A pressure and a vision regulation method and device for irrigation of a body cavity (1), in which method an inflow liquid pump (2) pressurizes the irrigation liquid in a feed line (13) and in which an outflow device (3) or an external suction source (20) drains the irrigation liquid from the body cavity (1) through a tubing (16) into a waste container (17) and in which a control unit (4) controls either the inflow liquid pump (2) only or both the inflow liquid pump (2) and the outflow device (3) depending on an inflow irrigation liquid pressure from a pressure sensor (5), where the first control unit (4) compares the inflow irrigation liquid pressure and flow with pressures calculated to correspond to pressure in the body cavity for the respective flow for a nominal surgical site and that a matching between the calculated values and the inflow irrigation liquid pressures is made by altering the effect of either the inflow liquid pump (2) only or the inflow liquid pump (2) and/or the outflow device (3) and/or the shut off valve. The above-mentioned pressure registration method and the device for irrigation of a body cavity is combined with an method for detecting blood cells, red blood cells, haemoglobin and/or debris in liquid coming from a surgical site so an automatically control and rinsing system is achieved keeping a clear vision in the viewing area of the operational site.
