Monitoring perioperative hepatic venous oxygen saturation (ShvO 2 ) in hepatectomy—Changes of ShvO 2 in hemorrhagic shock

Hepatic venous oxygen saturation (ShvO 2 ) is an indicator of the hepatic oxygen supply‐to‐demand ratio, which can be used to estimate adequate hepatic blood flow if hepatic oxygen is constant. We monitored ShvO 2 intraoperatively and postoperatively in a patient who underwent right hepatic lobectomy. Decreases in ShvO 2 were noted during surgical maneuvers which included manipulation of the hepatic hilum and mobilization of the liver. The ShvO 2 recovered immediately after termination of these procedures. After the operation the patient developed hypovolemic shock due to postoperative bleeding; blood pressure dropped from 120 to 90 mmHg and the ShvO 2 fell from 70% to 30%. Dopamine (5μg/kg per min) was administered to maintain the blood pressure. Temporary cessation of the dopamine infusion caused a decrease in ShvO 2 (from 85% to 75%) without a major change in blood pressure. Dopamine increases hepatic blood flow, and accordingly, this decrease in ShvO 2 must have been caused by cessation of the dopamine infusion. This finding suggests that ShvO 2 can be used to determine optimal dopamine dosage for maintaining hepatic blood flow. From these observations, ShvO 2 accurately reflects changes in hepatic blood flow and ShvO 2 monitoring was helpful in avoiding hepatic ischemia during the periperative period in a patient undergoing a hepatectomy. Unexpected changes in hepatic blood flow can be immediately identified by monitoring ShvO 2 , enabling more rapid intervention.