Large venous air embolism in the sitting position despite monitoring with transoesophageal echocardiography.

A 49-year-old male with neurofibromatosis type II was scheduled for posterior fossa craniotomy and excision of a right acoustic neuroma and placement of an auditory brainstem implant in the sitting position. Intra-operatively, the patient was monitored with transoesophageal echocardiography which detected two major episodes of venous air embolism. Despite immediate treatment the patient's gas exchange progressively worsened during surgery and a chest X-ray showed extensive bilateral pulmonary infiltrates. The patient developed acute respiratory distress syndrome and required inotropic support in the intensive care unit. Although transoesophageal echocardiography allowed rapid detection of venous air embolism, there was no evidence of therapeutic benefit.