Gabriele M. Barthlen, MD, PhD
Dr. Gabriele M. Barthlen, a German native, is ABMS board-certified in both Sleep Medicine and Neurology. During her academic career, she directed sleep centers at prestigious institutions such as New York Hospital (Cornell) and Mount Sinai in New York City, as well as at the Freiburg and Munich Universities in Germany. She has published widely resulting in 3 books, 15 peer reviewed articles, 33 scientific abstracts, and over 250 invited lectures. She has dedicated 20 years of her professional career to enhance the diagnosis and treatment of patients with sleep disorders, and excels in sleep study interpretations. She has been a Fellow of the American Academy of Sleep Medicine since 1988, and is a former President of the Hawaii Sleep Society. Dr. Barthlen was also elected to “America’s Top Physicians” by the Consumers Research Council of America in 2004, 2010, and again in 2012.
Shih Hao Lin, MD
Dr. Shih Hao Lin is an internist and also an expert in sleep disorders. Dr. Lin is skilled at incorporating internal medicine and sleep medicine. He is a member of the American Academy of Sleep Medicine (AASM) and also board certified in internal medicine (ABIM). Dr. Lin completed his residency at St. Joseph Hospital in Chicago and his sleep medicine fellowship training in the prestigious Boston Medical Center. His specialty includes sleep study interpretation, diagnosis, and treatment of sleep disorder (including sleep apnea, insomnia, restless leg syndrome, narcolepsy, and circadian rhythm disorders). Dr. Lin is dedicated to patient care and offers the best quality of care possible, with the application of evidence-based treatment. His current research is based on the screening for sleep apnea in acute stroke patients with the publication in Journal of Clinic Sleep Medicine(JCSM).
Zachary Manlucu, RN, APRN
Zachary Manlucu is the advanced practice registered nurse at the Sleep Center Hawaii office in Hilo. He is board certified through the American Academy of Nurse Practitioners.
He graduated with his Masters of Science in Nursing in the Family Nurse Practitioner track from Simmons University in Boston, Massachussetts. At Simmons University, Zachary was a distinguished member of the Sigma Theta Tau Honor Society. He obtained his Bachelors of Science in Nursing from the University of Maryland Baltimore in 2013. His experience as a registered nurse includes acute rehabilitation and advice triage. During this time he assumed roles as a triage nurse, code blue nurse, preceptor, and charge nurse. On his free time, Zachary enjoys doing outdoor activities such as hiking, swimming, and playing basketball. You can also catch him cheering for his D.C. United soccer and Milwaukee Bucks basketball teams.
Michael Choi, PA-C
Michael Choi is the Physician Assistant at the Sleep Center Hawaii office in Aiea.
He obtained his Bachelor of Science degree in Psychology from Andrews University, after which he graduated from University of Central Florida with a Master of Science degree in Industrial/Organization Psychology. He then worked in data analytics for a health care company in Orlando, Florida, but eventually decided to change careers and pursue becoming a Physician Assistant. With the support of his wife, he realized his goal and graduated from Baylor College of Medicine in Houston, Texas. It was there he also conducted research at Texas Children’s Hospital and wrote a thesis exploring the relationship between mental health and health outcomes among children with heart failure, heart transplant, and on ventricular assist device. When not seeing patients, Michael spends his time at church, playing basketball and tennis, rock climbing, and hiking/camping with his wife and two dogs.
Gabriel Izumi, PA-C
Gabriel Izumi is a physician assistant with more than 20 years of clinical
experience spanning respiratory therapy, critical care, emergency medicine, urgent care, family medicine, and orthopedic surgery.
He earned his Master of Clinical Health Science degree from the University of Washington MEDEX Physician Assistant Program in 2024. He also holds a Bachelor of Arts in Healthcare Administration from University of Hawaii–West Oahu and an Associate of Science in Respiratory Therapy from Kapiolani Community College. In addition to his physician assistant certification, he is a Registered Respiratory Therapist.
Before becoming a physician assistant, Gabriel spent over two decades as a lead respiratory therapist at The Queen’s Medical Center, where he specialized in airway management, mechanical ventilation, trauma response, and critical care medicine. His experience participating in Code Blue, Trauma, Rapid Response, and Neonatal Resuscitation teams strengthened his ability to provide care across patient populations, while working collaboratively with other team members.
Throughout his clinical training and practice, Gabriel has always found a way to continue using his respiratory skills and knowledge with many patients he meets. And now, he will be able to continue sharing his respiratory knowledge working as a physician assistant at Sleep Center Hawaii. In his downtime, Gabriel enjoys time with his family which usually involves attending his children’s sporting activities during the weekends.
Brian Panganiban, D.Sc, MPAS, PA-C
Brian Panganiban is a board-certified Physician Associate who brings over 18 years of clinical experience.
He graduated from the Interservice Physician Assistant Program at the University of Nebraska Medical Center in 2007 and completed the U.S. Army Flight Surgeon Course in 2008 where he specialized in Aviation Medicine. Brian served with distinction on two combat tours and went on to complete the Army Baylor Emergency Medicine PA Residency in 2013, earning a Doctorate of Science in Emergency Medicine.
Following his retirement from the U.S. Army in 2017, Brian served as the lead Physician Associate for trauma and acute care surgery at The Queen’s Medical Center in Honolulu until 2024. He is now proud to serve the local community as a Physician Associate with Sleep Center Hawaii, where he is committed to delivering compassionate, evidence-based care.