RESUMO
Hemorrhage is the major cause of cardiac arrest developing in the operating room. Many human factors including surgical procedures, transfusion practices, blood supply, and anesthetic management are involved in the process that leads to hemorrhage developing into a critical situation. It is desirable for hospital transfusion committees to prepare hospital regulations on 'actions to be taken to manage critical hemorrhage', and practice the implementation of these regulations by simulated drills. If intraoperative hemorrhage seems to be critical, a state of emergency should immediately be declared to the operating room staff, the blood transfusion service staff, and blood bank staff in order to organize a systematic approach to the ongoing problem and keep all responsible staff working outside the operating room informed of events developing in the operating room. To rapidly deal with critical hemorrhage, not only cooperation between anesthesiologists and surgeons but also linkage of operating rooms with blood transfusion services and a blood bank are important. When time is short, cross-matching tests are omitted, and ABO-identical red blood cells are used. When supplies of ABO-identical red blood cells are not available, ABO-compatible, non-identical red blood cells are used. Because a systematic, not individual, approach is required to prevent and manage critical hemorrhage, whether a hospital can establish a procedure to deal with it or not depends on the overall capability of critical and crisis management of the hospital.