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Medical City Dallas
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Chris Mowan, MBA, FACHE

President and Chief Executive Officer, Medical City Dallas


Chris Mowan joined Medical City Dalla as President and Chief Executive Officer in July 2016. Previously, Chris served three years as CEO of MountainView Hospital, a complex teaching hospital in Las Vegas, Nevada. During his tenure at MountainView, he oversaw a $90 million facility expansion, achieved unprecedented ER growth and launched graduate medical education programs.

Chris’ career with HCA spans more than 20 years, starting with roots as an Medical City Healthcare division manager to roles as COO at Del Sol Medical Center in El Paso and as COO at Sunrise Medical Center and Children’s Hospital in Las Vegas, which was ranked as the #1 facility in Nevada by U.S. News & World Report under his leadership.

Chris is a graduate of Indiana University and holds a master’s degree in business administration from Southern Methodist University. He is a Fellow of the American College of Healthcare Executives. Chris lives in Dallas with his wife, Natalie, and two daughters, Chloe, 10, and Ashley, 8.

Keith V. Zimmerman, FACHE

Chief Executive Officer, Medical City Children’s Hospital

Keith V. Zimmerman

Keith V. Zimmerman was named CEO Medical City Children’s Hospital in December of 2012 as interim, and permanently in August 2013. Zimmerman has 23 years of healthcare experience, and joined Medical City as Chief Development Officer in January of 2011.

Prior to Medical City, Keith was the System Vice President of Business Development at OhioHealth in Columbus, Ohio. Prior to OhioHealth, he held multiple operational and business development roles in healthcare.

Keith holds a Master’s of Business Administration in Health Care Management from Regis University in Denver with Graduate Honors, along with an undergraduate degree in Business Administration from the University of Louisiana. Keith is married with two sons.

Susan Shreeve

Chief Financial Officer, Medical City Dallas Hospital & Medical City Children's Hospital

Susan Headshot Revised

Susan Shreeve received both her Bachelors of Science and Masters of Accountancy degrees from Brigham Young University. She began her career as a CPA with Ernst and Young in Riverside, California with a focus on: Acute Care Hospitals; Post-Acute Care Hospitals; and Physician Groups. She was subsequently recruited by two of her longtime clients: San Bernardino Community Hospital and Loma Linda University Medical Center.

While working for Loma Linda University Medical Center, Susan was asked to become the Sr. Vice President of Finance for a newly developed organization: Loma Linda University Health Care. Loma Linda University Health Care’s charter was to merge 20 physician specialty groups as part of an integrated delivery system.

Susan joined HCA in 1997 as Chief Financial Officer for Bayshore Medical Center in Pasadena, Texas. Susan transferred to Kansas City as Chief Financial Officer for Research Medical Center, Belton Regional Medical Center, and Research Psychiatric Center in 2004.  Currently, Susan is the CFO for Medical City Dallas.

Susan and her husband, Mark, are the parents of two sons, Tanner and Jacob.

Michael Gruber, MD

Chief Medical Officer, Medical City Dallas & Medical City Children's Hospital

Michael Gruber, M.D.

Michael Gruber, MD, was named Chief Medical Officer at Medical City Dallas in August 2015. Dr. Gruber is a board certified urologist and a tenured leader at Medical City, and he has served on the medical staff since August 1982. As Chief Medical Officer, Dr. Gruber leads Medical City’s overall clinical strategies and works with physicians to emphasize patient safety, patient care and quality outcomes.

Dr. Gruber was President of the Medical Staff in 2013, then Chairman of the Privileges and Credentials Committee in 2014. He is a member of the American Urologic Association, Texas Medical Association, Dallas County Medical Society and the South Central Section AUA. He has been named one of D Magazine's Best Doctors each year from 2001 through 2015. Additionally, he was chosen as one of Texas Monthly's Super Docs from 2004 through 2015.

Dr. Gruber graduated with honors from the University of Texas at Austin where he was a member of the Phi Beta Kappa Honor Society. He completed medical school and his urology residency at the University of Texas Medical Branch in Galveston, and he completed his surgical internship at the University of California in San Diego.

Zach Mueller, DNP, RN, NEA-BC

Senior Vice President and Chief Nursing Executive, Medical City Dallas

Zach Mueller

Zach Mueller, DNP, RN, NEA-BC, is Medical City’s Senior Vice President and Chief Nursing Executive. He joined Medical City in 2011, and has more than 15 years of experience in healthcare. As a Registered Nurse, Zach has worked as a clinician in oncology and in the emergency department, and has served in a variety of leadership roles including in director roles over education, pediatrics, and cardiovascular services. Prior to joining Medical City, Zach served as Associate Chief Nursing Officer at The Medical Center of Aurora in Colorado.

Zach is active in several professional organizations, including the Emergency Nurses Association (ENA), and the American Organization of Nurse Executives (AONE). His career achievements include speaking nationally and internationality on a variety of nursing and healthcare topics, as well as being named a Dallas-Fort Worth Great 100 Nurse in 2014.

Zach holds two doctoral degrees, a Doctor of Nursing Practice and Doctor of Nursing from the University of Colorado, as well as a master’s degree in nursing, and two undergraduate degrees. He is board certified by the American Nurses Credentialing Center as a nursing executive, advanced.

Angie Buckmeier, MHA, BSN, RN

Chief Nursing Officer, Medical City Children's Hospital
Vice President of Nursing for Women’s & Children’s, 
Medical City Dallas & Medical City Children's Hospital


Angie Buckmeier joined the senior leadership team at Medical City Children’s Hospital in 2015 to serve as the Chief Nursing Officer and Vice President of Nursing for Women’s & Children’s Services. With more than 26 years of nursing experience and 23 years at Medical City, Angie started her career as a pediatric staff nurse and progressed through a variety of leadership roles in pediatrics including the specialties of general pediatrics, oncology, craniofacial and well-baby newborn care. Angie also served in leadership roles for Women’s services as the manager of Postpartum and Director of Women’s Services. Prior to her current role, Angie served as Director of Nursing for maternal and infant services at Parkland Health and Hospital System.

Angie’s key accomplishments in her leadership roles include maintaining staff turnover under national benchmarks, achieving and maintaining the highest patient satisfaction scores in the organization, impressive quality improvement and outcomes in CLABSI, falls, and exclusive breastfeeding, among others.

Angie received her Master of Healthcare Administration degree from University of Phoenix, her Bachelor of Science degree in nursing from University of Louisiana at Monroe, and was named a 2010 DFW Great 100 Nurse. Angie is married and has two sons.

Eric Reichle, FACHE

Chief Operating Officer, Medical City Dallas

Eric Reichle Headshot Photo

Eric Reichle, FACHE is the Chief Operating Officer at Medical City Dallas. He joined Medical City in 2016 and brings healthcare leadership experience from HCA International in London, England and HCA Corporate in Nashville, Tennessee. Eric is an experienced healthcare executive who has served as a board member on The Bridge Nashville, on the Senior Executive Program for the Scarlett Leadership Institute, the Young Professionals Advisory Council of the Minnie Pearl Cancer Foundation and the Young Leaders Council of Nashville.

Eric transitioned to Medical City from his former role as Executive Director and Vice President of Operations at HCA International in London. In that role, Eric was responsible for developing the HCA International strategy, along with identifying and executing operational growth initiatives. During his time in London, he co-led the development for HCA International's largest capital project - The Shard Diagnostic Centre and The Cancer Treatment Centre.

Prior to joining HCA International, he served as Senior Director of the Strategic Resource Group at HCA's corporate headquarters in Nashville, Tennessee. In his position he worked with HCA executive and hospital leadership to strategically plan service line growth, physician network development, care continuum development and physician integration. 

Eric graduated from the University of Notre Dame with a Bachelor of Science degree in Science-Business Collegiate Sequence and was a member of the varsity cross country and track and field team. He also received a Masters in Healthcare Administration from Trinity University in San Antonio, Texas, where he was a recipient of the Trinity University Healthcare Graduate Assistantship and served as the Service and Social Chairman of the Trinity University Healthcare Student Association.

Eric and his wife Lara have two children, Sloane and Harry, and a dog named Corby. He enjoys listening to live music, watching college football, reading and running, and has completed two marathons and about 10 half marathons.

Jay deVenny, FACHE

Chief Development Officer, Medical City Dallas

Jay Devenny Headshot

Jay deVenny, FACHE, is the Chief Development Officer at Medical City Dallas. In this role, Jay supports all service line strategic development and coordinates the strategic planning process while integrating hospital operations and affiliation development.  His leadership has strengthened multiple tertiary service lines including neurosurgery, orthopedics, heart and vascular, GI, oncology, bariatrics and transplantation.

Prior to joining Medical City, Jay spent seven years leading various administrative and business development roles within Baylor Health Care System. He served as director of professional services at Baylor Regional Medical Center at Plano from 2008 through 2013, where he grew scoliosis, orthopedic oncology, weight loss surgery and pain management service lines. Additionally, he opened satellite scoliosis clinics in Fort Worth and Fort Lauderdale, Florida. Jay also served as a marketing and public relations consultant and administrative resident at Baylor Regional Medical Center at Plano, championing business development and operational initiatives.

Jay holds a Bachelor’s in Communication Studies from University of Kansas, a MBA in Health Services Management from University of North Texas and is a Fellow of the American College of Healthcare Executives (FACHE).

Jay enjoys spending time with his wife, Betsy, and two children, Hunter and Harper. He enjoys playing golf and traveling with his family. 

Jennifer Reeder, MBA/HCM, RN, CCRN, NE-BC

Vice President of Clinical Excellence, Medical City Dallas Hospital


Jennifer Reeder, MBA/HCM, RN, CCRN, NE-BC, is Medical City’s Vice President of Clinical Excellence. She joined Medical City in 2012 as the Director of Critical Care Services and has 14 years of nursing experience. Jennifer has extensive clinical experience in various specialties within adult critical care and transitioned to work in quality management in 2014. In her role, she has oversight for Quality Management, Risk Management/Patient Safety, Organizational Development, Patient Advocacy, Infection Prevention & Control, and Advanced Clinicals (CPOE) departments.  

Prior to joining Medical City, Jennifer led critical care and cardiac teams within the Methodist Health System. Her key accomplishments included leading her team/hospital to first-time accreditations as a Chest Pain Center and Acute Heart Failure Center. Jennifer is a member of the American College of Healthcare Executives and was named a Dallas-Ft. Worth Great 100 Nurse in 2014.

Jennifer received her Bachelor of Science in Nursing from the University of Texas at Tyler in 2001 and her Masters of Business Administration in Health Care Management from the University of Phoenix in 2004. She holds advanced certifications as a critical care nurse and nurse executive.

Shanna Warren, MAM, SPHR, SHRM-SCP

Vice President of Human Resources, Medical City Dallas


Shanna Warren, MAM, SPHR, SHRM-SCP, is the Vice President of Human Resources at Medical City Dallas Hospital. She joined Medical City in 2015 from another Medical City Healthcare hospital, Medical City Plano, where she most recently served as Vice President of HR, Employee Health and Co-Ethics Officer.

In her role at Medical City, she leads all human resource functions, employee health and our volunteer team. Her goals for the human resource department include increasing employee engagement, reducing vacancies and maintaining Medical City’s successful employee retention rates.

Prior to serving at Medical City Plano, Shanna managed training and recruitment at The Arc of San Diego, one of the largest, most comprehensive providers of services to children and adults with disabilities in San Diego County, and served in human resources roles at ValueOptions Healthcare and Sears, Roebuck, Co. 

She holds a Bachelor of Science degree from LeTourneau University, a Masters in Human Resources Management from Dallas Baptist University, is a certified Senior Professional in Human Resources by HRCI and by the Society for Human Resources Management and a Licensed Facilitator by Development Dimensions International.

John Walker

Associate Administrator, Medical City Dallas

John Walker Associate Administrator

John Walker joined Medical City Dallas in August 2016 as the Associate Administrator.  Prior to Medical City, John served as the Associate Administrator at Medical City McKinney where he oversaw pharmacy, laboratory, the senior health clinic, plant operations, food & nutrition services, environmental services, and security.

During his time at Medical City McKinney, John achieved top employee engagement scores, opened a senior health clinic, increased patient experience scores in his role as service excellence champion, and served as the chief staffing officer.  Additionally, he gained experience with many projects including product line development, strategic planning/capital acquisition management, and construction management.

Prior to joining HCA, John worked in commercial real estate at Swearingen Realty Group in Dallas. John holds a Master of Science, Healthcare Administration degree from Trinity University, along with a Master of Business Administration degree, with an emphasis in finance, and a Bachelor of Business Administration degree in finance from Texas Tech University. 

John has served on the board of directors for Community Lifeline Center, he is a member of the American College of Healthcare Executives, and he was inducted into the Garland Sports Hall of Fame in 2013.  He resides in Plano with his wife, Kendall, and son, Graham.