Weight Management Staff

Dr. David Lauter, M.D., F.A.C.S
Medical Director, Bariatric Medicine
He has practiced surgery in the Pacific Northwest since 1992. During that time his private practice has included general, vascular, surgical oncology, bariatric and minimally invasive laparoscopic and robotic surgery.
In 2012, he closed his private practice to allow time to pursue a number of other interests including overseas humanitarian surgery with Doctors Without Borders/MSF. Since then, he has worked with MSF in the Central African Republic and Democratic Republic of Congo.
“The success of bariatric weight loss ultimately depends upon a patient’s commitment to living a healthy lifestyle, which is why it is so important that every patient undergo complete evaluation as well as begin a program grounded in success from the start. This is what NorthStar has always provided and the advantage of a complete and locally based program has to offer.”

Anna Peters, ARNP
Nurse Practitioner, Bariatric Medicine
Anna was born and raised in San Francisco and is the youngest of three children. After graduating High School in San Francisco, Anna attended nursing school in Hawaii. Anna graduated with her Family Nurse Practitioner degree in 2002. She has practiced in various specialties, and discovered her passion when she found the specialty of Bariatrics.
Anna’s career has taken her across the globe where she worked for the Saudi government as a nurse. After completing her graduate degree, Anna had the opportunity to work in conjunction with the US Army to develop and manage a bariatric program in Hawaii. It was at this time that Anna discovered her passion for Bariatrics.
Anna believes losing weight and becoming physically fit is a journey. She desires to help people reach their weight loss goals and maintain optimal health for a lifetime. She finds the element to success is a true commitment to oneself, and having the support of professionals providing guidance through the process is essential. Anna believes its important to show yourself you can lose weight and that your confidence is reborn once you achieve even a five pound weight loss.
Anna has worked at Stanford University and the University of California in surgical weight management. She helped patients reach their preoperative weight loss prior to surgery, and monitored and provided guidance for patients post surgery. She also participated in research studies regarding the positive effects of weight loss. Her most recent experience is in medical weight loss.
Anna loves to travel and experience many cultures. She has found that the immersion into other cultures has broadened her horizons and given her the ability to see things from other cultural perspectives.
In her spare time Anna enjoys socializing with friends and discovering new ways to use herbs and spices in preparing healthy nutritional meals.
Sleep Medicine Staff

Zachary Webb, MD
Medical Director, Sleep Medicine
Dr. Webb has an interest in all aspects of sleep medicine. He considers good communication to be vital to diagnosing and treating his patients. “Most sleep problems are treatable. Helping patients understand the cause of their sleep disorder is instrumental in successfully treating the problem.”
Dr. Webb’s wife is also a physician, who practices pediatrics in Mount Vernon. They moved to this area one year ago because of proximity to the Cascade Mountains and the Pacific Ocean, as well as having family nearby in Seattle. Both he and his wife grew up in the Pacific Northwest and had always hoped to set up their practices in this region. In his free time, Dr. Webb can be found biking, hiking, spending time with his wife, woodworking, and gardening.
Cathy Chen, PA-C
Physician Assistant, Sleep Medicine
Cathy graduated from the University of California, Davis Physician Assistant program in 2018. She started in Family Medicine until discovering a passion for helping patients regain restful sleep. She has worked in Sleep Medicine since 2020 and especially enjoys guiding patients through cognitive-behavioral therapy for insomnia and supporting patients as they adapt to PAP therapy.
Prior to her career as a Physician Assistant, she received her BS in biology from the University of Washington and worked in the non-profit sector connecting older adults to social and health services.
In her free time, she enjoys being outdoors with her dogs, trying to cuisines, writing stories and reading.

Earl Franklin, PA-C
Physician Assistant, Sleep Medicine
Earl joined NorthStar Medical Specialists in 2016 to work in the Sleep Medicine Department. “People often underestimate the importance of sleep and how much it can affect their overall health and well being.”
Earl enjoys spending time with his family, doing CrossFit, spending time outside working in the yard and hiking, riding motorcycles and playing as well as building guitars.
Pulmonary Staff
Trudy Zimmerman, LRCP, RT
Respiratory Therapist
Sophia Tallberg
Pulmonary Rehabilitation Specialist
Sophia Graduated from the University of Alaska Fairbanks with her Bachelor’s Degree in Biological Sciences. Shortly after, she decided to continue her education and interest in exercise science, by earning her certification in personal training from the National Academy of Sports Medicine. Sophia joined the North Star Medical Specialist team in the Pulmonary Rehabilitation department in 2022 after moving to the Bellingham area from her hometown in Alaska. Sophia has been active in sports and exercise all her life and hopes to inspire others through movement.
During her free time, Sophia enjoys weightlifting, taking her dog on runs, hiking, skiing, volleyball or anything that keeps her active. She also enjoys cooking, traveling and expanding her book collection.
Ryan Joiner
Exercise Specialist

Donald Berry, MD
Medical Director, Pulmonary Rehabilitation
Dr. Berry is exceedingly active in the medical community. He is currently the director of the Critical Care Unit and Respiratory Care Department at St. Joseph’s Hospital. He directed the St. Joseph’s and St. Luke’s Hospital Pulmonary Rehabilitation programs before their discontinuation in 1988. His extensive background in Pulmonary Rehabilitation from the University of California, San Diego’s renowned training and research center, make his expertise uniquely valuable.
Dr. Berry grew up in New England but has made Whatcom County his home with his wife and children since 1985. In his free time, you might find Dr. Berry golfing, skiing, fly fishing, hiking with his dog or listening to classical music. He also enjoys photography.
Operations Staff

Christopher P. Mathews, RT, LRCP
President, CEO
Christopher Mathews is President and CEO of NorthStar Medical Specialists and NorthStar Associates, PLLC. His primary interest in starting the practice was to utilize his experience and background as a Respiratory Therapist to provide care in an outpatient setting serving patients with few options to slow the progression of their disease. Having worked in acute care settings for almost 14 years, he saw patients with chronic lung disease frustrated by their disease and wanted to help them manage their symptoms, improve their quality of life and help prevent recurrent hospitalizations. By providing a safe, evidence based outpatient treatment program Christopher envisioned a way to bridge the gap in care options in Whatcom County through Pulmonary Rehabilitation and outpatient Respiratory Therapy.
Christopher’s experience and knowledge in building this program were only further advanced by his ongoing professional interests in Sleep and Bariatric Medicine. Bringing these three medical disciplines together in a complimentary, accessible environment has been the long term vision of the practice.

Alyson Carlyon
Vice President of Operations
Alyson Carlyon is NorthStar’s Vice President of Operations. Alyson started as a patient services representative and quickly became an integral part of the NorthStar team. Seventeen years later, Alyson is still very passionate about her job and remains committed to NorthStar’s mission of helping those in our community achieve a better quality of life through sincere, individualized care. Alyson oversees daily operations and continually cultivates a culture for staff of support and positivity. At the root of her decision making, training and daily duties is her core value of patient care always coming first.
Outside of the office, Alyson is a true adventurer. She is a competitive OCR athlete, an avid runner and one of the founding members of the Bellingham Distance Project, a local competitive running team. Alyson loves spending time outdoors with her husband, Joel, and their son Jethro. You can often find them running, snowboarding, climbing or trekking through the mountains.
Clinical Staff

Tracy Lahr
Clinical Coordinator
Julie Gomes Ruiz
Patient Care Technician/CPAP Technician

Mckenzie Oliver
Patient Care Technician/CPAP Technician

Don Gorsegner, RPSGT, RST
Sleep Lab Coordinator
Katie Kipling, CPSGT
Sleep Lab Technician
David Quang, CPSGT
Sleep Lab Technician
Kent Carpenter, CPSGT
Sleep Lab Technician
Administrative Staff
Kimberly Gallegos
Office Manager

Carissa Englert
Patient Services Representative/Billing Specialist
Mackenzie Tonn
Patient Services Representative
Lia Shannon
Patient Services Representative
Bariatric Surgical Staff

Lily Chang, MD, FACS
Lily Chang, MD, is a minimally invasive general and bariatric surgeon at Virginia Mason Medical Center in Seattle, WA. She received her medical degree from Tufts University in 1996. Her residency training was at the University of Washington, and she then completed fellowship training in Minimally Invasive Surgery also at University of Washington in 2002. She has been performing bariatric surgery for over 20 years.
At Virginia Mason, Dr. Chang serves as the Program Director for the general surgery residency program as well as the Bariatric Surgery Director for the MBSAQIP-accredited bariatric center of excellence. She also serves on various committees including the Perioperative and Procedural Services Steering Committee and the Credentialing Committee.
Dr. Chang is dedicated to providing the best possible care for her patients, improving quality, and training the future generation of surgeons.