Objective:Antimicrobial use in the surgical setting is common and frequently inappropriate. Understanding the behavioral context of antimicrobial use is a critical step to developing stewardship programs.Design:In this study, we employed qualitative methodologies to describe the phenomenon of antimicrobial use in 2 surgical units: orthopedic surgery and cardiothoracic surgery.Setting:This study was conducted at a public, quaternary, university-affiliated hospital.Participants:Healthcare professionals from the 2 surgical unit teams participated in the study.Methods:We used focused ethnographic and face-to-face semi-structured interviews to observe antimicrobial decision-making behaviors across the patient's journey from the preadmission clinic to the operating room to the postoperative ward.Results:We identified 4 key themes influencing decision making in the surgical setting. Compartmentalized communication (theme 1) was observed with demarcated roles and defined pathways for communication (theme 2). Antimicrobial decisions in the operating room were driven by the most senior members of the team. These decisions, however, were delegated to more junior members of staff in the ward and clinic environment (theme 3). Throughout the patient's journey, communication with the patient about antimicrobial use was limited (theme 4).Conclusions:Approaches to decision making in surgery are highly structured. Although this structure appears to facilitate smooth flow of responsibility, more junior members of the staff may be disempowered. In addition, opportunities for shared decision making with patients were limited. Antimicrobial stewardship programs need to recognize the hierarchal structure as well as opportunities to engage the patient in shared decision making.