A pressure sensing apparatus has a pressure sensor component that includes a pressure sensing port, a pressure sensor for sensing a pressure of a fluid in the pressure sensing port, and a digital processor communicating with the pressure sensor for performing calculations involving fluid pressures sensed. The pressure sensing apparatus further includes a first chamber in fluid contact with the pressure sensing port, a second chamber fluidically connectable with a patient's cerebrospinal fluid system, and a membrane located between the first and second chambers so as to transmit fluid pressure from the second chamber to the first chamber.