Diathermic knife for coagulating tissues - has monitoring current added to HF coagulating current in order to control end of operation as function or resistance of coagulating tissues

摘要

The device is used to coagulate tissues and operates with a monitor current (ic) is applied in addition to the high frequency coagulating current. The monitoring current is very low, calibrated and clearly identifiable from the coagulating current. During the coagulation operation, the monitoring current magnitude, which is a function of the resistance of the coagulating tissues, is measured. When the magnitude of the monitoring current reaches a lower predetermined limit, the coagulation operation is automatically cut off. The diatermic knife can be mfd. as a monopolar knife comprising a thin active electrode (3) applied to the tissues to be coagulated and a large surface electrode (7) placed in contact with the patient. The device can also be manufactured as a bipolar knife comprising two thin active electrodes.