American College of Surgeons. He has an interest in academic research and surgical education.

Outside of the hospital, Dr. Coleoglou Centeno enjoys traveling, spending quality time outdoors with his family, and maintaining an active lifestyle.

Dr. Alexandra Ferre is a board-certified general surgeon.

Dr. Ferre is a trauma and acute care surgeon at Denver Health Medical Center and an Assistant Professor of Surgery at the University of Colorado School of Medicine.

Originally from Caracas, Venezuela, Dr. Ferre earned her medical degree from the Universidad Central de Venezuela. She completed a year of research at Cleveland Clinic Weston before entering general surgery residency at the Cleveland Clinic. She went on to complete fellowship training in surgical critical care, trauma, and acute care surgery at the University of Colorado and Denver Health.

Her clinical interests include the comprehensive care of severely injured patients, complex emergency general surgery, and healthcare disparities. She is an active member of several professional societies, including the Eastern Association for the Surgery of Trauma, the American Association for the Surgery of Trauma, the Panamerican Trauma Society, and the American College of Surgeons, where she also contributes to committee work. Dr. Ferre is committed to advancing patient outcomes through evidence-based practice, education, and mentorship of future surgeons.

Mandi Roberts, MD, is a board-certified general surgeon with expertise in surgical critical care, minimally invasive surgery and bariatric surgery. She earned her medical degree from the University of South Carolina School of Medicine in 2013 and completed her general surgery residency at the University of Texas at Austin Dell Medical School in 2018.

Dr. Roberts went on to complete a fellowship in minimally invasive and bariatric surgery at Carolinas Medical Center in 2019, followed by a fellowship in Surgical Critical Care at Eastern Virginia Medical School in 2023. She is certified by the American Board of Surgery in both General Surgery and Surgical Critical Care.

Dr. Witt earned her Bachelor of Science in Neurobiology from the University of Washington, graduating with College Honors and Magna cum Laude. She went on to complete her Doctor of Medicine at the University of Michigan Medical School, where she graduated with Distinction and was inducted into Alpha Omega Alpha. She then completed her General Surgery residency at the University of Washington, including two years of research training under a T32 Pediatric Injury Training Grant.

During this time, she also earned a Master of Public Health in Epidemiology and received research awards from the Schilling Research Foundation and the American Association for the Surgery of Trauma. Upon completing residency, she was honored with the Golden Grenade Award, voted by residents as the graduating chief who was most selfless and supportive of her peers. She then completed fellowship training in Surgical Critical Care and Trauma and Acute Care Surgery through Denver Health and the University of Colorado. She is board certified in both Surgery and Surgical Critical Care.

Daniel VanDerPloeg, MD, is a board-certified general surgeon specializing in surgical critical care. He earned his medical degree from the University of Kentucky College of Medicine in 2015 before completing his general surgery residency at the University of Colorado General Surgery Residency in 2020. He then completed a fellowship in Surgical Critical Care through Denver Health and the University of Colorado in 2021.

Dr. VanDerPloeg is certified by the American Board of Surgery in both General Surgery and Surgical Critical Care.

D. Dante Yeh is a board-certified surgeon specializing in general surgery, surgical critical care and trauma surgery. He earned his medical degree from Boston University School of Medicine in 2004 and completed his general surgery residency at Jackson Memorial Hospital in 2009.

Dr. Yeh went on to complete fellowships in Surgical Critical Care in 2010 and Trauma Surgery in 2011 at the University of California, San Francisco School of Medicine. He is certified by the American Board of Surgery in both General Surgery and Surgical Critical Care.

Dr. Nguyen completed her general surgery residency at St. John’s Episcopal Hospital, where she served as Chief Resident, followed by fellowship training in Surgical Trauma Critical Care at the Icahn School of Medicine at Mount Sinai Elmhurst Hospital. Most recently, she completed the American Association for the Surgery of Trauma–Acute Care Surgery Fellowship at Emory University/Grady Memorial Hospital. She brings with her an impressive background in trauma and critical care, a strong academic record with numerous publications and presentations, and a dedication to quality improvement in surgical care.

Originally from Colorado, Dr. Nguyen is especially excited to return home and continue her career in the community where she grew up. Along with her clinical expertise, she has a long history of community engagement and volunteer service in Denver, reflecting her deep commitment to caring for patients and families both inside and outside the hospital.