Development and Clinical Deployment of the Systematic Urgent Team Response in the Operating Room (SUTO) Protocol for Intraoperative Massive Hemorrhage: A Technical Report

Massive intraoperative hemorrhage is a time-critical event requiring simultaneous hemodynamic resuscitation, bleeding source control, transfusion support, equipment preparation, and escalation to multidisciplinary support. This technical report provides, to our knowledge, the first English-language description of the Systematic Urgent Team Response in the Operating Room (SUTO) protocol for intraoperative massive hemorrhage. The protocol was previously developed and reported in Japanese as an institution-specific response system. This English-language report was prepared with permission from the original journal and describes the protocol for an international readership, with additional emphasis on simulation-based preparation and clinical deployment during an actual episode of intraoperative massive hemorrhage. The SUTO protocol was designed to convert the general principles of hemorrhage management into a locally executable, role-based workflow, with predefined procedures for emergency activation, command assignment, task allocation, transfusion support, equipment mobilization, and escalation to cardiovascular surgery and interventional radiology support. The protocol was posted at the entrance of each operating room as an environmental cognitive aid and linked to a dedicated massive hemorrhage cart. Multidisciplinary in situ simulation was conducted using actual operating room equipment to rehearse emergency activation, parallel task execution, transfusion preparation, and escalation pathways. Clinical deployment is illustrated by an unexpected massive hemorrhage caused by splenic artery injury during surgery for esophagogastric junction cancer. Emergency activation, commander declaration, transfusion preparation, equipment mobilization, and consultation with cardiovascular, hepatopancreatobiliary, and interventional radiology teams proceeded in parallel. Definitive hemostasis was achieved by proximal and distal ligation of the injured splenic artery, and the patient was discharged on postoperative day 17. Although causality cannot be inferred from a single clinical deployment, this report suggests that the SUTO protocol may provide a shared operational framework for rapid multidisciplinary coordination during high-acuity operating room crises. Regular simulation and feedback-driven revision are required to maintain organizational readiness as staff and workflows change.