wherein the tubing is provided with optical sensors configured to be at an outflow site of the body cavity to identify an amount of blood cells, red blood cells, haemoglobin and debris in the irrigation liquid, and to give signals to {HEAD ~ a second control unit} indicating {TAIL ~ the amount} of blood cells, red blood cells, haemoglobin and debris, 
indicating
wherein the tubing is provided with optical sensors configured to be at an outflow site of the body cavity to identify an amount of blood cells , red blood cells , haemoglobin and debris in the irrigation liquid , and to give signals to { HEAD ~ a second control unit } indicating { TAIL ~ the amount } of blood cells , red blood cells , haemoglobin and debris ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH