Patients with chronic liver disease may present with different degrees of respiratory dysfunction whose differential diagnosis is important before elective surgery. We report the case of a misleading diagnosis of peri-operative respiratory failure in a cirrhotic patient who underwent mastectomy. Intra-operative respiratory failure was ascribed by the anaesthetic team to pulmonary embolism and after the operation this diagnosis was still suspected. Despite postoperative heparin treatment, pulmonary gas exchange remained severely impaired. On the hypothesis of a right to left shunt, we performed transoesophageal echocardiography with a bubble test and confirmed hepatopulmonary syndrome. We administered anticoagulant therapy to the patient following surgery, increasing the risk of haemorrhage. We also continued orotracheal intubation and mechanical ventilation longer than was needed. Respiratory symptoms in a patient with liver disease should not be underestimated and up to 20% of these patients may have hepatopulmonary syndrome.