As the Medical Director of Addiction Medicine at South Shore Health, I work to tackle the defining medical challenge of our time: Substance use and alcohol use disorder.

In addition to seeing adult patients at South Shore Hospital, I work with colleagues across South Shore Health to develop and implement a comprehensive addiction medicine treatment program. This program will connect patients with the resources they need to manage substance use disorder, no matter if they come to us through the Emergency Department, primary care, or another setting. Additionally, I serve as Medical Director for Spectrum Health System's opioid treatment program, ATS/detox, CSS, and therapeutic community in Weymouth.

Prior to my work at South Shore Health, I helped launch the Bridge Clinic at Boston Medical Center, which connected patients with treatment options for substance use disorder. I also served as Medical Director for Spectrum Health Systems’ Opioid Treatment Program in Weymouth.

In my spare time, I enjoy baseball, reading fiction, snowboarding, and cooking.

My focus is to provide high quality health care and excellent communication with my patients. 

I have worked clinically as a PA since 2014 in a variety of health care settings including hospitals, clinics, and subacute rehabs. This has provided me a deeper understanding of the healthcare system and the trajectory of the patient experience across multiple healthcare settings. Outside of work, I love music, traveling, and food.

William Tollefsen, MD is the EMS and MIH Medical Director for South Shore Health. Dual-boarded in Emergency Medicine and EMS Medicine, Dr. Tollefsen works clinically as an Emergency Physician at South Shore Health in addition to his role as EMS Medical Director.

One of few physicians in the country to receive the prestigious "FAEMS" recognition, Dr. Tollefsen is also the Medical Director for OEMS Region IV, serving 61 cities and towns of the Metro-Boston EMS Council. As the current EMS Medical Director for eight municipal and three private ambulance services on the South Shore, Dr. Tollefsen interacts and provides oversight for over 400 Paramedics.

Dr. Tollefsen graduated from New York Medical College and completed residency training in Emergency Medicine at Harvard University, Brigham and Women's, and Massachusetts General Hospital. He completed a fellowship in Emergency Medical Services and Critical Care Transport at the University of Massachusetts, where he worked as an Emergency Physician and Flight Physician for UMASS LifeFlight. He completed an MBA at the Isenberg School of Management at UMASS Amherst, and holds a Master of Medical Science degree from the Boston University School of Medicine.

A former pre-hospital provider, he is actively involved in EMS system design, paramedic education and Critical Care Transport Systems. He works closely with multiple EMS, Fire and Law Enforcement agencies throughout Massachusetts.

His research interests include systems of care, resuscitation, airway management, and paramedic education.

Dr. O'Brien is Medical Director of Maternal-Fetal Medicine at South Shore Health. 

As a Maternal-Fetal Medicine physician, I am dedicated to caring for women and families navigating high-risk and medically complex pregnancies with expertise, compassion, and individualized attention. 

I strive to integrate evidence-based medicine with a holistic approach that recognizes the physical, emotional, and social factors that shape each patient’s experience. 

I am also committed to advocating for equitable healthcare and improving access and outcomes for marginalized and underserved communities.

I have been a vascular surgeon for more than 25 years since completing my training at the then Deaconess Hospital in Boston. A native New Englander, I returned to my home state to practice, and was Chief of Vascular Surgery at Brown/Rhode Island Hospital until I left to join the team at Brigham Vascular Surgery in October 2016. Having led an academic department for many years, I sought to bring that level of experience with state-of-the-art vascular care to the community hospital setting and was recruited specifically to lead the division at South Shore Hospital. Since my arrival, South Shore Health has supported this vision for vascular care, opening a new Endovascular OR Suite for complex aneurysm repair; developing a multidisciplinary limb preservation team together with Podiatry, Plastic Surgery, and the Wound Care Center; and organizing community outreach and education events to allow for screening and prevention of vascular disease.

In my occasional free time, I am an avid boater and the South Shore has proven to be the perfect environment for me to pursue my other passion!

I enjoy getting to know patients and treating the whole person. I focus on preventative care and supporting patients to reach their health goals.   

The doctor-patient relationship is at the center of your health care, and I strive to provide care that is collaborative and inclusive. I have a holistic approach, working with patients to treat the cause of medical problems, and reducing prescription medicines when it is safe to do so.   I am also pro-active, coordinating care and advocating for patients as they navigate the health care system. I enjoy caring for newborns, children, and family members of all ages, as well as helping with stress management and healthy lifestyle changes. 

When not working, I enjoy spending time with my family and my extra-large dog, reading, running, cooking, and playing flute, piano and guitar.