A system to minimize fluid turbulence inside a tissue cavity during endoscopic procedures. A body tissue cavity of a subject is distended by continuous flow irrigation using a solenoid operated pump on the inflow side and a positive displacement pump, such as a peristaltic pump, on the outflow side, such that the amplitude of the pressure pulsations created by the outflow positive displacement pump inside the said tissue cavity is substantially dampened to almost negligible levels. The present invention also provides a method for accurately determining the rate of fluid loss into the subject's body system during any endoscopic procedure without utilizing any deficit weight or fluid volume calculation, the same being accomplished by using two fluid flow rate sensors. The present invention also provides a system of creating and maintaining any desired pressure in a body tissue cavity for any desired cavity outflow rate.