Four physicians joined our Adult Cardiothoracic Anesthesiology Fellowship and one joined our Pediatric Anesthesiology Fellowship. Please help us in welcoming them to the Department of Anesthesiology!
Incoming Adult Cardiothoracic Anesthesiology Fellows
Michael “Mikey” Berentzen, M.D.
Berentzen earned his medical degree from St. Louis University School of Medicine and finished his residency here at the University of Florida (UF) Department of Anesthesiology. He has a Bachelor of Science in human biology from Utah State University.
During his residency, Berentzen was the chair of the Visiting Professors Committee and a member of the Resident Recruitment Committee. At the 2025 Gulf Atlantic Anesthesia Resident’s Research Conference, he earned third place for his oral presentation. His recent research interests cover catheter placement and the mitral valve.
Kellen Creech, D.O., MPH, M.S.
Creech received his medical degree and Master of Public Health from Nova Southeastern University College of Osteopathic Medicine. He completed his anesthesiology residency here at the UF Department of Anesthesiology, where he was a chief resident. Additionally, he has a Master of Medical Sciences from the University of South Florida and a Bachelor of Science in biology from Ave Maria University.
During residency, Creech was a member of the paired period committee and the Anesthesia Process Improvement Committee. Additionally, he was inducted into the Alpha Omega Alpha honor medical society and UF Gold Humanism Honor Society for his high academic achievement, leadership, and character.
Kody Russelburg, D.O.
Russelburg earned his medical degree from Marian University College of Osteopathic Medicine and finished his anesthesiology residency at the University of Central Florida. He has a Bachelor of Science in biochemistry from the University of Southern Indiana.
During residency, Russelburg earned Best Overall Resident and the Trauma Star award. He also scored in the top ten percent on the American Board of Anesthesiology BASIC Exam. In addition, he has been involved in quality improvement projects that have focused on preoperative methadone for elective spinal surgeries and improvement of medication labeling.
Allyson Tragesser, M.D.
Tragesser received her medical degree from the UF College of Medicine (COM) and completed her residency here at the UF Department of Anesthesiology, where she was a chief resident. She also earned her Bachelor of Science in health science at UF.
Tragesser was inducted into the Alpha Omega Alpha honor medical society for her high educational achievement and professionalism. As a chief resident, she earned numerous accolades, like the Outstanding Resident Educator Award from the UF COM Society of Teaching Scholars and seven awards at the 2026 Residents’ Graduation, including the Chair’s Award for Best Resident and an outstanding achievement award in the Division of Cardiothoracic Anesthesiology.
Incoming Pediatric Anesthesiology Fellow
Abigail Schirmer, M.D.
Schirmer received her medical degree from Florida State University and completed her residency here at the UF Department of Anesthesiology. She also has Bachelor of Science in nutritional sciences and microbiology from UF.
During residency, Schirmer was an active member in the department and the national anesthesia community. The American Society of Anesthesiologists recognized her for her academic accomplishments, character, and leadership by awarding her the Resident Distinction Award, selecting her for its Resident Scholar program, and choosing her to be president-elect of its Resident Component. She was also inducted into the UF Gold Humanism Honor Society for showing humanistic character and compassionate patient care.
Learn about our Adult Cardiothoracic Fellowship Program.
Learn about our Pediatric Anesthesiology Fellowship Program.