A 31-year-old woman with blood type AB (-) suffered from a massive postpartum hemorrhage at private practice. She fell into severe hypotension and anemia (hemoglobin concentration of 5.5g/dl). She was immediately brought to the ICU in our hospital. Blood pressure increased following rapid infusion of a massive volume of crystalloid and colloid, but severe hemodilution (hematocrit 5.3%) occurred. Then she lost consciousness and her ventilation was impaired. We were able to start blood transfusion 2 hours after her arrival at the ICU, and she received a probe laparotomy and hemostatic operation. She recovered consciousness one hour after the operation with no neur-ological complications. It is suggested that a safe threshold of hemodilution for a conscious state would be similar to that under anesthesia.
