===== 🧪 Vacuum ===== In neurosurgery, a **vacuum** refers to a controlled negative pressure environment applied to [[drainage system]]s. It enables passive, continuous evacuation of fluid—such as blood from a chronic subdural hematoma—through a catheter connected to a sealed collection device. Vacuum-based systems (e.g., SEPS) use low-level suction to promote safe decompression of the subdural space, minimize reaccumulation, and avoid the risks associated with manual aspiration or high-pressure systems.