VENOUS AIR-EMBOLISM IN SITTING AND SUPINE PATIENTS UNDERGOING VESTIBULAR SCHWANNOMA RESECTION

OBJECTIVE: This study retrospectively compares the incidence of venous air embolism (VAE) detection and morbidity in the sitting and supine positions. All patients underwent vestibular schwannoma resection via the retrosigmoid approach by a single surgical team. METHODS: A total of 432 consecutive operations were reviewed, 222 of which were perform ed with the patients in the sitting position and 210 of which were per formed with the patients in the supine position. Charts were reviewed for evidence of intraoperative VAE, intraoperative hypotension seconda ry to VAE, postoperative morbidity related to VAE, and other variables to compare the groups.RESULTS: This study demonstrated a 28% incidenc e of VAE detection when patients were in the sitting position compared to a 5% incidence of VAE detection when patients were in the supine p osition (P < 0.0001). Intraoperative hypotension secondary to VAE was noted in 1.8% of the sitting patients and 1.4% of the supine patients (P = 0.72, no significant difference). Postoperative morbidity caused by VAE was noted in one sitting patient (0.5%) (pulmonary edema) and i n no supine patients (P = 0.48, no significant difference). Blood loss was slightly greater in the supine group, and operative times were si milar in both groups, despite that the average tumor size of patients operated on in the sitting position was 2.8 cm versus 2.2 cm in the su pine group (P < 0.0001). CONCLUSION: Our results indicate that althoug h there is a higher incidence of VAE detection in sitting patients, th e morbidity is not statistically greater. We conclude that because mor bidity from VAE is similar in either position, patient positioning sho uld be based on surgical team preference.