This invention describes a method for processing pressure signals derived from locations inside or outside a human or animal body or body cavity. Different aspects of the invention relate to a method for optimal differentiating between cardiac beat- and artifact-induced pressure waves, and a method for obtaining new and improved information from said pressure signals. More specifically this invention describes a system for use in draining fluid from a brain or spinal fluid cavity. The inventive method for processing of pressure signals is used to control the mass fluid flow rate of said system for draining fluid.
