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In 1968 Drs. George Chatas and Sam Carter founded A4 while providing anesthesia services at St. Joseph Mercy Health System. 47 years later St. Joseph Mercy Health System remains one of A4 largest sites of service. Today, A4 is comprised of 95 board certified/eligible anesthesiologists with subspecialty training/certification in pediatric, obstetrics, cardiac, regional anesthesia, critical care medicine, transesophageal echocardiography, and chronic pain management.

A4 provides physician anesthesia coverage for over 150,000 cases annually and performs over 11,000 pain management procedures per year. A4’s revenue is $45 million.
At each facility, we have an anesthesiologist that is the appointed Medical Director of that site. A4 is committed to working with Hospital Administration to provide leadership at all levels. We are privileged to have 3 of our partners serve as Chief of Staff at three separate hospitals. A4 offers 5 different service lines including; Anesthesia, Perioperative Management, Critical Care, Pain Management, and Office-Based practice.