A system and method for monitoring the pressure of an injection site, utilizing a fluid operating in the laminar regime flowing through a calibrated tube, and measuring a pressure at one end of the calibrated tube with a pressure sensor, as well as a fluid velocity with a flow sensor, such as an elastic filament velocimeter, that comprises a nano-scale sensing element. Additional elements may be utilized, including the use of data acquisition units, processors, user interfaces, pumps, syringes, and control loops.