2025 Poster Presentations
P224: INTRAOPERATIVE VENOUS AIR EMBOLISM DURING ENDOSCOPIC TRASSPHENOIDAL SURGERY: A CASE REPORT AND RECOMMENDATIONS FOR MANAGEMENT
Thomas Hanks, BS; Kyly Hiatt, BS; Spencer Raub, BA; Jessica Eaton, MD; Dominic Nistal, MD; Kaity Hartl, MS, PAC; Fatima El-Ghazali, MD; Aria Jamshidi, MD; Samuel Emerson, MD, PhD; Manuel Ferreira, MD, PhD; Jacob Ruzevick, MD; University of Washington
Background: The risk for venous air embolism (VAE) is increased any time there is a pressure gradient between the surgical site and the right heart. While an extremely rare complication, transsphenoidal pituitary surgery can increase the risk for VAE due to the slight reverse Trendelenburg intraoperative positioning that is commonly employed. The following case describes this rare phenomenon and subsequent peri-operative management.
Case Description: A 53-year-old female patient with no relevant past medical history presented with several days of severe headaches and sudden-onset visual changes. Imaging revealed a hemorrhagic sellar mass consistent with pituitary apoplexy. There was clear compression of the optic chiasm and adjacent subarachnoid hemorrhage. Physical exam was remarkable for near-total blindness bilaterally and a non-reactive right pupil. The patient was placed on stress-dose hydrocortisone and taken emergently to the operating room for endoscopic transsphenoidal resection of the mass.
In the operating room, a standard direct endoscopic transsphenoidal approach to the sella was performed. As the tumor resection proceeded, venous bleeding was encountered during exploration of the cavernous sinuses, and the patient experienced an abrupt drop in blood pressure. There was discussion between the surgeon and the anesthesia staff about the need for additional steroids; however, Trendelenburg positioning, copious irrigation and prompt hemostasis restored her pressure. Thus, it was felt that this was likely caused by a VAE. Shortly after resection resumed, there was another episode of hypotension accompanied by a decrease in end-tidal CO2 that resolved with similar maneuvers to those employed during the first instance. No central line was available for air aspiration during this case.
Postoperatively, the patient experienced vasospasm of the left MCA and ACA braches which was accompanied by transient left-sided weakness. This was managed conservatively with blood pressure augmentation without the need for angioplasty, and the patient regained function of her left side. Her vision slowly improved above baseline, and she was discharged home without further complication.
Follow-up exam at 3 months postoperatively revealed steadily improving vision with no further neurologic or endocrinologic deficits.
Discussion: The most plausible cause of this phenomenon is drawing of air into the venous system due to the pressure gradient which exists between the right heart and cranium in the reverse Trendelenburg position commonly empoloyed for endoscopic pituitary surgery. Other theories for the etiology of VAE include the presence of venous channels in the non-pneumatized parts of the sphenoid bone which is removed during the transsphenoidal approach. These channels may serve as portals for entry for air emboli. Positioning of fat grafts for sellar reconstruction has also been postulated as a potential mechanism for forcing air emboli to enter the vascular spaces of the cavernous sinus and may increase risk for VAE.
Conclusion: VAE during pituitary surgery is an extremely rare but potentially serious complication. Techniques and principles similar to those applied in open surgeries are an effective way to manage this complication and may allow for continued resection of tumor if the patient stabilizes.