Portrait of Michael Green, MD

Michael Green, MD

Resident Physician, Class of 2027

Department of Anesthesiology Featured Member: May 2025

Michael is a CA-1 in the anesthesiology residency class of 2027. Originally from Michigan and raised in St. Louis, he earned his undergraduate degree in biochemistry from the University of Colorado at Boulder. After college, Michael joined the Peace Corps and spent time teaching in Ecuador. He later moved to Phoenix, Arizona, where he helped license and expand a free primary care clinic for uninsured individuals ineligible for public healthcare—an experience that sparked his passion for increasing access to high-quality medical care and ultimately inspired him to pursue a career in medicine.

In true adventurous spirit, Michael attended medical school at La Universidad Autónoma de Guadalajara in Mexico. More than a decade after leaving St. Louis, he was excited to return home and join the department as a resident physician.

Michael values the exceptional training environment at WashU Medicine, where he sees a wide variety of complex cases as part of a quaternary care center, while also helping care for the local community in a safety-net hospital role. He’s proud to be part of a department that welcomes people from all backgrounds, including many who’ve followed nontraditional paths—just like him.

Outside the hospital, Michael enjoys hiking, traveling with his wife and dogs, and cycling. A personal goal of his is to visit every U.S. National Park—he’s already made it to 23, with 40 more to go!

Portrait of Ottavia Green, MD

Ottavia Green, MD

Resident Physician, Class of 2023

Department of Anesthesiology Featured Member: May 2021

Ottavia is a current CA-1 resident in the Department of Anesthesiology. She was born and raised in Jamaica and migrated to Florida with her family in 2011. She attended college and medical school there before moving to St. Louis to battle the winter. She is interested in working with the pediatric population after residency.

During her spare time, she enjoys watching anime and reading manga. She is currently learning Japanese as a means of watching her anime without needing to use subtitles. She is also a fan of the show ‘Survivor’ and is contemplating applying to the show once she overcomes the fear of sleeping outside in the cold. Ottavia currently lives in the central west end with her 12 plants all of which have names. Prior to the COVID pandemic, Ottavia also enjoyed solo traveling. Her favorite country visited so far is Thailand.

Portrait of Tori Greenberg

Tori Greenberg

Senior Coordinator of Payroll & Administration

Department of Anesthesiology Featured Member: April 2025

Tori joined WashU Medicine nearly five years ago and became part of the Department of Anesthesiology in December 2022. As the Senior Coordinator of Payroll & Administration on the finance team, she handles monthly clinical payroll, new hire onboarding, and various administrative tasks.

Originally from St. Louis, Tori earned her undergraduate degree in Human Resource Management from the University of Northern Iowa, where she was also a member of the swim team. In her free time, she enjoys staying active, cooking, exploring local breweries, and watching Cardinals games.

Stephen Gregory, MD

Stephen Gregory, MD

Division Chief, Perioperative Medicine; Medical Director, Center for Preoperative Assessment and Planning (CPAP)

Department of Anesthesiology Featured Member: February 2020

Stephen grew up in Wood River, Illinois and attended McKendree University for his undergraduate degree, where he was also a member of the track and field team. He went to medical school at Saint Louis University before moving to Duke for his anesthesia residency. In 2016, he moved back to St. Louis for a cardiac anesthesia fellowship at WashU and joined the faculty after his fellowship year. Stephen is currently the director of the CPAP clinic and co-director of the physiology course at the School of Medicine, and he splits his clinical time between the CPAP clinic and the cardiac operating rooms. He is interested in the influence of cognition on perioperative outcomes and in using telemedicine to improve perioperative management. In his free time, he likes to rock climb, cycle, and spend time with his wife, Katie, and their two children, Richter and Emery.

Portrait of Andrew Griesbaum, ACNP

Andrew Griesbaum, ACNP

Nurse Practitioner

Department of Anesthesiology Featured Member: March 2026

Andy Griesbaum is an Acute Care Nurse Practitioner, practicing in the ICUs at Barnes-Jewish Hospital and Christian Hospital. He has been a member of the Department of Anesthesiology art WashU Medicine since 2021. He earned a BA in History from the University of Michigan in 2009—followed by a BSN in 2014 and MSN in 2020, both from Barnes-Jewish College Goldfarb School of Nursing.

Andy's wife, Maggie, is also a Nurse Practitioner, and together they have a four-year-old daughter and a 7-month-old son. When not at work, Andy can be found indoctrinating his children into Michigan sports fandom, tinkering in the woodshop in his basement, watching historical documentaries, or playing games like Dungeons and Dragons.

Russell Groener

Russell Groener, MD

Assistant Residency Program Director; Associate Professor, Anesthesiology

Department of Anesthesiology Featured Member: October 2020

Russell is an Assistant Program Director for Residency Education and an Associate Professor in the division of pediatric anesthesiology. He grew up in South Africa, graduating with a medical degree from the University of Cape Town. Before beginning his anesthesiology residency training in Johannesburg, he worked as a general practitioner in Manitoba, Canada, backpacked through South America for 6 months, and spent time at a rural hospital in South Africa, training nurses to practice primary health care in villages where there were no doctors.

After residency, he came to Washington University for fellowship training in pediatric anesthesia. He joined the faculty in 2002, after being in private practice in Cape Town. He especially enjoys working with residents and helping them develop from anxious tutorial newbies into skilled clinicians.

Outside of work, he enjoys gardening with his wife, running with his dog, and playing squash as often as he can.

Fun fact: “I was 33 years old before I was able to vote for the very first time. I stood in line for more than 6 hours with people like me without a single complaint - we were just so excited and overjoyed to be able to vote for Nelson Mandela to be president!”

Portrait of Ryan Guffey, MD

Ryan Guffey, MD

Fellowship Director for Regional Anesthesia and Acute Pain; Associate Professor, Anesthesiology

Department of Anesthesiology Featured Member: February 2020

Ryan was born near Detroit in Michigan but spent time growing up in both the Detroit area and St. Peters, MO. He went to medical school at Wayne State University where he met his wife, Amy. Together they attended residency at Emory, and Ryan went on to study Regional Anesthesia and Acute Pain at the University of Pittsburgh. He has been an attending at Washington University since. Ryan is the Regional and Acute Pain Fellowship Director and his research focuses on pain after breast cancer surgery and enhanced recovery. He enjoys travel, hiking, architecture, cooking, and smoking BBQ.

Portrait of Gaurang Gupte, MD

Gaurang Gupte, MD

Resident Physician, Class of 2026

Department of Anesthesiology Featured Member: June 2025

Dr. Gupte is a rising CA-3 anesthesiology resident from Fort Worth, Texas. He earned dual degrees in biology and electrical engineering from the University of Texas at Arlington and completed his medical education at Washington University School of Medicine in St. Louis. Drawn to the program’s exceptional training and robust clinical opportunities, he chose to stay at WashU for his residency.

Gaurang leverages his background to explore the neural mechanisms of anesthesia-induced unconsciousness through research. His clinical interests include trauma anesthesia, prehospital medicine, and critical care.

Outside of the hospital, Gaurang enjoys running, hiking, and motorsports. He has a strong interest in rural medicine and aspires to one day have a hobby farm. Inspired by the late Irish anesthesiologist Dr. John Hinds, he hopes to use his passion for prehospital care to serve his community and support high-risk international motorsport events.

Portrait of Teresa Hammann, MSN, APRN, AGACNP-BC

Teresa Hammann, MSN, APRN, AGACNP-BC

Nurse Practitioner

Department of Anesthesiology APP of the Quarter: April 2021

Teresa was born and raised in St. Louis, MO and joined the department in 2016 after graduating from the ACNP program at Saint Louis University. Prior to becoming a nurse practitioner, she was a bedside nurse in the emergency department and cardiothoracic ICU at Barnes-Jewish Hospital. Outside of work, Teresa enjoys spending time with her husband Brett and their boxer, Shirley. She also enjoys travelling, cooking, SCUBA diving, reading, and spending time outdoors running, hiking, kayaking, camping, and gardening

"I feel blessed to have been chosen to be part of the SICU APP group as my first job out of school. I enjoy the fast paced environment and have an amazing group of co-workers that have helped me learn and grow in my profession!"

Teresa was named the Q1 2021 APP of the Quarter! She is always attentive to the staff and patient needs and is a great resource to have on our care team! Congratulations, Teresa!

Mark Hanak, MD

Mark Hanak, MD

Resident Physician, Class of 2023

Department of Anesthesiology Featured Member: February 2021

Mark is one of the current CA-1 residents in the Department of Anesthesiology. Originally from the Washington D.C. suburbs, he attended the University of Virginia for both undergrad and medical school. Following graduation he moved to St. Louis with his girlfriend, Alison, who is an OBGYN resident here at WashU.

When choosing a residency, he was drawn to the department’s diverse faculty and clinical opportunities. “I wanted to be able to learn from not just the national but also international leaders in the field. There are many ways to approach anesthetic management and getting to train here broadens one’s perspective.”

Outside of the hospital, Mark enjoys running, snowboarding, cooking, attending concerts (pre-COVID), and spending time with Alison and his 1 year old Pyrenees/Shepherd mix, Osley. They recently moved into a house and Mark is excited to start up a home garden this Spring.