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Executive Team

Richard Hammett CEO

Richard Hammett, Chief Executive Officer

Richard Hammett is the President and Chief Executive Officer of The Medical Center of Aurora (TMCA) and Centennial Medical Plaza (CMP), comprising four-campuses including a level II trauma center, three emergency departments, and three outpatient imaging centers. Licensed for 346 beds, TMCA/CMP employees 1,600 employees and is the fourth largest private employer in Aurora, Colorado. Richard has served in this position since August 1, 2012.

Richard has a twenty year career in executive hospital leadership and served within HCA since 2005. Prior to joining TMCA/CMP, Richard resided in Austin, Texas where he served as Chief Operating Officer (COO) at St. David’s Medical Center from 2007 until 2012. In this role he oversaw major service lines, ancillary and support services for the 385-bed tertiary referral hospital and 64-bed rehabilitation hospital. The hospital was named a Top 100 Hospital (Reuters/Truven) for four consecutive years in 2009, 2010, 2011 and 2012. Prior to that role, Richard served as Senior Vice President of Strategic Planning and Business Development for St. David’s HealthCare (from 2005 to 2007), a $4 billion, seven-hospital healthcare system with 90 locations throughout Central Texas.

Long active in the communities he has resided, Richard serves on the board of the Colorado Hospital Association and the Aurora Economic Development Council. A Fellow in the American College of Healthcare Executives, Richard received his Master of Business Administration and Master of Science in Health Administration from the University of Alabama-Birmingham. He received his Bachelor of Science from the University of Alabama. He and his wife, Amy, have two daughters and one son. Richard enjoys his family, running, snowboarding, and almost anything else involving the outdoors.

Bryce Dehaven

Bryce Dehaven, Chief Financial Officer

Mr. Dehaven is the Chief Financial Officer at The Medical Center of Aurora; including its Main Campus, North Campus, Centennial Medical Plaza and Saddle Rock ER. He has nearly 30 years of financial leadership experience in the healthcare industry. Prior to joining TMCA/CMP in 2013, Mr. Dehaven served as CFO to Orange Park Medical Center, a 297-bed facility in Jacksonville, Fla. Before relocating to Florida, he was CFO to 3 hospitals in Independence, Mo. and San Jose, Calif.

Mr. Dehaven completed his undergraduate studies at the University of Arizona, and received his Master in Business Administration (MBA) from the University of Colorado at Denver.

Dianne McCallister

Dr. Dianne McCallister, Chief Medical Officer

Dr. McCallister joined The Medical Center of Aurora as the Chief Medical Officer (CMO) in 2013. She provides medical leadership to The Medical Center of Aurora's Main and North Campus, as well as Centennial Medical Plaza and Saddle Rock ER.

Prior to joining The Medical Center of Aurora, Dr. McCallister served as Chief Medical Officer and VP Patient Safety and Quality Systems for Porter Adventist Hospital in Denver. Before entering into these leadership roles, she practiced as a partner in large Internal Medicine groups in the Denver area. Additionally, she served as Chief Medical Resident at Presbyterian/St. Luke's Hospital and as an instructor in Internal Medicine for University of Colorado School of Medicine.

Dr. McCallister is a board certified Internal Medicine physician, with over 25 years of clinical experience. She holds an MBA from Denver University and is certified as a Green Belt in Six Sigma Process Improvement Methodology.

Ryan Simpson COO

Ryan Simpson, Chief Operating Officer

Mr. Simpson has been in hospital executive roles for 15 years and is currently Chief Operating Officer for HCA/HealthONE's Medical Center of Aurora; including its Main Campus, North Campus, Centennial Medical Plaza and Saddle Rock ER. Having started this role in June 2011, he is responsible for the daily operations of these facilities.

Prior to joining HealthONE, Ryan served in HCA's Nashville market as Chief Operating Officer for The Sarah Cannon Cancer Center and TriStar Oncology Services. Prior to this he was with Baptist Health System of East Tennessee in Knoxville, and then Middle Tennessee Medical Center (MTMC) in the chief operations role.

Ryan graduated with a B.S. in Finance and Marketing from Birmingham-Southern College, and then received his MBA and a Masters in Health Administration from the University of Alabama at Birmingham. He is a Fellow in the American College of Healthcare Executives (FACHE) and is currently a board member of the Aurora (CO) Chamber of Commerce.

Erica Rossitto CNO

Erica Rossitto, Chief Nursing Officer

Erica Rossitto, RN, BSN, MBA/HCM joined The Medical Center of Aurora as Chief Nursing Officer in November 2013. With over 10 years of nursing leadership experience, Erica oversees clinical and quality strategies for The Medical Center of Aurora and its campuses: North Campus, Centennial Medical Plaza and Saddle Rock ER.

Erica came to The Medical Center of Aurora from North Suburban Medical Center (NSMC), a HealthONE facility, where she served as CNO for 5 ½ years. Prior to her role as CNO to North Suburban Medical Center, Erica served in various nursing leadership capacities in the HealthONE system and in Louisiana.

Originally from Louisiana, Erica is a Registered Nurse, having received a Bachelor of Science in Nursing with a Minor in Psychology from McNeese State University in Lake Charles, Louisiana, where she graduated Cum Laude. She earned her Master of Business Administration/Healthcare Management from University of Phoenix in 2006.