Paradoxical Air Embolism Without Patent Foramen Ovale During Craniotomy in the Sitting Position

Craniotomy in the sitting position entails risk for venous air embolism (VAE). A 50-year-old male underwent pineal region mass resection through a sitting position craniotomy. Intraoperative transesophageal echocardiography confirmed the absence of intracardiac shunt. During craniotomy, VAE was noted inside the patient's right heart, leading to hemodynamic instability. After repositioning to the supine position, significant crossover of air into the left heart was noted. Postoperatively, multiple small embolic strokes were noted. Patients who undergo craniotomy in the sitting position and are not found to have a patent foramen ovale (PFO) are not free of risk for paradoxical air embolism (PAE).