Automatically controlled bipolar electrocoagulation--"COA-COMP".

Modern bipolar electrocoagulation has certain limitations, especially regarding the regulation of the short coagulation course. Studies on the electrical parameters of tissues during heating led to the conclusion that impedance changes in a typical and reproducible way. Furthermore, the impedance value proved to be close to minimal at the moment of coagulation. Laboratory tests were performed to correlate the pressure strength of the sealed artery to the impedance change. The tests proved that strong seals were achieved when the coagulation was interrupted soon after minimum impedance. Good seals were also achieved with later interruption of the heating but the well-known phenomena of sticking of the forceps to tissues and charging of the tips with charred tissue became more prominent. Further electrocoagulation gives carbonisation, fulguration and risk of new haemorrhage. Based on these results, micro-computerized equipment was built which cut off the coagulation soon after minimum impedance, i.e. when good strength without sticking was achieved. This equipment was tested clinically and the trials showed that the method is practical and most reliable. The microcomputer also allows automatic start of the coagulation as needed during opening or closing of wounds, as well as providing a built-in test of the equipment. This equipment saves time and labour and increases safety.