Monitoring of Intravascular Volume Using Pulse Pressure Variation during Hepatic Mass Resection in a Dog

A 14-year-old castrated male Pomeranian presented with chronic gastrointestinal symptoms.Physical examination revealed a palpable abdominal mass.Blood analyses revealed elevated hepatic enzyme activities and mildly prolonged prothrombin time without clinically significant coagulopathy.Heterogeneous masses affecting the right medial lobe of the liver and multiple nodules in the spleen were identified on computed tomography.The hepatic mass and spleen were surgically removed.Mechanical ventilation with sevoflurane and oxygen was administered to maintain anesthesia.The right dorsal pedal artery was cannulated to monitor blood pressure and pulse pressure variation (PPV).Hypotension occurred during hepatic mass manipulation and lobectomy; however, aside from these hypotensive episodes, the dog remained stable during surgery.In all hypotensive episodes, an increase in PPV > 13% was observed prior to hypotension, and the dog stabilized after fluid resuscitation and blood transfusion.The dog was recovered without complications.On histopathological examination, the mass was identified as hepatic cellular carcinoma.This case report suggests that PPV can be used to identify hypotension due to intravascular volume deficit during mass manipulation or hepatic lobectomy in dogs.