Internal Jugular Vein Flow in the Sitting Position

During neurosurgical procedures, patients need to be placed in sitting position for surgical access especially in surgeries in the vertex or posterior fossa. Due gravitational effect of sitting position the flow in IJV may be reduced. Venous air embolism (VAE) is a common complication of sitting position craniotomy and carries high mortality and morbidity. Venous pressure decreases as the head of the patient is raised above the heart. Hence, negative venous pressure in the cerebral venous system promotes entrapment of air in accidental opening of the sinuses. Common methods to prevent VAE in sitting position include increasing the venous pressure by either jugular venous compression and/or increasing the venous pressure by adding positive end expiratory pressure (PEEP). Both these methods can decrease venous return and can lead to brain swelling.. In addition, improper neck position can cause the kinking of the IJV which may lead to decreased venous drainage and increased ICP. This has been shown to be the contributing factor for intraoperative brain swelling and postoperative neck and tongue swelling leading to airway obstruction. Optimal brain perfusion is best in the neutral position of the head, but surgery cannot always be performed with this.