[Venous air embolism following repositioning from sitting to supine]

We have experienced a patient in whom venous air embolism reoccurred, when the patient's position was changed from sitting to supine. A 40 year old male with Arnold-Chiari malformation underwent suboccipital decompression and cervical laminectomy under the sitting position. During surgery, three episodes of venous air embolism were detected by high pitched sound through precordial ultrasound Doppler stethoscope, an abrupt increase in pulmonary arterial pressure, a decrease in end-tidal carbon dioxide concentration; and a small amount of bubbled air was removed from the central venous catheter. At the end of surgery when the patient was turned to supine position, the signs of venous air embolism reappeared and 3 ml of bubbled air was also removed. This case suggests that there is some remaining air in the large veins of the upper part of the body once the air embolism has occurred during sitting position and thus we need to confirm that no air is left in the large veins before repositioning. We should be cautious of reoccurrence of venous air embolism whenever patient's position is changed.