Executive Team

Steven Herber, MD, FACS

Adventist Health St. Helena & Vallejo


Dr. Herber completed his plastic surgery training in 1992 at Yale University School of Medicine, where he was also a faculty member. He received his medical degree and surgical residency training at Loma Linda University School of Medicine, where he later returned to teach in the Department of Surgery after completing a fellowship in pediatric reconstruction and maxillofacial surgery.

As an active researcher, Dr. Herber contributed widely to medical journals, textbooks, and conferences, and appeared in the media as an authority on a variety of reconstructive procedures.

In 1998, he founded the St. Helena Institute for Plastic Surgery and has practiced in the upper valley for 24 years. He accepted an executive role at St. Helena Hospital in 2011 and became its president in 2014.

Hoda Assadian, MS, Operations Executive


Hoda Assadian is the operations executive for Adventist Health St. Helena. Prior to this role Hoda worked for Adventist Health Northern California Region in various process and performance improvement leadership roles since 2011. Prior to this she worked at LAC+USC Medical Center in Los Angeles as a Process Improvement Analyst and research assistant.

Hoda holds a Master of Science degree in industrial and system engineering in healthcare from the University of Southern California (USC). She is certified in many notable change/project management programs including Lean, Master of Change Management, 6Sigma Black Belt and Project Management Professional. In addition, she is a CAPE Examiner (California Awards for Performance Excellence).

Deborah Mensch, RN, BSN, MHSA, NE-BC, CPXP, Patient Care Executive


Deborah Mensch is an experienced nursing leader, currently serving as patient care executive at Adventist Health St. Helena.

Deborah leads acute care hospital operations as well as oversight of nursing practice. She has served in nursing leadership roles with Adventist Health, Sutter Health and Geisinger Medical Center.

Deborah earned her Master’s Degree in healthcare administration from Marywood University and a Bachelor’s Degree in nursing at Penn College. She holds certifications as a nurse executive and as a patient experience professional.

Tim Lyons, MD, MHCM, Chief Medical Officer

Timothy Lyons

Tim Lyons, M.D., is chief medical officer at Adventist Health St. Helena and an anesthesia-intensivist with board certification in anesthesiology, critical care and echocardiography. In addition, Dr. Lyons is the Department of Anesthesiology co-chair at Adventist Health St. Helena.

He graduated from the College of Medicine at Northeastern Ohio University and completed his residency in anesthesiology at University Hospitals of Cleveland, Case Western Reserve University and completed a fellowship in critical care.

Tim completed a fellowship in cardio-thoracic anesthesiology at the Cleveland Clinic Foundation. He has served as assistant professor of anesthesiology, co-chief of the cardiothoracic intensive care unit and division chief of cardiothoracic anesthesiology at University Hospitals of Cleveland. Tim has a Master’s in Health Care Management from Harvard University’s T.H. Chan School of Public Health.