Meet Our Team
Dr. Gerhart Flacke, M.D.
Dr. Flacke has been working as an anesthesiologist in Tucson since 2006 and did subspeciality care in cardiac and obstetric anesthesia. He is a former Chief of Cardiac Anesthesia at Tucson Medical Center.
After dedicating decades working in a hospital, he is thrilled to be work exclusively in an ambulatory setting which is allowing him to maximize the time he has with his beloved family. Prior to starting his medical career, Gary was a professional triathlete for ten years and competed at the worldwide level.
Medical School: Creighton University School of Medicine
Residency: University of Arizona
Board Certifications: American Board of Anesthesiologists
Memberships: American Society of Anesthesiologists, Society of Cardiovascular Anesthesiologists (2008 – 2018)
Dr Guzman is from Puerto Rico "La Isla del Encanto.” She finished residency in 2016 and immediately started working at Tucson’s busiest hospital, Tucson Medical Center. While at TMC, she honed her skills to become a very well-rounded anesthesiologist.
She loves Tucson. She has embraced the perks of living in such a beautiful state and loves hiking, biking, and camping trips with her family. She channels her love of nature and faith in God and is known for her encasing those around her with a sense of calm and serenity.
Medical School: Ponce School of Medicine & Health Sciences
Residency: University of Arizona
Board Certification: American Board of Anesthesiology
Memberships: American Society of Anesthesiologists
Dr. Monica Guzman, M.D.
Dr. Marietta is the founder and CEO of Desert Sunrise Anesthesia. She is a Harvard-trained anesthesiologist and been providing anesthesia care in Tucson since 2013.
She realized that control over her schedule was something she needed as her family grew and the pandemic gave her time to ponder about what was most important in my life. Facing so many unknowns during the pandemic gave her the bravery to take a leap of faith in her professional career and start her own solo practice which has evolved to a group of anesthesiologists aligned with the similar core values.
Medical School: University of Missouri-Columbia
Residency: Beth Israel Deaconess Medical Center
Board Certification: American Board of Anesthesiology
Dr. Neesann Marietta, M.D.
Dr. Marietta is the founder and CEO of Desert Sunrise Anesthesia. She is a Harvard-trained anesthesiologist and been providing anesthesia care in Tucson since 2013.
She realized that control over her schedule was something she needed as her family grew and the pandemic gave her time to ponder about what was most important in my life. Facing so many unknowns during the pandemic gave her the bravery to take a leap of faith in her professional career and start her own solo practice which has evolved to a group of anesthesiologists aligned with the similar core values.
Medical School: University of Missouri-Columbia
Residency: Beth Israel Deaconess Medical Center
Board Certification: American Board of Anesthesiology
Dr. Annette Monterrosa.
Dr O’Neill has been practicing anesthesia in Tucson since 1997. He has served as the Chair of Anesthesia and the Chair of the Department of Cardiac Anesthesia at St. Mary’s Hospital. He has also been on faculty as an Assistant Professor of Anesthesia at the University of Arizona Medical school.
After dedicating over twenty-five years working in cardiac anesthesia, he is thrilled to focus on outpatient anesthesia. It is rewarding to see how surgeries have evolved and support this movement. Patients who previously were admitted for days after surgery are now going home the same day with better outcomes.
Dr. O’Neill was raised in an Air Force family in Rome, New York and loves anything involving bikes (10 last count), back country camping, hiking, shooting sports, and horses. He is a proud father of three Tucson Badgers.
Medical School: University Texas Southwestern Dallas
Internship/Residency: Northwestern University, University of California Davis
Board Certifications: American Board of Anesthesiologists, National Board Echocardiography
Memberships: American Society of Anesthesiologists, Tucson Velodrome Committee (2019 – present)
