Monitoring perioperative hepatic venous oxygen saturation (ShvO₂) in hepatectomy—Changes of ShvO₂ in hemorrhagic shock

Abstract

Hepatic venous oxygen saturation (ShvO₂) 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 ShvO₂ intraoperatively and postoperatively in a patient who underwent right hepatic lobectomy. Decreases in ShvO₂ were noted during surgical maneuvers which included manipulation of the hepatic hilum and mobilization of the liver. The ShvO₂ 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 ShvO₂ 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 ShvO₂ (from 85% to 75%) without a major change in blood pressure. Dopamine increases hepatic blood flow, and accordingly, this decrease in ShvO₂ must have been caused by cessation of the dopamine infusion. This finding suggests that ShvO₂ can be used to determine optimal dopamine dosage for maintaining hepatic blood flow. From these observations, ShvO₂ accurately reflects changes in hepatic blood flow and ShvO₂ 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 ShvO₂, enabling more rapid intervention.