Air embolism during trans-sphenoidal pituitary operations.

Doppler ultrasonic cardiac monitoring of patients undergoing trans-sphenoidal pituitary operations in the semisitting position has revealed the occurrence of venous air embolism in 3 of 31 consecutive cases. One such case is presented. Air may be drawn into the venous system whenever a gradient exists between the site of operation and the right heart. During trans-sphenoidal operations the most likely portals of venous air entry include the intercavernous connections within the sella, venous channels through nonpneumatized bone, inadequately sealed subnasal vessels, and vascularized metastatic tissue in the pituitary. Because the potential for morbidity and mortality from air embolism is so great, rapid diagnosis with the Doppler unit and prompt treatment, including aspiration of air from the right atrial catheter, administration of 100% oxygen, performance of the Valsalva maneuver, saline irrigation of the wound, and hemostasis of open vessels, are essential. Technetium-macroaggregated albumin (TEMAA) lung scans are helpful in postoperative verification of venous air embolism.